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76' CB360T Running Issue

Sounds like someone set carb sync way off?
Soaking carbs is almost always a VERY BAD IDEA as the throttle shaft seals get dried out and start leaking air, the seals on push bar between carbs get destroyed and the pilot jet plus primary main jet discharge nozzle don't get cleaned.
Gas in the oil just means you got engine clean inside, the teeny tiny amount left over will evaporate out of new oil as soon as engine gets hot.
What? Throttle shaft seals are just soft felt to help protect the shafts from being destroyed from dirt. They are dust seals. Think about it. If they were intended to prevent outside air coming in then why aren't they rubber or o-rings?
 
I haven't been here in a few days, so I'm just now catching up with the conversation.
I read everything up till now before posting anything.

I will let the others advise you about refilling with oil.

The thing I've been wondering is, in addition to the points possibly being mis-adjusted, is the oil issue.
When I was in my early-mid teens (late 70s) my dad owned a boat shop, and so naturally we worked on lots of outboards.
One of the cardinal rules when doing a tune up and putting in new points (or just checking/resetting the existing points), was to never touch the face of the contacts with your fingers, and always make sure your feeler gauge was clean and oil free.

On outboards at least, even the smallest amount of oil from a fingerprint or gauge (or the small leak you mentioned) could stop the points from conducting a spark across the contacts sometimes, rendering them all but useless.
Good point, did not think about this. Grab a white business card and spray some contact cleaner on it. Run it through each set of points multiple times until it the paper comes up clean. Then hold the points open and blow with compressed air.
 
The felt seals work in conjunction with brass 'washers' and on most there is also a light spring to push operating arm against carb body (I fit springs to later carbs or when it's missing)
I tried Teflon 'seals' one time, causes way too much friction on shaft until they are reamed out to be nothing more than a spacer.
Rubber (Viton) was even worse and not really an option as carbs were not designed for them
Felt was probably cheapest easiest option not requiring any special tooling to mould 'rubber' and even if washers are set too deep doesn't cause drag on throttle shaft.
Don't forget, I've been dealing with these carbs a long time (since C J was 'new' model in 76/77)
 
No big updates yet but plan on getting some progress made tomorrow!

I don't want to get into a debate about oil but since I'm new to the vintage honda engines, I just wanted to make sure using Rotella t6 isn't going to somehow bung up a bearing or something. It's sitting here and figured its fine to put in but I've found there's little I should be sure of without a general consensus. I looked at former posts but want to make sure I didn't overlook anything specific to t6


Thanks for everyone's continued input, its greatly appreciated

Borrow a real one from someone if you have to
I would like to get one as part of my garage so any recommendations are appreciated. I have a desire to make this more of a part of my day to day but I don't have a ton of $$$$ to throw at this atm but I don't want to be cheap.
The thing I've been wondering is, in addition to the points possibly being mis-adjusted, is the oil issue.
I was wondering if this could have some relevance along with them still being misadjusted so I'm going to clean them (which is why I suggested it but I appreciate the nod) but imagine my surprise if someone said "Well on this particular model the points just loved oil so Honda..."
Grab a white business card and spray some contact cleaner on it. Run it through each set of points multiple times until it the paper comes up clean. Then hold the points open and blow with compressed air.

(don't try and slide it out without opening points again first)
Heard

@ancientdad I just wanted to run past and confirm this is the orientation of the points cables you were referring to minus the swapping of R and L spark boots.

PXL_20240917_034604118.jpg
 
The orientation of wires under the cover is important bit, if it isn't right, left side shorts out on cover.
I run points wires under the HT leads, it tucks in under cooling fin.
You may also have a cable clip missing on top of motor plus wiring harness clips missing?
Even if everything is correct, it will short out if you don't have the gasket in place (at least you can cut them out of cereal box )
It doesn't hold pressure, just becomes a spacer and keeps water out
 
@ancientdad I just wanted to run past and confirm this is the orientation of the points cables you were referring to minus the swapping of R and L spark boots.
Yes, that's what I was referring to so you can also swap plug wires between sides to see if the dead cylinder follows the swap. Basically what you've done is changed which points and coil are powering the dead cylinder with the points and coil that was previously actively powering the plug in the cylinder that runs, to eliminate the plug, points and coil as culprits.

