Btx le gearing

[woodzynh]

Preventing secondary coil bind they are 5/16 lock washers so it cleared the helix.

Hmmm, don't believe I'm getting any coil binding but not sure the symptoms


Sent from my iPhone using Tapatalk

 

[Dieselxtx]

Hmmm, don't believe I'm getting any coil binding but not sure the symptoms


Sent from my iPhone using Tapatalk

I ran 102 without it shimmed but with 6-1 wind it makes coil bind worse I did it for more of a preventative

 

[Dieselxtx]

Does anyone know if I can run a 21/50 gear combo with the MTX chain on my BTX LE, MTX gearing is 21/49 I was hoping to just buy the 21t sprocket and MTX chain?

 

[Joshua]

I have the 18 BTX LE, and I want to change to MTX gearing. What am I going to need? Gears I know for sure, what about the chain? How about the clutching, I ride at sea level so I'm thinking the stock clutching in my BTX will be fine

 

[PeeWee86]

I was reading through this thread and I shook my head. With the exception of the original post nobody else has listed what gearing they currently have, only their snowmobile model. This makes it much more difficult for others to respond.

2017 Sidewinder gearing:

Track Lengths: 129 – 137 = 9T Drivers x 2.86 Pitch & 21/41 Gearing

Track Lengths: 141 x 1.6 & 153 X 1.75= 8T Drivers x 3.00 Pitch & 21/41 Gearing

Track Lengths: 141 X 2.25 & 153 x 2.25= 8T Drivers x 3.00 Pitch & 24/50 Gearing

Track Lengths: 162 X 3.00 = 7T Drivers x 3.00 Pitch & 21/49 Gearing

In 2018 there was a change to a dropped chain case in the Sidewinder MTX which allowed for 8t tooth drive sprockets. The over all gear ratio went up but the sprockets and chain did not change. So “MTX gearing” could be could be more than one combination. The same confusion can happen from someone describing “XTX gearing” or “LE gearing”.

This chart shows standard gear ratios and required chain lengths when everything is new. I have heard of people creating some non-standard combinations by going up one tooth on one of the sprockets after the chain has stretched. Obviously these non-standard combinations would only work on a case-by-case basis. I do not recommend going down on sprocket size from these combos. The chain will have too much slack.

Your gearing will have an effect on your clutch setup. It’s hard to give too much advice ahead of time. Pick the gears you want and try out your current clutching. If it’s not doing what you want come back to us and described what it’s doing. At that time it will be much easier to give advice to correct any clutch issues. -PeeWee

 

[BlineBraap]

I was reading through this thread and I shook my head. With the exception of the original post nobody else has listed what gearing they currently have, only their snowmobile model. This makes it much more difficult for others to respond

2017 Sidewinder gearing:

Track Lengths: 129 – 137 = 9T Drivers x 2.86 Pitch & 21/41 Gearing

Track Lengths: 141 x 1.6 & 153 X 1.75= 8T Drivers x 3.00 Pitch & 21/41 Gearing

Track Lengths: 141 X 2.25 & 153 x 2.25= 8T Drivers x 3.00 Pitch & 24/50 Gearing

Track Lengths: 162 X 3.00 = 7T Drivers x 3.00 Pitch & 21/49 Gearing

In 2018 there was a change to a dropped chain case in the Sidewinder MTX which allowed for 8t tooth drive sprockets. The over all gear ratio went up but the sprockets and chain did not change. So “MTX gearing” could be could be more than one combination. The same confusion can happen from someone describing “XTX gearing” or “LE gearing”.

This chart shows standard gear ratios and required chain lengths when everything is new. I have heard of people creating some non-standard combinations by going up one tooth on one of the sprockets after the chain has stretched. Obviously these non-standard combinations would only work on a case-by-case basis. I do not recommend going down on sprocket size from these combos. The chain will have too much slack.

