CL360 head/engine sourcing/repair question

CaptRudolf

CaptRudolf

New Member
Joined
Apr 15, 2022
Total Posts
8
Total likes
0
Location
Minneapolis, MN
Well, I got a bit too specific in my Introduction, so I'll just re-post it here since this seems to be the right spot for it:

...I started helping a buddy work on his bike a few years ago. Well someone didn't tighten the valve adjustment locking nut on the right intake. Dropped a valve. Gacked up the head, piston, and cylinder pretty good and I'm wondering where to look for a new head/engine. It also has a broken kickstart shaft, so I'm leaning toward a used engine - some of questionable quality are available from time-to-time on ebay. OR open it all up, swap the kickstart shaft, bore the cylinders .25 over, new pistons, new/used complete head.

I'm trying to minimize the amount of time I'll have into it, so a used engine sounds appealing. My understanding is the CL360 and CB360 engines are the same (not sure the years, but I'm mostly seeing '74-76' engines for sale) but the CJ360 is NOT the same.

Wondering if anyone here has any input on whether I should wait for a complete engine to show up on eBay (or if there are any other good sources for good 2nd hand CL/CB360 engines) or where to start looking for a complete head if I do the top end rebuild (again, really hoping to not spend the time required to do that right). I have seen a service on ebay for ~$300 to do a complete head overhaul, which would save some time and effort on my side, but I'll still need a complete/good condition head...

Looking forward to the discussions!

Cheers,
-Rudolf


For entry into the hall of shame:
IMG-0485.jpgIMG-0482.jpgIMG-0481.jpgIMG-0479.jpg
 
Usually, for a valve to drop that bad the collets/cotters were not properly fitted to spring retainer.
The inside of the valve cap will show the adjuster backing off and there would have been a terrific clattering.
Were you trying to rev it out as it was running on one cylinder?
At idle the engine would pretty much just stop dead
 
Thanks, Dad & PJ. I had seen both of those on eBay - first one looks nice, but I'd still need a cam & valves, valve grind, etc... starts to get $$$ pretty quick. Maybe I have to readjust my expectations on how much this will cost. Second one turned me off, but I suppose I certainly could ask more questions.

PJ- it's my buddies bike. He called me while riding and said it was making a chattering noise. I believe I suggested that he stop riding, but the decision was made to drive it over to my place. It started, ran, and drove... underpowered and noisy, but it did! Last I looked, the top 1/4" or so of the valve is still firmly seated in the retainer. My guess is that the adjuster backed out enough so the valve didn't fully open, it go hot, stretched, and eventually broke :cry:. Not sure, but at this point I'm more interested in getting it fixed and swapping to electronic ignition. Or selling the whole thing as a project. It's a nice bike though.
 
The only complete engine on eBay right now is in NY, local pickup only for $750 OBO. There has to be a salvage yard somewhere near you that has one. A local riding buddy used to live in Wisconsin and he found salvage yards there with lots of vintage bike parts when he used to go back for the summers until the last few years, he brought a CB450 engine back for me from up there.
 
Please check me here: I would NOT want to re-install this cam, correct? If I got a new head & valves I would certainly have to grind the valves to the head, but how necessary are new valve guides?

campits.jpg
 
You'd need to have the head inspected by a machinist to be sure of all the tolerances against the FSM. That cam might be repairable, we're working on getting a good servicer for cam and rocker arm/follower repairs and refinishing. There is a good service out there already but their prices are high, you'd spend more to get the cam done than on that best used head from eBay.
 
Capt. Rudolf,

I have a complete CB 360 with a stuck motor that can be yours for the hauling. Bike is in poor shape, but I was told that the motor was stuck from sitting. Castings should be salvageable for a rebuild.

I am just north of Mpls. If you are interested, shoot me a DM.

Did I mention "FREE"?
 
CaptRudolf said:
Well if this isn't some forum magic I don't know what is. Thanks TT! DM sent.
Click to expand...

We keep telling people this is the best vintage Honda twins forum on the internet, and this is a great example of why. This is how it's supposed to be. (y)
 
mike in idaho said:
The rod and the crank throw probably got hammered pretty well too, I would look for another engine.
Click to expand...