PJ is absolutely right about the points cover causing a shorted connection when the points wire is not correctly oriented to clear the cover once installed. This is how the wire terminals should be oriented on the connector bolts on the points. Note the left points wire is attached to the inside of the points connection under the nut, as opposed to the outer area under the bolt head which would bring it too close to the cover.

350points correct.png
 
The orientation of wires under the cover is important bit, if it isn't right, left side shorts out on cover.
I run points wires under the HT leads, it tucks in under cooling fin.
You may also have a cable clip missing on top of motor plus wiring harness clips missing?
Even if everything is correct, it will short out if you don't have the gasket in place (at least you can cut them out of cereal box )
It doesn't hold pressure, just becomes a spacer and keeps water out
I've read this before but until I saw the picture Tom shared, I didn't realize the left could/should be oriented the other way. I'll do that today too. PO had the points cover off and the daughter selling the bike said she never heard it run so my guess is he was messing with it and couldn't figure it out

I've since replaced the gasket with one I cut myself out a while ago and the wires are out to show a clear example of what colors are which. The wires only want to go back the way they were originally left on the bike (under the fin). Clips and other mounting hardware may be obfuscated though

Here's a photo1000007849.jpg
 
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Also, the 6mm bolts (10mm heads) being used instead of the #3 JIS screws that should be holding the points plate are closer to the left points spring than the screw heads would be.

1726607281888.png
 
Alright folks

Followed Tom's advice and decided to swap the coil/wires to see if I could get the other side to fire and now it seems like both sides are firing? Both pipes were hot but I don't want to assume just because it's hot that it's working. Videos should hold some answers hopefully. When I started it, it was on choke and then after some time it began to like coming off of it. It still doesn't love to idle and will rev and dip back down from time to time unless i tamper with the idle screw. I am open to suggestions about the carbs once i nail down this electrical issue, I know they've been mentioned as a possible culprit with potential bad sync. Just don't want to start too many things and lose track of what we've tried so on

It starts immediately whether kick or electric start. This is still on the Li-On Noco jumper.

 
Also, the 6mm bolts (10mm heads) being used instead of the #3 JIS screws that should be holding the points plate are closer to the left points spring than the screw heads would be
I would never have known or thought tho look to see if they were JIS or not. Thank you for pointing that out. I have a set of allen key bolts that could go in but I'll have to see if they provide any more wiggle room
Yep, left side wire is too close to cover
I'll take the time to move it over. I've heard of these screws shorting out on the cover but not the wire. Good to know for the future.
 
I've heard of these screws shorting out on the cover but not the wire.
It's actually the size of the terminal on the wire itself, which is why the orientation is important. But, you were running it with the points cover off so the test will be if it still fires on both once the cover is back on.
 
It still doesn't love to idle and will rev and dip back down from time to time unless i tamper with the idle screw.
What I'm hearing is the right cylinder (seemingly based on the second video) is trying to run late in the video, but either the pilot jet is still clogged a little or the sync is way off. It revved up high to begin with because you've been trying to get it to idle on just one cylinder and thinking the idle speed still wasn't high enough, so as you noticed you had to dial it back down a lot from where it was once both cylinders are at least partially contributing.
 