View attachment 141380


Your gearing will have an effect on your clutch setup. It’s hard to give too much advice ahead of time. Pick the gears you want and try out your current clutching. If it’s not doing what you want come back to us and described what it’s doing. At that time it will be much easier to give advice to correct any clutch issues. -PeeWee

PeeWee86

Looking for a base recommendation on clutch weight or starting point for my sled after current mods was wondering if you could help

2017 AC HC Turbo 153 0-5000 altitude

21t top
48t bot
2.28 ratio
Track height 1.75 backcountry x

(275 hp Precision EFI tune with exhaust)

What weights for clutch would you suggest as a starting point

Not looking for top end speed I think gears I have are adequate (105mph)I do like a hard engagement and bottom end pull would stock spring helix be adequate ?

Ultimaxx belt

Any info or recommendations to someone who could help would be appreciated

I’m (new) trying to engage and learn cheers!

 

[PeeWee86]

The following is a cut-and-paste from the Venom Performance Products catalog. It is the best concise clutch tuning tips that I have seen. If I was going to write my own clutching tips they would look almost identical. Of course the Bible that many people use is the Aaen Clutch Tuning Handbook. I have owned my copy for almost 30 years.

CLUTCHING TROUBLESHOOTING TIPS

You must make sure EVERY part of your drivetrain is working before you start tuning on your clutches. The first things to check before you go buy clutch tuning components are:

• Is your motor running like it should? If you cannot pull stock clutching, you have an issue somewhere.

• Do you have a fresh, broken-in belt? Even though your belt may not be shot, it could be worn to the point where you don’t get the same performance.

• How are your motor mounts? A motor that moves in the chassis under power will not keep clutch alignment and calibrations go out the window.

• Are your clutches in alignment? Check your alignment with an alignment bar.
• Do you have sufficient traction? A studded track is a must for flatlanders if you want consistent results.

Once you have all of these things in line, here are some tips to get your clutching spot on. The first and most important key to getting good clutching is to have good data. This means a recording tachometer or other playback device. In my years in this business I have learned that people cannot watch a tach and give good feedback. It’s also dangerous. Max recall on a stock tach is meaningless, also. Once you have good data, these are some of the things that can happen on full throttle pulls from a dead stop: (RPM on the left scale, and MPH on the bottom scale).

• Ideal- The ideal shift curve climbs to your rpm of max horsepower quickly and stays there throughout. This graph assumes 8200 is the ideal RPM.

• Low- If your RPM is low throughout the shift curve, you are over-clutched. You need to drop gram weight in the drive or drop helix angle (initial and final) in the driven. Going up on spring rates in both the drive and driven clutches will also raise operating RPM.

• High- If your RPM is high throughout the shift curve, you are under-clutched. You need to raise gram weight in the drive or raise helix angle (initial and final) in the driven. Going down on spring rates in both the drive and driven clutches will also lower operating RPM.

• Climb- If your shift curve climbs then you have too much helix at the beginning and/or not enough initial driven clutch spring.If you are using adjustable shift weights, you may have too much weight in the heal of the weight (nearest the pin).

• Fall- If your shift curve drops then you have too much helix angle at the finish, too much gram weight in the drive, and/or too much initial driven clutch spring. If you are using adjustable shift weights, you might have too much weight in the tip of the weight (farthest from the pin.)

• Overflash- This occurs when the drive clutch has complete traction on the belt, but the driven clutch does not let it shift soon enough. More initial helix angle and dropping driven spring preload will fix this.

• Slip- This looks like overflash, but the motor is bouncing off the rev limiter at the start. This is caused by the drive clutch not getting full traction on the belt. This can be caused by too much gearing, not enough initial helix angle, too hard of a belt compound, too much drive clutch spring preload, and not enough heal weight in the drive clutch weights.

• Bog- While similar to climb, a bog is more pronounced and can indicate a belt that is shot, a motor problem, or a broken motor mount. A bog that bad generally is not due to clutch tuning.

 

[PeeWee86]

If you’ve added more horsepower and we are going under the assumption that your clutching was working well to begin with, you will in all likelihood to have to add gram weight to the clutch arms. Since you have an Arctic Cat I’m not sure if they have a factory adjustable arm. If you need to purchase new clutch arms I am totally sold on the newer designs that use magnetic adjustable weights. OSP is one website sponsoring vendor here that have this style arms for your Arctic Cat. (We like our sites sponsors!) Other non-website sponsor vendor options would be from Straightline Performance or from Bikeman Performance. I’ve had racing sponsorship deals with both of these companies in the past so that biases my suggestions to work with them.

