I have some large 3/4" sockets - I don't remember the size of that nut.

Clamp the clutch down with c-clamps using some wood and loosen the nut. When reassembling, you will be able to compress the spring by hand and clamp it with the c-clamp before you get the nut back on.

i don't know if this will help but on my friends 250cc for the nut that held the clutch on we used a 1 9/16 socket it was tight and had to tap it on the nut.the 1 5/8 socket was just a little loose for me i thought and didn't want to round it off
but i think if the nut is the same on yours either one will work.
the sockets where 12 point we used and had some wear in them.
pud

Well once i put a vise together,it wasnt to bad.17mm was the size i think.i put in a quarter inch shim and stood on it to first start the thread.well i learn about the clutch tonight!slipping the whole thing and the belt back on was interesting,i now know about those rollers,yep a few fell down.my investment in a half inch drive electric impact was worth it.

sorry about that i thought you where shimming the spring on a 250cc
well i guess the main thing is you got it the big nut that holds my clutch and spring on my 150cc is 1 1/2
pud

I was curious if you would get similar results if you changed to a 1500 RPM torque spring? Wouldn't the larger spring limit the amount of pulley travel like the shim does? The reason I ask is because I have already changed the torque spring and I was wondering if there would be any benefit if I added a shim as well or if that would limit the pulley travel too much. My reasoning is that a 1500 RPM spring when fully compressed might be 5/16 larger than the stock spring fully compressed therefore you might get similar results to adding a shim.

was reading old forums on shimming i tried this and it is the best mod i have done yet and did not cost me a penny. muffler shops have lots of scrap pipe laying around and most will give you some if you ask.

Shimming is great, and depending on your cvt using a tq spring and shim you can dial in your cvt. With the Joyner cfmoto hi/lo tran I can shim the wht malossi spring, with the cn250 shimming the blue polini is way too much.

Greg

Wow,I have been away from buggynews for a long time.I cant believe the positive feedback on shimming.
I'm the original kammak who did this shimming.I'm trying to get my original username back,the board has changed and since then my email has changed and I couldn't get logged on.
Ken

Why bother changing the spring? Isn't shimming supposed to eliminate the need to spend money buying springs?

shimming is good as long as the spring dosent bottom out. The more you compress the spring the faster it wear out or breaks.