74 CB360 cranks, backfires, but won't run

[stl360+450]

@stl360+450 no worries. I only had to pull the tank, hump, rearsets, license plate, and loosen the left clip on. The most frustrating part was the kickstand getting caught on EVERYTHING haha

I've had to get picked up at least four times, so I can sympathize.

• CB360: electrical short between starter solenoid and seat. Didn't figure it out until I got it home.
• CB450: flat rear tire. Valve stem broke off in a turn. (first time)
• CB450: blew up a piston on the highway. (second time)
• CB450: battery ground connector broke due to fatigue. Couldn't spot it on the roadside. Spotted instantly in the garage. (third time)

This doesn't include situations where I could limp the bike home somehow, e.g., broken clutch lifter rod (CB450), broken clutch cable (CB360), broken woodruff key on the oil pump gear (CB360; pushed it home one mile through a city park for a shortcut), blown main fuse (CB450; rode a Bird scooter to go buy fuses), etc.

I'm glad you could get picked up!

 

[dlogreen]

Right on.


The clutch and cable adjustment should not be affected by bumps or anything of the sort. Something just not have been right with the setup.

Without the lock nut at the handlebar, could the cable be falling out of position at the lever? Seems like it would be obvious if that were the case.

I guess the pop is the actuator going too far and slipping out of position, which would reduce cable tension. This would seem a more likely scenario. You mention multiple manuals as well as CM. Do you have the proper CB360 Factory Service Manual?

I'm including the Owner's Manual description of the clutch adjustment.

View attachment 56514

EDIT: CHILTON. that's what I got in addition to the official, yt vids, and the forums

Yah I got the official one from the site and the C something one, not Clymer, and it was working great.... All I can think is that the little nub at the actuator isn't sitting flush when I adjust it so it's slipping and then binding? I'll figure it out while I'm on the sidelines

 

[dlogreen]

I've had to get picked up at least four times, so I can sympathize.

• CB360: electrical short between starter solenoid and seat. Didn't figure it out until I got it home.
• CB450: flat rear tire. Valve stem broke off in a turn. (first time)
• CB450: blew up a piston on the highway. (second time)
• CB450: battery ground connector broke due to fatigue. Couldn't spot it on the roadside. Spotted instantly in the garage. (third time)

This doesn't include situations where I could limp the bike home somehow, e.g., broken clutch lifter rod (CB450), broken clutch cable (CB360), broken woodruff key on the oil pump gear (CB360; pushed it home one mile through a city park for a shortcut), blown main fuse (CB450; rode a Bird scooter to go buy fuses), etc.

I'm glad you could get picked up!

I Ubered home and got my ride and tools and a few flashlights and got to work. It was about 3 miles away but already 9pm when I got home. Better than leaving it at a gas station with minimal cameras overnight

 

[dlogreen]

Pays to be a little bit of a packrat when it comes to sourcing parts..... Installed and good to go. Now we wait for points and repair/sheath wiring tomorrow. Could have maybe sorted the points earlier but couldn't get the left point plate screw off cuz it was stripping and I didn't have my JIS w me

Good thing is that the two M6 bolts just above the points are stripped so I had planned to do helicoils when I swapped the camshaft. Now I can do it all at once and make everything right.

 

[dlogreen]

Guys, I'm glad to say I was wrong..kinda. the camshaft didn't fail just the nut they was holding the washer and cam in place. It can still be used as a backup!!! With better securing of course.

I'm in there now and the broken point is likely the reason for the engine dying and running on the right cylinder only until it flooded or killed the battery. Also I think the point cam and advance lost contact w the nub so it couldn't turn with the shaft.

Either way I'm doing the swap cuz I'm in here and then hopefully my points get here asap

Also clutch is working just fine with the left clip on loose to pivot around the fork tube so thinking my routing was the issue possibly.... I'll hafta brainstorm a better path I think.

Anyhow. Thought the update would be good and overall I feel better about it
Nice brown plug tho

 

[crazypj]

I don't think the carbs are the issue, either, but I wonder about the initial 23mm and later 20mm float height settings. I believe the stock setting is 18.5mm, so your higher values would be more lean, yet you believe your exhaust will operate like straight pipes, which also tend to lean out the mixture. I guess you have a larger secondary, but I wouldn't change from the stock float height until a later point in the tuning, if at all.