The OSP arms have a flatter curvature than the arms from some of the other vendors. The whole “Clutching on the Cheap” thread on this website is worth reading but is really about flat profile weights as much as it is about inexpensive clutching.

https://ty4stroke.com/threads/clutching-on-the-cheap.129971/

Flatter profile weights will generally upshift better and squeeze the belt better than a more curved profile. If you read COTC, the OP would lead you to believe that there are no downsides to a flat profile weight. When another person tried to discuss the cons of the flat profile they were quickly quashed.

There is always a downside or every clutch tuner in the world would be running flatter profiles. The downside is that they may not back shift as well and they will have more trouble with snow surface transitions. For example you might have a great working set up going down hard packed trails but then when you get off the trail into some deep powder the extra load will drag the RPMs down more with a flatter profile weight. This effect is much more pronounced on a peaky two-stroke engine that it is on a four stroke with a more broad torque curve, but the negative effect is still there. So which direction would I go? If you find yourself riding in consistent conditions I think I would look at a flatter profile weight. The BTX is designed as a crossover snowmobile. If you ride trails and off trail equally I would lean towards a clutch weight with a little more curvature.

Once you have an adjustable weight set up it’s a matter of reading the RPMs and following the suggestions that are given in the clutching tips above. Simple, right? -PeeWee

 

[BlineBraap]

If you’ve added more horsepower and we are going under the assumption that your clutching was working well to begin with, you will in all likelihood to have to add gram weight to the clutch arms. Since you have an Arctic Cat I’m not sure if they have a factory adjustable arm. If you need to purchase new clutch arms I am totally sold on the newer designs that use magnetic adjustable weights. OSP is one website sponsoring vendor here that have this style arms for your Arctic Cat. (We like our sites sponsors!) Other non-website sponsor vendor options would be from Straightline Performance or from Bikeman Performance. I’ve had racing sponsorship deals with both of these companies in the past so that biases my suggestions to work with them.

The OSP arms have a flatter curvature than the arms from some of the other vendors. The whole “Clutching on the Cheap” thread on this website is worth reading but is really about flat profile weights as much as it is about inexpensive clutching.

https://ty4stroke.com/threads/clutching-on-the-cheap.129971/

Flatter profile weights will generally upshift better and squeeze the belt better than a more curved profile. If you read COTC, the OP would lead you to believe that there are no downsides to a flat profile weight. When another person tried to discuss the cons of the flat profile they were quickly quashed.

There is always a downside or every clutch tuner in the world would be running flatter profiles. The downside is that they may not back shift as well and they will have more trouble with snow surface transitions. For example you might have a great working set up going down hard packed trails but then when you get off the trail into some deep powder the extra load will drag the RPMs down more with a flatter profile weight. This effect is much more pronounced on a peaky two-stroke engine that it is on a four stroke with a more broad torque curve, but the negative effect is still there. So which direction would I go? If you find yourself riding in consistent conditions I think I would look at a flatter profile weight. The BTX is designed as a crossover snowmobile. If you ride trails and off trail equally I would lean towards a clutch weight with a little more curvature.

Once you have an adjustable weight set up it’s a matter of reading the RPMs and following the suggestions that are given in the clutching tips above. Simple, right? -PeeWee

Unbelievable response thank you very much for taking the time to reply this kind of information is what makes a forum valuable direct to the point and detailed as a mechanic this is spot on stuff I will read thoroughly and evaluate what’s needed

 

[Joshua]

If you’ve added more horsepower and we are going under the assumption that your clutching was working well to begin with, you will in all likelihood to have to add gram weight to the clutch arms. Since you have an Arctic Cat I’m not sure if they have a factory adjustable arm. If you need to purchase new clutch arms I am totally sold on the newer designs that use magnetic adjustable weights. OSP is one website sponsoring vendor here that have this style arms for your Arctic Cat. (We like our sites sponsors!) Other non-website sponsor vendor options would be from Straightline Performance or from Bikeman Performance. I’ve had racing sponsorship deals with both of these companies in the past so that biases my suggestions to work with them.

