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Sensei
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Did you rotate the crank to a position where neither exhaust cam lobe had pressure on it and remove the cam chain tensioner before removing the tach drive box? .......
This would have required removal of the exhaust cam tappet cover and the round alternator cover as well.....Both of which will have to come off to reset the exhaust valve clearances anyway....
IF you didn't, it is possible you damaged the bearing surfaces .... If you didn't recheck/reset valve clearances afterwards (engine STONE cold), you may have bent a valve...

Did you "jigsaw-puzzle" all the rag bits to prove that ALL had been removed before firing it up?...... I would have pulled the engine and disassembled down to the head gasket right then.......
 

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Man, I wish you had mentioned the oil leak and your plan to change the gasket before you did it... Steve's concern, of course, about the potential tach side cam bearing damage and tach drive alignment is a very valid one. At this point Ethan, you might be better served by pulling the engine and taking the head off to be sure of the situation
 

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Discussion Starter #83
Yeesh, I wish I had mentioned something too. I just assumed that I could pull that cover. Steve, I appreciate your tips. Unfortunately, I think the answer to every question is no. I did reset valve clearances afterwards, but the engine was not stone-cold.

Sounds like yes, I'm going to need to pull the engine again. Not what I had in mind, of course. Luckily I don't think it will take me as long the second time around, though.

Not sure if this is something I can get to this summer, because I just bought a house... finally I will have access to a garage though! I will document my progress in this.
 

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Discussion Starter #84
It's been a long time, but after my move I'm finally getting this project back up and running. Now have a garage to work in - dream come true.

The exhaust cam basically wouldn't rotate. Really stiff to turn the engine over. I am suspecting something related to the right exhaust valve... After pulling the head, I manually rotated the cam. Rotating the exhaust cam against the left valve, I felt the torsion bar working properly and springing the cam back when let go. On the right side, that springiness was absent. The cam stuck.
Pulled the exhaust cam out and the right exhaust valve.
Cam bearings look good. I don't think I ran the engine long enough to cause any damage. Also the cam spins freely when cams are not pushing on the valves.
With the right exhaust valve out, though, I can't see if it's bent or not. I'm attaching a picture of the valve. I laid it on my straightedge and can't see any obvious bends...
Before I removed the valve, I did an acetone test on both exhaust valves. The right passed, the left didn't. I had my valves professionally lapped and sealed before so that is strange.
I put the right exhaust valve into the head and manually rotated it (like if I was lapping), and as far as I can tell, no hang-ups or rough patches....


Is there anything else I should be looking for?
306178
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The stem looks like it's running too tight a clearance. You might contact Chris about this since he did the head.
 

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Discussion Starter #86
The stem looks like it's running too tight a clearance. You might contact Chris about this since he did the head.
Good point. I've contacted him and will report what he says. At the very least I'll just bring my head to him to get another tune up. Luckily I have plenty of extra valves...
 

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Discussion Starter #87
Contacted Chris, and decided to just give him my the head and check it out. Glad I did.

No bent valves 😅. But he found debris in both exhaust valves, causing leaks.

307654


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Discussion Starter #88
He ended up just doing a full valve job on all valve seats, and the head looks great! Chris only charged me $80 for everything, including figuring out the issue, cutting the seats lapping all the valves, and finding a leak in one of my air intake "boots."

Can't recommend more Chris Schumann and his Schumann Motor Works.

Will update on progress as the motor goes back together with EXTREME care. No rags in any intakes.

307656


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Discussion Starter #89
Assembling the engine. New head gasket fits but not much room on the right cylinder. Doesn’t overhang the cylinder opening so as far as I know I’m OK. Yell at me if you disagree.

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If it's the clearance around the top of the cylinder you're concerned about, it's fine. Remember, the upper part of the piston, where the rings are, is a bit smaller and as long as the head gasket fire ring is slightly larger than the cylinder diameter, it's normal. Stock head gaskets are designed to work with up to S-4 pistons (4th over, 1.00mm oversize)
 

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Discussion Starter #92
Thanks Tom. I think the head gasket fire ring is just very slightly larger than the cylinder. The piston is only .50mm oversize after all, and I got a new OEM gasket.

In other news, I figured out why my bike was so hard to turn over after changing the front right cam bearing cap gasket (see post #80 above for a refresher). Apparently the gasket material I was using was thinner than the OEM gasket on the bike, and when I put the new gasket on the cam bearing cap, the side clearance of the cam shaft became too tight. Luckily, it was actually too tight to run, and I came out unscathed. There were shims on both ends of the cam, and after taking those off, I now am back within spec. First time I've learned the "true" importance of gasket thickness.

Now both camshafts rotate freely and I'm ready for the next step.

Next, reuniting the bottom and fresh top end of this engine.
 

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Discussion Starter #93
Engine assembled - head on, timed, cam chain staked, tensioner in, a couple of rotations to make sure everything feels smooth.

Now I've gone to adjust valve clearance and I have no clearance to adjust with! I'm perplexed. I turn the engine to the LT mark with timing marks on cam lined up, and turning the tappet adjuster, I can't seem to find any clearance within the range of either intake or exhaust on the left side. Rotate the rotor 180 degrees and same thing on the right. Am I missing something? Is this a result of the valve job?

I've sent Chris who did the work a message, but I'm just hoping that I don't have to disassemble again, or get a new head, god forbid...
 

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Cam and rockers done by Delta Cam? There's been some issues there lately.
 

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Discussion Starter #95
No, actually cam and rocker from parts engines.

The only big change is a valve job from Chris Schumann. I might need to break the cam chain once more and get the tips of the valves ground down slightly.
 

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Discussion Starter #97
Drat! Well, luckily Chris is local. He’s happy to do it for free - just a bummer because I’ve put the engine together.

I don’t want to cut any corners, but while I order another cam link, does this mean I need to buy a new head gasket, or can I reuse the brand new one that I just compressed when tightening the head?
 

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You'll probably get away with reusing the gasket BUT what if it doesn't seal properly? Do you really want that much practice pulling the top end apart to save a few dollars?
 
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