how can i get more power out of a 2 stroke 90cc atv? i have a machine shop, and am a certified welder and have no ideas of how to get more performance from this 90cc...im lookin for light weight suggestions, and more torque, maybe clutch tinkering...

 

is it worth putting a bunch of money into it?

 

not really, just some messing around with and makin it lighter, the only upgrade i plan to buy is a jet kit...i have a bunch of aluminum to add on...i just need more torque and less weight

 

What kind of quad is it. If it is the normal 90cc 2 stroke motor that most 90cc 2 strokes have then there are tons of mods.

 

OK, 2 stroke 101...
As you see, jetting is not your answer. As we see, you need advise before tinkering. [img]i/expressions/face-icon-small-smile.gif[/img]
A carb is jetted for the way a motor runs with the volumes and air/fuel flows. Your stock jetting was designed to be used with your stock motor.
An aftermarket pipe is usually the first step to change volumes/flows and increase power.
After a pipe, internal motor work is needed to increase the volume and flow efficiency.

With that said, do a compression test. Shaving the head .030 will bump up the compression and give you the torque your wanting (or close). Use solder to check the piston to head clearance, you may want to go .040 depending on compression. 150# is your target.

Now is when you "may" need to re-jet. Like a few have posted, check the plug color. Milk chocolate is good.

Now is when clutch tuning may be needed also. as you will have changed the power charachteristics. Usually lighter rollers to start the clutch expierementation.

"i just need more torque and less weight".. Weight isn't a problem if you have moore motor. [img]i/expressions/face-icon-small-happy.gif[/img] LOL

 

he said its a old manco 90,probably not woth spending money on.

 

yeah im orderin up a cheap jet set and i have custom built a air snorlke duct but still am working on the air breatehr design, its a normal 2 stroke motor and idk what else to do to it, and i dont feal like spendin more than 50 bucks, -30 for the jet kit

 

Well, shaving the head is free cuz you own a machine shop.
So your kids riding time has a $50 dollar value eh?! [img]i/expressions/face-icon-small-smile.gif[/img]
We've tried that, didn't work. Good luck! LOL [img]i/expressions/face-icon-small-happy.gif[/img] [img]i/expressions/face-icon-small-happy.gif[/img]
You'll be hooked...Tell him guys. [img]i/expressions/face-icon-small-happy.gif[/img]

 

you drilled the main jet out and now it is way to rich and it runs like crap because of it.

you dont need a over priced jet kit. you need a few jets for it thats all, stock and maybe a few bigger. get your self a set of fiberglass perforamnce reads.do your home work on finding the engine model and what mopeds or whatever the heck other machines it comes in. and look in europe and asia for what mopeds or little scooters it comes in,then see what hop up parts are made in asia for it on ebay or just on the internet "google it". they will have over size carbs , performance reeds cage's and intakes, a K@n clamp on air filter, and a pipe, there will be clutch up grades all sorts of stuff. mabe crank case stuffers. lightened fly wheels. there is a large scooter and race mini ATV after market.

you will need a realistic budget of about 300 bucks to get anything done worth doing. so get real stop farting around and do your home work. dont ruin this good bike by finger $#@&ing it to death .