18.5 is wrong number, bike will run rich.
I've been using 21mm since around 2012 when E10 was mandated 'everywhere' to keep corn producers happy. ( personally, I hate the stuff but dislike paying extra $1.35 a gallon even more)

I've done similar cam repair a couple of times, works OK as long as points cam extension is running true.
It's better to face off end of cam and make a new extension with 8mm or 10mm thread.
You need to get some decent filters, those small 'pods' restrict airflow above ~6K.
The Keihin three jet carbs can't be properly jetted to run with 'pods', no matter what those guys in Houston and others say, properly modified, bike will run at least as well as stock but usually better.

Went back to look at pictures. reply 16, you can see ATD wasn't in correct place and 'knock pin' dented at 3 o'clock position which tried to bend extension.

 

[wentwest]

Gravity always wins!

 

[dlogreen]

The dent in that pic is from the guy before me. I noticed that too and I bet he struggled to get it running cuz he didn’t line it up.

yesterday when I went in to look it had loosened enough to spin away from the nub so it wasn’t even engaging. I tightened it back up earlier with it off the bike and it was very much firmly seated. If tightened it doesn’t appear to move independently at all.

Also, I’m on hold cuz the turd that sold be the cam sold me one for an XS400 so I sent it back. I had it in the package until I needed it to keep from accidentally damaging it…. Grrr. Refund on the way and new proper cam should be here early next week

 

[wentwest]

It seems like most of these projects run into the same storm of crap at some point. Now it's your turn, but when you get it done let's hope all this stuff fades into the past and you have a sweet running ride.

 

[crazypj]

The dent in that pic is from the guy before me. I noticed that too and I bet he struggled to get it running cuz he didn’t line it up.

yesterday when I went in to look it had loosened enough to spin away from the nub so it wasn’t even engaging. I tightened it back up earlier with it off the bike and it was very much firmly seated. If tightened it doesn’t appear to move independently at all.

Also, I’m on hold cuz the turd that sold be the cam sold me one for an XS400 so I sent it back. I had it in the package until I needed it to keep from accidentally damaging it…. Grrr. Refund on the way and new proper cam should be here early next week

Ha! good excuse to blame previous owner for weakening the cam extension piece causing it to break when you 'burped' it
I've got an early XS 400 head and cam so I know nothing will fit.
XS 400 Rear wheel with drum brake did go in my 'slightly modified' XS650, it was easier than finding a cast drum brake rear wheel for XS650

 

[Coolatula]

Thanks a ton so far.

So after new rings and cleaned pistons, head, valve cover, and gaskets, I triple checked the timing when I first put the camshaft back in…

And with everything buttoned back up, I’ve also checked the valve lash, pointed gaps, static timing with a light and multimeter, and I mean it’s as exact as I feel I can get it using my naked eye.

That said, obviously the advancer was removed and it sat while I chopped the frame and built the new harness and hump seat. I did notice it has a different lobe on either end so maybe that’s where I’ll check tomorrow before tearing the carbs out again.

Would I just pull off the advancer and flip over the cam?

Also compression is pretty good and wants to turn itself over on the compression stroke when manually rotating, so that part I’m fairly certain of.

If the timing was 180 out, would flipping the points bullet ends correct that? As far as I know the coils only fire as a result of the points breaking so left or right only matters for orientation based on which opens when…

For the carbs, I felt something was goofy cuz at one point I tried to restrict the intake and then I got gas dribbling out the exhaust…. But that could have just been cuz it wasn’t igniting and being expelled thru the exhaust valve

I think that's everything.... I'll check the advance cam in the am and then retry before I pull anything else apart.

Oh, float height.... I have some Vinton rings that might a little more proud of the groove than stock, so 0.5mm puts me closer to that 18.5 recommended... Though i do think the float needles are getting hung up. I'll address that after the cam if it's not behaving better.

I appreciate you guys. I will say old sohc twins are a breeze compared to dohc or even sohc 4s.

Here's a pic so you can see how she sits currently.... I'll be updating the build thread this weekend I hope. View attachment 56052View attachment 56053View attachment 56054

If the advancer is 180 out a good YT video "Honda CB350 Twin Timing Advance Unit" by
@Amotorcyclenut shows how to fix it.

