skikman Posted May 16, 2012 Share Posted May 16, 2012 hi all.i have an old yamaha sr250 that is nocking/ticking from the inlet valve adjustment.i have been resetting it and each time the adjuster is going down and now to a point that i have to take off the locknut turn the bolt then put the nut back on.the top of the adjuster bolt is now below the top of the nut.surely thats not right.before you ask it is set at tds with timming marks matching up and on the right stroke.the bike is quiet for about 10-20 miles then the knockings back and a big gap at valve clearance.the top of the valve is now beaten pretty bad from it being run loose.cant adjust it any more.the exhaust side is ok.what you think????.ps i could take pics if needed. Quote Link to comment Share on other sites More sharing options...
megawatt Posted May 16, 2012 Share Posted May 16, 2012 Pix would help mate.Sounds like a problem with the valve to me. Best to remove it , check seat and do some measuring! Quote Link to comment Share on other sites More sharing options...
Tango Posted May 16, 2012 Share Posted May 16, 2012 Think the valve stem is gone mate......or the cam follower is duff. The cam follower mount is not loose is it? You are right that the adjuster should not be so far down that you have to take the locknut off to adjust it. I'd stop using the bike if I were you coz by the sound of it a dropped valve is the next step which won't be cheap to fix. You need to get the top end off the engine and as Megawatt says put some pix up. By the sound of it though I think the valve stem is shot.... Quote Link to comment Share on other sites More sharing options...
megawatt Posted May 16, 2012 Share Posted May 16, 2012 What Bob said. It's probably already bent and everytime you run it, it is bending more, affecting the clearance. Only a matter of time before the valve head snaps off Quote Link to comment Share on other sites More sharing options...
Colin the Bear Posted May 16, 2012 Share Posted May 16, 2012 Not a massive job by the way, but yes stop running it. If the vave hits the piston or snaps and drops in, it will be. Quote Link to comment Share on other sites More sharing options...
skikman Posted May 16, 2012 Author Share Posted May 16, 2012 right ok folks bikes locked up in the back yard and will not be moved till io get it sorted.heres some pics Quote Link to comment Share on other sites More sharing options...
eastanglianbiker Posted May 16, 2012 Share Posted May 16, 2012 i would drop the points cover off and see if you can remove a backing plate to se into the camshaft and check that the lobe hasnt worn away Quote Link to comment Share on other sites More sharing options...
Tango Posted May 16, 2012 Share Posted May 16, 2012 Top of the valve stem looks a bit mushroomed to me..... Quote Link to comment Share on other sites More sharing options...
skikman Posted May 16, 2012 Author Share Posted May 16, 2012 Top of the valve stem looks a bit mushroomed to me..... yea think its gone through the hard metal.might be a bit of a c nt to get out.cam may be shot too.i can see a few marks on it just looking in.a well its head off then Quote Link to comment Share on other sites More sharing options...
Tango Posted May 16, 2012 Share Posted May 16, 2012 Fraid so mate....but best to get it sorted before it really messes your engine up..... Quote Link to comment Share on other sites More sharing options...
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