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Zak125m
05-24-2009, 01:57 PM
Hey thanks for looking at my thread, I just rebuilt my old 125m with new rings and gaskets due to blown head gasket, and its all done and put together and runs good now, has good power and doesn't spit or sputter or anything, idles and revs up fine too.

But it does make a noticeable amount of clatter from the head of the engine, I checked valve clearance at least 5 times and did it to the T according to the manual so then I checked the cam chain tension and that is good too, but it doesn't stop the clatter. I'm thinking it has to do with worn out springs or something to do with the valve mechanism itself, the valves are not leaking I checked that before I put it together so the valves seal fine and everything. Or is it possible its normal for the machine? Its not horribly loud but its not quiet either.

I am wondering if I can replace the springs, and all the other components in that line of things without actually removing the head, I don't want to take the valves out, just replace the springs and whatever else the rocker arm hits to push the valve open. Or maybe a solution as to why this thing is making what sounds like valve clatter? I used an automotive stethoscope and it sounds like it is coming right from under the valve covers.

Yamaha_Rules69
05-24-2009, 02:24 PM
Yes you would have to remove the head in order to replace the valve springs. I dont think the springs would cause the noise unless they were broken, which is fairly unlikely. Are you sure you adjusted the valve clearance correctly? When one valve is being pushed down, the other valve should have free play at the rocker arm, and this is the best tome to adjust it to spec. Then turn the engine over a little, until the other valve starts to open, and adjust that one. Double check them, and go from there.
It could be a number of other problems, but I would definatly double check the rocker arm clearance first. Did you look at the rocker arms where they come into contact with the cam lobes? Look there, and also look at the cam bushings, and the places the cam rests for wear. Good Luck!!

Zak125m
05-24-2009, 06:48 PM
Well, the springs arent broken I was just thinking since if it was already all apart and the springs are 25 years old I would just replace them, I checked online for prices to the parts and everything I would need is pretty cheap and the valves themselves dont need to be replaced as far as I can tell. But the head gasket isnt expensive either, I'll take a look at the valve clearance again maybe i'll find something new, and save myself a lot of trouble, hopefully. Thanks a lot for the advice.

Erics350x
05-24-2009, 08:32 PM
Did you have it bored out or just re-ring it? It could be valve adjustment, cam chain rattle, or piston slap.

Zak125m
05-25-2009, 12:45 PM
Did you have it bored out or just re-ring it? It could be valve adjustment, cam chain rattle, or piston slap.

Cylinder looked good so i honed it and just threw a new set of rings on it. I put my automotive stethoscope on the cylinder while it was running afterwards and the piston isnt slapping sounds pretty smooth, i hear the clatter coming from right under the valve cover cap using my stethoscope.

One of the other members on this forum sent me a link to the repair manual and I adjusted the valve clearance quite a few times already and it isn't helping. Also tried adjusting the cam chain and tighten it up but it didn't help either. Thats why I thought it might have something to do with the mechanical parts of the valves themselves.