Boosted sled top speed on snow? Clutching advice needed

[kinger]

Fergie - Ok that is what I am looking for. I'll keep playing with the clutching you got more power then me and 1 tooth lower gear so I may go back to stock gearing.

Thanks for the help.

 

[kinger]

Ulmer just called me and reminded me that when I had the sled initially it had 10T drivers and a 1" hacksaw. Since then I swapped out for the cobra, 9T extros, and the gearing changing.

I'm a idiot for not remembering this (Nice to have the memory form Ulmer for me!!!)

He is going to do some notes to other sled with similar setups to me and send me a new recipe and I will adjust the weights for the first time. I think this will help a ton. There is a lot of things that changed from when he had it dialed in.

Thanks again everyone!

 

[Habich76]

It sounds to me like it is asking for less helix angle and/or more secondary spring rate for more belt clamping force. My guess is the secondary angle is too steep and it is loading the primary beyond what it is capable of pulling. Blowing up the belt is a definite sign of slippage which is from the extra load the taller gears are placing on the drive system. I'd put the other gears back in and mark the primary clutch sheaves then take it for a speed run. Don't go up in gear ratio until the pen mark is gone or at least within 1/4" from the top. I bet you have a good amount of tuning to do with the old gear set before you can move up teeth in the final drive.

 

[kinger]

Thanks Hanich76.

I haven't heard back from Ulmer yet and were leaving next week to hopefully catch some fresh snow.

Here is my plan,

Pull out 3 grams form the weights if I can I'm not sure what washers are in there now (they are super tips) and if I can I will pull weight from the tip first and if not then the mid.

I'll add 5 degrees of helix back in as I have reduced that much just playing with the shockwave to get the RPM's up.

I want to hit 10,800 then settle to 10,500 and hold that all the way through.

I'll mark the primary and see if I can get within a 1/4" of the top.

Anything else I should be looking for?

 

[mmaman207]

Olav Aaen clutch tuning handbook.... buy it... its gospel when it comes to clutching. They are getting harder to come by, but you can usually find them on Amazon.

 

[kinger]

Yep i have it and on the second read made me feel much more comfortable with clutching. Any tips specific to my application?

 

[mmaman207]

First... never adjust the secondary to change RPM... this is chasing your a$$ for sure.
Sounds like your back at square one anyhow... going to 9 tooth, gearing change, and a track change... your clutching needs attention.
I would say the rest of the guys have covered it... start with the felt pen and check the belt in the primary after you put the helix back where it was...then adjust primary weights and springs to get your RPMs right... then move to secondary to get helix and spring right for your riding style.
Habich76 sounds like he has it nailed... you are def making to much heat with slipping... and Im sure never getting to 1:1 or beyond.
I see lots of testing and 4 letter words in your near future.

 

[kinger]

Cool thank you!

 

[Essarex]

I had a 128 cobra with 100 studs and pulled 127 on the speedo down a plowed road and got out of the throttle a little early. I'm sure it would have broke 130 if I stayed in it.

I'm running 7.5 psi with stock compression.

Any snow cover at all, like what you may have had on the lake, will have a significant impact on top. Plus, your cobra will pull you down compared to the hacksaw.

But, you are more concerned about that ETEC hanging with you. You should be able to pull more mph than what you did, and as was mentioned earlier, you are making heat and not speed by evidence of the blown belt.

I just did the opposite of you,,,,I replaced my cobra with a hacksaw, mainly to get more life out of my slides. The cobra just sat too far off the bad snow surfaces I have been forced to endure this winter.

Now, my clutching is way off as I am underreving quite a bit. It seems that the lack of traction is causing the helix to allow an early upshift and I'm off the power peak. Was 10,600 now it is closer to 9,800. My top end has suffered.

 

[kinger]

Thanks for the reply, that is interesting, I could not stand the hacksaw even with a million studs in it. I hope it works for you.

I'm going for one last run this weekend and going to really examine the rpm's. I'm going to change my shockwave helix back to where it was and a new belt and see how far I can rev.

If its still short i'll pull some weight before next year.

 

[tube]

KEEP SHOCKWAVE run 66g polaris weights and pins grind the tips just a but so they clear with a yamaha orange primary spring and 3 washers cut 30 thou. off the primary sheaves run a multi angle shock wave helix with 60 thou. cut off the end 1 turn out and a black yellow spring and hang on best clutch kit ever this apex rocks runs 10800-11000 depending on conditions ----2006 Apex GT

 

[kviper]

To check for coil bind in driven clutch just put it in a clutch compressor, coil should not touch when fully compressed. If belt was getting bad and worked good before I would set everything where is was known to work, wash a new belt with dish soap, clean clutch faces with acetone, run 10-15 mi easy to break in and see what you come up with. Than I would try new spring's if it is still not right. If everything is tight and smooth with no binding it can only be things that can change like belt condition alignment or spring's. I will say 10-11 LB on a super is close to 7.5 or so on an efficient Turbo and condition's are everything but mustard bucket's should fall easily! LOL

 

[kinger]

I forgot to update this but I needed different springs in the clutches and bam this baby hauls the mail. With the 13.5x151 track I can easily hit 30-40mph faster then stock 800's in almost any snow. What a beast!