Jetting question and no top end power

[tntauto1127]

I bought a used l/c 08 DRR50 with custom ported cylinder by 609 in NJ. I changed the gas/oil mixture from 32:1 to 40:1. Would that change the jetting? A new plug and 2 race motos the plug was chocolate brown on half and white on the other half. I was thinking lean because it seems like the bike is not pulling hard on top the way it should My 06 a/c drr Kool Kids smokes this one. 16mm carb on both 3.5 roller, 780 belt, Malossi yellow spring in tranny. Did the marker test, belts going almost to top in 100 yard hole shot test. 16" holeshots 19/29 gears

[bulldogfallon]

What rpm is the quad launching and what rpm does your cvt shift occur?

Have you asked 609 where the quad should make it's peak pwer so that you can set the CVT to shift at the corresponding rpm.


A CVT set up can doom a fast motor and that goes double on a 50cc mini.


Your set up is not one that we would run....that may be holding you back more than anything...


Belt travel is a bi-product of a properly tuned CVT...really not something you tune for....I don't see why it is the first thing tuned for.

It is the result of tuning the rest of your CVT properly....


Rollers weights are NOT used to give or take belt travel as their primary role.....they are used to set the rpm of your shift....

Ex) If you ran too heavy of weights then you wouldn't reach your peak power rpm range until after the pulleys shift out...then the motor would pull again and you would think that your belt travel is fine, but really your not using your engine power effectively

Really you need to lock the shift rpm that allows the cvt to run at one rpm (peak power or just under) while the pulleys are shifting.



Launch the quad so it over revs and locks into your torque rpm and then decide on rollers that let you rev and lock close to the rpm where the motor makes the most power.

Then basically everytime you touch the gas you either have torque or peak power....no lagging under or over the power range.



Belt travel is over rated in my opinion.....What good is it if your not shifting and running in your peak power range??

Chances are that if you are tuned this way belt travel will there as well.


Ex) What if you made peak power at 10,500?
If you were running 4.5 gr rollers, but didn't get full belt travel what would be done? Your shift rpm is 10,200 right now?

If you add weight you may feel that belt travel will come?...well maybe it would, but you would also risk of dropping your shift rpm lower than the 10,200 so you are further underneath your peak power and will only see this power after pulleys shift out and motor starts to pull on it's own again.

[raidernut]

wow thats deep gary!!:D

[tntauto1127]

Thanks for the info Gary. Seeing how I'm relatively new to the CVT I may have to read this a few more times to digest the info and try to appy it.

[bulldogfallon]

There is a nice diagram on our website in the tech section.

It shows the rpms rise to shift rpm, then flat line as speed is gained and then finally raise again after pulleys shift.


Like a 10 speed bicycle....you pedal the same amount but you go faster.

Once you run out of gears your leags start to peddle to create more speed.

Get an rpm gauge....it will make tuning make sense and much easier to collect data.


The other variables include...belt length, torwue spring, pulley angles etc

Call me anytime