Couple Question's

This is a pretty good guide for getting your 2 stroke up and reliable. https://docs.google.com/document/d/1GcesQihc7-mm3hJGf7UPiqOaRXZ8ekUT99QUZq2qXXE/mobilebasic?pli=1

Most any engine can handle upgraded intake and exhaust without any internal changes. Internal engine changes are usually needed when you rev the engine much higher than stock. You increase the rpm range on a 2 stroke with porting mods. Four strokes generally require a bigger cam to increase rpm capability.

Hi, as ur planning on increasing compression, I would recommend changing the small end bearing (piston wrist pin bearing) to a wider & better quality item (if u have a 66cc). The stock bearing is a low quality 10x14x13 that drifts axially on the gudgeon as the bosses in the piston can be up to 16 or 17mm apart, thus the bearing can drift like, half outta the rod almost. Replace it with a quality 10x14x15 bearing, or if u can get one, a 10x14x16. I think NTN make a 10x14x16. If u check on Jags site I think he says to do this bearing change if increasing compression. Its recommended many times on this forum also. Hope this helps. Cheers

Hi,I'm not sure where u'd find a guide on changing that bearing but it's pretty easy. The good folk here would talk u thru it. Remove the head & slide the cylinder off. Now stuff a clean rag down into the cases so nothing can accidentally get dropped in there, or anything for that matter. Now u need to remove one of the circlips that keep the gudgeon pin in place. A pair of long nose pliers will do for this. The clips r shaped like an "e", so look at it & work out which way to twist it to compress it. Take ur time & be carefull not to scratch the piston. Remove the clip from one side & u can push the pin thru from the other with the circlip still in. With the pin out the piston will lift off & the bearing can be slid out of the rod, the new one placed in & the piston put back on. It must go back on in the same orientation as it was before. Marked on the crown (top) is an arrow that must point toward the exhaust port, or front of the motor. It'll be easiest if u have the pin already in the side of the piston, just a tad past the boss so u can locate it in the bearing & slip it home. Replace the circlip. Before u slide the cylinder on, notice in each ring groove there is a pin to locate the ring ends. This is to keep the ring ends out of ports. They,ll be at the back of the piston, (either side of the intake port). Make sure the rings r located properly & then use ur fingers to squeeze the rings into the grooves (compress them) while u slide the cylinder on. From there u should be right, u only need to torque ur head up. Its a good idea to replace the 4 acorn type head nuts with decent quality nuts & use flat washers. Also, replace the fasteners that mount the motor to ur frame with high tensile ones. The junk ones that come with these Chinagirls are notorious for breaking. Cheers