Cam chain adjustment on 1979 GS750?

[andrewm]

I've looked around on here but couldn't find any info so hopefully i'm not repeating a thread.

I've been noticing some higher pitched noise over my engine when driving around recently. Kind of pingy/rattley but it stays in time with the motor so I guessed it was the cam chain or loose valves?

Took the valve cover off today to take a look and the valve chain seems loose. well when your rotate the engine around it's loose at certain points and tight at others. So my question is since the cam chain adjustors on these bikes is automatic is there something wrong with mine or can I make an adjustment that would tighten the cam chain?

I'm also going to check my valve clearances tomorrow when the engine has cooled but a friend who's owned / worked on bikes for many years seemed to feel it was the cam chain slack that was causing the noise as well.

Any ideas or advice is greatly appreciated.

Thanks!
Andrew

 

[koolaid_kid]

It would behoove you to rebuild the cam chain tensioner using bwringer's excellent guide: http://bwringer.com/gs/camchaintens.html
It is not too expensive or difficult to do once you remove the carbs. And it is not at all unusual for this to be necessary on a 30+ year old bike.
Best of luck.

 

[Steve]

My wife's bike has been running just fine for years. In the process of replacing a missing exhaust bolt, I ended up replacing a cylinder liner.
(That story will be told in another thread, sometime soon.)

While things are apart, I tend to look at everything. The carbs got dipped (again), cleaned and painted (again) and the intake boot o-rings replaced (again). This was all done 5 years ago, but I figured "why not?". I also took the cam chain tensioner out for examination and saw a sizeable dimple in the tensioner rod that was preventing it from doing its job. I got a picture of it, but don't have it posted to Photobucket yet (I'll do that tonight).

Check your tensioner to make sure it's right. BassCliff has a link on his site to bwringer's write-up on how to rebuild the tensioner.

.

 

[andrewm]

Thanks guys, have downloaded the rebuild pdf. i'll give it a go.

Thanks!
Andrew

 

[BassCliff]

Hi,

In addition to Mr. bwringer's fine tutorial, here are some more tips from my little website.

Cam Chain Tensioner Repair

Reset Cam Chain Tensioner


Thank you for your indulgence,

BassCliff

 

[andrewm]

update

update

so finally got around to taking my cam chain adjustor out. strange thing was when I went to tighten the lockscrew it was already tightened as far as it would go thus making me think it wasn't even ever really working even though i rode it for a season with no real issues until the start of this season. also that could have caused the scoring in photos 3 & 4.

photo 1 - top of pushrod some slight scoring is this normal or would you need this to be perfectly smooth?

photo 2 - there is a very very slight depression on the angled part of the pushrod, would sand down if this was the only problem.

photo 3 & 4 - is that groove supposed to be in the push rod? I'm pretty sure it's not but couldn't really tell from the photos in bwringers rebuild guide, there looks like it might be there in one of his photos.

i'll probably try to get a new pushrod from the dealership. i'm waiting on a new spring anyways so haven't gone and picked up my parts that have come in. any input is appreciated. thank you for your time!