The OSP arms have a flatter curvature than the arms from some of the other vendors. The whole “Clutching on the Cheap” thread on this website is worth reading but is really about flat profile weights as much as it is about inexpensive clutching.

https://ty4stroke.com/threads/clutching-on-the-cheap.129971/

Flatter profile weights will generally upshift better and squeeze the belt better than a more curved profile. If you read COTC, the OP would lead you to believe that there are no downsides to a flat profile weight. When another person tried to discuss the cons of the flat profile they were quickly quashed.

There is always a downside or every clutch tuner in the world would be running flatter profiles. The downside is that they may not back shift as well and they will have more trouble with snow surface transitions. For example you might have a great working set up going down hard packed trails but then when you get off the trail into some deep powder the extra load will drag the RPMs down more with a flatter profile weight. This effect is much more pronounced on a peaky two-stroke engine that it is on a four stroke with a more broad torque curve, but the negative effect is still there. So which direction would I go? If you find yourself riding in consistent conditions I think I would look at a flatter profile weight. The BTX is designed as a crossover snowmobile. If you ride trails and off trail equally I would lean towards a clutch weight with a little more curvature.

Once you have an adjustable weight set up it’s a matter of reading the RPMs and following the suggestions that are given in the clutching tips above. Simple, right? -PeeWee

My plan is to change my gearing to MTX from BTX LE. I was just going to switch to MTX clutching as well, right from Yamaha. Is that a good idea?

 

[PeeWee86]

I would not spend the money on the clutching setup from an MTX. That combination is set up for 10,000 feet of elevation and a 3 inch tall lug track in addition to the lower gearing. If you are determined to lower your gearing, ( I am going to try to talk you out of it in a minute) I think it would be more cost effective to tweak the factory clutch setup that you have. If necessary you could switch to an aftermarket set of magnetic adjustable clutch arms like I had recommended above. The lack of easy adjustment is a big negative for the Yamaha OEM clutch arms.

If you are riding at lower elevations and you are continuing to use the original 2 1/4” track I am inclined to believe that the factory gearing is pretty well matched. The LE’s already have lower gears than the standard BTX SE’s that use the 1 3/4” track. Have you switched to a taller lug track? What are you attempting to accomplish? There have been others on this forum that have decided that the factory gearing on the MTX is too low when riding at lower elevations. Especially if they’ve moved away from the 3 inch lug. I would hate to have you spent money on a gearing change and realize that you took a step backwards. The gearing combinations that I would consider are the 24/50 which I believe you have already have, or the 22/48.

For the cost of a set of gears and a chain I would be more inclined to spend I little more money on a tune that would increase your horsepower. More horsepower will more easily pull the gearing that you already have. -PeeWee

 

[Joshua]

I did switch from a 2 1/4'' to a 2.5'' track. I have the LE sidewinder and I do a lot of back country riding, and I'm looking for instant front end lift.

I have considered a tune multiple times. However I'm not interested in spending hours and hours trying to figure out clutching. I had a 15 Viper Turbo and it took me 2 winters to figure it out. And I'm afraid a tune will effect my sled negatively, as in stock forum it starts right away and runs perfect. Remember I have a 15 Viper and it was on times a bitch to start and it idle like #*$&@.

 

[PeeWee86]

That makes sense. The seasons are short and it’s no fun spending days dialing them in when you want to be riding down the trail. 21/49 and 22/48 both use a 90 pitch chain and the gears are much cheaper than the cost of a new chain. You are probably never going to try to spin that tall track at 90 miles an hour anyway.

 

[Joshua]

That makes sense. The seasons are short and it’s no fun spending days dialing them in when you want to be riding down the trail. 21/49 and 22/48 both use a 90 pitch chain and the gears are much cheaper than the cost of a new chain. You are probably never going to try to spin that tall track at 90 miles an hour anyway.

Maybe a dumb question but since my BTX has 7 tooth drivers, if I go with MTX gearing will I achieve the same ratio as an MTX with the 8 tooth drivers?

 

[rla1]

Maybe a dumb question but since my BTX has 7 tooth drivers, if I go with MTX gearing will I achieve the same ratio as an MTX with the 8 tooth drivers?

hey Joshua,did you change your driver's to 7 tooth,because if you have btx le you have 8 tooth drivers or did I miss something since I have been watching this thread