What I'm hearing is the right cylinder (seemingly based on the second video) is trying to run late in the video, but either the pilot jet is still clogged a little or the sync is way off. It revved up high to begin with because you've been trying to get it to idle on just one cylinder and thinking the idle speed still wasn't high enough, so as you noticed you had to dial it back down a lot from where it was once both cylinders are at least partially contributing.
I can take the carbs apart and inspect them. is there a better bench synching technique than using a wire under the throttle valve? I also do not have a carb sync tool or gauges so I'll have to get those at some point but figured I should let everyone know what my limitations are atm
 
Bench sync is only to get it enough so the bike will start, but if this bike has vacuum for ports for sync gauges (not sure with this model) then you absolutely need to get gauges. Don't get the cheap ones on amazon or ebay. The Morgan Carbtune Pro works pretty well. It's currently $130, but about as good as it's going to get at that price range: https://www.amazon.com/CARBTUNE-PRO-4-W-Pouch/dp/B018UTHGPE/. MotionPro makes one as well, but that one uses fluids and the markings aren't for cmHG, just a reference point: https://www.amazon.com/MOTION-SYNC-CARB-TUNER-Manufacturer/dp/B008YFQJW6/. Both are about the same price. Whatever you do, test them by hooking up one bank and note the reading, then swap to another bank make sure it reads the same. It should, but I have heard of instances where they were way off and caused tuning problems.
 
Howdy from a rainy Allegheny valley.

Of the suggestions made earlier I am going to source a stroboscopic timing light, carb sync tool, vacuum ports, and gauges. I'll update the thread once I have more info after those items come in.

In the meantime, I have some more videos of the the bike running today under the same configuration as before except this time with the points cover on after having adjusted the L points wire away from the cover. Both pipes are hot when running. I'll swap the plugs and wires back and see if anything changes with a timing light tomorrow

 
Toward the end of the first video you can hear one cylinder intermittently firing, it's the little popping sound occasionally that slightly changes the rpm. Again, either the pilot jet or passage is probably not yet completely clean, or the mixture screw is wrong or mucked up, or the sync is just way off. So it's currently mostly running on one cylinder, as it does in the second video.
 
What's the compression in the cylinder that doesn't fire ?If you don't have a compression meter, you could take out the spark plug, put your thumb on the hole, and try to start the bike with the electric starter, you should not be able to keep your thumb on the spark plug hole.

To ignite, only five things are needed:

- fuel
- air
- pressure
- spark
- correct timing

If everything is there, it should run, so check the boxes to see what isn't there.
 
What's the compression in the cylinder that doesn't fire ?If you don't have a compression meter, you could take out the spark plug, put your thumb on the hole, and try to start the bike with the electric starter, you should not be able to keep your thumb on the spark plug hole.

To ignite, only five things are needed:

- fuel
- air
- pressure
- spark
- correct timing

If everything is there, it should run, so check the boxes to see what isn't there.
I asked about compression in post 42, previous page, but either he doesn't yet have a gauge or hasn't checked it yet. Absolutely a possibility.
 
I don't have a compression gauge atm. I tested the bike when I got it home a few months ago with the thumb trick and both cylinders had compression. Tested it again just today and same outcome.

I will say, the R cylinder (which IS the trouble cylinder) seems a bit weaker than the L but not by much if at all which could be a clue but not confirmation unless I'm able to locate a compression gauge.
 
Auto Zone and O'Rielly's rent them
Hot dog, I never thought about this. We have a robust hardware store near us that rented out all kinds of tools and I can't believe it hadn't crossed my mind that AZ or O'Rielly's would also have the same program. I have one a stone's throw away from my house so that'll be the route i take, thank you for the suggestion

Noticed something else today while testing the timing light I purchased. The R pipe was cold when I had it on the kickstand but when I put it up on the center stand (and level-ish ground) it began to fire. I'm wondering if this is a possible float/fuel delivery issue in conjunction with the timing being off, but with so many variables its not worth throwing darts, just figured id mention it in case it comes up later.

