1972 CB350K cam shaft and side cover issues

Honda55

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Ok, so I think I'm nearing the finish line with my CB350 motor rebuild. I say 'think' because I've seemingly run into a problem with the cam shaft. I've got the cam shaft installed with the rockers properly positioned on both ends and I'm now trying to install the cylinder head side covers. But both side covers are a very tight - if not impossible - fit and trying to make the fit easier by turning the motor over isn't working, because the motor won't turn. It was turning up to the point that I installed the cam case and the cam sprocket. (I aligned the sprocket flat line with the LT on the alternator rotor before inserting the camshaft.)

Also, the rockers appear clean, with no pitting or great wear. Same with the cam shaft. The cam chain tensioner is off to allow more leeway with the chain.

My questions are: Why is it so hard to install the side covers? Should there be such resistance in turning the motor over at this point? Is there an ideal alignment for the cam shaft that allows the side covers to be more easily installed?

I've attached several photos and can share more if needed.

Any and all suggestions most welcome.
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Camshaft should be lobes down

crank may be jammed by excess chain at the bottom. Rotate backward and lift camshaft to unjam

you should time camshaft with covers on and rockers not installed

install rocker pins one side at a time once set
 
Camshaft should be lobes down - done

crank may be jammed by excess chain at the bottom. Rotate backward and lift camshaft to unjam - done

you should time camshaft with covers on and rockers not installed - tried this

install rocker pins one side at a time once set - tried this

And I've got the tensioner off.

Looking at the stacked pieces, I notice that the bottom housing the pistons has a small space. (see photo) I hesitate to lift this off and have to go through fitting the rings again. Motor turns over. Is this space likely to be closed when tightening the head bolts? Or, should I remove the cylinder to make sure its fully seated? (Banging with a soft mallet doesn't work.)
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The cylinder isn't seated. I suspect it's hung up on the dowels. Best course of action will be to disassemble the engine to get to those dowels and clean them up so they will slide in/out of the recesses they sit in.
You can try seating the cylinder by using a 2x4 place on top and smacked with a hammer BUT there's a chance of doing other damage plus wood chips falling into the engine.
 
I think you're right. At the very least, it will allay any doubts. I'll have at it and post the result. Thanks
 
Honda55 said:
I think you're right. At the very least, it will allay any doubts. I'll have at it and post the result. Thanks
Click to expand...

The very reason we always ask for pictures. A gap like that is the culprit, doesn't take much to remove all available slack from the cam chain.
 
When digging back into the engine be careful those little pieces that rest on the cam chain tensioner roller pin don't fall into the bottom end
 
Good point. I've kept these gremlins in mind. But a quick glance tells me they are still in place. Hope to have time Tuesday to tear it down to the pistons.
 
You need to stack some washers or a couple larger nuts and some washers onto at least two studs. I usually do 4. Tighten down and you will be able to assemble.

Make sure you have the crankshaft in the correct position and the pin on the cam pointing up for the correct valve timing. I then hold the cam up while rolling the rotor approx 9o degrees counterclockwise.

I have also found putting a light chamfer on the lower edge of the cam box and put assembly lube onto the rocker arm shafts aids assembly.
 
What O-RINGS did you use at the bottom of the cylinder Jugs.
99.( % of the ones that comes with Gaskets Sets are the wrong size.
Honda OEM which are still available every day from any Honda Dealer are the ONLY ones I've ever seen that fit.
The ones that comes with the Gasket Sets will not allow the Cylinder Jugs to seat and will cause that gap.
 
O rings may indeed be the problem. See photos below. The rings sit above the rim. Head bolts might compress them. But, unless someone suggests this is not a good idea, I'm going to try to press them in myself to see if they will sit properly. I still have the old ones somewhere. These came with the new gasket set. Hopefully, they are not, as Yendor suggests, the wrong size. We'll see. Once I do this and get all the heads on I'll stack some washers and tighten, as Boomer343 suggests.

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Yes. Replaced thje new ones with the still-good-to-go old ones. Everything seats properly now as seen in photos. Thanks all!
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...I may have spoken too soon. The cam covers fit nicely with the rotor at LT and the cam sprocket level. But so with the the rockers. When the rotor is turned the chain stops moving as though it's jammed. Jams totally with all rockers in. I've tried with only two rockers, but the cam shaft still jams, as seen in the video below.

(Used bolts to temporarily hold down cases as suggested by Boomer343.)

It may be that the chain is doubled or caught up somehow in the crankshaft way below. I'm going to try jimmying things about to see if it loosens up somewhat. Will post the outcome regardless.

