rat weight settings and results

[yukon yamaha]

I have just put a set of rat weights in my nytro and my settings are...
39 degree helix wrapped to 80
14.5 rollers
rat weights w/ 2gram ball in each ... about 69 grams on scale
green silver green spring

Thinking about putting 2.5 gram balls in them, testeing results should be next week

 

[Super Sled]

Are you boosted? If not, that's pretty heavy. I ran 1.5 grams in each arm (my Attak) last winter and my rpm's were pretty good, maybe a tad high, never hit the rev limiter tho. This winter I am starting with 2 gram balls in each arm cavity to try it and see where it goes. Let me know how much the 2.5 gram balls pull down your rpm's please.

 

[yukon yamaha]

This nytro is not boosted, it does have alot of upgrades... did you run any weights in the tip of the weight or did you just have the ball put in?

 

[Grimm]

Let us know what your engagement rpms are with that spring.

 

[Super Sled]

I've never run any tip weights -- I figured that would just raise rpm's more, which I didn't want. But I bet with more weight in the cavities you could add more tip weight to fine tune, I just never got that far tuning to need to do that. I actually wish there was a spot in the heels to add a bit of Fixed weight. Oh well. I'm thinking going to the 2 gram cannonballs in each arm cavity will drop rpm's some, well see.

 

[Grimm]

I ran 2.5 gram ball bearings in the Rat weights last spring...as far as I know, this is/was the recommended setup on the Nytros.

I'm using a Heel clicker black primary spring and engagement is at 4500 rpms. I'd just got a set of 14.5 rollers, hoping to drop the engagement rpms. I may try installing the O-S-O spring I have if the rollers don't help much.

 

[yukon yamaha]

I just had a chance to run the machine up, with the track off the ground it would engaige at 3500+- when i was standing on the sled it would start at 3700-3800+-....... not a bad place to start, i just dont know what the max rmp will be i could not get a goot length of packed snow, I did smell a little burnt belt? The belt has over 1000kms on it .....
Yes the starting point in the instructions is 2.5 gram balls, if this works good i will try the 2.5 balls and compare

 

[Super Sled]

Ya, mine is an Apex and Turk and PTT recommended I start with 1.5 gram ball in each cavity. I think that is a tad light. I'm now trying 2 gram ball in each, but may switch to 2.5 gram cannon balls in each cavity to try it out.

 

[kurtasaurus80]

I just removed my stock weights (60.3g) and installed these RAT weights (67.1g + 2.5g ball). That was a huge jump! I also installed the black heelclicker primary spring (140-400) My secondary is untouched; but I did tighten in up to 80. With this set up I seen 105mph at 8440 RPM. It pulls like a team of clydedales but would like to see my RPMS up around 9000. Any suggestions?

Would the 39 helix make a difference? Should I be dropping the ball weights...say to 1 gram.

 

[shadow44]

Not sure how the rats work in terms of tip weight, but 1 gram is roughly worth 200 rpm

 

[fxnytroxtx]

I installed rat weights with 2.5g balls on 09 xtx with stock primary spring, and it engages at 3200+-, so I took it for a spin on my backyard (grass) I hit 76mph @8000rpms and I ran out room. So my question is it to be ok or should I get black heel clicker with 14.5 rollers?

 

[Grimm]

fxnytroxtx, keep riding it as is and get it out on the trails, see if you can get to about 8700rpms.

I installed the 14.5 rollers with my Rat weights (2.5 grams) with the black HC spring. I am happy about engagement dropping to about 3700 rpms from 4500. However, it doesn't feel like it pulls down low like it did before and my top rpms were only 8400 and speed was only 150km/hr.

I'll probably swap in the 15.6 rollers and try the O-S-O Yamaha spring and see how it works.

yukon yamaha, have you tested your setup yet? Results?

Personally, I think the Rats need a new custom HC spring in the 120-400 range. I think this is why Turk gave up with these weights last year.

 

[yukon yamaha]

yes I have been testing for the better part of 28 hours and my results are not really that great! I machined my clutch down so i could run a skidoo primary sping 130-350 trying to get more rpm out of the machine

I have been able to keep the rpm down to 4200-4400 but my max is only 8400 no matter what clutching set up i use....

I have tested with helixs from angels 41 all the way down to a 53-35 and still nothing.... The machine pulls very very! hard but still short 1000 rpm.... i have been useing a white white secondary spring at 80 degrees and i just jumped over to an EPI purple spring from my turbo and i did gain aother 250 rpm with it set at 10 degrees,
Now even with no ball in the weights i still cant hit my rev limiter.... next step is to cut some weight off the tip of the weight and try to get it down to 58 grams..... I will be doin alot of testing this coming weekend and i will try to scan all my run results and post them..... I have been keeping a very detailed list of all the changes i have been doin

 

[nytroman20]

Have any of you guys tried a white hc spring? It's a 170-300 I believe. If running the 14.5's it may engage around 4000 but it might get your top rpms back. Just a thought.

 

[yukon yamaha]

Today on lunch i shaved the tips of the weights and all three weights are now 64 grams , if that still doesnt work i will take out 4 more grams and re-test