I'll have some time with the bike tomorrow to switch wires back, work out the timing, and hopefully come back with a compression reading that's good enough to continue
 
Noticed something else today while testing the timing light I purchased. The R pipe was cold when I had it on the kickstand but when I put it up on the center stand (and level-ish ground) it began to fire. I'm wondering if this is a possible float/fuel delivery issue in conjunction with the timing being off, but with so many variables its not worth throwing darts, just figured id mention it in case it comes up later.
Now this points to float level issues.
 
360's will run OK if compression is low, all thev way down to 120psi.
You have set valve clearanced correctly at TDC compression?
It's very probable right side valve was open and may have something on seat which will wear off pretty quick if running right.
Re-set right tappets 0.04" exhaust and 0.03 intake, that will bring compression up slightly so they match.
Bench sync 360 carbs will be quite close as long as ignition and valves are right.
Problem is, many people adjust them wrong, have washer missing or link 'fork' bent so adjuster screw can't do it's job.
Pretty sure I have various pictures of 360 carb problems
 
Found some pictures of 360 carbs, this is how they arrived for me to fix and modify

1. sync adjuster screw , washers.
There should be a large washer under spring with a smaller (usually dished) washer underneath screw head with U bracket between them.
This has both washers on top, you can easily run out of adjustment before carbs are in sync.
The threaded hole on right side should be full throttle adjuster / over travel screw (this one is missing)
2. throttle link between right and left carbs, clip and seal missing. The link mount is also bent

3. From the top, Idle adjuster screw and cable, throttle cable pulley, screw plug for link, sync adjuster
I have a load of carb pics showing minor or major faults I've fixed since 2008
Shawn-2.jpg
Shawn-4.jpg

Syncadjuster.jpg
 
Thought I should add this as it's quite common
On the right side of picture below the sync screw the throttle shaft is visible with a missing plug.
The drilling to left of shaft goes directly to intake and causes lean running.
This set had both plugs missing, bike didn't run
Vadim3.jpg

Vadim4.jpg


Far left is stock throttle shaft plug still in carb.
I have no idea how many replacemen't I've made, - a lot
CB360-leftcarb.jpg

Aluminium throttle shaft plug, I made a lot for CMC that should have been no more than $5.00 each, he sent some out at more than three times the price (And I gave him a good deal when he was starting (10? years ago) so even $5.00 was 100% mark up.
Shawn-7.jpg
 
Aluminium throttle shaft plug, I made a lot for CMC that should have been no more than $5.00 each, he sent some out at more than three times the price (And I gave him a good deal when he was starting (10? years ago) so even $5.00 was 100% mark up.
Well isn't that shocking... seems the leopard's stripes have been the same all along.
 
Hard to believe isn't it?
And just based on PJ's statement, it would seem CMC has had that agenda all along. And apparently not something he cooked up after realizing some early success, but probably from the very beginning. Which to me makes it all the more deplorable, leveraging a forum member's generous efforts into a large profit margin for yourself under the guise of helping young vintage Honda owners. Uh-huh.
 
Gotta smash that like and subscribe button Tom. If you're not monetizing your hobby for the grind then get out of the way for the rizz sigmas.
 
Alright, yall another update from sunny southwest PA

@crazypj thank you for thinking of this. I've check the carbs and yes, I do have the parts you've highlighted as often missing. I try to do a parts list of everything I have and as I take it apart take notes or photos of orientation especially for reassembly. For things like this that you don't normally service this would be something that could slow down or halt a project for sure if you don't know what to look for.

-Compression on both cylinders (WOT, no airboxes, choke open) was 160.

-Timing is very close but not perfect yet so I will continue working on that. Had both cylinders firing a little past the F marks using a timing light. I cant remember where, but I thought I read that the advance for the timing is somewhere in the ballpark up to 12? If anyone has recommendations of how to dial it in I'm all ears.

-I can also do another points gap clearance adjustment. Plus @crazypj mentioned valve clearances again but I'm not too sure if that's necessary with compression both being at 160?

