clutching help needed on 2018 SW BTX 153 2.25

[sumtinwong]

well so goes the battle my riding buddy dropped 17,000 on the 2018 SW BTX 153 2.25 which has ben a pretty impressive sled!! by far the nicest 4stroke I have ever got to rally on and not just the hp the sled as a whole is unbelievable for what it weighs and how easy I/we can blast through the tight trees way more nimble than we were expecting! so on to the problems... on the 3ed belt in 330 miles and the bottom end of the sled is as lazy as we have ever seen! I have dun the research for him as he is not a tinkerer and I am a gluten for a challenge. I have all the small things dun shimmed helix {do to the evidence of coil bind on the spring} got the offset as close to 61 mm as possible set the belt deflection sanded the helix to get all the ramps to contact the rollers and checked the rollers for wear/flat spots in both prim. and 2edary none of witch got us happy with the clutching so we are looking at clutch kits from thunder. weights {adjustable}, glide washers, spring, 911 cover,- helix, rollers, spring my question is has any one tried thunders kits in the steep and deep? or is their any other kits that you would suggest? we do quite a bit of boon docking so we are in and out of the throttle WOT to nothing a lot. I feel like we need to slow the up shift to allow the turbo to spool and speed up the back shift to keep it responsive. we are hoping to get the skis to lift off the line {and still keep the warranty} we ride together a lot and im on a turbo 2016 axis assault and we have hade to miss some cool spots because he could not yank the skis up across a small creak or over fallen trees with out doing 30 mph or more! well im sure you see what we are trying to achieve and I have always ben on a 2smoker and am good with the clutching on them but this ain't no 2smoker lol... but it has more than enough HP if we can just get it to the track when we need it so any and all comments/help are appreciated and welcomed from all the TY crew!!!! help school me on these beasts! thanks.

 

[Sherlock]

I'd also like to know the answer, blowing belt only when stuck. no power at all down low

 

[neech68]

well so goes the battle my riding buddy dropped 17,000 on the 2018 SW BTX 153 2.25 which has ben a pretty impressive sled!! by far the nicest 4stroke I have ever got to rally on and not just the hp the sled as a whole is unbelievable for what it weighs and how easy I/we can blast through the tight trees way more nimble than we were expecting! so on to the problems... on the 3ed belt in 330 miles and the bottom end of the sled is as lazy as we have ever seen! I have dun the research for him as he is not a tinkerer and I am a gluten for a challenge. I have all the small things dun shimmed helix {do to the evidence of coil bind on the spring} got the offset as close to 61 mm as possible set the belt deflection sanded the helix to get all the ramps to contact the rollers and checked the rollers for wear/flat spots in both prim. and 2edary none of witch got us happy with the clutching so we are looking at clutch kits from thunder. weights {adjustable}, glide washers, spring, 911 cover,- helix, rollers, spring my question is has any one tried thunders kits in the steep and deep? or is their any other kits that you would suggest? we do quite a bit of boon docking so we are in and out of the throttle WOT to nothing a lot. I feel like we need to slow the up shift to allow the turbo to spool and speed up the back shift to keep it responsive. we are hoping to get the skis to lift off the line {and still keep the warranty} we ride together a lot and im on a turbo 2016 axis assault and we have hade to miss some cool spots because he could not yank the skis up across a small creak or over fallen trees with out doing 30 mph or more! well im sure you see what we are trying to achieve and I have always ben on a 2smoker and am good with the clutching on them but this ain't no 2smoker lol... but it has more than enough HP if we can just get it to the track when we need it so any and all comments/help are appreciated and welcomed from all the TY crew!!!! help school me on these beasts! thanks.

Hey guys. Just finished up my clutching on a 2018 153 mtx winder. I have the hurricane 240 flash in it. As a stock winder and with the flash the bottom end was a dead dog! Lol. Coming off a 250 hp supercharger nytro this was unacceptable. Here is your answer. Run 8bu00 primary weights. Will have to run out to check on primary spring but it is the same as we run on the turbo nytro. I then put a Dalton reverse helix 33/37 on just today. And now, hang on. Holy ski lifter from start to finish. The bottom end is unbelievable now and the power that hits in the middle to end is crazy!! In marginal snow I hit the Rev limiter on bottom end. In good snow, no such issues. Top end revs across fields breaking trail stayed at 8800. Awsome!!!!!!

 

[rla1]

Neech68 if you have mtx it is 21/49 gears which is lower than the btx at 24/50 so probably will take diff setup, but i like your thinking.

