Cam shaft bushes or bearings?

[scharny61]

I need to replace the camshaft in my 80 special (Oceania model SF) due to wear. I've got a replacement on ebay. My original appears to have bushes inside but the replacement has nothing. Question - do I get new bushes or go for bearings? Would have thought bearings would be preferrable. Also, my manual shows bearings and oil seals.
Can't recall the one with bushes having any oil seals.

 

[I am Carbon]

i have an 80 sg us model. there are no bushings on the cam. there are bearings on the cam. two on each end. how ever there are bushings on the inside of the cam for the rod that goes through the cam for the points advance rod. which I'm sure that your oceana model has. the us 80sg has TCI so there are no bushings in my cam.I think you can upgrade to bearings on the inside if you want to.

 

[5twins]

There's no seal IN the camshaft although Yamaha does call the outer bushing a "SEAL,LABYRINTH". It's really just a bushing with grease retaining grooves cut into it's I.D. In this application, bushings work just fine. The advance rod doesn't turn much, probably less than 1/4 turn, from full retard to full advance and back again. It doesn't spin round and round in there like, say, a wheel on an axle or a tranny shaft.

 

[scharny61]

Oh, I see. I imagined that the shaft or advance rod turned at the same speed as the cam itself. I see what you. So, putting the bearings in on their own is OK? I've ordered the bearings so I might as well give them a go.
Thanks to both of you for your help.

 

[5twins]

The advance rod turns WITH the cam, it doesn't spin separately inside it. It just rotates back and forth that 1/4 turn or so in there. I saw that roller bearing upgrade but in this application, I feel it's overkill. If you keep the bushings greased, they may never wear out. But there's the rub, nobody really ever did grease them, lol.

 

[scharny61]

Can't imagine myself greasing something hidden like that. Out of sight etc. thanks 5twins.

 

[XSLeo]

I think the first year or two of the 650's they used the needle bearings in the cam, they swapped to bushings to save money, but found the bushing work just as well.
Lubing the bushings isn't something you do a lot. once in a year or two should be plenty. Easy to do just pull the advance rod, clean out old grease, put in new and put the rod back in.
Leo

 

[5twins]

Actually, every 5 or 6 years is probably sufficient. Consider the fact that the originals that were lubed during assembly at the factory (and usually never again since) are just now starting to bind up some 30+ years later.

 

[Classic]

I think every 25k is probably good. Whenever it's time to change the points and/or advance springs.

 

[scharny61]

Actually, every 5 or 6 years is probably sufficient. Consider the fact that the originals that were lubed during assembly at the factory (and usually never again since) are just now starting to bind up some 30+ years later.

I wonder if the Japs thought the bikes would even be on the road 30 years later. Wouldn't imagine thats good for business when they want to sell you more bikes.

 

[xsfanman]

I have read many posts on this site, RE:top end noise after the engine heats up.
On my 79 special it was the ATU bushings being worn. The shaft mooved about 2 mm side to side and 1.5mm up and down. That made noises like tappets or loose chain .It also made the idle erratic.





79 Special restored to original except a 2 into one from mikes

 

[scharny61]

I have read many posts on this site, RE:top end noise after the engine heats up.
On my 79 special it was the ATU bushings being worn. The shaft mooved about 2 mm side to side and 1.5mm up and down. That made noises like tappets or loose chain .It also made the idle erratic.




79 Special restored to original except a 2 into one from mikes

Thanks for that, I've gone with the roller bearings only at this stage and all seems OK sofar. I've only just started it for the first time though after a complete rebuild.
cheers

 

[Marvelicious]

I wonder if the Japs thought the bikes would even be on the road 30 years later. Wouldn't imagine thats good for business when they want to sell you more bikes.

Thats why Japan kind of cleaned house on the vehicle market for quite a while there. The American car companies think that way; the Japanese just went ahead and built the best vehicle they could for the money, without the planned obsolescence. They aren't quite as overbuilt as they used to be: they taught us how to build efficient factories and we taught them how to only build as good as necessary.

 

[scharny61]

very true. I admire their ingenuity.

 

[cmyoch]

Dumb question, does the roller bearing replace the labrynth seal only? Do you still use the inner brass seal?