03 estart to an 01 engine

Do not mix and match parts. There were some production changes. If I were to do it I would swap all the parts involved with the starter right down to (including)the clutch basket.

berger is right... but even swapping right to the clutch basket is not enough because the crank and counterbalancer gears are also part of the problem.

However, all the parts ARE the same with one exception... the inner freewheel hub on the sprag gear (800-248-01 is the part number for an 01 I think, but please verify that from the parts list).

So, bottom line... use the parts from the 03 in your 01, but make sure you get a new inner freewheel hub.

The problem is the gear pitch, it is slightly different starting in 03. I have run the parts combination you are talking about and it actually will work.. but it will make a ridiculously loud whining noise because of the differences in the gear cuts.

just to give you all my take on it.

If fitting say the 2003 starter clutch and sprague assembly only as well as the starter motor and everything outside the engine then the following should be true:

2003 stuff will slot straight in a 2001 bar the inner freewheel of the sprague assembly. DON'T use this or the thing will make a right racket! you can still buy the 2001 starter freewheel so fit that.

there are lots of people who break the teeth off the freewheels so you'll have no trouble selling it as a used item here (or anywhere).

If you were to be fitting clutch basket from 2003 as well, well you need the 2001 primary gear as well I believe. Duane has it mostly right I think but I think the factory changed the gears in late 2001 model year and was defo changed for 2002 model? also not sure why the CB got involved Duane but maybe you went through this and have spotted something I haven't? the intermediate shaft/W/P shaft has a step in it in 2002 but the mesh of the teeth is the same.

upgrades that you should also do are :
I sell a starter repair kit which stops the sprague slipping AND the starter clutch slipping
put an extra strong 'beefy' starter motor on.
a CTZ7s or YTZ7s battery on it.
mount the solenoid into the middle of the bike on a 2004+ sol. Mounting bracket for cleaner lines.
if buying new HT cables get the 2004+ enclosed HT cables. two red and the one black.

If you wanna contact me 'Torque Monster' for getting through this and prices feel free to and PM me.

regards

Taffy