 

[ancientdad]

If the advancer is 180 out a good YT video "Honda CB350 Twin Timing Advance Unit" by
@Amotorcyclenut shows how to fix it.

I've not watched that particular video by that guy, but he's also the same guy who thinks adjusting 350 valves by ear when the engine is running is a good idea. We don't subscribe to videos from backyard sources here.

 

[dlogreen]

Ha! good excuse to blame previous owner for weakening the cam extension piece causing it to break when you 'burped' it
I've got an early XS 400 head and cam so I know nothing will fit.
XS 400 Rear wheel with drum brake did go in my 'slightly modified' XS650, it was easier than finding a cast drum brake rear wheel for XS650

Yah in this case it was def like that before…. I got some pictures on my digital cam from when I took it off and noticed. But obv they figured it out enough to get it running when I bought it (though I think that was the shop who sold it for him on consignment). They had a bunch of old bikes they’d gotten at least running enough to test ride.

Anyhow, to the guy @Coolatula , the Chilton manual references the 180 but didn’t say how it should look so the CM video actually helped cuz he had a 312 advance to visually reference. Good for some things, but def not buying parts marked up ridiculously high

Anybody commenting on the older posts with suggestions, they've been addressed and documented in later posts. So just keep reading.... Obv what has worked for me won't necessarily be 100% for you tho.

Also guys, when i got the valve cover off I noticed my right exhaust tappet adjuster had backed all the way off which explains why left cylinder was brown and perfect while right was darker no matter what I did and also not wanting to hold idle when I pulled the other plug. It's addressed and assuming I didn't snug it as much with my offset cuz of the angle when I set tht valves before. When I put the new shaft in I will make certain it won't budge again. Like I said, it pulled and revved and hauled ass with no burping or stuttering anywhere all the way thru wot where I was hitting some Twisties around 50mph in 3rd

I got the new threads in for those two M6 bolts (you can kinda see on the background of my spark plug pic how it just wiggled free)

Lastly, on the points plate, wtf do we call this dense spongy thing in the middle below the cam? And how did I/can I replace it and with what?

THANKS IN ADVANCE

 

[dlogreen]

If the advancer is 180 out a good YT video "Honda CB350 Twin Timing Advance Unit" by
@Amotorcyclenut shows how to fix it.

Been fixed but thanks for the heads-up. Now it's essentially permanently imprinted on my brain how they go. I'm a musician that plays live and has about 200 cover songs (lyrics and guitar, keyboard progressions and leads) memorized. I'm almost to the point where I can service this bike without the manual bc I've read and reread the thing so many times and have the visuals stored up there with the text and physical/manual tasks to accompany. Not quite eidetic but similar.... There's a bunch of info on why musical people tend to hand enhanced recollection trying semantic memory to procedural memory and cognitive retention. Hehe, my human bio nerd is showing

I'm sure the senior members of this group have a similar relationship with these bikes after decades with them. That so cool

 

[EzPete]

That sponge thing is felt, designed to be oiled and help keep the cam slightly lubed so it doesn’t wear down the heel of the point and start throwing off point gap.

I’ve remade them out of those felt furniture sliders, shaped and shaved with a razor to the right size. Or you can buy a small sheet off amazon for basically a multiple lifetime supply of felt.

 

[dlogreen]

That sponge thing is felt, designed to be oiled and help keep the cam slightly lubed so it doesn’t wear down the heel of the point and start throwing off point gap.

I’ve remade them out of those felt furniture sliders, shaped and shaved with a razor to the right size. Or you can buy a small sheet off amazon for basically a multiple lifetime supply of felt.

sweet. I'll grab some at the store later and replace it. I have a new (used) points plate coming for peace of mind bc of the previous fudge and to have a spare, but I'll get this one back

 

[dlogreen]

Yeeeeehaawwwww, despite the most crappy weather the past few days, I got the new points plate off an already running bike installed and it fired up right away...my old one after I swapped the point wasn't firing on cylinder 1, so I need to examine all the places it should be sparking and where it shouldn't... I have a feeling it was the wire nut at the bottom and something with the old fragile wiring. Anyway, was revving like hell and ripping like 42 in second... haven't taken it out on the real road for fear of deja vu in this windy and misty weather. Hopefully later this week when it clears up.

