Proven resolutions to the G4 clutching delema

snochuk · Apr 8, 2017

OK
Post clutching resolutions here that have worked.
BRP's bulletin releases to date, gearing changes, weight changes, combinations and alternate clutching systems used to stop the belt replacement costs and frustration.

Be nice to have one stop to find solutions to try.
Thanks in advance for your input.

Teth-Air · Apr 8, 2017

Has anyone tried a Polaris clutch yet?

snochuk · Apr 8, 2017

Teth-Air said:
Has anyone tried a Polaris clutch yet?

Mountain Magic has a Polaris machined to fit and a machined and balanced that can be stand alone primaries or can be teamed up with a Team Tied for a bullet proof fix. A balanced wobble free primary and a zero scrub floating secondary and longer crank life. Win win win.

Just sad that a mod shop beat BRP to a fix....about 2Kish but then you are headache free.

Again cost to sled owners when BRP should be solving and supplying for their customers.
Since rep has killed tradein this is one way to at least have a reliable sled you feel confident in.

Tchetek · Apr 8, 2017

Obviously the clutches and belts are hot!

Thanks But Curious if a thermal imaging camera would show the trouble spots.

Low shift vs full shift

Or

High wobble vs low wobble through the full shift range?

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BeachSled · Apr 8, 2017

Dean at Mad Motorsports has a kit finalized. He had a guy out testing it, he rode 9 days on the same belt and it still looks good. In the group of 850s the stockers all burnt a belt a day and the sled with the kit performed solid!

Just passing along some info, I don't have an 850 but I do feel for you guys. Might be worth giving Dean a call to talk about the setup he has.

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Kakwasledder · Apr 8, 2017

Well, first of all I would like to know what skidoo has for new gearing for the 2018. I can almost guarantee that it will be lower. I blew a belt at 650km and geared mine down 2 teeth on the top and now I have over 2000km on the new belt. I didn't really notice any difference in speed or bottom end torque, although I probably lost a mph or two on top end. But I don't care about top end speed. I setup the belt deflection like Dave Norona suggested with the belt about an 1/8" higher than the bottom cog on the top of the belt. I only had to readjust it after about 1900km. Oh I know everyone is going to want to go higher gearing, but it worked for me.

I also added weight to the primary, to bring down the rpms, and it worked well but I need to tweak it a little more. . But I know the clutching still needs work.

As for heat, I have checked other 8oo xm's with the TRA's, and after 4-5 pulls on the same hills, both mine and the TRA's are about the same temps, I can put my hand on them but cant leave them there long. So not sure there is a problem there.

This is only my observations and what has worked for me. I believe gearing down would help a lot.

Daag44 · Apr 8, 2017

Items to Lower Belt Temps

1. Clean clutches and belt.
2. Proper Belt Break-In.
3. Belt deflection kept adjusted.
4. Pivot Weight adjusted for Maximum Power Engine Speed.
5. Proper Clutch Alignment.
6. Engine Shims if necessary.
7. Proper Secondary Spring Tension.
8. Gearing Changes for the application.
9. Belt Heat Evacuation.

All these items have brought down belt temps dramatically as per experienced Summit owners and professional tuners out West as early as the beginning of December 2016.

snochuk · Apr 8, 2017

Re: Items to Lower Belt Temps

Daag44 said:
1. Clean clutches and belt.
2. Proper Belt Break

These are all excellent pints that help and have applied all to this sled (except #8 as sled not overrevving on pulls but still may down as top end unimportant to me) and most points to all my summits since my first summit in 2002.
Just searching if there is more as you still can't hold hand on primary.
Third full day of hard riding took out belt.

Cutting holes inbehind A arms next for a 4"ish vent to put air straight to primary.