-Carb Tune and new fuel line is in but still waiting on the vacuum fittings and carb synch tool

Should I make sure the ignition timing is spot on before messing with anything involving carb tuning? On that same note I will be removing the carbs once more to inspect any issues involving the floats or jets. I've heard many people swear up and down to use a guitar string on the carb body and others who throw a cross up at it and say just to soak or hand clean. I use chem-dip for soaking, btw.
 
Plus @crazypj mentioned valve clearances again but I'm not too sure if that's necessary with compression both being at 160?
One thing you need to remember is these adjustments are a regular maintenance item at much smaller intervals than modern bikes need. From the CB360 owner's manual

1726861570702.png
Should I make sure the ignition timing is spot on before messing with anything involving carb tuning?
Yes, because retarded or advanced timing, as well as sloppy advancer operation, will directly affect each cylinder's performance.
 
Re-set right tappets 0.04" exhaust and 0.03 intake, that will bring compression up slightly so they match.
@ancientdad My understanding of this procedure was based on the fact that we were still on the hunt for compression being part of the problem here. I may be misunderstanding though and wouldn't be the first time. With both reading 160, I'm a little hesitant to readjust just to readjust if this method was so that compression would equalize.
 
@ancientdad My understanding of this procedure was based on the fact that we were still on the hunt for compression being part of the problem here. I may be misunderstanding though and wouldn't be the first time. With both reading 160, I'm a little hesitant to readjust just to readjust if this method was so that compression would equalize.
I didn't re-read and see that, but PJ isn't wrong about slightly looser valve adjustment allowing the valves to more fully close and maybe "clean up" the seats a little allowing the compression to rise a bit (along with a minute change in valve timing likely helping). But, at 160 each I'd doubt compression was an issue.
 
Main reason for slightly wider clearance is valves can 'hammer down' to correct clearance when any carbon, rust, or whatever is removed.
It's way more noticeable with shim and bucket motors that haven't been checked in years because they are 'quiet' (A VERY BAD THING' on some motors, particularly early Suzuki GS shim over bucket and Honda 900 DOHC)
160 is good should run fine.
You should have had these parts out for cleaning, primary discharge nozzles are often left in carbs and quite often the pilot jets are stuck with oxidation or gummed in with old fuel.
Primary main jets are 68, some people have found a 65 works better but new ones are a little too long and need to be shortened. DO NOT USE LARGER Primary main jets
The secondary main jets are still in emulsion tubes, normally have 100~105
All the cross drillings in emulsion tubes and pilot jets should be 0.80mm, all aftermarket are 0.60mm
Primary discharge nozzle should be 1.20mm at tip, they are often damaged and may be over or under size.
Ultrasonic cleaning doesn't fix the oxidation, even when left too long so carb bodies get pin holed from excess 'cleaning', they have to be removed to clen. White vinegar actually works quite well on brass but all holes still need checking.

Jerry - fuel parts - before.png
 
Main reason for slightly wider clearance is valves can 'hammer down' to correct clearance when any carbon, rust, or whatever is removed.
It's way more noticeable with shim and bucket motors that haven't been checked in years because they are 'quiet' (A VERY BAD THING' on some motors, particularly early Suzuki GS shim over bucket and Honda 900 DOHC)
160 is good should run fine.
You should have had these parts out for cleaning, primary discharge nozzles are often left in carbs and quite often the pilot jets are stuck with oxidation or gummed in with old fuel.
Primary main jets are 68, some people have found a 65 works better but new ones are a little too long and need to be shortened. DO NOT USE LARGER Primary main jets
The secondary main jets are still in emulsion tubes, normally have 100~105
All the cross drillings in emulsion tubes and pilot jets should be 0.80mm, all aftermarket are 0.60mm
Primary discharge nozzle should be 1.20mm at tip, they are often damaged and may be over or under size.
Ultrasonic cleaning doesn't fix the oxidation, even when left too long so carb bodies get pin holed from excess 'cleaning', they have to be removed to clen. White vinegar actually works quite well on brass but all holes still need checking.

