Honda Spree and Elite 50 Forums

Are there any high compression big bore kits? Or anyway to make a 49cc dio into a higher compression motor?


I've taken a new liking to high compression motors, as my friend builds and tunes turbo cars to run on E85 fuel..
If possible, I'd like to purchase a high comp kit for my scooter, and run on e85 just for the fun aspect, as well as gaining power..

Also, if there aren't any kits, what tricks are there to raising compression? Has anyone every attempted to SLOWLY tig some metal to the top of the piston? I'm just not sure how it would work on these moped 2 stroke pistons, as the pistons look so 'crapily' made compared to my car/dirt bike pistons..

I am by no means an expert in this area, but I am pretty sure lowering the jug, or shaving a little off the head is the prefered method.

mill the head. adding extra weight to a piston is heading in the wrong direction, as any weight you add has to be pushed back and forth ten thousand times per minute. the less rotating weight, the better. and milling the head is a more precise, measurable method.

there is a thread here somewhere that a guy shimmed the jug and milled the head. check it out. the thread was very informative about how he got high compression.

Greetings:

Groove head for Viton O-ring. Lose head gasket. Run #8 plug, premium fuel, extra oil and richer main. Watch temps.

No need to groove head, just lap and use some hylomar or high temp silicone.

jus pull the head gasket , make sure there is clearance. Spray copper gasket sealer or silver paint , put back on and recheck.
increased compression will make more power but more heat and more wear and tear..
aloha
D

Don't even post crap like that

Off topic, but towelieee do you drive a Fit?

bradthreee wrote:Off topic, but towelieee do you drive a Fit?

No?
I drive a honda prelude, and a honda f4i.

maddog wrote:Don't even post crap like that

are you talking to me?

Has anyone every attempted to SLOWLY tig some metal to the top of the piston?

Somewhere on the vast 'net there was a guy that did up a big write up on chainsaw racing. He was welding piston tops and cases (to make more room for ports). For the engines he was using the head/cyl was one piece, so dropping the head apparently was not an option.

BTW - probably have the terminology wrong, but fantastic circle wheelie shot

Towlieee wrote:Also, if there aren't any kits, what tricks are there to raising compression? Has anyone every attempted to SLOWLY tig some metal to the top of the piston? I'm just not sure how it would work on these moped 2 stroke pistons, as the pistons look so 'crapily' made compared to my car/dirt bike pistons..

Adding mass to the piston is not a good idea with an little motor that is gonna turn 10,000 rpm. If you want more dome, either find a piston without the wrist pin holes and have them machined in lower or get a longer rod.

I have however, often wondered why no one has thought of milling the top of the jug to get the compression up (or back up to where it was) by moving the piston closer to the top of the bore. This would be ever effective for those that raise the jug to change the port timing.

Like Bear said, deck it.