1982 Bravo Clutch Tuning

[brendon444]

Any recommended setups to get a little more out of this sled. Recently changed engine mounts and cleaned secondary.

Now cleaning primary and replacing rollers. I see in the manual it references removing the shims(washers to lose clutch weight) assuming this would increase engagement rpm and top rpm like a traditional weighted clutch. Would this be worth doing? Any gain to be had? I also seen someone suggest adding a primary spring shim?

When the sled shifts out the RPMS seem to drop and slowly build. I understand this is a low performance sled but looking to have a great running bravo for my aggressive up and coming sons.

 

[74Nitro]

You're on the right track. Just remove one of those washers from each roller arm and test run.

 

[74Nitro]

You could probably drop one jet size on the main unless you're running below -15 celcius.

 

[brendon444]

Thanks there is a total of 4 washer per weight. Was going to remove 2 each side and try.

I already dropped the main to 105 from 108. Usually kids are to cold to ride at -20C or below.

Also went up one heat value on the plug to a 7. Fouled a few plugs last year.

 

[74Nitro]

I would go back to the 8 for the spark plug.
I would only remove one washer each side. Removing all of them is a big move.
However, given that they have no tachometer, you'll just have to use yours ears and seat of the pants feel, to find the engines sweet spot.

 

[brendon444]

Yes no tach makes tuning little more difficult lol,

Will go back to the 8 heat range.

 

[Maim]

the gauge on the right is a tac i got from a 1980 srx that runs off of the head lamp wiring. there where other sleds that did it the same way so you might be able to find a used one for your sled for tuning the clutch.

 

[74Nitro]

I've been working on a cutomers old short track bravo. The clutch spider slider buttons were ready to fall right out. I put in new Yamaha ones, with the Yamaha shim washer behind each one. The clutch is quiet now. I also replaced a roller and pin, ramps are good. Then I removed one of the four washers. Seemed to work good. I would think two is the most, and after that it might rev too high.

 

[brendon444]

I've been working on a cutomers old short track bravo. The clutch spider slider buttons were ready to fall right out. I put in new Yamaha ones, with the Yamaha shim washer behind each one. The clutch is quiet now. I also replaced a roller and pin, ramps are good. Then I removed one of the four washers. Seemed to work good. I would think two is the most, and after that it might rev too high.

Thanks for the info. I will start with one washer per side like the recommendations.
My buttons look good surprisingly. I ordered new rollers/bushings as they had flat spots. Also smoothed the ramp as it had slight flat spot at full engagement.

 

[brendon444]

Thanks for the info. I will start with one washer per side like the recommendations.
My buttons look good surprisingly. I ordered new rollers/bushings as they had flat spots. Also smoothed the ramp as it had slight flat spot at full engagement.

Also book says 5750 shift out rpm. Any power to be had up higher?

 

[brendon444]

@74Nitro

Also noticed a shim in the secondary clutch. I removed that today to tighten up belt deflection to get the belt riding higher In the secondary.

Parts diagrams don’t show one.

 

[brendon444]

Update:

Sleds back together, rpm has increased and when shifting doesn’t drop as much rpm. Better throttle response.

Belt sits slightly above secondary after removing shim and doesn’t squeal or move at idle. Better response.

Overall the sled is faster acceleration, haven’t tested top end yet.