Cam chain tensioner rod damper

[Grinder]

I bought the damper(18-0873) from Mike's awhile back and decided to finally install it today. When I pulled out the old rod assembly I had no damper at all. The motor has never been apart and I am the original owner so it came from the factory that way. The Yamaha parts list shows a damper for my bike (77D) though. Was this a mid year add on or service bulletin fix or ???

The rod on my bike always had to be out past the nut for it to be quiet. Now with the damper the rod is just about flush with the required movement and is quieter as well. From previous posts it looks like some bikes had a copper washer damper also. Anybody know what the story on this is??

 

[5twins]

I tried to figure this out but couldn't get the complete story. I know a copper damper washer was used up until sometime in the early '80s, then the thicker rubber/metal one was introduced. I know the damper assembly was changed several times during the production run. Early versions had a lock nut on the adjuster screw, around '78 they eliminated that and just used the cap to lock it in place. Then they went back to using a lock nut on later models - I'm thinking the "no lock nut" idea didn't work too well.

I'm surprised adding that newer thicker washer to your '77 allowed the rod to adjust correctly near flush with the screw. I put one in my '78 in place of the thinner stock copper washer and then the rod wouldn't come out far enough to be flush. Needless to say, it was a pain to adjust that way because I couldn't observe the rod movement. I "fixed" it by substituting the rod, spring, screw, and lock nut from a later model. Now I can see the rod end for adjusting purposes and also gained the lock nut feature.

 

[Grinder]

Maybe the spring on mine is a little weak or something, but it worked out good with the damper in place. I just can't figure out why there was no damper on mine at all. That was the first time that assembly has been out since Yamaha installed it, so I know nothing was ever lost or not reinstalled by a PO. It doesn't seem like an item that would break/wear out and drop down into the crankcase if that's even possible. My 77 just has the cap to lock it down also.

 

[5twins]

You're not the 1st to report the washer missing. Factory mistake during assembly I'm guessing. Maybe yours was a Monday morning or Friday afternoon build, lol. After looking it up, I see '76-'78 and some '79s had no lock nut. I never had any problems setting the tension but always wondered if tightening the cap was changing my adjustment on me (turning the adjuster screw).

 

[Grinder]

I often wondered if the lock cap was changing the adjustment too, but I can turn it on by hand almost all the way on so it's just that last bit of tightening that would change things but it wouldn't be much. Whether the adjustment stays where you put it is a whole other story without the locknut. My bike has lasted 33yrs so far so they must have done something right. Maybe a Monday afternoon bike!! Thanks for the info 5twins.

 

[xjwmx]

To me it seems like the actual position of the adj screw vs some ideal position is so indeterminable that an incidental half a turn as your were cranking down the cap is as likely to help it as hurt it, if it makes any difference to it at all.

 

[XSLeo]

I have a 75 adjuster and an 82 adjuster. The adjuster screw part and the plunger part are a set. You cant use the 75 plunger in the 82 screw. If you slip them together with out the spring, the plunger comes out by about 1/16 inch past the screw on the 75 and about 3/16inch on the 82. If you put them togther with the wrong parts, one way the plunger is back inside the screw by about a 1/2 inch, the other it sticks out by about a 1/2 inch.
Other years may fit a bit differently. So if you add the damper check to see if your plunger still comes out past the screw.
On some there is room for the thick damper, others only the copper washer.
Just be aware there are differences and you might have to make allowances on the adjuster.

 

[XSLeo]

Heres a couple pics of what I have. The top one is the 82 in each pic. One shows the plunger sticking out when together. The 82 has the damper in place.