Daag44 · Apr 8, 2017

Gearing, Track Speed and Max Engine Speed

Gearing, Track Speed and Max Engine Speed are all things to be seriously considered. One of the reasons that gearing changes will affect belt temps is where the belt rides in the clutch sheaves. Take the Summit 850 163" with 21/51 gearing. The 1:1 clutch ratio brings a sled set 8100 rpm from factory to roughly 107 kph (66 mph). If the trail out speed to your favorite riding area reaches over 119 kph (74 mph) then the belt gets awfully close to the max overdrive which not only increases belt speed dramatically, but also forces the belt to turn around the secondary in a very tight radius. Depending of the duty on the belt and belt slip this can quickly cause a belt to blow-up without much warning.

Max Engine Speed also plays a large role in this equation. BRP mentions the Max Track Speed for the 21/51 Gearing to be 123 kph (76 mph) with the risk of hitting the Rev Limiter. To reach this Max Track Speed in Full Overdrive Shift the Max Engine Speed needs to be 7800 rpm. Most Summit 850s that I see in videos from the West are turning 8100+ rpm out of the box in roughly position #3, so here we see the possibility to reach the Rev Limiter.

When selecting a Gearing change or making no change to gearing, the Track Speed needs to be considered for the most severe riding conditions and Trail Out.

Daag44 · Apr 8, 2017

Re: Gearing, Track Speed and Max Engine Speed

snochuk said:
Daag44 said:

1. Clean clutches and belt.
2. Proper Belt Break

Click to expand...

These are all excellent pints that help and have applied all to this sled (except #8 as sled not overrevving on pulls but still may down as top end unimportant to me) and most points to all my summits since my first summit in 2002.

Just searching if there is more as you still can't hold hand on primary.
Third full day of hard riding took out belt.

Cutting holes inbehind A arms next for a 4"ish vent to put air straight to primary.

Can you provide the full calibration of your sled?

Also, do you have any videos of your riding so that I can hear the Max Engine RPM?

Daag44 · Apr 8, 2017

Affects of Gearing Changes

Kakwasledder said:
Well, first of all I would like to know what skidoo has for new gearing for the 2018. I can almost guarantee that it will be lower. I blew a belt at 650km and geared mine down 2 teeth on the top and now I have over 2000km on the new belt. I didn't really notice any difference in speed or bottom end torque, although I probably lost a mph or two on top end. But I don't care about top end speed. I setup the belt deflection like Dave Norona suggested with the belt about an 1/8" higher than the bottom cog on the top of the belt. I only had to readjust it after about 1900km. Oh I know everyone is going to want to go higher gearing, but it worked for me.

I also added weight to the primary, to bring down the rpms, and it worked well but I need to tweak it a little more. . But I know the clutching still needs work.

As for heat, I have checked other 8oo xm's with the TRA's, and after 4-5 pulls on the same hills, both mine and the TRA's are about the same temps, I can put my hand on them but cant leave them there long. So not sure there is a problem there.

This is only my observations and what has worked for me. I believe gearing down would help a lot.

Something to consider with gearing is the recovery in Track Speed changes. So between Track Speed up a climb and trail out, there is a compromise. In fact, any change in the Driveline calibration is a compromise. So whatever works for your sled simply works.

Considering the 850RE has a great deal more Low End Torque than the 800RE, I see no trouble to Gear Up or Down, or to keep the same stock gearing. It all depends how the gearing is used for the application, and how well the clutching is calibrated to match the gearing. For instance if a gearing change transfers more of the Engine Power to the track, it will likely change the Max Engine RPM and may require adjustments in the Primary and Secondary, and even in the Alignment.

ktmsx350f · Apr 8, 2017

Re: Affects of Gearing Changes

Good trend so far hopefully can stay on track and just post up what you have as your calibration or have been involved in!!

ktmsx350f · Apr 8, 2017

snochuk said:
Mountain Magic has a Polaris machined to fit and a machined and balanced that can be stand alone primaries or can be teamed up with a Team Tied for a bullet proof fix. A balanced wobble free primary and a zero scrub floating secondary and longer crank life. Win win win.

Just sad that a mod shop beat BRP to a fix....about 2Kish but then you are headache free.

