Cam chain adjustment issues

[oberling]

When I put my '80 away for the season, it had a lot of valve train noise. Today I decided to try to diagnose it. When I adjusted my cam chain tensioner last, I set it so that the rod was flush with the adjustment nut on a non running engine. I did this again, but the rattle didn't go away, and it seemed like the rod was moving back and forth a lot. I heard some other people say that you should adjust it on a running engine by turning it in until it has stopped moving back and forth, and then backing off half a turn or so. I tried using this method and I had to turn the adjustment nut in really far. I stopped when the rod appeared to be only moving back and forth a few mm, and the engine rattled a lot less. The problem is that the rod is now sticking out a lot, maybe 3 or 4 mm. Most places I see only suggest that it should be roughly flush.

I know the tensioner itself is pretty worn since I had the top end apart last spring (should have replaced it) however I thought this adjustment system with the rod was supposed to compensate for wear. Could my spring be bad? Do you think it's even safe to run the engine?

 

[bosco659]

If the rod is sticking out that far you may be missing the tensioner damper. Remove the tensioner assembly and have a look (damper is the copper washer behind the spring - yours may be black).

 

[oberling]

Looks like that's my problem. Must have lost it when I had the engine apart and not noticed. Thanks a bunch my guy.

 

[Kevin Werner]

Wow.... Nice catch...

 

[bosco659]

Looks like that's my problem. Must have lost it when I had the engine apart and not noticed. Thanks a bunch my guy.
View attachment 209140

You should be able to buy the damper from Yamaha.

 

[5twins]

Unfortunately no, not the copper washer. Only the thicker rubber/metal one that was used on the later models is available. But it only works properly (allows setting to the manual spec) with the later, shorter 59mm adjuster screw. Your '80 should have the older 60mm long adjuster screw, unless it's been changed .....

 

[oberling]

Does anyone know how thick that copper washer is? I put a hardware store washer in it, but it's too thin, and two of them together are too thick. I eyeballed the difference with one washer and it sounds so much better. That washer has been missing for the lionshare of the miles I have put on the bike. My pipes are pretty loud so it's been easy to ignore the noise, but it has always more or less sounded like an egg beater at idle. I heard people say this engine had a noisy valve train so I sort of assumed that was how it was supposed to sound.

Thanks again for helping me catch that, bosco!

 

[bosco659]

The copper washer would be 2mm thick. Follow the info provided by 5T and you’ll be good. I was just relaying intel provided to me from 5T last month, that helped fix my problem.

 

[Jan_P]

Thinking out loud redneck style
Option 1 no washer sticking out a bit -- but if the dome nut has room inside which I believe it has and can adjust so it is
quiet ?? it is not perfect since the chain can rattle

Option 2 another washer fex aluminum if not copper is available

I did try some kind of hydraulic dampers with sound vise good results don't remember if it was that one
https://thexscafedotcom.wordpress.com/2011/01/10/61/

I don't have it in now .not sure about the bearing loads.

 

[5twins]

You can't adjust the clicking noise away if the damper washer is missing. The head of the spring-loaded plunger strikes the back of the adjuster screw during operation and that's what causes the clicking. You need a soft washer of some sort to soften that strike or it clicks.

 

[bosco659]

On my ‘79 it was noisy with the damper missing, even with the tensioner tight.

The hydraulic damper is interesting. Never heard of that before. Might search for interests sake.

 

[Jan_P]

Well perhaps Unknown in the States

Some info there " Auf Deutsch " some online translation does it. ( Google translate )

https://www.twins-inn.com/epages/78...ize=10&PagerSize=5&SearchString=kettenspanner

https://www.twins-inn.com/WebRoot/Store10/Shops/78210236/MediaGallery/Einbau_HSKS.pdf

I had a noisy chain and installed one of those or something like that .and it improved .If I recall right it was easy to install. : I got the impression right or wrong that it gave higher force on the chain.
And since I like Stock I now have a stock tensioner