ALL,

Have a question here and I am almost at the point of giving up... My son has an 04 150cc Yamoto that just does not run like it should or like it used to. I now understand how a CVT works so when i say shifting, please understand that i mean automaticly into the next gear. The bike used to be twice as fast as it is now. The RPM's are there and there is no more to give on the throttle side. The bike starts of fine, but really seems to not go past second or third gear when it is "shifting". I have the cover off of the CVT and i can watch the belt slide up and down as you go faster or slower. To this point, here is what I have done:

Cleaned the old carb.
Replaced the carb and cleaned it of course
Adjusted the valves (starts like a dream now)
Replaced the roller bearings in the front of the CVT
Replaced the enitre back clutch assembly
New belt for #^*&@ and giggles

Looking for some help on this one.... Thanks for all of your help smb05 your the best!
Thanks again

 

I dont think you really understand how the cvt works. There is NO gears! It is belt drive with continously variable clutches. As the rpm's raise the belt will rise on the drive clutch. As the belt rises on the drive clutch the belt will lower on the driven clutch. This in turn gives an infinate gear ratio. If you have a problem then it sounds like the drive clutch is worn. You can replace the drive clutch roller weights to get different shift rates. This is a Honda GY6 clone motor and there are alot of hop up parts and replacement parts for the clutches.

 

2many, I do understand that there are not any gears... I was just using the word shifting to try and describe that it does not seem to be getting into a higher ratio or "gear" to go faster. By drive clutch, do you mean something different than what I have already replaced? Can you explain that to me please?

 

used2boat,
I will be the first to admit I dont know much about this, but could it be something as simple as a brake dragging? Is it alot slower then it was before or just a little?

 

Did you have the problem before you changed the rollers or afterwards?..I'm wondering if you have a set of rollers that are lighter than the stock ones?..This will reduce your top speed as the variator needs that wieght to be able to shift into high gear.

 

OOps I just reread your post and you said you replaced the roller "bearings"...Is this an actual bearing or is it the rollers inside the variator?

 

oldyeller,

The same thing started happening on the old setup, so i replaced the rollers that are on the front, there were six of them, also replaced the guide the front pully rides on. On the back, i took off the main nut where the clutchs and spring is at and replaced that entire assembly. As far as i know, there is nothing else in that area to change. As for lighter rollers, it was OEM to start and replaced with OEM. Thanks!!

 

Use a marker and run a line from center of the front clutch variator out. Then run the machine on the ground. This will tell you if your clutchs have full travel. Sitting on a stand and checking gives a false reading.

Providing it's traveling to the limit::: I gotta ask,,
What's the compression?

 

LT80,

I will give that a try in the morning, as well as testing the compression. What should that 150 be giving me for a reading? For what is worth, the belt on the CVT does travel from the very bottom of the pully all the way to the top edge of the pully. So that leads me to believe that #1, there is no more anyway?? What does that make you think?

 

Was the aluminum track for the rollers worn down. After 400 hrs on my
Redcat 150 (GY6 Motor) the rollers wore the track down and changed
the performance. I replaced the front pully (drive) and the performance returned.
When you inspect the roller track use your finger to feel for a raised bump
at the end of the roller travel spot.
good luck