SixtyNine!

[mysta2]

Kit, I'm sure you know more about these than I do...

Nope, you may be exactly right, but I don't know... and I can't remember the sources of the information I've got rattling around in my head so they may have very well been referencing only the front sprocket. One thing for sure though... I'm going to find out.

Damn, now I have to find a CB front sprocket.

Question for anyone who's got one: How many teeth on it?

 

[HerrDeacon]

Nope, you may be exactly right, but I don't know... and I can't remember the sources of the information I've got rattling around in my head so they may have very well been referencing only the front sprocket. One thing for sure though... I'm going to find out.

Damn, now I have to find a CB front sprocket.

Question for anyone who's got one: How many teeth on it?

Kit, just based on the parts diagrams for both the CL and CB, they appear to have different gear ratios. Although, I wasn't sure what years your were comparing so there may be differences based on years. Also, the CB front sprocket has 16 teeth.

 

[ridesolo]

Nope, you may be exactly right, but I don't know... and I can't remember the sources of the information I've got rattling around in my head so they may have very well been referencing only the front sprocket. One thing for sure though... I'm going to find out.

Damn, now I have to find a CB front sprocket.

Question for anyone who's got one: How many teeth on it?

I'll try to root around in the garage tomorrow and check my stuff. My bike came w/ some boxes of extra parts including a couple of front sprockets. Not sure, but it seems like the CL had a 16 tooth on the front and the CB had a 17 tooth.

I seem to remember the publicity from way back when they were making "Scramblers" (of course this is ANCIENT history for my poor old brain to dig up) and the differences between a CB and a CL (whether it was a 175, a 350/360, or a 450) were the sprockets, the handlebar, the exhaust, seat and different paint. For some reason I think they always insisted on a drum front brake for the CLs as well. They never said anything about having a closer ratio gear box that I remember, but it would seem like a logical thing to do. Of course the Scramblers weren't much in the way of true off-road bikes anyway, anything much more rugged than a logging road would leave them floundering and hopelessly overweight. The SL350 was more of a true off-roader; I wouldn't be surprised if that one really did have different internal gears.

 

[mysta2]

hmm, different by year huh? SixtyNine is a '75 but I don't know what the CB set I've got cam out of, can't remember. Just checked and she's got a 16tooth front.

I've got an old article reviewing the CB when it first came out, I thought some of the info was in there, but I can't find it at the moment.

Thanks for raising the question Ridesolo, this is exactly the debate I hope to resolve.

 

[CCRider]

The service manual shows the gear ratios to exactly the same for the CL and CB 350's with the exception of the final drive. 16T/38T for the CL and 16T/36T for the CB.

CC

 

[mysta2]

I've got a 34tooth here from SixtyNine... I think it's from SixtyNine.

Where in the 350 manual does it state those spec differences? I've got the 360 service manual... and don't know if it has that info or where it would be...

Never mind, feeling stupid. The page in the back does not distinguish between the two in gearing it only separates the CL out in the top categories covering things like width and brakes. So I may have thrown away some money... still going to have a look though. It does toward the back in a supplement covering the CJs state differences there in gearing (most importantly the lack of a 6th) But these specs don't cover drive sprockets or finals.

 

[mysta2]

My office:

Irregularities in the head:

What do you make of this?

 

[Swagger]

At minimum those parts should be hard-faced and reground to spec, those pits are a bad sign...

 

[boomshakalaka]

At minimum those parts should be hard-faced and reground to spec, those pits are a bad sign...

what does that? Overheating? Insufficient supply of oil to the cam?

 

[Swagger]

Low oil pressure generally, these are pits and not really scores (linear) so I doubt that excessively dirty oil was the issue. Basically you're right though, without sufficient lubrication all those metal to metal contact areas get HOT. Hot enough to tear small bits material loose and deposit it on other parts. Not good...

 

[crazypj]

You can see by witness marks on base circle of cam that its been run with too little clearance ('tight valves')
What does head look like?
CB360 cam bearing seize before anything else goes south.
The cam is still usable but I would change the 'bad' rocker arm and set clearance with go/no go method as Honda only use 0.002" intake and 0.003" exhaust.

PJ

 

[Kanticoy]

Pay very particular attention to the oil passages in the head of these bikes. They don't have cam bearings, they just rotate on the journals in the head and rely on oil lubrication to rotate freely. I always wished two things for these motors...that there was a way to install cam bearings, and (as you have fooled around with in the past) there was an aftermarket cam slipper. That is the only downside to these bikes to me. I burned a head up in my last 360 because the oil passages got clogged, the cam didn't get lubricated, and the journals got too disfigured to use the head or the cam anymore. I equate the failure to the cam chain sliders breaking in half and bits from that getting clogged in the oil passages.

You guys probably knew this stuff already, but for those who haven't been there, maybe it'll help. It all started when I started seeing smoke coming out of the valve breather tube.

 

[Rocan]

Pay very particular attention to the oil passages in the head of these bikes. They don't have cam bearings, they just rotate on the journals in the head and rely on oil lubrication to rotate freely. I always wished two things for these motors...that there was a way to install cam bearings, and (as you have fooled around with in the past) there was an aftermarket cam slipper. That is the only downside to these bikes to me. I burned a head up in my last 360 because the oil passages got clogged, the cam didn't get lubricated, and the journals got too disfigured to use the head or the cam anymore. I equate the failure to the cam chain sliders breaking in half and bits from that getting clogged in the oil passages.

