Belt slip - clutch modification???

[dirtdobber]

20161103_054052[1].jpg20161103_054120[1].jpg

I hope these pics show what I'm trying to show. The belt is glazed. I sanded a portion of it so you could see the shiny (glazed) part versus the unglazed part.

The other pic is the drive clutch surface. You can see the slick portion versus the portion that I have sanded. It will be interesting to see how long the roughed part stays rough.

[Dan67]

Well the green spring is the stock tension on our clutch. On my hustler I installed a red spring which keeps the cvt in lower gear longer and allows a quicker downshift as the red spring is much stiffer then the green. My t-20 chain runs to a large 38 tooth sprocket. So I really need the bottom end torque.

[dirtdobber]

Thanks Dan. I will probably order the green spring at some point and give it a try. Best I can tell my driven spring is the black one, as it has 7 coils. When I get the new belt on and adjust the tension, I"m going to have someone drive me around while I watch the clutches. I want to see their behavior when the torque demand increases and decreases.

[Dan67]

If you'd like, I can drop my old green spring in a flat rate box and mail it to you to try out. Just pm me a mailing address.

[dirtdobber]

Dan that's a great offer. I"ll send you a PM. Thanks

[dirtdobber]

For what its worth, here's where I am on my issue. I bought a new belt but I have not installed it. I measured the new versus my old and they are so close to the same width I'm just going to run the old for now. I roughed the faces of the drive and driven clutches and tightened the belt. I also sanded the glaze off the belt. This made a significant improvement. Much to my surprise, tightening the belt stopped the creep shown in the first video.

I went for a ride over the weekend and paid attention to how I was driving. I found that on a tight trail the machine is too fast, meaning a little above idle the clutch engages and the machine starts off slow but picks up too much speed (for the type of trail, that is), so back to idle I go and the cycle repeats itself. Obviously a stronger spring is in order to slow things down on the tight trails so I can keep the clutch engaged. Things are looking good!

[dirtdobber]

20161203_080311[1].jpgGot the red spring. Big difference between it and my original (black spring, I believe). Got it installed yesterday.

Drained the transmission fluid. With about 12 hours operation on it the fluid was nasty. Castrol has a CVT automatic transmission fluid that I put back in it. It has built in friction modifier. Anybody ever used it?

Anyway, its raining here so I didn't get to test drive, but I can tell from the short trip from the workshop to the garage the new spring is going to make a huge positive difference in machine performance!

[allwheeldrive]

How did this ever work out? I've got a Comet 780 that engages much too quickly (lots of bite no slip) and was thinking the red spring might let the engine idea and not turn the transmission.

[dirtdobber]

Allwheel it worked out just fine. I installed the red spring, used some coarse sandpaper to scuff all my pulley sheaves, and adjusted the engine so that I have about 1 inch of deflection in the belt. I have taken it out for about 4 hours since these adjustments and it performs sooooooo much better. It will spin the tires with ease now, and my top speed is good - somewhere between 25 and 30 mph (according to a 4 wheeler pacing me).

I saw your thread. I don't know anything about a coot or what type of transmission it has, but......if it has a T-20.......I would say back off your belt tension just a bit and give it a try. The photo you posted looks like the insides of a Comet 780 drive clutch. I have an old spare laying around I can photo for you if you want.

[Delduck]

I don't know if I'm allowed to do this but here goes. My belt is set at 1 3/4 deflection on a max4 with a new clutch, motor, and trans, and red spring And seems to have no speed can't tell about power yet because I did a trial drive on grass at the shop. Should I tighten up the belt to 1 inch deflection? If I was suppose to put this in a new thread please let me know. I apologize.

[dirtdobber]

Delduck I suppose there could be lots of things going on. First of all, I don't know how fast is "no speed at all" is, but here are some things to think about:
1) Your new engine - is it governed? If so, it may not be reaching the rpm you need to get your speed up. I don't run a governor at all on my engine - I just removed all the linkage and the throttle cable ties directly to the carb.
2) Is your test run a wide open stretch? It takes some room to get my Hustler "wound up", so to speak, to achieve top speed.
3) The more rolling resistance you have, the more torque required to move your machine. The more torque required = slower your ground speed. Rolling resistance increases on soft ground and with low pressure tires.
4) Ratios. I wonder if your machine is just set up with a low gear ratio?
5) Belt slippage. Can you tell if you have any slippage? It would probably do you good to scuff the pulley faces to ensure a good grip on the belt.
6) Belt tension. You may need to tighten your belt a little. As I understand these systems, you want the belt just tight enough so that at idle the transmission will spin with the laterals in the neutral position, but loose enough that it will not move the machine or squeal the belt if you engage the laterals.
7) I can't think of anything else since my wife keeps interrupting me!!

[Delduck]

Thanks dirtdobber the mechanic is going to look into it more but I have at least 1/2 inch of room on the belt. Not shure about the governor and if I would say my old 18 hp did 24 mph this 23 is only moving at 12 mph but I have not had but 10 min on the machine, although I did run it strait for 60 yards and no increase in speed. The clutch just came in from Richards tonight so we threw it on and tried it out. Thanks for the reply I'm going to ask him tomorrow about the stuff you touched on. Thanks again

[dirtdobber]

If it ran 24 mph before, it should do it again. Your new clutches should be the same diameter as your old ones. You haven't changed sprockets to change any ratios there. Even at 1/2 inch out of adjustment on teh belt you should still get really close to your 24 mph.

[ARGOJIM]

The new 23 is probably not turning enough rpm, have your mechanic set it at 4000 rpm in neutral.

[Delduck]

Will do thank you. I'm assuming that is at wide open on the throttle correct? These questions sound stupid to me but after $1000 dollars a 3 people later it's easier to ask these stupid questions than pay by the hour for someone else to learn.