Thunder Products (Big Venom Viper kit) with Heavy Hitters

[yamamn]

Set your weight up like this....

Take the 3/4" out of the heel, take the 1/4" set screw, bury it in the heel and then follow that screw with the 3/4" so you have 1" full screw. (Make sure you test the weights to see if they swing and clear the clutch weight clearance area.

The middle I would run empty or the 3/8" aluminum

The tip, try the 3/8"steel alone. Might take a little time, but gotta get that rpm up from 7,900

ok thanks. will try hopefully today

 

[4StrokeAddict]

I'm having issues as well. If I nail it from 20-30 MPH, I watch my RPM climb to 8400-8600, get to 85 MPH, then my RPM drops to 7800 while the sled struggles to climb to 95MPH. When this happens, my boost drops from 5.5PSI to 3.4 PSI which means the engine isn't producing anywhere peak power anymore. I'm picking up a 8DN belt this week, but I think that will only make things worse if my limited understanding of clutch voodoo is correct. 8DN seems to somehow provide a higher gearing effect. I don't need more higher gear at the moment...

Terry I know you suggested playing with weights. Any thoughts on where to start?

Edit: I forgot to check my max RPM after my runs. I did record on the Pod-300 and will have to check it. I don't think I'm hitting the rev limiter though.

Edit 2: I'm machined for overdrive. I wonder if they set it up for a stock clutch?

 

[smoothride]

Back on from the weekend...sorry to leave you guys hanging here.

Yes, the Venom kit is touching the rev limiter on take off in loose snow and trying everything to get more weight in the heel.

Made up 3 brass 1/4-28 set screws 1.100" long and had SnoNinja put them in his sled. He said it was better, but now hits the rev limiter in the midrange and top end. Tried the gates belt (worn belt) and was better, but still touched rev limiter in soft snow. Man, would I like to see us guys get SnoNinja's sled on hard pack and not touch the rev limiter. The brass are too soft and when installing, they stripped. Going to try and find some tungsten screws to test.

I think the brass fixed the take off, but now more weight would be needed in the middle and tip to be perfect.

A lot of my testing was done on hardpack and some on loose snow. But I was also 141 compared to the shorter lug tracks.

You can try to get it perfect but it will not happen. My friend has this kit in a 129 viper with the soft touch spring in it with no mods with 8dn belt has never hit the rev limiter. On the hard pack road in Gaylord hit 106 mph at9 9000 rpm. This weekend he put a scandal can on it but never got to try it on a hard pack road tho. But now he said it what's to pull his arms out of his sockets. Lonn setup the weights and he has not touched them. He said he has to be careful in the twisty trail because of so much put. He said he also was in some loose condition and never hit the rev limiter but didn't hit it from a dead stop.

 

[NOS-PRO]

You can try to get it perfect but it will not happen. My friend has this kit in a 129 viper with the soft touch spring in it with no mods with 8dn belt has never hit the rev limiter. On the hard pack road in Gaylord hit 106 mph at9 9000 rpm. This weekend he put a scandal can on it but never got to try it on a hard pack road tho. But now he said it what's to pull his arms out of his sockets. Lonn setup the weights and he has not touched them. He said he has to be careful in the twisty trail because of so much put. He said he also was in some loose condition and never hit the rev limiter but didn't hit it from a dead stop.

Thats where I was this past weekend...Gaylord

And yeah, my arms are sore today.

 

[NOS-PRO]

I'm having issues as well. If I nail it from 20-30 MPH, I watch my RPM climb to 8400-8600, get to 85 MPH, then my RPM drops to 7800 while the sled struggles to climb to 95MPH. When this happens, my boost drops from 5.5PSI to 3.4 PSI which means the engine isn't producing anywhere peak power anymore. I'm picking up a 8DN belt this week, but I think that will only make things worse if my limited understanding of clutch voodoo is correct. 8DN seems to somehow provide a higher gearing effect. I don't need more higher gear at the moment...

Terry I know you suggested playing with weights. Any thoughts on where to start?

Edit: I forgot to check my max RPM after my runs. I did record on the Pod-300 and will have to check it. I don't think I'm hitting the rev limiter though.

Edit 2: I'm machined for overdrive. I wonder if they set it up for a stock clutch?

Yup, too much weight, some needs to come out of the middle and a lot from the tip. I would say 1-2 grams out of the middle and 3 grams out of the tip. When you are low on rpms, your engine isn't building boost so clutching for the turbo can be hard at times. Yes, the 8DN will grab more than the 8JP, but the Gates belt grabs even more than the 8DN.

Check your pod and see what you had for rpms. Need to be middle to high 8 for boost to work better. 8,800-8,900 would be really good.

 

[smoothride]

With this kit to changes weights do you have to take the weight out to change the weights or do you leave they in the clutch.

 

[NOS-PRO]

There is a "clamp" tool you get with the kit. This holds the primary together so you can take the weights out.

Now, if you are just messing with the heel weight, you can change that without taking out the weights....but you have to remove the weights to change the middle and tip. Very simple tho and after the first time it will be 2nd nature to you.

 

[smoothride]

Thanks nos-pro.

 

[murdered141]

You can try to get it perfect but it will not happen. My friend has this kit in a 129 viper with the soft touch spring in it with no mods with 8dn belt has never hit the rev limiter. On the hard pack road in Gaylord hit 106 mph at9 9000 rpm. This weekend he put a scandal can on it but never got to try it on a hard pack road tho. But now he said it what's to pull his arms out of his sockets. Lonn setup the weights and he has not touched them. He said he has to be careful in the twisty trail because of so much put. He said he also was in some loose condition and never hit the rev limiter but didn't hit it from a dead stop.

No mods is the key word here, after you open up the exhaust, it will hit maybe once or twice on take off, but when you open up the intake, then it bounces off 4 to 5 times on take off and once when you get on it in midrange like mine does, I am hoping Evo's flash with raised rev limiter is the answer.

 

[4StrokeAddict]

Yup, too much weight, some needs to come out of the middle and a lot from the tip. I would say 1-2 grams out of the middle and 3 grams out of the tip. When you are low on rpms, your engine isn't building boost so clutching for the turbo can be hard at times. Yes, the 8DN will grab more than the 8JP, but the Gates belt grabs even more than the 8DN.

Check your pod and see what you had for rpms. Need to be middle to high 8 for boost to work better. 8,800-8,900 would be really good.

Thanks NOS. I'll make some adjustments next weekend, but won't make it up north to test for a couple weeks. We are planning a week long backpacking trip in the western UP the second weekend of February. Let me know if you will be in the area.

 

[NOS-PRO]

This weekend will be there for the TY ride, then next weekend at the I-500 and then Gwinn hopefully.

 

[4StrokeAddict]

This weekend will be there for the TY ride, then next weekend at the I-500 and then Gwinn hopefully.

We are headed west from Ishpiming on the 8th, coming back through Ishpiming on the 29th.

 

[murdered141]

We are headed west from Ishpiming on the 8th, coming back through Ishpiming on the 29th.

You must like snowmobiling allot, 21 days is a long time.

 

[Janne339]

Is the Big Venom secundary spring identical to the Yamaha stock silver?
Lenght = 75 mm
Wire dia = 5,5 mm
Number of turns = 4,86

 

[murdered141]

Is the Big Venom secundary spring identical to the Yamaha stock silver?
Lenght = 75 mm
Wire dia = 5,5 mm
Number of turns = 4,86

Noooo!!