Free and cheap CVT mods and tuning

Ok, I just did this mod. I removed one weight. accelaration has improved a lot. I didnt notice any gain in top speed. but no loss either. All in all, its a great mod. It should come in handy at the track...

Measure your belt..I dont have it in front of me..Pretty sure it's 1/2"....Go there and it's the first one ..18'...Works well..removing one weight tomorrow..we'll se how that goes...

Anybody have any info on mods for the 380-X Inferno CVT?

from the pics i've seen of the transmission casing on the inferno, it doesn't look like a cvt type transmission. i'd like to see a pic of one opened up.

A-

I did this mod also. I have a Digi-Tach so I can tell you the numbers.
Before the mod(all 4) top speed 34 mph 6900 RPM
After mod(just 3) top speed 30 RPM 7700

What does this mean? Before my belt had much better hookup. My belt has got to be slipping its azz off now! I also noticed that my CVT cover is HOT!
Thier is also a hissing white noise now that I'm sure it must be the belt and pulleys.

Accelleration is a hair better but not that much.

I have looked inside one it has a gear reduction 9 tooth on the front sprocket 32 tooth on the rear sprocket 3.55 to 1. it has a double row chain like the non cvt x bikes so it is not cvt. the cateye that has the x frame has a derby type cvt on it it has the best cvt for racing.380 x has the gear reduction.I wish people would not rename them its so hard to tell which has what on it stop the x madness thats why everyone thinks 380x has a cvt because of cateye/x frame/derby cvt bike.

So it's not worth doing...? I have a smaller belt...hmm. I'll try it anyway..

There is a lot of varience from one CVT to another in these bikes which is why it is not always a free mod, you need 6 weights in there that are of lighter individual weight. Your belt is slipping or your rear clutch is not shifting, this is why it is important to leave the cover off while tuning so you know when the shift is taking place or if the rear clutch is not shifting. BTW 7000RPM seems kind of low for a modded X1, Troy's slightly ported motor is spinning 10,800rpm and is hitting 41mph with the rear clutch still never shifting, the springs in that back clutch are too tight, we have them locked out because on the tracks we race you need the accelaration out of the corners and there is never enough room to hit top speed. We are using a Tiny-Tach on that bike. Can you post a picture of the Digi-tach that you are using and a link to some specs or a place to buy one? The Tiny tach has a 1.5 second delay so you have to stay in it for a while before it registers correctly, we had to switch from the standard model to one that counts every other fire when we exceeded 10kRPM so the 10,800 is actually 5,400 on the new tach that counts half since they only go up to 9999.

Here's a pick of my Tach:
http://www.beautifulbraids.com/images/gazdt2.jpg

It is very accurate. It has a range above 30,000 rpm.
My bike on a bench will reach 12,000 rpm but with my load only 6900 and then 7700 with the mod but the topspeed was decreased by 2 MPH or more. My engine is completely stock.

The 10,800 rpm is while riding down the road, 41mph without the benefit of the higher gear when the rear clutch shifts, we are getting too much slip when you let it shift right now. This motor is ported and has a window cut into the piston that seemed to make all the difference (on the intake side) as well as it uses a tuned pipe from Pro-line. I just tried installing a front varieter from a moped (it is larger) in the X1 CVT and it looks like it will fit after only minor cutting and grinding, I will also have to have a center shaft machined to fit this varieter since it is a 16mm one, I have to call a friend of mine whose kid's 50cc atv used a 13mm shaft varieter that we replaced, it will be a little closer since the X1 uses a 12mm shaft. I like that tach you've got, I just can't see spending the $110 on it for my purposes since I have a good shop tach for test runs, I just use the cheap tiny tach for mounting on the bike, but if I had to have one tach to do both jobs that would be a really nice unit. I like discussing this stuff with you since you actually use test equipment to verify your claims and not the usual I do 60 on the stock speedo. I will try to get this varieter to fit and if it does it will give us a ton of choices right up to the Turbo Kit overdrive varieters that add plenty more top speed without sacrificing accelaration, they use 8 weights shaped like bullets instead of rollers to push the belt up on the pulley. Please don't expect me to get you results of this right away, I rarely get time to play with something this experimental in the shop. It has been a month since I did anything on my X1 that I am swapping a Cag motor into, I have it mated to the CVT and clutch working but have not got any further than that. Anyway, I have noticed that some of the sponsors here are now offering the lighter roller weights on their websites as a mod so this must be catching on.

