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Discussion Starter · #1 ·
Seems my clutching needs to fine tuned and I am looking for suggestions. It's been ported, so I think it may be pulling 130-135hp.

It disengages alot at about 5000. It also engaes at 5000-5100. It seems to shift out prematurely also. Upon take off it rev's up to 6000, then rpm drops right away and you can hear the motor drop off. Then if I hit it, it seems to pull strong.

I have 280 ramps, 200-320 Erlandson spring, solid steel pins. Stock new biege spring in secondary set at 19-20 lbs. Set my offset and c to c. Track spins a little when its off the ground and the belt is about 1/8 above the sheaves. Has the stock 52-47 helix. New 067 belt. I marked the clutchs and it looks as though the primary is not bringing the belt to the top and the secondary seems to be almost totally open. TRA is at 3.

Also it will pull only to 7800. But if I stop sometimes and the clutchs disengage, the sled will pull to 8000. Kinda like they are aligning sometimes and not aligning other times.

Anybody have some suggestions I can try. I have done this type of clutching alot on my old 96 583, but its been a few years, so maybe I am missing something simple.

Gonna get a BRP 200-320 and check that spring out. Maybe need heavier pins. Had a 230-320 BRP spring and it engaged about the same and finished about the same. Thinking this Erlandson spring is bogus although it is new.
 

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The Erlandson yellow is known to bind. Try a doo spring. With 280's I like a bigger spring like a 230-380. Sounds like you are running Don's recommended setup. I could never get it to work. I hate 280's while others love them. Nothing wrong with the stock 297's, 230-320 18 g pins, 50 deg helix. Keep clicker in 2 or 3 and add or subtract weight to your desired RPM.
 

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I have a modified 98 that I run about that same HP.

I am running 145 ramps with Thunder Shift arms, adjustable pins (19 gram pins) and the aluminum weight in the 2nd position and a purple/purple (160/320) spring.

I have plenty of belt pressure. It engages at 4100 and shifts out to 8000K.

I am running Cat roller secondary with a Red spring/white stripe in the 2nd position and an SLP overdrive Helix 58/55.
 

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Discussion Starter · #4 ·
Oof, Not goona do the thunder/slp set-up. Will get a 200-320 brp, heavier pins, and a 50 deg. helix and try some more.

Yup, Don's set-up, thought I would try it anyway.
 

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OK...so you don't want that set up. I was't giving it to you to run. I was using it as an example...why do you want that sled's engagement over 5000K? You want that motor to engage in the low 4000 to high 3000RPM range. Stock engagement is around 3700 with a peak of around 7700.

It is disengaging because you have the engagement higher than what you are running on the trail. You can't run an engagement RPM of 5100 and expect to keep the clutch engaged at 5000.

If you want to run that engagement, you have run steeper gears so the motor is forced to stay above that RPM range at the speed you usually travel.

That motor is a torque motor, not a HP motor. You have the equivalent of setting the clutch to run like a Small Block Chevy motor when you have a Pontiac motor. Small blocks get their power from a large piston and small rod. Pontiac's have a small piston with a long rod. Same with the 670. Small piston, long stroke - compared to other motors of its size. That is what makes it such a good trail sled, and a great mountain motor. TONS of torque.

Unless you have modified the exhaust port timing, your motor is a torque motor.

I modified the exhaust port timing (raised) to run a few more RPM's upstairs to get more speed across the lake.

I still have TONS of low end torque.
 

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Discussion Starter · #6 ·
Stock engagement is listed at 4200. Peak at 8000-8100. Stock spring is 200-290. I do not believe that a 200-320 or a 230-320 would get me from 4200 to 5000-5100. Think I need more weight and I have some BO primary springs.
 

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Adding pin will affect the engagement a little, but mostly the top end. Playing with pin weights is not the place you want to start with engagement RPM's.

I wasn't sure what the engagement was on the HO. I gave a standard 670, which is what my motor was.

The bottom number (first) is the engagement pressure, the top number (second) is the top end pressure when the spring is fully compressed with clutch in the full shift out position.

The ramp and spring is going to dictate the engagement more than the pin weight. The spring pressure and pin weight is going to affect the top end more than the engagement. The height and angle of the ramp is going to determine the engagement, shift pattern and belt pressure. Some ramps have a detent in them to run higher spring pressures. You can grind on the ramps to change this detent to move the engagement around.

The bottom number (first) spring pressure should be lowered to allow it to engage earlier. Keep the top number (second) the same and the pin weight the pin weight the same.

If you are happy with the shift pattern, keep the same ramps. If you are not happy with the shift pattern of the ramp, change to a smaller (height) ramp. It will exert more pressure on the belt, thus bringing down the RPM's.
 

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The spring is not your problem it's the 280 ramps. Throw them in the garbage and put in a set of good ol 286's.
Drop your top gear at least 3 then hang on.
 

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Mikadoo said:
The spring is not your problem it's the 280 ramps. Throw them in the garbage and put in a set of good ol 286's.
Drop your top gear at least 3 then hang on.
[snapback]697344[/snapback]​
I concur on the ramps. I'm sure about the 286's, 146's are also an excellent choice.
 

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Discussion Starter · #11 ·
Well it has been a year and I am trying to dial it in. Last year I could only get 500 miles on a belt. I had alot of issues, but hre is where I am going ot start this season.

160-320 primary
20.6g full pin weight (Fett Adj.)
297 ramps
2003 Ski Doo Roller secondary
beige secondary
50 strt. cam
16 lbs. on the secondary.
new 067 belt
#2 clicker position

Think the upshift will be awesome, but at the expense of the backshift. will decrease pin wt. it under rev's.

Anybody got a better idea?
 
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