chris c Posted November 8, 2008 Share Posted November 8, 2008 I just got a 1980 yamaha xs850 and it makes a valve trane rattle it has 30,000 miles on it and I am unaware of the service history. I changed the oil with the proper weight and it still does it. Do the valves have to be adjusted on this model? Maybe the timing chain? it kinda sounds like a chain but it doesnt skip time or anything fires right up on one kick. runs great besides that high pitch noise. any help would be much appreciated chris Link to comment Share on other sites More sharing options...
Cy Welch Posted November 8, 2008 Share Posted November 8, 2008 I just got a 1980 yamaha xs850 and it makes a valve trane rattle it has 30,000 miles on it and I am unaware of the service history. I changed the oil with the proper weight and it still does it. Do the valves have to be adjusted on this model? Maybe the timing chain? it kinda sounds like a chain but it doesnt skip time or anything fires right up on one kick. runs great besides that high pitch noise. any help would be much appreciated chris If it's like the 1100 (which I hear it is) they do need to be adjusted. Also it takes a special tool and shims to adjust the valves. Link to comment Share on other sites More sharing options...
JimR Posted November 8, 2008 Share Posted November 8, 2008 If it's like the 1100 (which I hear it is) they do need to be adjusted. Also it takes a special tool and shims to adjust the valves. Yes they are bucket & shim system and should be adjusted at 10,000 miles (Yamaha say 6000 but that is to short a time). But from experence the noise you have sounds like it could be a stuck cam chain tensioner (dead easy to fix), basically remove the tensioner from the l/h side of the cylinder undo the lock nut and adjuster bolt (care to be taken as the plunger will fly out of the housing). On the plunger there may be burs and or dents where the bolt has been over tightened, clean these off and reassemble the adjuster unit with the plunger pushed all the way home. refit to the cylinder then slacken the adjuster bolt. Slowly turn the motor 3 to 4 turns clockwise (viewed from the left of the bike) watch the end of the tensioner plunger move in & out, tighten at the point that the plunger is deepest in that should set the chain at the correct tension. But at 30k miles if it's not had a chain fitted fit one could be well worn by now Regards Jim Link to comment Share on other sites More sharing options...
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