skik Posted May 12, 2012 Posted May 12, 2012 hi all.there was a slight rattle coming from the top end of my sr250.thought it might had been valve clearance but i've reset them and the noise was still there.anyway coming home today the noise got worse to the point that im afraid to ride it any further.looks like im going to have to take the head off for a look but any ideas what i should look for first?
Moderator DirtyDT Posted May 12, 2012 Moderator Posted May 12, 2012 Look at the timing chain. There is an adjuster on it. It is located on the cylinder and should be protected by a cap. Rear nearside of the barrel. Take the cap off There is a rod in the center and the rod and threaded part should be flush. If they are not flush, loosen the big nut close to the cylinder and the turn the smaller nut at the end of the threaded part until it is flush with the inner rod. Tighten up the big lock nut and the replace the cap.
skik Posted May 12, 2012 Author Posted May 12, 2012 Look at the timing chain. There is an adjuster on it. It is located on the cylinder and should be protected by a cap. Rear nearside of the barrel. Take the cap off There is a rod in the center and the rod and threaded part should be flush. If they are not flush, loosen the big nut close to the cylinder and the turn the smaller nut at the end of the threaded part until it is flush with the inner rod. Tighten up the big lock nut and the replace the cap. do you mean turn the wee nut until it is flush with the big nut.if thats right the wee nut is way out
Moderator DirtyDT Posted May 12, 2012 Moderator Posted May 12, 2012 No. The threaded part with the small nut on it should be hollow. Inside it is a rod. It is the rod and the small nut that have to be level.
skik Posted May 12, 2012 Author Posted May 12, 2012 turned the wee nut until flush.i mean until i cant get the spaner on anymore..still the same but i've noticed that the noise is coming from the top right side [the side where the plug is single cylinder]
Moderator DirtyDT Posted May 12, 2012 Moderator Posted May 12, 2012 When you adjusted the tappets you did them at normal temp (not hot) and the engine at TDC? To these tolerances? Valve clearance (cold): Intake valve 0.05
skik Posted May 12, 2012 Author Posted May 12, 2012 When you adjusted the tappets you did them at normal temp (not hot) and the engine at TDC? To these tolerances? Valve clearance (cold): Intake valve 0.05
Moderator DirtyDT Posted May 12, 2012 Moderator Posted May 12, 2012 Before I took the head off I would just check behind all of the inspection covers - tappets and chain, just to make sure that a lock bolt hasn't shaken loose. you can also check the tightness of the chain in case it is the tensioner that is not working.
skik Posted May 12, 2012 Author Posted May 12, 2012 Before I took the head off I would just check behind all of the inspection covers - tappets and chain, just to make sure that a lock bolt hasn't shaken loose. you can also check the tightness of the chain in case it is the tensioner that is not working. right i took off the inspection covers to have a look at the valve rocker arms and found that the inlet clearnance was way loose i mean mad loose.also noticed that the locking nut on that side looks like it has been replaced.its a 9mm and the exhaust is 10mm surely they should be the same.reset it but will do it again in the morning when its cold.never tried starting it yet want to wait till tomorrow.should i change the locking nut for a locknut[if you know what i mean].it must be shaking loose.
Moderator DirtyDT Posted May 12, 2012 Moderator Posted May 12, 2012 Not sure if they should be the same but it may not hurt to change them. If it is that then it might save taking the top off. Use normal nuts. It will probably melt the plastic in a Nyloc nut. It should hold by being tight against the rocker.
skik Posted May 12, 2012 Author Posted May 12, 2012 Not sure if they should be the same but it may not hurt to change them. If it is that then it might save taking the top off. Use normal nuts. It will probably melt the plastic in a Nyloc nut. It should hold by being tight against the rocker. thanks will do that.o by the way was i right in screwing the wee adjuster nut on the cam chain ajuster in until i could'nt get the spaner on[flushish] or should i put it back to where it was
Moderator Airhead Posted May 12, 2012 Moderator Posted May 12, 2012 i think the thread pitch may be fine and not the usual thread for whatever diameter they are...if they arent stripped why change them, they are probably high tensile too! was the nut loose? or just the gap had grown? you have been tinkering with the tensioner and not knowing how its done? perhaps the chain jumped a cog, check the alignment marks again
skik Posted May 12, 2012 Author Posted May 12, 2012 i think the thread pitch may be fine and not the usual thread for whatever diameter they are...if they arent stripped why change them, they are probably high tensile too! was the nut loose? or just the gap had grown? you have been tinkering with the tensioner and not knowing how its done? perhaps the chain jumped a cog, check the alignment marks again the nut did'nt seem loose but the wee adjuster was away up.no way did i set it there.when i did set them at the start i checked and rechecked.anyway how come it went noisy all of a sudden,there was only a slight ticking before.awell fingers crossed for tomorow when i start it.
Moderator Airhead Posted May 12, 2012 Moderator Posted May 12, 2012 again...check the alignment marks!
skik Posted May 12, 2012 Author Posted May 12, 2012 again...check the alignment marks! will do and let you know tomorow how i get on thanks
Moderator DirtyDT Posted May 13, 2012 Moderator Posted May 13, 2012 In terms of the cam chain. I hope you haven't tightened it up too much. The chain should have some slack in it so it might be worth checking that when you check the alignment marks. DO you have a manual for the bike?
skik Posted May 13, 2012 Author Posted May 13, 2012 In terms of the cam chain. I hope you haven't tightened it up too much. The chain should have some slack in it so it might be worth checking that when you check the alignment marks. DO you have a manual for the bike? In terms of the cam chain. I hope you haven't tightened it up too much. The chain should have some slack in it so it might be worth checking that when you check the alignment marks. DO you have a manual for the bike? i dont have a full manual just bits of oline stuff.i started the bike this morning and there is no knocking but a whineing noise.im thinking i might have the chain to tight.when you say tighten the wee nut in till its flush with the inner rod do tou mean the bottom of the nut or right in so as you cant get the spanner round it anymore
YPVS TONE Posted May 13, 2012 Posted May 13, 2012 The camchain and valve clearance have to be set cold with the engine at TDC on the Compression stroke. If you remove the gear lever and the LH side engine cover you should see a T mark on the flywheel which you align with a timing mark / pointer on the crankcase at about the 11oclock position. When you have these lined up rotate the flyheel back and forth a bit while watching the valves. If both valves move you are on the wrong stroke and you need to turn the flywheel 360 degrees. As DirtyDT has said the pushrod inside the adjuster should be flush with the end of the adjuster with the engine still set in the above position. If it's whining it sounds like you have the camchain too tight. Once set start the engine and with the adjuster cap off make sure you can see a bit of movement on the tensioner pushrod .If not loosen the adjuster off a bit until you see the pushrod move slightly in and out. Tony
Moderator DirtyDT Posted May 13, 2012 Moderator Posted May 13, 2012 Have a look at your PM's on the forum.
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