[video]https://studio.youtube.com/video/aX0gXhvh-mo/edit/basic[/video]
 
How many times have we seen the SAME THING the Gasket Sets come with Cylinder Base O-Rings that is an Incorrect Diameter.
Close but NO CIGAR
 
Honda55 said:
...I may have spoken too soon. The cam covers fit nicely with the rotor at LT and the cam sprocket level. But so with the the rockers. When the rotor is turned the chain stops moving as though it's jammed. Jams totally with all rockers in. I've tried with only two rockers, but the cam shaft still jams, as seen in the video below.

(Used bolts to temporarily hold down cases as suggested by Boomer343.)

It may be that the chain is doubled or caught up somehow in the crankshaft way below. I'm going to try jimmying things about to see if it loosens up somewhat. Will post the outcome regardless.

[video]https://studio.youtube.com/video/aX0gXhvh-mo/edit/basic[/video]
Click to expand...

YouTube video can't be viewed without logging in.
 
How does it feel when it reaches resistance? It looks like you're turning it with only one cam bearing on the cam, I can see the other end of the cam wiggling
 
Feels like it's binding somewhere. Oddly, after I align the LT and the flat line and install the rockers, the line shifts even though the LT remains the same. Could this indicate the chain is coming off on the cam shaft below?
 
It's really hard to tell without being there. Unless the cam chain is really old and stretched, it's unlikely it has the amount of slack in it that would be necessary to double up anywhere, whether under the crankshaft sprocket or otherwise. I haven't rebuilt a 350 top end in years so I'm not the best guy to help, but the cam timing should not vary because you put the rockers in. It only takes a slip of one tooth on the crankshaft while the cam bearings are off and you're putting the rockers in for the line on the cam sprocket to be off
 
It's not the chain, which is new and exactly the same size as the old one. I'm going to have to fool with it some more. Perhaps in the morning when it's warmer, it being fall and all.
 
Does it help to put the bike in neutral?

late edit: It maybe you routed the chain incorrectly through the tensioner rollers?
 
My approach to problems of this nature is to take things apart to figure out what I've done wrong. I've tried the other approach of making things work even if they fought me the entire time and it's usually ended up costing me.
 
A few suggestions:

- make sure your rocker pins are oriented straight up, this is the point of maximum clearance. If they’re too far down, you’ll need to depress the valve spring to turn the camshaft. Looking at the YouTube video it doesn’t seem they are.
- is your cam chain tensioner installed already? If so, can you turn the camshaft all the way around without it installed?
- when the camshaft lobes hit the rockers, they can be very difficult to turn, don’t be too afraid to give it a little, but by no means should you be exerting yourself to move the thing.
- those o-rings that come in the gasket kit are ridiculous. I can’t believe so many of them don’t fit.
- to what LDR said, a lot of thirty minute jobs have been turned into two hour jobs when someone tried to make it a ten minute job [emoji2371]


Ed
1972 Honda CL350
 
Was too busy to work on it today. But I'll take up all these sugestions, ie:

I'll try putting it in neutral. Hadn't thought of that.

As for the other suggestions:
- make sure your rocker pins are oriented straight up, this is the point of maximum clearance. If they’re too far down, you’ll need to depress the valve spring to turn the camshaft. Looking at the YouTube video it doesn’t seem they are. WILL TRY THIS
- is your cam chain tensioner installed already? If so, can you turn the camshaft all the way around without it installed? NOT INSTALLED YET
- when the camshaft lobes hit the rockers, they can be very difficult to turn, don’t be too afraid to give it a little, but by no means should you be exerting yourself to move the thing. WILL GIVE IT A LITTLE MORE PRESSURE, THOUGH NOT TOO MUCH. DON'T WANT TO JAM IT UP
- those o-rings that come in the gasket kit are ridiculous. I can’t believe so many of them don’t fit. TRUE THIS
- do what LDR said, a lot of thirty minute jobs have been turned into two hour jobs when THIS WILL BE MY LAST RESORT. HOPEFULLY NOT NEEDED.

Later.
 
Honda55 said:
- when the camshaft lobes hit the rockers, they can be very difficult to turn, don’t be too afraid to give it a little, but by no means should you be exerting yourself to move the thing. WILL GIVE IT A LITTLE MORE PRESSURE, THOUGH NOT TOO MUCH. DON'T WANT TO JAM IT UP
Click to expand...

Just to be clear: when rotating the engine enough to begin opening valves (obviously, with the rocker arms in place), you must have both cam bearings in place. Do not attempt to rotate the engine and start opening valves with only one cam bearing.
 
MrPepper said:
Does it help to put the bike in neutral?

late edit: It maybe you routed the chain incorrectly through the tensioner rollers?
Click to expand...

The chain is routed correctly through the tensioner. But on the note of making sure it’s a neutral, and at the risk of revealing myself to be much of a newbie, how do I ensure the motor is in neutral?


