I understand that the 20's have a shim in the spider than the 19's didn't under the spider...Might be an issues there with belt tolerances ( sheave offset's)
Mds weights worth it on the alpha?
- Thread starter Vern
- Start date
The shim in front of the spider to set the roller to weight clearance is thicker on the 18-19 clutch. The MDS weight profile was designed for the 18-19 clutch shimming I believe. For a test need to swap in a clutch from a 18 or 19 and see how it pulls with MDS weights installed.
If it works good may just need to get the shim and spider nut from the older clutch installed. Not sure where to purchase it from though.
If it works good may just need to get the shim and spider nut from the older clutch installed. Not sure where to purchase it from though.
In 2018 the clutch that didn’t have the shim in front on the spider was used on the low elevation 800 sleds (ZR and XF) And had the taller nut that stops the travel in on the clutch. (Needed because of missing the thickness of shim)
That clutch worked great converting 16 and 17 sleds to the new setup!
My 19 M8000 has the same shim as the 18 did. And where the shim is installed does not affect belt tolerance because it does not have a step in it.
I had the same issue with my '20 and MDS. Would not pull over 7900rpm. Steve suggested that I needed to get a different spring and try that.. Unfortunately I just took wts out and went back to stock. I had his set up on my '15 and it was night and day from stock in all riding, but then again it was wts and spring as a kit where as the '20 kit was just wts. Hard to beat the stock setup but will try again this winter at some point. Steve is great to deal with!
Time to bring this post back up.
so I finally got a couple rides in with the jaws pipe installed on my ‘20. The few times I got to open her up it appeared I did gain 1-200 rpm with stock clutching other than 45 helix. So since it appeared I needed to bring the rpm down a bit I was going to try the Mds again and see what happened, and maybe try a few different primary springs.
Upon swapping out the weights I did some investigation and found out that the Mds weight tips were resting on the moveable sheaves and then hitting the rollers enough that they were actually holding the sheave probably .025” or better from being able to fully open. I uploaded some photos to try and show the difference.
Could this have anything to do with the performance issues I’ve had with these weights, or is that a normal thing with Mds? I wouldn’t think it’s normal having the weights smashed into the rollers at rest. The stock weights have a bit of room to wiggle when the clutch is fully open. Would it be worth grinding a bit off the tip of the weights to get them to set down in a bit further and allow the clutch to be able to fully open, Or are they just flat not going to work? Those with ‘20s that are successfully running Mds, are yours the same way?
so I finally got a couple rides in with the jaws pipe installed on my ‘20. The few times I got to open her up it appeared I did gain 1-200 rpm with stock clutching other than 45 helix. So since it appeared I needed to bring the rpm down a bit I was going to try the Mds again and see what happened, and maybe try a few different primary springs.
Upon swapping out the weights I did some investigation and found out that the Mds weight tips were resting on the moveable sheaves and then hitting the rollers enough that they were actually holding the sheave probably .025” or better from being able to fully open. I uploaded some photos to try and show the difference.
Could this have anything to do with the performance issues I’ve had with these weights, or is that a normal thing with Mds? I wouldn’t think it’s normal having the weights smashed into the rollers at rest. The stock weights have a bit of room to wiggle when the clutch is fully open. Would it be worth grinding a bit off the tip of the weights to get them to set down in a bit further and allow the clutch to be able to fully open, Or are they just flat not going to work? Those with ‘20s that are successfully running Mds, are yours the same way?
I have a spare clutch from a 2018 low elevation sled that has no shim at all under the spider. I would like to get the shim and spider nut from a 18-19 clutch used in the mountain sleds and install it. Then run the same setup with MDS used in my 2019 for a test. But don’t have any close access to someone who could rebalance the clutch.
Vern
I just checked mine. When against the roller there is about .125 inches of clearance where yours hit. At rest the weights actually swings a little bit.
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Interesting, so that would mean the spider has to be shimmed differently wouldn’t it? Yours is a ‘20 as well right? Wonder why they would send out clutches with such variance
I tried the MDS in my 2020 Hardcore yesterday and I must say WOW! I was pulling 8200 all day long with them. Those weights combined with the Jaws pipe, V-force reeds, SSI head and a an ECU re-flash REALLY pull hard. They have a ton of weight in them as well for our altitude. I think the stock weights were 70.2 grams and the MDS are 73.9 if I remember correctly. I would have to say the Steve from MDS may be right when he said that if you can't pull RPM with his weights, it's not the weights, it's something else like clutch misalignment, a too low total force primary spring, a too high degree of a helix or some other issue.
I have no doubt that the weights should work, but obviously cat has something going on with certain sled. With my findings of the Mds weights on my sled hitting the rollers to the point it’s holding the clutch partially engaged all the time, I’m wondering if it’s a spider shim variance or something. Especially where CB.8 says his Mds weights don’t hit the rollers at rest and actually have a bit of free play.
Just for the sake of science, You should check yours out and see if your weights are smashed into the rollers or if you have a bit of clearance at rest.
I will try to remember to look today Vern. I know you're a skilled tuner and I don't doubt one bit what you are saying. I am just happy to see they work on my 2020. I tried the 105/285 Cat primary spring installed now and so far I like it. I believe I did gain a few RPM by doing a clutch alignment. Mine was off by .035".
For the most part I know how each component of the clutches affects the performance, but I dont know if Id consider myself a skilled tuner. I don’t know what or if any difference there will be from the weights already being engaged with the roller like on my sled vs. one that has the extra clearance. it was just an observation I made, so now I’m curious.
I’m glad they’re working for you. I was actually going to try some different springs this go round to see if I could get the Mds to work until I seen how the weights were sitting in my sled. If I find out It’s a non issue I’ll probably carry on with trying different springs with the Mds.
I’m glad they’re working for you. I was actually going to try some different springs this go round to see if I could get the Mds to work until I seen how the weights were sitting in my sled. If I find out It’s a non issue I’ll probably carry on with trying different springs with the Mds.
I rode some wicked heavy weird snow last weekend. At times in could only pull 7950 but still pulled like a freight train. I did pull a washer and installed a new primary spring as it felt like it was starting to get week. Today no matter what I did in any situation pulled Rpms all day long.
The stock spring was a 120/265 per Steve’s recommendation I went with the venom 130/280. No real difference in engagement.
The stock spring was a 120/265 per Steve’s recommendation I went with the venom 130/280. No real difference in engagement.
I had same experience here in PNW. R’s were the same . Went out again this weeknd , not as deep and heavy . But sled ran like a freight train. You running his helix ? It helped me
I’ve been emailing Steve and it is sounding like the weights resting firmly against the rollers is normal for his set up. So I guess that rules out that theory.
I ordered a 120/280 spring from bdx and found an slp spring in my collection that is supposedly 110/290 on these sleds according to their website, so I’ll probably give those a try. I was going to buy the 130-280 venom spring that Steve suggested, but they wanted as much for shipping as they did the spring so I couldn’t do it.
One things for sure, it sure would be helpful for testing if it would snow
I ordered a 120/280 spring from bdx and found an slp spring in my collection that is supposedly 110/290 on these sleds according to their website, so I’ll probably give those a try. I was going to buy the 130-280 venom spring that Steve suggested, but they wanted as much for shipping as they did the spring so I couldn’t do it.
One things for sure, it sure would be helpful for testing if it would snow