That crossed my mind as well. Is there a good way to check the crank/connecting rod/wrist pin for a case like this? I don't see any indicated tolerance in the FSM...
 
The only thing you can do is pull the cylinders and check the big end of the rod for excess clearance, you shouldn't be able to feel any up and down movement and you can use a feeler gauge to check side to side clearance, there should be a spec for that in the FSM somewhere. The small end of the rod could have suffered too, the wristpin should fit smoothly with no binding and should have no perceptible excess clearance as well. I went through one of our 360 FSMs yesterday and was surprised to not see a spec for the secondary windings on the coils, but there should be specs for the major engine components.
 
Heads are getting much harder to find in good condition so even a bare head with good cam bearings is worth getting..
If re-boring, it's a bit more expensive for the bore but Suzuki GS850 piston conversion is more than worthwhile.
You also need gaskets from Lani at Copper Gaskets.
The improvement is way out of proportion to the work involved (if you look up any of the CB360-390 conversions over the years)
With the various modifications I've listed over the last 12 years or so bike can easily be made on par with a stock 500 cc motor from the 1970's and accelerate to 60~70mph as quick as most 500~600's from 1980's (which shocks the hell out of people,, particularly when you have a 'Vintage' plate on a little bike :lol:)
I think coil secondary resistance is in the Electrical General Manual, around 8~10K/Ohm's with plug cap ON?
 
Quick update (will add some pictures from my phone later if I can figure it out) - Twin Town graciously donated his CB360 to this resurrection and after brute-forcing it into the van and stripping it down I found that the right cylinder was full of some sort of ash/particulate that had solidified and also had filled with oil while I was tipping it out of the frame (oil drain plug is impressively stripped and stuck, so I didn't drain the oil). This necessitated a look into the cylinder and also allowed confirmation that the right piston is stuck in the cylinder. Removed the head and filled the top of the right cylinder with PB Blaster (will try the ATF/Acetone trick if this doesn't work) to see if I can free it up, allowing me easy access to see whether one of the CB pistons are usable.

The head looks to be in good shape (one dent - see picture with circle). Looks like it may have been burning some oil - either bad rings, valve guide seals, or bad head gasket are my guesses. Looks like the right valves are a bit corroded. So right now I am thinking of sending the head out to be cleaned up and reworked (found Schumann), salvaging a piston from the CB engine, honing the original cylinders (or honing/using the CB cylinders - whichever look better/are within spec) and probably getting a new set of rings and engine gasket kit from those guys in Houston.

I think I know the answer to this, but I'll ask anyway - what is the general consensus on inspecting and re-using piston rings (assuming the gaps are within spec)?

Same question with cam chain tensioner guides - the ones from TT's CB engine look to be in pretty good shape.

Better to just replace both with new as long as the engine is out and open??
 

Attachments

  • IMG_0760.jpg
    IMG_0760.jpg
    196.6 KB · Views: 14
  • IMG_0759.jpg
    IMG_0759.jpg
    241.3 KB · Views: 13
  • IMG_0757.jpg
    IMG_0757.jpg
    243.1 KB · Views: 11
  • IMG_0755.jpg
    IMG_0755.jpg
    221.6 KB · Views: 17
  • IMG_0754.jpg
    IMG_0754.jpg
    224.5 KB · Views: 12
  • IMG_0740.jpg
    IMG_0740.jpg
    268.7 KB · Views: 13
  • IMG_0780.jpg
    IMG_0780.jpg
    251.2 KB · Views: 14
  • IMG_0778.jpg
    IMG_0778.jpg
    298.4 KB · Views: 11
Last edited:
You're spending good hard earned money on having Chris do the head. So finish that work with new parts. Rings sometimes can be reused for an emergency repair but they won't live and the engine will never be right. Tensioner parts? If they are in good like new condition fine but anything less means new ones.
 
That top end looks pretty good compared to how the rest of the bike looked! Don't see any scuffing on the cam, everything looks well oiled.
Since you have the crankcase apart, tip the engine upside down and fill the cylinders from the bottom with 50/50 acetone and automatic transmission fluid. I have had success using this method.
Get her going and let's meet up for a ride!
 
You must log in or register to reply here.
Back
Top Bottom