I would like for my daughter's ds 90 to go faster. Currently it is stock and couldn't cut it at the dunes. What can we do for it? Is there an internal governer similar to what I took out of her LT 50? What else can be done?

 

Depends on the year. I assume you are talking about the two-stroke?

There are five possible places they restrict performance. My sons had three of them.

Carb slide limiter.
"Washer" tacked onto the exhaust pipe right at the manifold.
"Washer" tacked onto the exhaust at the very back (silencer).
Clutch variator limiter.
CDI RPM block.

My son's 03 (new, it was a leftover) had the manifold washer, exhaust washer and clutch variator. Less than hour of work and the ATV hauls the mail.

Look over those areas...they are pretty easy to see and easy to fix. I ordered a clutch kit anyway as the CVTs are really fun to play around with. They can be tuned for any style of riding and can really change the character of the quad. Getting the engine spooled up a bit more may really help you in the sand. I would really consider a clutch kit if you spend a bunch of time at the dunes.

 

Actually talking about an '06 and I think it is a 4 stroke. It is where you do not pre-mix oil.

 

In that case...

Clutch variator will probably have a limiter
CDI will probably have one too.
Exhast will be choked on both ends as well.

Have you adjusted the thumb throttle screw out? That alone keeps you down to 1/4 throttle and I believe all dealers are required to deliver them in that low setting.

 

Thanks for the info, all we have done so far is take out the thumb throtle screw.