MCX 180 Clutching Update

[Shermanator]

We may have a winner here. We switched to Vernon Yamaha's setup for the clutch this season and after a couple trips out on it I think we have a winner!

14.5 rollers
blu/whi/blu primary
EPI purple or green Cat spring secondary
51 degree helix
8BU arms, empty!
18T top gear

First off, although we didn't have the deep snow to try this setup in, yet, we did have a couple good hills and did multiple pulls before checking clutch heat etc. Right off the bat, clutch heat was down 60 degree's! That's huge! Last season we'd do one good pull and the belt was melting, this time, we're in the ballpark with the 2 strokers! RPM's are down at tad, max was 8600 but even at that we're still getting 60mph track speed anywhere we want. It'd be real sweet if we could actually get more than 500 km out of a belt, more money for gas! Sherm

 

[Thistledoo]

Sherm can u post what you had in there before please??

 

[Tarzannr1]

We may have a winner here. We switched to Vernon Yamaha's setup for the clutch this season and after a couple trips out on it I think we have a winner!

14.5 rollers
blu/whi/blu primary
EPI purple or green Cat spring secondary
51 degree helix
8BU arms, empty!
18T top gear

First off, although we didn't have the deep snow to try this setup in, yet, we did have a couple good hills and did multiple pulls before checking clutch heat etc. Right off the bat, clutch heat was down 60 degree's! That's huge! Last season we'd do one good pull and the belt was melting, this time, we're in the ballpark with the 2 strokers! RPM's are down at tad, max was 8600 but even at that we're still getting 60mph track speed anywhere we want. It'd be real sweet if we could actually get more than 500 km out of a belt, more money for gas! Sherm

Is this on a 162 nytro and what is the low gear?
Epi spring ? where can i get one?

 

[Shermanator]

Thistledoo, we had the 15 rollers, 8BU's with max weight, sameo primary and secondary springs and a 19T on top.
Tarzann1, the purple EPI spring (I assume) can be bought at any dealer that deals with turbo's, the Alpine Turbo spring is the same, sameo with the green Cat spring. My sled does have the 162" on it, lower gear is the stock one.

I have no doubt that the gearing down has a huge effect on the lower clutch temps but obviously we've got the clutches pretty much married up now. Sherm

 

[Thistledoo]

so your running 18/40 with a 68 link stock chain?

the only thing that surprises me is the 51 deg helix.

 

[Tarzannr1]

I think that its the 14,5mm rollers and the 51 helix that lower the heat and not the 18 tooth.
I would try a 21-40 giring and get a chain that fits this perfectly with not so much slack in it.

 

[Thistledoo]

21/40 would melt belts and secondary clutchs in our snow conditions.....

 

[summitboy]

I would think the 18 tooth definitely helped with the heat. Not sold on the 51 being the heat saver. Lol, if i ran that 21/40 on my Pex i could liquify the secondary lol. JMO

 

[Tarzannr1]

Maybe i am wrong.
But 14.5mm rollers more pressure on the belt
51 helix ore maybe a 51-43 helix and a 20 ore 21 giring will result in lighter weights and you will get more hp to the track?
Any one tryed this and then see what temp there is ? I have not.

 

[Shermanator]

Yup, stock chain, tensioner has about a 1 1/2" left in it although I don't think I'd want to go any further than it is! I think its a combo of everything thats done the trick, the 18 for sure but the clutching. It runs great, my partner said the same thing on his, backshifts lightning fast and just plain rips! With the 19 top last year and the 15 rollers it obviously wasn't matched up to the tension the purple EPI spring was supplying in the secondary and we were getting insane clutch/belt heat. The 14.5's do put more pinch on the belt but I'm not sure how to get the extra 200-300 rpm out of it with the arms at no weight. I guess it doesn't much matter when its working as good as it is, time and big snow will be the real test though....Sherm

 

[SNAFU]

Interesting findings. I had always thought that smaller helix angles would increase belt side force. So I would have expected less force with a greater angle helix, more slippage, and higher temperatures. Also the larger helix angle may cause the primary to shift out quicker and you aren't picking up the rpms. You could also try to put the stock GWG primary spring back in. It has the same starting force as the BWB, but a higher finishing force and this should bring your rpms up a bit without affecting bottom end engagement.

Keep us posted on your results. I am still trying to figure mine out too. I should be heading out next weekend and will report back on my set-up.

 

[Shermanator]

I was wondering if going back to that primary might help out with a few rpms, will have to try it, thanks Snafu! Ya, Nick at Vernon Yammy should know what he's doing and its nice when they share their info with us layman's, saves alot of time and alot of money! Sherm

 

[Climbmax]

Make sure you wind the EPI to the proper tension.....the timing of the EPI spring and the OEM spring are different......1-0 is the proper winding.
Its the set up guys........run it on my 180 162 sled and it rips hard. 51 for upshift on the little tracks. If you are running 174's you need to go to 47 helix.
Safe sleddin
RS

 

[Tarzannr1]

Anyone who have tried the white Heel clicker primary spring 170-300 ?

 

[Tarzannr1]

Make sure you wind the EPI to the proper tension.....the timing of the EPI spring and the OEM spring are different......1-0 is the proper winding.
Its the set up guys........run it on my 180 162 sled and it rips hard. 51 for upshift on the little tracks. If you are running 174's you need to go to 47 helix.
Safe sleddin
RS

What will you recommend for my Nytro mcx 270 153"
I have a green articat spring in secundary

 

[Shermanator]

Yup, its at 1-0, it'd be danged tough to set it anywhere else, she's tough to change belts now! Climbmax, you getting top rpm outta yours with the setup? My concern about changing the primary to a stiffer spring may change the tension on the belt as well in the primary....Sherm

 

[SLEDIT]

split helix

I don't get to the mountians all that often ride at 1700' mostly had trouble with spinning the track hard and over revs out of the hole with a straight 45deg dalton helix and epi purple spring at 1 in sec 0 in helix. I am now running a 50/44 dalton industries R series helix I would even go 52/44 next time the split is not equal 20% steep then straight. Thought this may help you Tarrzann, in your vids looks like you ride some flater ground. I have a diff primary setup STM supreme tool 60 gram base adjustabe weights set at 76 grams and a blue brown blue spring 16.5 rollers 180 kit 2.5x162 setup is working great here and was happy when i did get in the mountians. This may not help any of you but thought i would toss it out there.

 

[Shermanator]

I picked up a new blu/whi/blu primary spring and it gave me another 200 rpm, spring obviously lost tension after 2 seasons! Its reliably hitting 8700 on every pull and after some further testing, clutch heat is still way down, this'll be our setup for the season! Sherm

 

[bdoe22]

EPI PURPLE

is the epi purple you guys are refering to the #acss-5 purple 86/148? and i am curious of the high helix angles....currently have mpi 180 kit- right now i am running 14.5 rollers, 8bu's, 17.3 inner, light alum with hole outer, blue pink blue, 45 helix and white sec spring....seems to do ok, pulls hard, but on a long deep climb will only pull ~8000 rpm. started with the stock 39 and would pull higher r's but didnt backshift very well.

 

[Shermanator]

Sorry but I can't even give you a part number for the EPI spring. As mentioned we were having big heat problems with our old setup and this one has pretty much alleviated that entirely.....Sherm