KSIThumper's CRF450 Aftermarket Clutch for the old XL350!


At long last !! My upgraded primary drive and clutch is back from the machinist. The company I used makes gearboxes for some of the top UK Superbike teams, and it looks like they did a great job.

It has a revised primary drive ratio (29/70 instead of  24/75) to speed up the gearbox and thereby reduce torque loads.

It's not that simple to make a smaller clutch though as it then clashes with the cush drive rubbers. We ended up with a special set up, using a CRF450 aftermarket billet clutch basket which is far stronger than the original XL one, and hard anodized too. The cush drive is essential, and is therefore retained.

The crankshaft has tiny Jap-special-size splines and no broach could be found to match, so the crank gear internal spline was manufactured using wire erosion techniques. Considering the work involved, the cost was not so terrible - $480 for this one-off. Webster gears are now unobtainable, so it's one of only two mods you can do to protect that fragile XL 'box if you have a big-cc motor. (The other is to fit a good chain tensioner; we are using a rubber-in torsion type, left over from the original Knobby Shop works bikes).

Later this year I will look at the manufacture of a batch of Webster-type billet gears if anyone is interested. Find me on the XL Board and lemme know... KSI-

Click the pics for bigger view...





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This site last updated (probably in my sleep) on 01/22/07

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