What is your secret technique 77 cam chain adjuster cover?

[XStretchified650]

I have been putting on the break-in miles on a complete restoration and I have a frustrating issue with the cam chain adjuster cover. I am looking for a helpful hint on how to snug down the adjuster cover without it making further adjustments to the cam chain tension.
The 77 adjuster does not have a locknut. I can set the tension for the correct plunger position just fine. But when I install the cover and am getting it close to full seating it rotates the tensioner bolt and I lose the proper setting. The cam chain gets over tightened, I can't see it but I know the bolt has rotated plenty.

I use a torque wrench but the bolt begins to rotate when I am still just able to turn it with my fingers. The cover does not leak. The O-ring looks fine and it protrudes nicely from the seat, I'll try a new one anyway. Has anybody solved this with a new O-ring?

I have had the bike for decades and in it's prior life I did not have this problem.

Did I tell you there is no locknut?

...XStretchified

 

[weekendrider]

When you had it apart did you push the plunger tight against the tensioner guide taking note of the position of the end of the plunger in relation to the end of the tensioner guide.
Is it flush or recessed?
When adjusting the tensioner guide can you still screw it in with your fingers?
It seems to me the resistance from the tension would keep it from turning but if it does. . . it does. Can you mark the amount of turns and under set it or when taking the cap off does the it back out.
Is there grit in the threads that is causing it to hang up OR is the adjuster actually bottoming out in/on the cap and it will have to go in after it hits the cap?
Seems there was a post about that. Where the end of the cap was broken by the force of trying to screw it in after the cap had bottomed out.

 

[5twins]

You have the type D tensioner, not one of Yamaha's better ideas in my opinion, for the very reason you state. All the other tensioner assemblies used had a lock nut. For some unknown reason, Yamaha decided to eliminate it on the type D assembly. Apparently, like you, they discovered the problem they created, and returned to using a lock nut on the next assembly, the type E .....

My "fix" is to upgrade the tensioner to the E type. The only difference between the D and E type is a slightly longer plunger and the addition of the lock nut. All you need do is swap those two parts onto/into your current set-up .....

These adjuster assemblies can be had for about $20 from eBay, a small price to pay for what I consider a very nice and needed upgrade.

 

[XStretchified650]

When you had it apart did you push the plunger tight against the tensioner guide taking note of the position of the end of the plunger in relation to the end of the tensioner guide. I am not sure if I understand your question exactly but adjusting the guide to set the plunger position works fine and it appears that there is sufficient room in the within the cap to cover these.
Is it flush or recessed? I set it a breath recessed.
When adjusting the tensioner guide can you still screw it in with your fingers? No, its has tension and I use a wrench. But that tension appears to be insufficient in staying put when I seat the cap.
It seems to me the resistance from the tension would keep it from turning but if it does. . . it does. Can you mark the amount of turns and under set it or when taking the cap off does the it back out. I've tried under setting it to compensate but I have no idea if it is ending up in the right spot. If I set it to torque and then remove the cover sometimes the guide will spin out also..but not always.
Is there grit in the threads that is causing it to hang up OR is the adjuster actually bottoming out in/on the cap and it will have to go in after it hits the cap? No grittiness in either the guide or the cap...clean as a whistle...and possibly part of the problem...Has the spring tension gone soft?
Seems there was a post about that. Where the end of the cap was broken by the force of trying to screw it in after the cap had bottomed out. I don't think that the cap is bottoming....no marks in there and I measured the protruding guide vs the cavity. It is damn close but I think that there is room. That is worth double checking. If it is bottoming it may be cured by a new O-ring.

XStretchified

 

[XStretchified650]

5twins...

I see your point in making a change to the improved model E adjuster. That would be a sure fix. Maybe I will end up there but I want to try and figure out this model D unit too.

What do you guys think about applying some thread sealing tape on the last few guide threads to improve the stiction of the guide to the housing?

Don't all engine builders use plumbing supplies?

...XStretchified

 

[5twins]

You've figured the D type out - it doesn't work right, lol. I don't recall the one on my '78 turning with the acorn nut, but how was I to know? How could I be sure it wasn't? There was no way to tell for sure so I upgraded.

 

[XStretchified650]

Okay...."Uncle"....I concede...I will look to Ebay and replace the little bastard.

But for the 300 miler I have planned for this weekend I will rely on the ring-of-teflon-internal-stiction-improver-device method. It's sorta like a lock nut....

....XStretchified

 

[5twins]

As I said, most of the parts between the two types are the same, even the housings. If you end up with a complete unit from eBay, no need to pull your housing off the motor, just swap the differing parts into it. The head on the E type plunger is longer. That makes the whole plunger longer. That means that at proper adjustment, the adjuster screw will stick out of the housing more. That provides the needed room for the lock nut and its copper sealing washer.

 

[Brian902]

Another method.

Adjust to proper tension making note of position, now turn it out say 6 turns, apply Blue Locktite to threads closest to the mounting plate, turn it back in 6 turns, let sit overnight, now add the cap.

Blue locktite is not that strong, but should give you resistance for future adjustments.