Also, when I tore the bike down, I found the right exhaust valve adjustment screw completely backed out.... and earlier I noticed the nut was really tight on the bolt even without tension. I will check it again tomorrow morning and see whether i have some bad threads on the nut and/or bolt, AND/OR the rocker. It seemed to cinch down firmly when I set the valves today, but if it doesn't wanna stay, I feel like I'm gonna clean it up and use a lil blue thread locker for some added resistance.

Happy hunting folks... thanks for the support, and now time to address crappy exhaust welds and exposed metal that needs to be repainted and then clear coated.

Oh and @crazypj, I know you said those pods wouldn't let enough air in, but it's revving to redline and no gurgles or popping so far while also burning a nice brown on the plugs. I'm not exactly concerned about doing a ton, but I want it to handle local highways when I wanna get out and open it up a bit. I think I'll give it a run on the back roads by my house tomorrow just going back and forth where if I break down, I'm not more than 3/4 a mile from my house since it's a back and out loop in two directions with a cut through. I ordered some other pods that are larger and might let a little more in, and I'm gonna do some side by side comparisons once the bike is warmed up. The strange aftermarket needle has been the best mod so far, and my CB160 adjustables came in too.... So I have 65 primaries to cut down and try, adjustable CB160 needles, and some larger secondaries 115 in the event I start running too lean up top or with the larger filters.

 

[dlogreen]

Yeeeeehaawwwww, despite the most crappy weather the past few days, I got the new points plate off an already running bike installed and it fired up right away...my old one after I swapped the point wasn't firing on cylinder 1, so I need to examine all the places it should be sparking and where it shouldn't... I have a feeling it was the wire nut at the bottom and something with the old fragile wiring. Anyway, was revving like hell and ripping like 42 in second... haven't taken it out on the real road for fear of deja vu in this windy and misty weather. Hopefully later this week when it clears up.

Also, when I tore the bike down, I found the right exhaust valve adjustment screw completely backed out.... and earlier I noticed the nut was really tight on the bolt even without tension. I will check it again tomorrow morning and see whether i have some bad threads on the nut and/or bolt, AND/OR the rocker. It seemed to cinch down firmly when I set the valves today, but if it doesn't wanna stay, I feel like I'm gonna clean it up and use a lil blue thread locker for some added resistance.

Happy hunting folks... thanks for the support, and now time to address crappy exhaust welds and exposed metal that needs to be repainted and then clear coated.

Oh and @crazypj, I know you said those pods wouldn't let enough air in, but it's revving to redline and no gurgles or popping so far while also burning a nice brown on the plugs. I'm not exactly concerned about doing a ton, but I want it to handle local highways when I wanna get out and open it up a bit. I think I'll give it a run on the back roads by my house tomorrow just going back and forth where if I break down, I'm not more than 3/4 a mile from my house since it's a back and out loop in two directions with a cut through. I ordered some other pods that are larger and might let a little more in, and I'm gonna do some side by side comparisons once the bike is warmed up. The strange aftermarket needle has been the best mod so far, and my CB160 adjustables came in too.... So I have 65 primaries to cut down and try, adjustable CB160 needles, and some larger secondaries 115 in the event I start running too lean up top or with the larger filters.

Guys!!!! I haven’t had a chance to tear into it cuz I hafta run but I was on a test ride and was losing power a little then brrrr…. Dead bike. Noticed the digital speedo was doing something funky but it was still revving fine at that point. Then I made a U-turn to head back to my house and it felt like the engine just gave up and it slowly came to a stop and wasn’t spinning and then when I hit the starter. It sounds like it’s just turning without any resistance..

So then I tried to kick it, and the kick lever has zero resistance, and just brings back without any sort of recoil

So that leads me to think that it’s a piston or valve issue. Neither of which I have the time to get into currently.

But for a little bit more information, the bike even wants to roll, relatively easily in first or second gear despite the clutch being out. Is it possible that the clutch seized up and so it feels like the bike is not able to engage, or is it possible that I blew rings in both Cylinders because I don’t have any sort of real resistance???

