Finally Austin/Yamaha test drive time...clutching way off

[Seann17]

Early test has clutch engaging at about 3500 rpm, WAY to high for what I want. I'd like the car to just pull away with very low revs for street use, no "launch". So, having very little experience in this area, I need to know what is available for springs etc for clutches to bring the engagement in much earlier. Haven't really left the drawing board yet...
Thanks,
Seann

 

[RobX-1]

Something like a soft start spring like the one Travis offers might be good cheap place to start.

 

[Seann17]

Something like a soft start spring like the one Travis offers might be good cheap place to start.

Thanks, I've emailed him

 

[Srxspec]

Yamaha 90501-550A2-00 is the lowest Yamaha spring available for starting rate.

 

[Seann17]

Yamaha 90501-550A2-00 is the lowest Yamaha spring available for starting rate.

What do I do with the weights if this soft spring is used?

 

[Seann17]

The spring that's in now is a yellow/silver/yellow, looking at the Yamaha chart it seems quite strong...35 preload, 2.5 rate, 118 total force.

 

[Teamblue4]

I have used the Yamaha 90501-581L5 primary spring in my Apex's with great results. Below 3000 rpm's engagement.

 

[Seann17]

I'm sure it's fine for the sled, but in the car I want almost instant engagement...anything off idle, I want to hear a load on the engine/drivetrain. It's something that no sledder would ever want, a very different application of power. Minimal revs to get moving....

 

[maim]

how much weight is in the hole closest to the pin? i like heel clicker drag n flies or the old 40/10 weights for lower end engagement. it will still need to rev up to engage but will stay engaged at lower speeds letting me crawl my sleds at less than 5mph.

 

[Seann17]

weight...hole...pin...?...you've lost me

 

[Yamajon1]

He’s talking about the pin that the weight pivots on. Some weights have holes in them that you can add or subtract weight bye installing a rivet or small bolts and washers. Weight added or subtracted at different positions on the weight arm will affect how the clutch shifts. I would start with putting in a lighter spring and leave the weights alone and see how it responds. The soft start spring will have a much lower and smoother engagement. Might help to post a picture of the weights you have since they may have been changed from stock

 

[Srxspec]

Again, Yamaha 90501-550A2-00 start rate is going to be the lowest spring available from anywhere. DO NOT start changing weights & springs all at the same time, because then you don't know what did what. You may have to go to the Yamaha short cover springs, inside of the long cover primary (what comes on the Apex) to achieve what you want as there is no where in snowmobiling that has engagement below 2,000 rpm.

 

[Seann17]

OK, here's what I've got...remember, car guy learning to talk "sled". Photos attached, Spring free length 89 mm, did talk to someone about putting a short spring in to achieve what I'm after. Rollers are tight side to side and roll free, no flat spots no holes or mods in weights from what I can see. Sheaves fine too. All looks good. Just need a spring to try.
Thanks,
Seann

 

[Seann17]

Took out the weights, cleaned them up each are 80 grams. "8FP 00" stamped in if I'm reading it right.

 

[maim]

try the spring 1st of course.

the weight you have

Took out the weights, cleaned them up each are 80 grams. "8FP 00" stamped in if I'm reading it right.

in picture has 3 holes in it that are filled with rivits (three circles on side of weight)