View attachment 37225
So I went through the carbs and took out the primary discharge nozzle which was pretty gunked up. I decided to just go through everything with a few small detail brushes and slapped em back together. Today I got the bike to run but under an interesting set of circumstances.

I have been using this motobatt MB12U which was recommended as a solid battery for the 360. Cycle gear had a sale on these weird batteries for $10 bucks each and I figured it couldn't hurt to just have 2 batteries hanging around if I need em for something.

I put both motocatt and unnamed batteries on a Noco Genius 2 to charge and both batteries read fully charged when I used them on the bike today. The motobatt puttered out after trying to start the bike only a handful of times over. I eventually put this other battery in (can't recall the name and I'm not near em atm) and once I tried starting the bike centered and not on the kickstand it began to idle.

I had also tightened the air/fuel mixture screw back in and backed it out 2 turns instead of 2 1/4

I was able to take it up and down the road after it had ample time to warm up and it was AMAZING. I can't believe the feel and fun this thing is capable of. I didn't ride the piss out of it, just up and back down the road. It didn't like the friction zone without a little gas, but otherwise it idled in neutral and shifted through gears. I think the timing is still a TAD bit off so I still need to address that but it hasn't been able to do this yet. I'm a bit puzzled and don't want to look a gift horse in the mouth but I like to know how my miracles happen, if you know what I mean. I'm going to tread lightly moving forward, though an any advice will be heeded!

Thanks!
 
So a mix of carb issues and ignition! And yes, these points bikes need a good battery or they never run right. Glad to hear you have finally sorted it out.
 
So a mix of carb issues and ignition! And yes, these points bikes need a good battery or they never run right. Glad to hear you have finally sorted it out.
I don't want to chalk it up to figured out quite yet, but yes. A victory in the right direction I'd say!
 
Indeed, lot's of progress. Sounds like small tuning is left for you. Don't forget to check the float height as being 2mm off can make a big difference in performance especially around 1/4 throttle.
 
Howdy once again

Coming back to this thread to ask if I should continue using this one for this bike specifically or start a new thread for each instance concerning other issues I might encounter i.e. carb and performance issues?

If not, I'll post this last thought here about carb tuning and move it to another thread if that's the most appropriate route. Regardless, here we go!

Work done/notes since last post:

-Replaced original spark plugs with the new resistant plugs just to see
-Timing is now spot on with both L and R sides firing as close to the mark as I can get them and she starts up with choke on after giving it a few kicks over with killswitch on
-Idles happily at 1200 (can take video)
-took the carbs back off to fix a gas leak due to pinched gasket (is this a fix that makes sense to do while the carb is still on the bike, has anyone tried this and found it helpful??)
-installed new flasher relay and successfully rerouted mixed up wires in the bucket. THANK YOU full color wiring diagram ( and a little guesswork/common sense go a long way)


2mm off can make a big difference in performance especially around 1/4 throttle

Is this in reference to both bowls' floats together, i.e L bowl is 19mm and R bowl is 16.5? Or to the individual floats per bowl i.e. L bowl float measures 18mm on one side and 21mm on the other. Thanks for your input!

The bike is sputtering in time when holding at any speed riding WOT it zips and prefers it over holding rpms. I figured "of course, I haven't synced the carbs with the tuner yet". When I synced them they read 34 cmhg for the L and 16 cmhg for the R. The bike was warmed up before attempting this.


PXL_20240928_195229635.jpg

The carbs did not fluctuate largely when I adjusted the sync screw. In fact, every time I adjusted the screw, both sides would move in tandem. I messed with the fuel/air mixture screw to no luck changing the left side. The right would dip a bit and the numbers would still change slightly but not enough to bring the L carb down to the correct range of 16-24cmHg @1200 RPM

My understanding is this: bench syncing only does so much but gets them close enough to start. However, is it possible I have to bench sync these with the proper wire feeler gauge like guitar string? I used a bit of a larger wire (bread tie wire) I had available a few months ago.