 

[ancientdad]

Does sound like compression loss, but you don't typically lose both cylinders at the same time (like a holed piston). If the cam chain broke you could have bent valves on both cylinders and have little to no compression.

 

[EzPete]

Cam chain would be the only thing I could think of - it would have been noisy as hell though.

 

[dlogreen]

Does sound like compression loss, but you don't typically lose both cylinders at the same time (like a holed piston). If the cam chain broke you could have bent valves on both cylinders and have little to no compression.

Just popped off points cover when there was no spark on a grounded plug. It’s the cam chain cuz no rotation at all….

So what’s next? Obv gotta pull off at least the valve cover but likely the head too. Check for debris, piston damage, valve damage?

Will I Need to tear into the bottom as well since the chain is down there or just fish it out, feed a new one and then press the rivet and plate back on?

 

[dlogreen]

Cam chain would be the only thing I could think of - it would have been noisy as hell though.

It was running and then rattling but I thought it could have been loud valves until it was dead :/

 

[ancientdad]

So what’s next? Obv gotta pull off at least the valve cover but likely the head too. Check for debris, piston damage, valve damage?

There will be bent valves, these engines are not non-interference. And there's a reason the cam chain broke or whatever happened, could be tensioner-related on these engines but it could also just be an old, failed cam chain from age and abuse from lack of maintenance before you.

Will I Need to tear into the bottom as well since the chain is down there or just fish it out, feed a new one and then press the rivet and plate back on?

Unless there's shredded debris in the bottom end, and no piston damage from valves, then fishing out the chain and replacing it with new might be an option but I don't know how easy it is to get a new chain around the crankshaft sprocket on this engine if the old one is broken and already off the rails.

 

[dlogreen]

There will be bent valves, these engines are not non-interference. And there's a reason the cam chain broke or whatever happened, could be tensioner-related on these engines but it could also just be an old, failed cam chain from age and abuse from lack of maintenance before you.

Unless there's shredded debris in the bottom end, and no piston damage from valves, then fishing out the chain and replacing it with new might be an option but I don't know how easy it is to get a new chain around the crankshaft sprocket on this engine if the old one is broken and already off the rails.

So typical case is full teardown? Including the bottom at least with the jugs off to see the crank.... And then new valves? So should I look for a new head with valves already mated and worn in or new valves and then lap them myself?

Never had this kind of engine failure before so

Editing cuz im assuming I should have piston damage too...I have an extra set at least. But I'll need new rings

What else is likely?

 

[ancientdad]

So typical case is full teardown? Including the bottom at least with the jugs off to see the crank.... And then new valves? So should I look for a new head with valves already mated and worn in or new valves and then lap them myself?

Never had this kind of engine failure before so

Editing cuz im assuming I should have piston damage too...I have an extra set at least. But I'll need new rings

What else is likely?

Based solely on your description of what happened, I'd guess bent valves might be all aside from the cam chain replacement. If the valve impact on the piston(s) was hard enough there could be valve guide damage where the guide protrudes into the port, but you won't know any of this until you tear it down. Since that top end can be done in the frame it won't be as bad as pulling the entire engine like a 350 or 450 would require.

 

[EzPete]

I’d say open it up first. At a minimum it’s removing the head (likely the cylinders as well) but you need to see if the tensioner is intact and how much damage is down there before firing up the parts cannon.

 

[stl360+450]

Isn't it also possible that the cam sprocket bolts failed or backed out? Would this normally destroy the chain also?

If the chain did break, I would tear the motor down fully and use an endless cam chain.

 

[dlogreen]

Isn't it also possible that the cam sprocket bolts failed or backed out? Would this normally destroy the chain also?

If the chain did break, I would tear the motor down fully and use an endless cam chain.

I'll look this weekend when I can get the valve cover off. If that were the case fishing them out would suck.... If I don't hafta I'm not splitting the cases... A press fit chain pin and sides should be fine. I wouldn't use a clip link and maybe a rivet style if I absolutely had to.

 

[stl360+450]

I remember being intimidated by splitting the cases until I was forced to do it, but it's really not a big deal. I understand your primary working environment is not conducive to a prolonged rebuild, but maybe you could borrow a friend's garage for a bit to do it.

