xr400 engine noise?

please help!!!

went out on my bike the other day,i get the usual tappet noise,but noticed every so often a 'metallic' knock,it only seemed to happen in top gear cruising about 50mph,cant exactly tell where its comin from but its very intermittent.i checked the oil which was very low,so decided to replace with a new filter n oil,i'm terrified now that the engine has been damaged,but surely engine damage noise would be there all the time.

the chain was loose at the time ,so i've sent for a new chain and sprocket set,hoping its just chain noise.havent run the bike since, but would appreciate any ideas what this noise could be.

n.b checked the oil filter ,there were no metallic particles in it. p.s new to this forum,seems the best place to get advice and stuff,cheers dudes.

If you ride the bike again before changing the chain and sprockets, get it up to speed where you've been hearing it and alternate power on and power off with throttle, alternating chain slack from top to bottom, see if you get the noise.

Do you have a skidplate installed? Could it be a rock getting thrown up by the front tire and hitting the plate?

If the noise seems to be coming from the engine area, take the tank off and check the frame in that whole area for cracks, the whole frame for that matter.

It could be a lot of things.

When you checked the oil level did you use the proper method as referenced in several posts here?

thanks for the advice,i've removed chain and sprockets already so i cant use the bike to try your idea,but i will check for cracks on the frame,thanks for the advice,i'll let you know what happens!!!

i checked the oil which was very low

How low? Did it register on the dipstick? Running bikes low on oil is never a good thing but if you catch it on time you might be able to save it. Keep the oil full and fresh and keep riding it, and find out if it's still making that sound.

could be a streched timing chain? simple 5 minute job

remove the chain tensioner and check how much adjustment is left. make sure to recoil the tensioner when replacing as failure to do so can put undue pressure on the chain and cause dammage

at last bike is sorted,it turned out the chain and front sprocket was knackered,thanks a lot for your help dudes-i'll give you all a shout if anything else goes wrong.thanks again:banana:

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