XR600 single carb head on a XL600LM cylinder?

A question for the specialists out here....

I have a XL600LM (stroke & bore like the XR600) in the shop and the head and rocker cover are a mess and ready for the garbage can.

I want to put a rebuild and ported XR600 - single carb - head on the XL cylinder...

There is a difference in bolt and dowel pin size ,I know but is it possible to use the XR600 head and rocker cover in combo with the XL cam,camchain  and rockers?

The thing will also receive a 102mm JE XR600 piston and a FCR41 carb.

Any thoughts?

I helped a fellow out earlier this year with a XR600 in Italy. He had the dual carb, early cam head set up. I supplied him with a dual carb head that my machinest modified to accept the late decom cam. This required machining a place for the decom plunger/spring assy. I also sent him a late style rocker cover and cylinder and 102mm piston, late cam, cam chain and drive sprockets. I had the head locating dowel holes machined to accept the larger late dowels to match the late cylinder. All in this was an almost $2000.00 job.

Edited by mcma111

Was that person named James (nick name  "fingers" here on TT)? Then I saw those parts when I was with him in Italy on summer holiday.

So best to put the LM cam in the XR rocker cover and check if the cam and rockers are in line? What about the camchain/sprocket ? The cams look the same... length,shape ..only is the sprocket on the other side of the flange.

I just checked...the XL LM cam doesn't correspond with XR (single carb) rockers..bummer...So I have to find at least a good XR cam maybe also the smaller XR chain/sprockets if they are not in line ...


The XL and late XR cames and rocker covers are different spacing due to the auto decom assy on the end of the cam. The late cam sprockets and chain are required.

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