Yesterday I swapped the front 10 tooth sprocket for a 12 tooth and we were planing on racing at our local mx track. The race got cancled because it was to muddy. (go figure) So instead we went trail riding for most of the day. It seems like the LT kept slowing down. It should have run faster with the bigger front sprocket, but it sure doesn't. It still winds real good amd it will spin the Shreders quite easly. I've mentioned before I was disappointed with its take off after trimming the rear shoes to 170 grams but now it seems like it pulls good once it moves up to about 25mph and then it done. A week ago it ran 40 easy with the 10 tooth sprocket. I know its about to die. It never did have good compression after I re-ringed it last time. And now its getting hard to start. I've ordered the big bore piston for it and was hoping to at least get it before it died. (its bored 80 over now) Would the lack of compression make that big a difference in the speed? I've also noticed noise from the cluches. I've trimed the rear shoes to 170 grams. Drilled the front rollers, put the longer front bushing in (from the older lt's) and put a new rear spring in (stock) Everything looks ok in there but why would it be making noise? It also will creep when sitting on a flat floor (like my shop) at idle. It idles just fast enough to keep it running so it can't be that. I'm afraid that trimming the shoes has done alot of this, and I cannot see improvement at all from doing that. Hopefully I will get the piston either this week or next and I may just go ahead and have it bored and put it in now before it dies completly. I would like to get this clutch set up figured out soon though.

 

Did you take the weight right off the very end of the shoes? The rear shoes trying to engage the drum is all that can make the bike start to move. We're at 155 grams and it works great. It has a nice medium engagement. For drag racing I believe more weight off would be better even yet. The first set of shoes I ground down was not taken off at the very end and it didnt improve the stall speed any. Mr Jack helped me with that problem.When you remove material from the shoes anywhere but the end you actually make the shoes work worse because your putting more inertia on the end due to more weight being there.

 

When you say the end, you mean the end opposite the mounting pin? (also opposite the spring mounting hole) If so, yes.

 

What's to wonder?!
You have little compression and now you over gear it. If you over gear my motors they fall on their faces also.
I've always said that clutch work does little till you have a motor. I feel that you have done a fair job on your motor, but the compression part is killing you IMO.
When you get your piston in and you correct the compression (head design), then you can figure out the clutchs. [img]i/expressions/face-icon-small-wink.gif[/img]

Creeping shows too much roller weight, too much shoe weight, or both. You haven't ruined anything at 170 grams. Other reputable LT builders like 170. Like Bubba said, 150+ works OK.
With the Trinity pipe I've had to go to 135 grams for the shoes and 3 stock rollers (30 grams). So you can see by that that you are in good shape. [img]i/expressions/face-icon-small-smile.gif[/img]