2003 LT80 Rattle......HELP!

[Ry007]

Hi, I have a 2003 LT80 that is all original except an FMF exhaust, UNI filter and Jet kit. There is a rattle somewhere in the engine towards the top end. this is "ONLY" at idle... when it revs the rattle stops and when it is warmer it isn't as prominent or doesn't rattle. Is it the rings??? I am dumbfounded because it runs like a champ! Help me...:confused:

[LT80]

Did it do it before the addition of the FMF?

Tell me more about this 125cc LT80.

[Ry007]

I fixed the rattle.....I had to retighten the head plus add loctite. I just got the 125 kit done last weekend. I Managed to get help from a friend that owns a machine shop. We ended up boring the case/cylinder and had to reshape the head to make it work(A common thing for any 105 kit). I ended up using an RM125 modded Piston at 11:1. The carb was just one he had lying around. the kit is for play, I don't know how reliable it will be, but the bike came with an extra motor so I thought I'd get a lil' crazy. It rips! I have the other motor stock with the orig. carb and just added a wiseco hi comp. I would recommend just going with the 105 kit if you do. You will definately have more reliability with it. Hope this helps.

[LT80]

The 105 kit is 96cc's with a stock stroke.
The max for boring a stock cylinder (or the sleeve of the kit) is 54.5/55mm and as you seen, it's mighty thin.
Yours is far from 125cc's.
Reliability shouldn't suffer much IMO.. Once broken in anyways.
I imagine it does go good. :)

My stock pistoned, stock carbed race motors have beem clocked at 53 mph. :D