Whatever happened, it's a bummer and I'm looking forward to seeing the other side of this repair.

 

[dlogreen]

I remember being intimidated by splitting the cases until I was forced to do it, but it's really not a big deal. I understand your primary working environment is not conducive to a prolonged rebuild, but maybe you could borrow a friend's garage for a bit to do it.

Whatever happened, it's a bummer and I'm looking forward to seeing the other side of this repair.

Still gotta get it there and have access when I want to work on it. If it’s not in front of me it’ll take so much longer.

Not even really the idea of splitting the cases that’s daunting, it’s just that I’ve been on the cusp of regular riding until something happens, and the solution has been annoying, but not likely to introduce a whole slew of new problems. And what I’ve needed to replace or repair Hasn’t been extremely costly, but if for some reason, something went wrong, not only would it cost me a ton of time, but I would imagine those parts would be harder to acquire for a reasonable price. If I absolutely had to, and then I would, but fingers crossed it won’t be as serious. And in the past when I’ve needed to split chains or shorten and link them while using the chain breaker, they have held up for the duration of the bike Until it was time to change it again. I’m more so worried that the Pistons were damaged or the valves and valve components are mangled.

 

[dlogreen]

Sooo opened her up....it's not catastrophic.....

Cam chain is completely in tact, but the freaking cam sprocket bolts came out! how the hell? So the cam sprocket spun up against the inside of the cover for a second, shearing some aluminum and leaving some debris, but it happened i guess at a lower speed than I thought cuz there's not much visible damage at all and the chain is in great condition.

I'll upload pics, but I found one of the cam bolts, and I'm looking for the other. I'll pull the cam shaft and see if I can look down in there to get it. I might need a scope if I can't see it easily... and then I'll pull off the clutch cover and check the oil and bottom for stuff down there. I think I got lucky, and with some added fortune, I can be back running this week!

Advice on the cam sprocket bolts tho? loctite, impact? what? I can't have this happen again

 

[dlogreen]

 

[dlogreen]

View attachment 56819View attachment 56820View attachment 56821

OK, so it turns out that when it detached the camp sprocket also rubbed up against the inside of the valve cover and scratched that up, but not to the point where it’s unusable and I can smooth it out where it gouged it a little bit

It does look like I’m still gonna have to pull the head off mostly because I can’t get a clear view of where that bolt might’ve ended up and I want to check the valves and the top of the pistons.

But ultimately, it doesn’t look like too much work and if I have to replace valves, that’s not the end of the world, but the cam chain itself is still in good shape moving freely, not seized up. There’s no damage that I can see at the top of the head other than Where the camp sprocket made contact.

Oh also, the camp sprocket was slightly bent, which I would imagine came from being under tension as it was loosening, but the other camp sprocket that came with the new camshaft is still available so I can swap that out easily.

I needed to pull the exhaust and do some re-welding anyhow so this just made that worth it.

Here’s a shot of the inside of the head

 

[ancientdad]

You got lucky, but just how lucky? You could pressurize the cylinders leakdown-style to find out if any valves are bent.

 

[stl360+450]

It looks like the threads were removed in the visible sprocket bolt hole. Many people use loctite on those cam sprocket bolts.

I hope you will get some advice from others in addition to myself, but I would recommend a full teardown. If you were still using that repaired cam, I would take this as a sign to replace it, along with the cam sprocket and chain.

Can you post a picture of the cam followers and journal bearings?

Also, you'll need to pull the head to remove the valves and see if they are bent.

 

[dlogreen]

It looks like the threads were removed in the visible sprocket bolt hole. Many people use loctite on those cam sprocket bolts.

I hope you will get some advice from others in addition to myself, but I would recommend a full teardown. If you were still using that repaired cam, I would take this as a sign to replace it, along with the cam sprocket and chain.

Can you post a picture of the cam followers and journal bearings?

Also, you'll need to pull the head to remove the valves and see if they are bent.

Nah I did the cam swap already and it was running great.

I have another cam sprocket and the head off already. Exhaust valves look stuck open, so I’ll remove them to get a look later this evening.

I might end up with a new head just cuz, but the further down I get the less anything I see. It happened fast and there’s no damage to the piston heads, cylinder, or valve cover. Cam journals are fine too. Nothing was loose to allow any thing to get into the cam journals and oil was pumping well because the galleries were semi full and everything was nicely lubed up.

