|
|
Post by Fox on Aug 9, 2011 15:02:15 GMT -5
So today I opened up the CVT on my bone stock Zip clone to clean it out and when I took the cover off I found that the Bando 788 belt that was in there was very loose like it had stretched out some so I took the Mitsubishi 792 belt off my 1E40FM engine to compare and it was actually shorter than the 788 Bando belt. Needless to say, I swapped the belts. The FM bushing was shorter so I swapped that as well. I kept the same 4 gram weights that were in there but with the shorter belt and bushing I've gained 5+ MPH on the top end but lost low end pick up. I mean it's really a dog off the line now and it's not as good on the hills and I live in the hills so should I get a stiffer contra spring, change back to the longer bushing or go back to the old longer belt?
THANKS
|
|
|
|
Post by 90GTVert on Aug 9, 2011 15:32:37 GMT -5
The shorter bushing is putting the two halves of the front pulley closer together at rest/off the line. Not only does that make the belt ride higher in the front pulley, but also lower in the rear pulley. Both giving you a less aggressive "first gear". No contra spring or roller weight will make up for that. You might be able to increase your performance on hills by getting RPM up more with a different contra or rollers though. They might help takeoff by increasing RPM, but getting full use of the pulleys will do more. CVT tuning to get the best out of it takes time and tinkering. You could try to shim the boss to make it just a little longer. Maybe go back to the other boss with the longer belt. The fact that the 792 is longer doesn't necessarily mean that the 788 is stretched. I have a brand new 792 here that is shorter than a brand new 788 of a different brand. Same thing is true with tires a lot, especially in cars. I had 275mm BFGs on my Mustang that were way wider than some other brand of 275mm tires of the same specs and same wheels on a friend's Mustang. Gotta love the precise standards in manufacturing of all kinds.
|
|
|
|
Post by 90GTVert on Aug 9, 2011 15:40:38 GMT -5
|
|
|
|
Post by Fox on Aug 9, 2011 16:25:49 GMT -5
Okay so I probably have the belt riding up in the pulley a little at idle so I think I'm gonna try the old boss with the new belt and add then add a shim if needed. I have to say I'm liking the extra speed a lot so hopefully I won't lose too much going back to the longer bushing.
Thanks again Brent.
|
|
|
|
Post by 90GTVert on Aug 9, 2011 16:36:18 GMT -5
Let us know what you try and how it works and if we can help.
|
|
|
|
Post by Fox on Aug 9, 2011 16:50:19 GMT -5
Will do!  |
|
|
|
Post by Fox on Aug 9, 2011 18:21:14 GMT -5
Okay so I put the old boss on there with the shorter belt and it improved off the line some but it was still worse than before so I installed one stock washer on there and now it's got decent pick up off the line but I lost a few MPH. No big deal. I ordered some 4.5 gram Dr. Pulley sliders from autotech today. Maybe they will help a little. I'm thinking a stiffer contra spring with the 4.5's should get me a little better take off without losing any speed. :dunno: I'm not sure what spring to get to be honest. I've never screwed around with them. I can spread the rear pulley apart easy with my fingers.
|
|
|
|
Post by 90GTVert on Aug 9, 2011 18:53:02 GMT -5
I stick with the stock contra unless I can't get the revs I want with the weights I have or if the belt slips. I used to mess around with contra springs more, but then it seemed like I could get the same results from the right weights in most cases and the rear pulley wasn't a PITA to deal with. I've become so accustomed to 90cc+ scoots though, that perhaps I have just forgotten what it's like to need to "downshift" on a hill?
|
|
|
|
Post by Fox on Aug 9, 2011 18:56:30 GMT -5
I want a 250 so I can hop on the freeway but I know I'd kill myself. lol
|
|
|
|
Post by 90GTVert on Aug 9, 2011 19:17:10 GMT -5
I want a 150 so I can get my M endorsement on something slower than the scoots I ride on the shoulder.  Actually I could use it now if I wanted to get it running to take the skills test for my license. Just don't feel like being around people if I don't have to. That's literally all that's kept me from an M license for the last few years. |
|
|
|
Post by Fox on Aug 9, 2011 22:21:08 GMT -5
I just went to the store and back and I've lost some hill climbing speed and a little on the flats so I think I'm gonna either go back to the longer belt, or add another washer to the drive boss. I thought that a tighter belt would be a good thing. I guess not. Like you said Brent these things are tricky.
|
|
|
|
Post by 2strokd on Aug 10, 2011 3:24:37 GMT -5
Ahhh, cvt tuning! A give and take world for sure! Hows the width on the two compare? Did you even try the longer belt with the wider drive boss? TBH, with OEM equipment i never could get full travel out of the pulleys unless i shaved or filed vari halves. Then it would shift different, wanting to hold first too long, then dump into second to hard as the rear pulley "passes the curve" .
You will need to find that sweet spot that suits your needs both ways. Meet in the middle so to speak. Do have any thinner spacers to play with for the vari? If not maybe finding and or making some would help allot. Did me when i played around with the OEM stuff allot. (ahh the memories lol) It can be tricky finding spacers with the correct ID and OD. Usually you have to shave down (or out) one or the other to make it fit the crank and make sure the vari will travel OVER the spacer. If not, well then its just a restrictor. Usually the stock spacer is from .4mm-1mm. You could shave one of those down if you have extras? Just remember to have a spare in case you went too far or something.
|
|
|
|
Post by Fox on Aug 10, 2011 15:35:25 GMT -5
Yeah I'll play around with it some more. It's running okay as -is but I would rather have more low end torque than top end speed. Right now it's right in the middle where it struggles up the hills cause the engine can't get up to full rev's.
Hey Robert, I want to order a new spring but I'm not sure which one. At $15 a pop I really don't want to buy all three. Which one would you recommend. The 1k, 1.5k or the 2k ?
Thanks!
|
|
|
|
Post by 2strokd on Aug 10, 2011 15:41:54 GMT -5
Tough call on a stock motor...?.. Hmmm, Just do what i did with my wife,s scoot and add a torsion control with the stock one. That put hers right on the money with 5g sliders. If no on the torsion control ide say go with the 1,500 if its from Carlos (Autotech). Might have to bump up the weights a bit though?
|
|
|
|
Post by Fox on Aug 10, 2011 15:54:42 GMT -5
I was going to get one from scrappy. You got a link for Autotech?  |
|
