www.zxrworld.co.uk

Hi guys, just finished my first year in racing (On the Irish short circuits) and since the bike had been used for a few track days in 2010 I decided its time to refresh the engine. So I have it stripped down at the moment. The big end bearings are well worn so ill be changing them anyway and the outer main bearings (the ones without the groove up the centre) are gone a bit shiny in places so they'll be changed but the rest of the mains look good to me, no marks and still a dull grey colour.
So the question is are they something you change as a matter of course or is it a case of leave well enough alone?
Also how do i order main and big end bearings, I thought there were usually colour codes on them but there is no marks i can see on them. There is a K stamped on the con rods (half on the rod half on the cap). I dont want to end up with the wrong size bearings.

Also is there andthing i should do with the gearbox while im down there. Its a close ratio box if that makes any difference.

Cheers lads

Check the manual for bearing sizeing....................it's straight forward enough
I would replace them all........................but then thats me.....................not cheap either


As for gear box look for wear on the dogs ...............IMHO ZXR gearboxes are damn good never seen one yet that was badly worn or damaged

The bearings should be colour coded on one side with about 6-8mm of red/blue or black paint.

If your not sure, then you can go by the crank and crankcase values (dot or not dot) as in the manual, though I have heard that if your unsure to just with the black ones.

You need to find the rod type too, the rods you have are probably 1208's, the L spec rods with the larger webbed sides.

normally the colour code on used bearings is impossible to see...........worn off I suspect

The crank codrod and crankcase markings are easy to understand just look in the manual

would the markings on the casing/ crank be obvious?? looking in the right place and cant see them. well nothin obvious so im thinkin i have a non marked set of casings but im afraid i just cant see them coz i dont know what they look like. also there are so many marks on the crank ( numbers etc) and rough finish on the webs i really dont know what im looking for... any pics anybody?? my con rods are marked with a K, 2 with a circle around the k and 2 without.. what does this mean as its a H in the manual... cherrs lads just very confused and dont want to be stuck with the wrong bearings