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The output shaft/front sprocket will turn w/o trying to turn the engine over. If it's in a gear then the engine/crankshaft will turn with the front sprocket
 
There was a sound in your video, and I couldn't figure out what it was at the time so that's why I posted about being in gear. After thinking more about it, it actually sounds like your starter motor is turning over when you rotate the engine

and as longdistancerider says, if your output shaft doesn't turn unless the engine is turning then you're in gear. To put in neutral, you need to shift to neutral. Is your shift shaft still installed? I would assume so since your clutch is all together. Might not be the issue. Might be the starter motor?
 
I’m going to take the clutch mechanism off as well as the oil drain - all of the right side - so I can see the shifting more clearly. I do believe it’s in gear so just want to make sure that I’m in neutral. Thanks for all the above advice.


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Yes the shift rod moves without moving the crankshaft so it must be in neutral. Now at least. Before putting the right side back on I’m going to see if I can get the rockers all positioned.


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What's the history on the engine?
the engine turning the starter motor is interesting. I don't ever recall hearing it when I turn the flywheel so your starter clutch rollers might be jammed on the idle gear surface?

2 ways to check are remove the flywheel or remove the starter motor and chain and check the gear spins in 1 direction only
 
I don't think the starter motor is the problem. The gear does spin in only one direction. I know this from having installed both this and the rotor and the starter.

To recap:
- it's in neutral
- the cam chain tensioner is off
- the tensioner cam chain is correctly installed
- the rotor is correctly installed and at LT
- the cam sprocket is level
- the rockers are, I believe, are as they were before disassembly
- the cam covers have no burrs or other impediments preventing proper seating
- the clutch is off the motor
- the crankshaft has turned nicely to this point and continues to turn until I try putting the cam covers on

The only thing I can think of is perhaps the rotor needs to be on the compression stroke. Yes?

Barring this, I'm going to reach out to local vintage Honda mechanics and see if they can resolve this in person. Mind you, I'm in no hurry since my frame is being modified and a new seat pan being added. Meaning I've missed this riding season.
 
Try this. Remove the rockers and assemble the cam, end covers/caps, sprocket and chain as it should be. Try turning the engine over. Moves freely?
Has any work been done to the head?
 
Works fine without the rockers and with the cam covers, sprocket chain, and all of that. No works been done to the top end apart from me taking it apart from the state it was in with the OP. It was working fine for several years then I had that bearing problem which sent me down this rabbit hole. The bearing problem is fixed. So that’s not the issue. I contacted some local mechanics And perhaps they can help in person.


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Hey there, just wanted to follow up to see if you were able to get an answer on this issue. I'm having nearly the exact same issue with mine: Everything operates smoothly until I get the rockers on and try to install the covers.
 
Jayhawk77 said:
Hey there, just wanted to follow up to see if you were able to get an answer on this issue. I'm having nearly the exact same issue with mine: Everything operates smoothly until I get the rockers on and try to install the covers.
Click to expand...

We try to "close out" threads with [SOLVED] when possible, but we haven't heard back from him in about a month as you can see. Hopefully we will soon, I hate unresolved situations. You should start a thread for your rebuild issues, lots of 350 owners here including LDR
 
Hi all. I haven’t been able to resolve my issue. I’ve been waiting for some time for mechanics to drop by. But between covered house renovations and restoration of some furniture, I’ve been short on time. I’d suggest if needed that this discussion be closed off. I may not resolve my issue. Until the new year. Thanks much.


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Honda55 said:
Hi all. I haven’t been able to resolve my issue. I’ve been waiting for some time for mechanics to drop by. But between covered house renovations and restoration of some furniture, I’ve been short on time. I’d suggest if needed that this discussion be closed off. I may not resolve my issue. Until the new year. Thanks much.


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Click to expand...

No worries, the thread will keep and since you haven't resolved yours either, once both of them are we'll close them out.
 
In reference to longdistancerider comment on stuck valve

i did encounter this when a good head was fully assembled and went through aggressive cleaning process and the valve was binding due to lack of lubrication

the fix was to disassemble the head and inspect (it's already apart) and lube and reassemble. Replace anything worn or out of spec, of course
 
So, after a long winter and now heading into spring, I managed - with the help of a local mechanic - to resolve the rocker / cam cover issue. The problem was that the engine wasn't properly at top dead centre (TDC), which meant the rocker arm wasn't where it should have been. With the engine at TDC, getting the cam covers completely on was also made easier because there were two of us - the mechanic and me - working on either side.

You see the result in the attached photos.

It was a simple job after all, but it took some time, several months in fact, to resolve this. All of the great suggestions/contributions above certainly helped and likely made finally resolving this vexing problem not only easier but possible.

Now, with this out of the way and the warmer weather all but here, I can get back to putting everything together again. (I did have the frame powder coated semi-gloss black and I'll soon install new tracker-style handlebars. I'm also having a custom brat seat made. I'll happily share these developments in another thread.)

A belated thanks for all the input on this.

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