 

[neech68]

I know about your gearing. This setup with th 8bu weights is what we run in the turbo nytros out here on the prairies. The reverse helix is a new addition to me just on my winder. The stock weights and hurricanes weights just are not aggressive enough for what you again trying to do. Trust me. Try the 8bu option. You should be able to find some very easy. Even on the stock helix which I believe even on yours is a 35 degree, they make a huge difference on your bottom end.

 

[sumtinwong]

with your flash you aren't just pushing more HP and torque but also a different power curve all together! did you try any of this set up on the stock sled? my concern is that stock it might leave dead spots in the shift out, where your power curve has superior ark and produces more torque AND hp at a lower RPM witch could leave a lesser sled {stock} with inadequate shift out qualities not to mention the gearing you have is lower witch crunches the power band even smaller, lets you spool up the turbo quicker do to running higher RPMs at the same MPH as the taller gearing and allows you to spin the track even easier and continue to build boost! I have NO doubt that you have found a sweet setup for what you are running but just don't know if your sled is in the same league as a stock one any more witch makes me question if the clutching would be proper with out adding HP+ torque+ better power-curve+ lower gears! like I said im a 2smoker guy and if you mod a 2stroke that much theirs no question you need to re-clutch the sled to match. like I said thou teach me!... this is a 4 stroke is the clutching that forgiving/flexible on them?

 

[neech68]

Yes, granted I'm running a tune. I may be a newbie to the forum but have been running 4strokers since they came out. And making them work takes clutching, trust me. Everyone thinks that these winders are something special! We are riding a cat chassis with basically a low boost nytro motor as stock. Nothing more. Talk to anyone with a low boost nytro turbo for there clutching. It will work. All I can tell you is that this motor will pull 8bu weights with the stock helix. Just need to put in a nytro primarspring. What part of sask are you from? You can drive my 200 low boost nytro or my 250 supercharger nytro anytime you happen to be in my area. And my winder. All on 8bu diet. Lol. Have tried many things with the four strokes. Can drive you crazy. Haha.

 

[joyrider]

Was watching this and Wondering what the complete 8 but part number is because on a search it shows several. 17 btx looking for better takeoff. Also any other associated parts needed. I'm dumb on abreviations so very simplistic answers needed lol. Thanks

 

[neech68]

8bu00 is the weights. Load up with heaviest rivets. They have two holes. As for the primary spring I just can't remember right now what it is other than a nytro spring. It's shorter and will not bind up like the stock winder spring. I will look in the morning at my sled primary spring and post it.

 

[rla1]

Be interested what primary spring in your sled and what you added for weight to your 8bu's.

 

[neech68]

Just checked. Yellow / silver / yellow. Heaviest rivets yamaha makes. Secondary on stock helix was 70

 

[rla1]

Interesting setup, guessing your bottom end is unreal if you have traction.Did not think that would work on a winder with the hp, must be the primary spring that makes the difference.my stock mtx viper with same gearing and loaded up 8bu's was hitting rev limiter on the prairies all the time and maxed out at 75mph, was ok if stayed off trail and in deep snow when could find it. Where in sk are you from.

 

[neech68]

Land of the snow. East Central. Preeceville . Yes. Bottom end is crazy, finally! In the snow, no issues for over rev and honestly have not looked at speedo for top end . And this reverse helix, thanks to nos-pro is the ticket for a turbo. Probably one going onto the 200 nytro. Throw away the primary spring off the winder and the weights. I honestly was ready to get rid of my winder, until the weight change. But my God, this helix is a huge difference. If a person don't stray from the pack and try stuff you just never get ahead, just stay in the pack. Then you see a sled fly by and say Wtf!! Never hurts to try different stuff. And again I say to nos-pro, thanks for the tip on helix.

 

[sumtinwong]

well just got thunders kit holeshot reverse helix 33-35 new rollers big-boy orange spring... their big venom kit{weights/spring/guild washers} and a 911 response clutch cover. I might order the reversed 33-37 from Dalton as that's the one I was looking at anyway. do you know the spring rates for the prim and 2edary that you are running? are the 8bu weights flat like what came stock in the SW or are they arced like the {what I would call} "normal weights"? thanks again for the help and the willingness to shear your knowledge on this topic its appreciated neech!!

 

[neech68]

Yellow silver yellow primary is 2.5 spring rate I believe. 8bu 00 weights have quite a curve to them. Stock winder and hurricane weights have a pretty gentle curve. The 33/35 helix will be good I think but you may at times hit the Rev limiter on bottom end if you are not in good snow. You won't get the big mid to top end pull that the 33/37 is doing. And also you might not have the pony power for it. Let me know how your 33/35 does. I might try it for the mountains! Time to go, she is snowing. Yahoooo