I'm a bit stumped right now and don't want to move forward with any more carb procedures until I sort this out here. One turn of a screw here, one adjustment there, and before you know it you've made significantly more problems for yourself so before all of that I'm going to clean the oil filter (i know, should have been done already) and replace the oil.

Thanks again!
 
You're fine keeping on with things here. But, a bread tie wire is pretty soft material and might have distorted during syncing due to the tension of the throttle return spring, which could have affected the sync accuracy.
 
When I mention the float height I mean 2mm off on either carb. I'm not familiar with this model like Tom is. But for example, if book says 15.5mm +/-0.5mm as spec then you want the float height to be in that range of say 15.0mm-16.0mm on each carb or it won't run right. It's best done with the carbs sitting upright. Trying to do it sideways/45 degree angle or upside down tends to make it off by 2mm when you check it properly in an upright position.
 
Took a look at my carbs today to try and equalize the vacuum and realized that neither side of my air/fuel mixture screw's had a washer. I went to the rebuild kits I purchased a while back and while they have the screw and the o-ring, the washer they provided is too big to go into the port. On the parts diagram I'm seeing what looks like a washer right before the spring on the mixture screw, unless that's supposed to be an o-ring instead?

Also, I know the wire technique is passe to some here and so I did some digging and found this comment. Ripped it off of an old thread but I don't think I understand the cables sync'd part? I can also PM and ask directly
Forget the video......With butterfly completely closed screw in the throttle stop screw until it just barely touches the carb body then in 3/4 turn......Adjust after cables sync'd and engine warm to 1200 RPM idle.....

I also noticed that as I went to try the wire trick for kicks that no matter how far down I got the adjustment screw down there was no way to get the R throttle to seat enough to grab the wire tight enough. L side is totally fine to adjust in any direction. I'm wondering is this is part of the issue I was experiencing trying to adjust the sync on the bike?

Also, the wire used was a high e string if that helps. not a thicker one like B or G

-Marcus
 
Also, I know the wire technique is passe to some here and so I did some digging and found this comment. Ripped it off of an old thread but I don't think I understand the cables sync'd part?
His comment was probably about an older model like a 175/350/DOHC 450 that did not have both carbs attached to a rack with combined linkage, they had separate cables to each carb and that was how you had to sync them.
I also noticed that as I went to try the wire trick for kicks that no matter how far down I got the adjustment screw down there was no way to get the R throttle to seat enough to grab the wire tight enough. L side is totally fine to adjust in any direction. I'm wondering is this is part of the issue I was experiencing trying to adjust the sync on the bike?
If you had the carbs apart and cleaned them, did you remove the throttle plates? If so, it's not hard to get one throttle plate off center slightly which could allow a large gap underneath and drastically affect your idle speed on that cylinder along with the vacuum reading. If you didn't, perhaps the PO did at some point.
 
The throttle plates can look right on the bevel but be upside down. The throttle plate has to be able to close fully when the carbs are separate, if it does then the issue is with the sync screw assembly. One washer above and one below the aluminum bracket.
 
Well, today we have some-a-good and some-a-notsogood.

Took the bike for a short cruise today ~6 miles after working on the carbs. Found that one of the washers was, in fact, doubled up on the throttle connector so thank you @crazypj and others for their insight. I was then able to successfully sync the R carb on the bike and both were reading 24cmHg on the nose. Kept doing small adjustments and went for a spin. Sounded great idling, throttle response was great, both cylinders firing, went through all the gears, then one time I shifted into 3rd from 2nd with the clutch fully released around 9k RPM (after about 4 minutes on the road ~10 running) and got a bit of a spin out of the gear almost like it was in neutral then it was fine. Kind of like the clutch slipped and thought it was my poor handling or something.

