G4 belt running to top of primary, very hot temps, found out cause

Been checking pdrive on the hill at 6500’, was surprised to see I’m running to top of primary, basically out of gear and maxed top end speed..50mph

maybe why I am seeing surging rpm from 8-8200rpm on gauge

did a long 100second wot pull and seen primary temps hit over 104c/225f on top of primary were belt was running.. I think this sled from past exsperince should be geard up at least one tooth on top sprocket..

Sled is completely stock with 3 percent breakin left, have 2.5 grams added to pivot bolt since 50percent breakin..
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Called Joey tonight and problem solved, here was his reply..

Had a good conversation with Joey from I backshift, he's one of the best if not the best with brp clutching.. Before I was into describing my problem More than a minute he already new of the problem, it's charterisics and what was needed to fix problem, he sure is welcome to share his wisdom on here, he says he has lots of good info on his website blog under G4 pdrive, he is running hard getting kits that work out the door, and this G4 is keeping him real busy..

first off stock gearing is good for 76mph on a 1 to 1 ratio which is more than needed for the G4 175.. This is almost good enough for turbo sleds if the rest is fixed correctly!!

he says if I'm only seeing 50mph on a hard pull and gearing is good for 76mph and belt is top in primary, it's very easy to find out what's wrong.. Had to think about it for a bit and it came to me..

belt has has to be slipping in secondary at bottom of sheives with least side surface area it's running on.. He's been seeing this lots and there is only two remedies.. First is to go to less helix for slower up shift or increase secondary belt spring tension with stiffer spring.. He highly recommends the latter one.. With so much snow load for mountain riding, large tracks and a strong motor, the secondary needs lots of squease to prevent slipping and heating of clutches and belt..

another gain of more squease will be that belt will now be able to run not as far up primary and not as far down secondary utilizing more surface area and allowing for a much cooler belt, less pealing of belt on cooling fins

he had me look at the lower secondary sheives and he was exactly correct, with heavy rubber deposits from belt slipping and above a dark shoe polish finish where it had extra heat added.. He said guys are reporting over 300f and belts don't last long, last year on 17s there was no cooling fins on secondary and this just happened that much quicker than this year..

he says many guys are telling you to drop secondary spring pressure and this just makes problem worse, or add more pin weight and this just makes it happen quicker.. Problem stands with secondary spring..

also has found problems with primary springs and that's a entire another issue to deal with latter, he's working on some ramps for turbo sleds and hoped to get them out soon


once again thank you Joey and can't wait for your arms.. Problem solved, and no need to gear up

Think you could be over doing it with black spring, silber is using the Green spring and they are not seeing problems.. Anyone try something in the 260 in finish rate ? For stockers?

Talking with dealer today, they will be swapping out springs now on there problem sleds, once again who is testing these sleds out for doo.. They had a entire year after last years BS to figure this out.. Little sad

Don't think one should have to spend money and time looking for a clutch kit after spending 18grand on a sled the month before.. This is doos problem, not the owner...

Yes thanks to BJ and JOEY, PAUL strateline for making up for doos lack of..

High Voltage said:

Yes BRP should have been able to figure their clutching problems out, but they haven’t. Now if you are on here, or DOOTalk you have been reading over and over the problems with belts exploding or ripping apart by hitting the belt guard holder. There are a number of clutch kits to buy advertising on here, get one! I don’t know who’s is the best, but they all are including a stiffer secondary spring. I don’t see anyone complaining that has one, so they must all be taking care of the issues. I put Big John’s in from the get go, and have 500 trouble free miles so far on a Gates belt. If you are burning through belts every time you go sledding,and are doing nothing but coming on here complaining I guess I just don’t understand what you don’t get.

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For myself I never blew any belts yet.. Just caught this on the hil.. But I bet out of ten new G4 owners less than two will ever get a clutch kit for their sled, maybe lack of experience or just don't think there is a problem, and yea they will keep driving it and just keep replacing belts.. Never knowing it's a brp incorrect set up problem..

High Voltage said:

How much are you spending on belts, and down time?

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Well did a few changes today to resolve the belt slip problem..

Installed the black 157/303lb secondary spring with a shockwave helix.. See how much helix this motor can handle, since it feels very Revy and lack of down low grunt.. Another buddy set his up similar and is pulling close to 46 degree helix

Will wait and try this out before doing a gear change, once this is figured, silber will be installed..

Ya for sure

I did a few pulls against the same sled last trip and he just had the hole shot every time and there was no way to catch him..

When he was not looking I had a little peak:eyebrows:and seen he had shock wave about 3.5 to 4 turns out and a green green spring in there.. :eyebrows:

It worked very well and he said his backshift was great..he geared up he said a tooth, I was going to leave it for this week and try stock thou..