Have you talked to anyone who rode the setup personally or just the shop? I assume 2k is both clutches ready to go calibrated a belt and everything needed

snochuk · Apr 8, 2017

Re: Gearing, Track Speed and Max Engine Speed

Daag44 said:
Can you provide the full calibration of

Also, do you have any videos of your riding so that I can hear the Max Engine RPM?

Sled is set up and pulls steady at 7900 to 8000 when i can find that tiny out of place display.
This can vary a bit depending on snow condition.

On flat ground between areas RPM modulated with thumb.
Not changing clutching every two miles.

My friends and I have been building and thrashing sleds with everything from nitrous to turbos for 30 years.
I'll pass on video asisstance from 5000km away.
But thanks for the offer, really.

Daag44 · Apr 8, 2017

Most common Driveline Calibrations

ktmsx350f said:
Good trend so far hopefully can stay on track and just post up what you have as your calibration or have been involved in!!

Dealers and Owners mostly. The most common calibration change was adding lots of weight to drop the Max Engine Speed to 7800-7900 and 8000 Max on Trail. Also a stiffer sec spring to match the change in the Primary. Alignment has been found to being all over the place and was the single most important change to lower Belt Temps. In extreme riding where long climbs were repeated or breaking trail went on for miles and miles, hot belts from the things listed above wore the sides too quickly needing more frequent adjustments in Belt Deflection and clutch/belt cleaning. Gearing-Up 1 on top gear has also shown to help, but this depends on how gearing changes affects the calibration as explained in the previous post. Blowholes were found to be a great help to evacuate excessive Belt Heat, especially when the Belt Heat Exhaust was blocked. All in all these were calibrations along with the points mentioned in a previous post that showed to lower the Belt Temps a great deal. Unless you have any specific questions on the calibration that I mentioned, I will leave you guys to your thread. Best of luck.

snochuk · Apr 8, 2017

ktmsx350f said:
snochuk said:

Mountain Magic has a Polaris machined to fit and a machined and balanced that can be stand alone primaries or can be teamed up with a Team Tied for a bullet proof fix. A balanced wobble free primary and a zero scrub floating secondary and longer crank life. Win win win.

Just sad that a mod shop beat BRP to a fix....about 2Kish but then you are headache free.

Have you talked to anyone who rode the setup personally or just the shop? I assume 2k is both clutches ready to go calibrated a belt and everything needed

Click to expand...

Call Ken at MM. He runs the same setup on quite a few sleds. Gets clutches machined and balanced in US.
Price varies on what U get.
I dont work for Ken so best get info from him. $1100 is fully machined and balanced primary.

That is where I stop. Call Ken.

pfi572 · Apr 8, 2017

$1100.00 is correct with balance and machining .

powpowpowpow · Apr 8, 2017

More than likely anyone who does the P85 will end up having crank issues or even issues with the P85 itself with broken springs and spiders. Read up on why the pdrive has the offset. Its a calibration and alignment issue that will be resolved eventually. No belt issues here, but would be nice to have a floater on the secondary.

Rene G · Apr 8, 2017

powpowpowpow said:
More than likely anyone who does the P85 will end up having crank issues or even issues with the P85 itself with broken springs and spiders. Read up on why the pdrive has the offset. Its a calibration and alignment issue that will be resolved eventually. No belt issues here, but would be nice to have a floater on the secondary.

Because the 950 shakes, rattles and rolls so much or the extra power from the 50cc's?

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Daag44 · Apr 8, 2017

Floating Secondary

powpowpowpow said:
More than likely anyone who does the P85 will end up having crank issues or even issues with the P85 itself with broken springs and spiders. Read up on why the pdrive has the offset. Its a calibration and alignment issue that will be resolved eventually. No belt issues here, but would be nice to have a floater on the secondary.

I agree it would be nice to have a Floating Secondary with a small 3mm play. If BRP could assure the secondary doesn't get locked down in the wrong place on the shaft, I wouldn't be surprised if they came out with it standard on all sleds. Time will tell.

Proven resolutions to the G4 clutching delema

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