After reading the posts on CVT cheap/free mods, I started my test by replacing the "stock length" belt which gave me a 36mph top speed WOT with the usual lack of tire-spinning takeoff (torque), then replaced belt with 1" smaller belt purchased from PBU. Take off throttle response was minimally improved, but top speed was decreased by approx. 3-4mph. Watching variater and rear clutch to be sure both were opperating properly, noticed the belt (new shorter one) didn't seem to ride up the front variater as high at top speed achieved, and didn't seem to go as deep down in the rear pulleys at top speed. Question: could the shorter belt be the prohibiting factor, or is it the lack of sufficiant power stopping it from running higher on the variater? if lack of power, will larger rear sprocket help?

In reply yes.

There is an optimum size belt for a CVT (any CVT) for it to work correctly. This includes section width and length.

Using a shorter length than optimum and you will see a reduction in the minimum/maximum ratios on the CVT.
Longer and the belt will slip excessively on the pulleys. Belts normally stretch in time and should be replaced occasionally. This is the trade-off for having a CVT over fixed gearing.

so you figure going to a larger rear sprocket from the stock (44 tooth I think) would help ? how about the remove 1 weight trick to bring the RPMs up ? what causes the belt to get driven down on the rear pulleys ? just tension caused by the front diameter being increased via the variator (front pulleys) ? whats the next larger size sprocket from the stock tooth count ? 52 ? thanks, your a veritable conacopia of knowledge on clutchs..so many variables, so little time !

P.S. I think I'm going to work with the stock length belt. It will at least have the broadest range..Some low/most of the top..can always scuff up pulleys between belt changes and a little light belt dressing

anyone know where to get a stock belt zhuping 13 x425Li it is really 13mm wide and 18 and quarter inchs long,the P.B.U. belt is 12,5mm wide and17 and 3/4 inches,Gates belt is 12.5 by 17 and 3/4 inches long the skinny belts ride lower in the front variator and cant get max overdrive even thou its shorter and rides lower in the rear pully.having a wider belt is the way to go it rides higher in front variator bike is faster even over shorter belt rides lower in rear pully also the other belts are not notched

Edited by PBP Webmaster:

This is the LAST time I am going to tell you to quit advertising in the forum unless you are a paid advertiser. If you are found trying to promote your company again without becoming a paid advertiser your access to PBP will be removed and your company name and website will be censored on PBP.

Ya trickjet, try Scooterparts4less, I think I saw the stock notched belts there. I think I can say that without upsetting the PBP people ? I guess we'll see if the post isn't edited..I'll have to read the "conditions of use again if not...lol

I personally found a LOSS in overall performance when removing 1 of the 4 weights from the front variator (pulley is easier). Using 3 weights did not create enough force to fully ingage the clutch. Maybe with a lighter rider than myself.

Installing the LARGER 54T rear sprocket helped BOTH accelleration and top speed because the bike is overgeared from the factory. This only applies to the X-1 CVT.

Pops

[quote=Pops Racer]I personally found a LOSS in overall performance when removing 1 of the 4 weights from the front variator (pulley is easier). Using 3 weights did not create enough force to fully ingage the clutch. Maybe with a lighter rider than myself.

Installing the LARGER 54T rear sprocket helped BOTH accelleration and top speed because the bike is overgeared from the factory. This only applies to the X-1 CVT.

Hey Pops you are correct in your thinking. The total of the centrifugal mass is what opens the pully all the way. Now on the other hand the rear spring tension(resistance against roller weights) can be raised to higher rpms before full shift occurs. You can also put lighter weights in to raise rpms before takeoff but will need to put more of them to keep the overall weight of the rollers high enough to fully open the pulley. Sometimes a mixture of weights work the best. As long as they are evenly installed/spaced. Hope this helps a little.
Troy Gansen

[quote=moto-x-troy
Hey Pops you are correct in your thinking. The total of the centrifugal mass is what opens the pully all the way. Now on the other hand the rear spring tension(resistance against roller weights) can be raised to higher rpms before full shift occurs. You can also put lighter weights in to raise rpms before takeoff but will need to put more of them to keep the overall weight of the rollers high enough to fully open the pulley. Sometimes a mixture of weights work the best. As long as they are evenly installed/spaced. Hope this helps a little.
Troy Gansen[/QUOTE]
Troy;

Already installed some shims behind the spring on the rear pulley. This slightly increased the accelleration as it keeps the bike in a lower ratio a little longer. Top speed was not effected.

Pops