best way to give my formula plus some low end power - Snowmobile Forum: Your #1 Snowmobile Forum

wobawoba969 · 03-05-2007, 01:51 AM

ok so i have a 1988 formula plus 521cc that i just rebuilt and i feel like it lacks the low end snap that newer sleds have but has plenty of go once it gets going i guess im lookin for input on clutching options and what kit would be cheapest and best and also ive seen that people change gear im guessing this would be the chaincase gears to put out a different ratio keep in mind where i ride i rarely see over 70mph and its near impossible to do over 85.

**smallengineguy** · 03-05-2007, 07:19 AM

CHange the clutch spring to a stiffer one. THat'll bring your RPM's up at takeoff.

upersleder · 03-05-2007, 08:08 AM

that, and if you never go over 80, you can drop a couple gears on the top and that will wake it up.

MXZ670Rider · 03-05-2007, 08:37 AM

and check the rollers and ramps in ur clutches may need replacing.

wobawoba969 · 03-05-2007, 09:32 AM

ive heard about changing the spring on the clutch but how do i know which spring to buy and where can i find one im new to modding snowmobiles so im in the dark with this one also can anyone tell me what gear to get?

97Mach1 · 03-05-2007, 09:45 AM

With it being a 1988 model (20 years old...), I would just put a new stock primary and secondary spring in, especially if you haven't replaced them in the last few years. New buttons in the primary and secondary as well (most aftermarket shops will have buttons for about $1 each, vs. at a Doo dealer for $6 each).

That should make a noticeable improvement in your bottom end performance.

If you still want a higher engagement, then I would consider a spring with a higher starting load. I don't have specs for your model, but have spring charts. If you let me know what colors are on your stock one (should be in your owner's manual), I can list ones with higher start loads.

**smallengineguy** · 03-05-2007, 09:53 AM

In the engine section, how-to's thread, there is a Ski Doo spring chart.