Clutching advice for 900 with Dynoport.

Alancour · Feb 14, 2013

I have an 05 fusion 900 with a full dynoport exhaust system. I would like some clutching advice for my sled.
I have sent an Email to Dynoport and am waiting on a reply.

My performance mods include

Full Dynoport Exhaust
RKTec 13:1 head
Team 419 helix
1.5 x 136 track with 900 switchback gearing.
SLP push/torque arms

Other than the Helix, the clutching is stock.
I don't know what RPM I should be running with the pipe but I am running 7600-7700rpm.
It feels like the clutching is absorbing a lot of power at lower speeds. I don't really feel the "arm stretching" torque that I hear these 900s have.
My 9 wont lift the skis on a groomed trail.
I have tried to grass drag my sled and aggressive throttle inputs will smoke my belt off the line.

My last sled was an XCR 800. When I hit the gas on the old sled, the skis would get light and it would just flat out pull.

I need to learn how to put the power of the 900 to the ground.

Any advice would be appreciated.

Newfusion900 · Feb 14, 2013

dynoport sells a clutch kit.

RichardsA4 · Feb 15, 2013

Alancour said:
I have an 05 fusion 900 with a full dynoport exhaust system. I would like some clutching advice for my sled.
I have sent an Email to Dynoport and am waiting on a reply.

My performance mods include

Full Dynoport Exhaust
RKTec 13:1 head
Team 419 helix
1.5 x 136 track with 900 switchback gearing.
SLP push/torque arms

Other than the Helix, the clutching is stock.
I don't know what RPM I should be running with the pipe but I am running 7600-7700rpm.
It feels like the clutching is absorbing a lot of power at lower speeds. I don't really feel the "arm stretching" torque that I hear these 900s have.
My 9 wont lift the skis on a groomed trail.
I have tried to grass drag my sled and aggressive throttle inputs will smoke my belt off the line.

My last sled was an XCR 800. When I hit the gas on the old sled, the skis would get light and it would just flat out pull.

I need to learn how to put the power of the 900 to the ground.
Any advice would be appreciated.

I have an 05 900 Fusion with the dynoport pipe and similar mods. I am running stock track w/ 144 studs. It has 24/38 gearing, 719 helix on the big angle, red epi primary spring, and team red/black secondary spring. After talking with Rich at Dynoport he told me to run the pipe at 7350-7500. I was running my stock 10-74's and it was running around 7600-7800rpm and seemed to loose power up top as well. I found a lot of people have good luck with 11 series weights but I didn't want to re-shim the primary so I switched them with 10-78's and it turns right about 7400. Now it will break the rivets off my snow flap while dragging the rear bumper into the ground, when it actually hooks up.

guidoxpress · Feb 15, 2013

IMO every 900 should be using the Team Black/White secondary spring...it has the best "grip" for the torque and applying the power to the ground. (you can get this from your dealer or SLP)

i also only run one of the following primary springs, and had awesome success..which i get from SLP

Blue/Pink, engages around 4000 rpms
Black/Green, engages around 3800 rpms and has the same finish rate as the blue/pink...so depends on where you want to engage at.

Alancour · Feb 15, 2013

Thank you for the replies.

Guidoxpress, do you have any advice on weights that will get me close with the Team Black/White secondary spring and Blue/Pink primary spring?

Alancour · Oct 9, 2013

Update...

I found that my stock primary spring was broken.

I installed team Black/White secondary spring and the Blue/Pink primary spring.
With the new spring combination, the sled runs at 8000 rpm.
I think I either need less primary spring finish pressure (currently 340)or more weight.

Should I install a set of 10-78 weight or drop my primary to 320 or 300 finish?

sartysrnr · Oct 9, 2013

Go with the heavier weights and keep the spring you have or go with the black /green.Like Guido said these things love spring pressure..

05900 · Oct 9, 2013

Washers in secondary Delrin...? 900 primary is different than 800 so parts do not interchange out of the polaris "kit" Bushings okay etc etc ...

guidoxpress · Oct 10, 2013

Alancour said:
Thank you for the replies.

Guidoxpress, do you have any advice on weights that will get me close with the Team Black/White secondary spring and Blue/Pink primary spring?

Alancour said:
Update...

I found that my stock primary spring was broken.

I installed team Black/White secondary spring and the Blue/Pink primary spring.
With the new spring combination, the sled runs at 8000 rpm.
I think I either need less primary spring finish pressure (currently 340)or more weight.

Should I install a set of 10-78 weight or drop my primary to 320 or 300 finish?

I would adjust your weights if you wanna drop weight..this is one reason I LOVE the SLP MTX weights, they are adjustable...and really help grab the belt...but you must have the primary shimmed cause the weights are slightly thinker then oem weights..

but I would stay around 8000rpms if you have it...I wouldn't go below 7800 if it was me...but no more then 8000 for sure.

sartysrnr said:
Go with the heavier weights and keep the spring you have or go with the black /green.Like Guido said these things love spring pressure..

they LOVE it,lol

05900 said:
Washers in secondary Delrin...? 900 primary is different than 800 so parts do not interchange out of the polaris "kit" Bushings okay etc etc ...

the Polaris P-85 primary clutch is the same within all models. the ONLY diff is the newer have 32mm tapers vs the 30mm. you can interchange primary springs from the pros, dragons, 900, edge..

not sure what you mean by the derlin, but I would use a derlin washer in the secondary for sure...under the spring cup, it will help the spring from binding and breaking. they also make a small derlin washer for under the primary spring to prevent from breaking like you did also, indydan throws them in when he balances clutches...he also sells them. Im gonna stock up before I move to AK...awesome idea!

Alancour · Oct 10, 2013

guidoxpress said:
I would adjust your weights if you wanna drop weight..this is one reason I LOVE the SLP MTX weights, they are adjustable...and really help grab the belt...but you must have the primary shimmed cause the weights are slightly thinker then oem weights..

but I would stay around 8000rpms if you have it...I wouldn't go below 7800 if it was me...but no more then 8000 for sure

Thank you Guidoxpress.

I was thought that the Dynoport pipe sweet spot was 7400-7500 RPM for an 05 900. I am currently turning 8000 rpm.

I am thinking about trying Dalton adjustable weights to get the rpms down. I already have the derlin washer under the cup in my secondary.

Sending my clutch to indydan is on my list of things to do. :face-icon-small-coo

guidoxpress · Oct 12, 2013

its gonna get down to personal preference at what RPM you think you need. I do know for a fact a few years ago theres a report done on a dyno on the rpm vs hp on the 900s..and the conclusion was the motors that broke crankshaft ends (clutch literally falling off) the motor was maxed out at 7400rpm. But the ones that were spinning around 7600-7900rpms weren't having the same issues....granted theres variables as always, like maintenance, clutch balancing, motor mounts ect....

But I have never clutched my sleds under 7800rpms, and they all RIP!

good luck bud

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Clutching advice for 900 with Dynoport.

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