hi guys my 1985 xt600 43f has always been a bit noisey when cold .so i have taken the clutch cover off to have a look . now if i grab the primary gear on the crank and try to move it up and down there is no movement but if i pull and push there is a small amount of play .the primary drive nut dos not seem loose . how much play is ok and where is it takin place , from my thinking it is the main bearings in the cases but this dos not seem right . i have worked on a 600 srx mono shock where the primary nut came loose and gave the same crank pull push movement ,but this went when nut was tightened ,your fast replys, experances greatly needed as bike in shed looking very sad and the tax is out on my zed zigazg

Of course a good idea to tighten all nuts (loosen and tighten again at the correct torque), in the process check the keys, especially the one on the balancer shaft.

Then, as for play: the main crankshaft bearings on the XT are "C" class, meaning that they have a relatively large play when cold - at warm engine this play disappears.

My advice is to either live with the noise, or find another cause - I never heard of failing main crankshaft bearings in the XT.
In case it is main bearings, this would mean the noise should be synchronous with the combustion, and should INcrease with engine load.

Auke

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Auke
http://aukemarieke.blogspot.com

I think Auke hit the nail on the head with the woodriff key. These are known to distort allowing for a bit of slap. If the sound you hear is a knocking sound not dissimilar to small end knock, it is most probably the key.

thanks for the replys guys ,the engine is back up and running .having found the crank nut not loose i figure the noise was just a combination off a very very cold day and the way the engine is when first started . im still concerned about the aparant crank end flote on a cold engine, the engine has always had a on off rattle when cold but this gos when warm ,its been like that since i got the bike about 12 months 3000 miles ago. the noise i was concerned about seemed diffarant some how, today was not as cold and all seemed normal . the engine has 21000 miles which i believe genuine . the class 3 bearings i take it have this side to side movement when cold , ive not come across this before so more information on this would be useful. again thanks guys for the info this is my first big single im used to old zeds , but love the xt as its a totaly diffarant thing to ride .if i have any more probs i will post again to pick your brains take care zigzag

on the off chance you are looking for a old Zed thou, ( Z1000A2) give us a pm

Thanks for the offer mate, a class bike , folk are going mad for big zeds you will have no problem selling it ,just wish i had more space/cash thanks again zigzag