You guys probably knew this stuff already, but for those who haven't been there, maybe it'll help. It all started when I started seeing smoke coming out of the valve breather tube.

what color was that smoke?

 

[Kanticoy]

It's white smoke and smells like...well burnt oil. The oil passages were completely blocked off upon inspection. In my experience, these 36o engines break slippers...slippers leave fragments...fragments get lodged....you get the idea. Your head is starving for oil when this happens and eventually it will seize.

 

[mysta2]

It's white smoke and smells like...well burnt oil. The oil passages were completely blocked off upon inspection. In my experience, these 36o engines break slippers...slippers leave fragments...fragments get lodged....you get the idea. Your head is starving for oil when this happens and eventually it will seize.

You're describing exactly how Loudbike went down, fun fun fun.

anyway:

this one and...

(the journal surfaces feel very smooth)

...this one look like the cam wasn't seated properly or something because the wear is only on one side. That's not a shadow, that's how it actually looks, you can see it possibly even better in the top pic.

I guess this is an opportunity to try out one of my delrin slippers... I've got a couple still laying around. The ones that didn't go with my Georgia motor

You want one Kanticoy?

I'd be happy to give you one if you'd be willing to test it for me, I'd put one in if I had a motor running.

 

[mysta2]

oh, and anyone who knows anything about Delrin please jump in with your opinions... I want them. Weather you think it's a monumentally stupid idea or brilliant... as long as you can back up your view with experience I want to hear it.

 

[Kanticoy]

I'd be more than happy to test one kit. I don't know much about delrin other than the fact that I have seen the 350 aftermarket versions available on the net. As far as the tensile strength I'm sure that it's more than sufficient. Also the meltig point should also be more than enough. Really the only unknown factors in my head are the friction stability as far as wear goes with prolonged exposure to the chain. The good thing that I can envision is that delrin has a tendency to "melt" away rather than shave off in fragments like the factory version. I think that the shavings that come off from the stock ones are what ends up getting stuck in the oil passages, because when I ran wire down through the passages in the old head to clean out the obstruction, what was stuck in there was oil soaked plastic. I confirmed this by putting them in a test tube over a burner and watched them melt. There was some metal shavings in there too, but not near as much of that as the plastic. Th metal was probably part of the journal that got shaved off. Unforunately I feel like without cracking the bottom cases there is no way to ensure removal of all of the debris. I always wanted to have the knowledge and equipment to machine ou the head and valve cover where the journals are to seat a sealed bearing assembly that fits over the ends of the cam...that way the cam spins on a bearing instead of metal to metal. I'm sure youve thougt of the same thing. I'd love to see that come to fruition.

And to any other builders reading this, I wouldn't use rtv gasked maker (liguid gasket) on motor parts either. I'd cut them from copper or cork. You can't guarantee that the gasket won't squeeze into the inside of the mating surfaces and flake off into the motor causing the same oil passage clogging issues.

Sorry for rambling on about this brother, it is just so relevant to what IMO is the weak point in the cb360. Other than that it is a well designed motor.

 

[Swagger]

Delrin should work fine, better than stock for sure though I'm sure someone will point out that only compressed virgin ostrich nipples are the only proper piece to use and that we're all losers for even considering going against their sage wisdom.

 

[crazypj]

Pay very particular attention to the oil passages in the head of these bikes. They don't have cam bearings, they just rotate on the journals in the head and rely on oil lubrication to rotate freely. I always wished two things for these motors...that there was a way to install cam bearings, and (as you have fooled around with in the past) there was an aftermarket cam slipper.

The problem is the oil pressure regulator.
Honda used/use cams running directly in head for a number of years before 360 came along
If you ride at high rpm cylinder head oil starves. (CB350 does same thing but takes longer with plunger pump, its why they do end feed for them)
I had CJ250 destroy itself after about 180 miles of sustained 70~85 mph riding which is why I started looking into reasons
In Britain there was a company doing ball bearing conversions, I have one in my 391cc CJ250. (rockers still get damaged eventually)
I wouldn't have any problem using that head, I would 'polish' the bearings and 'destroy' Mr. Honda's precision machining though (to get some extra bearing clearance)
I found that opening up feed holes in crankcase (under bottom of cylinder) helps significantly.
I'm working on two different modifications to hopefully prevent it happening on my motors.
I like the look of delrin slippers, even bought a sheet to cut up but haven't had time to make one.
Wasnt sure about stability without spring steel backing though?
Are they CNC machined?

PJ

 

[mysta2]

...Wasnt sure about stability without spring steel backing though?
Are they CNC machined?...

Yes they are CNC machined to match the profile of the original, I started with exactly the stock size and shape and figured I could add or subtract material if they were too soft or stiff, but it worked out fairly perfect right out of the box. I have very little worry about them wearing prematurely as delrin is often used for just such an application(final drive chain tensioner)... my biggest concern is what the heat will do to it.