Took it another 2 miles and then the bike started hobbling on one cylinder again I think. I began to lose power and the bike shut off at a light. Every other stop it was a delight on the idle. I got it back home where I discovered it might have been a fuel delivery issue since I believed the fuel filters I have on aren't sufficient at delivering gas. Since it started right back up after seeing gas go through the filters I thought I had resolved it and took it back out. Another few miles and I hear a sound coming from my L Muffler and sure enough the bolts securing the muffler mount on that side were beginning to to loosen. I pulled over, kicked myself in the butt for not bringing my toolkit with me this go around, and tightened what I could with my gloved hand and went a mile up the road to a local garage that lent me a 12mm to tighten it up. While riding up the hill the motorcycle had no real jump in acceleration however I was trying to be gentle.

Once I had tightened the bolts enough to get the bike back home the bike wouldn't start and began making a horrible sound with the starter like nothing I had ever heard before (video links will be included). I've had to replace the starter clutch on this particular bike but I'm wondering if it's possible the work I did was insufficient or there's a reason the starter clutch failed in the first place that I'm missing?

I loaded the bike on a van and once I got it home I took a look at the oil out of curiosity and there was a considerable amount of silver residue in the oil.


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No chunks but I can try to find a strong enough magnet to see if it isn't aluminium.

Next I found the battery to not be in any condition to start anything. Between my insistent turning over of the motor and most likely forgetting to turn the key off after the multimeter read a draw of 12.23V with the starter but it also didn't like the kick starter. It's fully charged now and will try it tomorrow.

Now I'm noticing not a lot of gas in the tank so I'm wondering if this is a culmination of a lot of things i.e. idling the bike to warm up, match the carbs leading to use of gas, running the bike on the road and up hills, not giving it a full tank, poor fuel delivery, however does any of this explain the substance in the oil? I had also cleaned the oil filter which was caked with crud prior to any of these rides.

These were the plugs after the ride.

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L and R side respectively


Right after sync

When the bike would not start again

Finally this


The sound with the starter worries me and same with the oil but I'm going to try to work on it tomorrow weather permitting!

Could this also be an issue of a missing fuel/air mixture screw washer?
 
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Well, I hope I am wrong, but it sounds like you had one or both pistons seize up in their bores. That could happen from running lean (fuel filters overly restrictive and starving the engine for fuel), timing a bit too advanced, climbing that hill at partial throttle, perhaps lugging the engine a bit. That combination of factors can cause detonation, which causes the pistons to heat and expand till they are too big for their bores and they start to smear aluminum on the cylinder walls, eventually seizing up. This would also explain the shiny silvery stuff in the oil.
 
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I hope you're wrong too 😅! Decided to drain what I had left in the tank (not much) clean out the petcock (had gunk that could have restricted flow), added fuel, replaced the oil, change out the fuel filters for just straight fuel line, and while the electric starter still doesn't sound happy (whining) I was able to kick start the bike easily after a few prime kicks and with choke, and it ran up the road and back after giving it time to warm up.

Embarrassingly, I may have just been really low on gas and the petcock was on reserve so I wouldn't have had a heads up anyways and this most certainly wasn't the first time I've ended up stranded like that because of being a dullard.

I'll still wait for a few other remarks before doing big open road tests, but in the meantime I'm just happy the bike starts and runs.
 
got a bit of a spin out of the gear almost like it was in neutral then it was fine. Kind of like the clutch slipped
It could be the clutch slipping, and if the adjustment at the lever is too tight (not enough free movement in the lever before starting to disengage the clutch) it might only need to be adjusted properly.
I've had to replace the starter clutch on this particular bike but I'm wondering if it's possible the work I did was insufficient or there's a reason the starter clutch failed in the first place that I'm missing?
Hard to say without seeing it, but in the video it is absolutely slipping. I don't recall the starter clutch being worked on in any of your posts, maybe I missed it.
 
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