Can

I’m gonna drain the rest of the oil and pull the clutch cover tomorrow. And use a combo of grabbers and magnets to find that other bolt which I think fell straight down into the bottom. There’s no signs of damage with the head off…

Cam threads are still in good shape as you can see in this photo I’m attaching so I think those bolts were just not as tight as I thought they were and I didn’t want to use an impact for risk of damaging the threads.

 

[stl360+450]

Okay, cool, I'm glad that the cam threads weren't damaged. I knew you had a cam on the way after receiving the wrong one, but don't recall you mentioning the swap. Loctite this time on the cam sprocket bolts.

Too bad about the valves, but I guess that would be expected in this scenario.

 

[dlogreen]

Okay, cool, I'm glad that the cam threads weren't damaged. I knew you had a cam on the way after receiving the wrong one, but don't recall you mentioning the swap. Loctite this time on the cam sprocket bolts.

Too bad about the valves, but I guess that would be expected in this scenario.

No worries.

Exhaust valves removed and yup, bent at the neck by the face, so no damage to the guides I could see with my light and running a probe across the surfaces.

one was bent worse than the other, but still in the same place, and they were a pain to remove because the face wasn't straight with the spring.

New ones are on the way, and I'm headed out to drain the oil and see what i find down at the bottom

 

[dlogreen]

Question....
If I need to get the bottom off without going thru the top, what will I need to remove? And are they a pain to reinstall?
Clutch basket, oil pump, stator cover?

I'm partially thinking I might have only installed one cam sprocket bolt because the area between the cam chain and the arm below is tight and I have used flexible magnets and lit up the area and there's no sign of a bolt. The chain is not damaged at all and there's no other visible markings in the space where a bolt would have and should have shredded my chain and the well on the way down.

I don’t wanna totally screw this up but I also don’t wanna keep chasing stuff after this. If I pull the engine and invert it should I be able to find a bolt if one fell down that space? Is there a possibility it fell and went into a different area of the case?

I’m going to button the top end up once my valves come and I suppose I could flip it over and see if anything falls out at that time. I don’t wanna take the cylinders off since I could damage the rings and they are brand new.

Just weighing options. But I recall being very concerned w my timing and possibly not flipping the engine over to install the other cuz I got distracted. Ugh

 

[crazypj]

OH NO, the dreaded cam sprocket bolt backed out.
Looks like you got 'lucky' though and it didn't snap the mount off cam.
I use blue Loctite and still worry about it (blue because I know it will be coming apart at some time)
I probably over torque a few ft/lbs as well, 1/4" drive ratchet and 6" extension with long deep 6 point socket.
i bought an inch pounds torque wrench but never use it, always seems way too lose, even screws into alloy covers (although may start if I ever get around to replacing everything with Allen heads)

 

[dlogreen]

OH NO, the dreaded cam sprocket bolt backed out.
Looks like you got 'lucky' though and it didn't snap the mount off cam.
I use blue Loctite and still worry about it (blue because I know it will be coming apart at some time)
I probably over torque a few ft/lbs as well, 1/4" drive ratchet and 6" extension with long deep 6 point socket.
i bought an inch pounds torque wrench but never use it, always seems way too lose, even screws into alloy covers (although may start if I ever get around to replacing everything with Allen heads)

Yup but all things considered I do feel lucky…. But to my point about checking the bottom of the engine. Could it be as simple and flipping it and shaking or even just removing the bottom half while inverted…. More involved but can’t be that much right?

I have a scope coming later this afternoon that I’ll use to confirm nothing down there before I go all out. But if I do see it and can’t get to it…. Thoughts?

Also turned over by hand, kick, even pulling the chain and there’s zero indication of binding. If a bolt got under that tensioner arm it’s pretty much just stuck there right? Im struggling to see where it could migrate to especially with ill acting as a resistant medium in the case.

Either way, I’ll report back later but just wanted some ideas on what I might expect… but I’m glad to know my jugs and head look good apart from those two bent exhaust valves.

 

[stl360+450]

Did you check the intake valves? Bent isn't always as bent as those exhaust valves, which are beeeennnnt.

 

[dlogreen]

Did you check the intake valves? Bent isn't always as bent as those exhaust valves, which are beeeennnnt.

I didn’t remove them but they are sitting completely flush like they were when I did them when I rebuilt the top end.

I’ll check later tonight to see if they are, but I really don’t think so. But might as well since it’s off anyhow and I can spend a lil time confirming. Those captives are a pain to take off even with a legit tool other than the lever handle ones I’ve seen. My other one bent so c clamp and a grooved pvc are handing it for now

 

[ancientdad]

I didn’t remove them but they are sitting completely flush like they were when I did them when I rebuilt the top end.

I’ll check later tonight to see if they are, but I really don’t think so. But might as well since it’s off anyhow and I can spend a lil time confirming. Those captives are a pain to take off even with a legit tool other than the lever handle ones I’ve seen. My other one bent so c clamp and a grooved pvc are handing it for now

Put some parts washing solvent (or kerosene) in the intake ports to see if there's any leakage.

 

[dlogreen]

Put some parts washing solvent (or kerosene) in the intake ports to see if there's any leakage.

no leakage! scope came way too late so ill check in the AM, but I'm gonna clean the head up a lil more while it's off. I believe the new valves will be here by the end of the week, and all things check out, I can have it back together this weekend as well. Loctite gonna be used for sure lol

 

[dlogreen]

no leakage! scope came way too late so ill check in the AM, but I'm gonna clean the head up a lil more while it's off. I believe the new valves will be here by the end of the week, and all things check out, I can have it back together this weekend as well. Loctite gonna be used for sure lol

FOUND IT!

HAAA! the bolt was sitting in the cam slipper area...the reason it wasn't interfering is that when I pulled the slipper, it settled into the groove where the round metal head would be, and sat comfortably....without a scope I'd never see it cuz it's almost obstructed by he frame and cam chain.

Pictures coming soon...but I'm going back to snatch it up and get my engine ready to rock and roll!!!!

 

[dlogreen]

Okkaayyyu guys. New cam sprocket, new tensioner slipper and timed, chain tension, valves spec after installing new exhaust valves and lapping them.

Bike started right up and revved strong buttttttt after warming up I'm having a long hanging idle followed by eventual sputtering and dying while sitting in neutral.

I re welded the exhaust elbow and then buttoned everything back up like before. Is it possible my advance is sticking if maybe the seal on the camshaft isn't fully flush? After it sits it starts back up and isles normally before I crack it open and then the high idle hang comes back.

Pretty much zero chance of an intake leak cuz I didn't remove the boots from the head. So no disruption of those gaskets. Maybe exhaust leak right at the head???

It's running strong when riding though but the chances of a random hang and then dying bike is sketchy.

Love to hear some ideas... Thanks in advance

 

[stl360+450]

Do you have a dynamic test light? That would enable you to see if the advance mechanism sticking and also confirm ignition timing.

I would check for air leaks anyways.

 

[dlogreen]

Do you have a dynamic test light? That would enable you to see if the advance mechanism sticking and also confirm ignition timing.

I would check for air leaks anyways.

no dynamic timing light...I will double check static timing tomorrow and do some tests for intake leak. I also might loosen and retorque the valve cover after I pull the points cover off to check the advance. If it's something like the seal protruding, then I can drive it back into place. The carbs also sat with a little ethanol free fuel in em for the last week and a half...so maybe pilots clogged?

I'll check the easy stuff and progress to the harder things...intake leak check, timing light static, pull carbs and blow out pilots real fast, advance unit and check the seal underneath (if it's sitting proud, I'll drive it back in with a deep socket).

i guess ill get on the amazon and find a dynamic light to use cuz it can't hurt.

I think I noticed a little puff or exhaust gas coming from the header area come to think of it....would that cause a hang? that's either an exhaust leak or head gasket leak yah?

 

[stl360+450]

I have a Harbor Freight dynamic light. Works fine and didn't break the bank.

Ethanol can clog up little jets fast if the carbs are left with fuel in the bowls.

I don't *think* a leak at the headers would cause a hang, but improper timing, air leaks, or issues with the advancer could. Carb balance also, but you've not changed the carb synch since it was running good.