Mtx clutching low elevation na

[Ben T]

Looking for some feedback on home brew mtx clutch setups that have worked to get a starting point for my clutching as I start tinkering. From reading other posts the factory setup is less than close which i found on the 70 miles currently on my sled. Can’t find a lot of post that reference there full setup springs weights helix for mtx. This is low elevation natural aspirated mtx.

Current setup
2016 SR Viper MTX 162
Ggg spring primary
8bu10 weights both rivets
37 secondary helix (8KG00)
3-1 wrap
Pink spring secondary
Stock Gearing

Sled performs very poorly in current setup poor upshift and back shift but does hold rpm.

Any helix / spring / weight suggestions? Anyone love there Low elevation clutch kit in a mtx?

 

[PeeWee86]

You’re staying at lower elevation. Are you going to keep the tall lug track or are you cutting it down? Either way I think you need to gear up. How far you gear up depends on what your snow conditions are going to be and how much track lug you intend to keep. The most inexpensive change is to keep your factory chain and go from the stock 21/49 to 22/48.
However, this may not be enough of a change if you’re going to a shorter lug track and keeping the original seven tooth drivers. The cost of the two sprockets is about $80 if you know where to shop. Search my previous posts. I have given part numbers for these two sprockets in the past.

It wasn’t clear from your post if your snowmobile had only 70 miles on it or if was purchased used and the 70 miles is the amount of miles you have driven it. These Vipers will continue to break in for 600 to 800 miles and your clutching will be somewhat of a moving target until it is broken in. Tighten the wrap in the driven clutch to 3/3. (Cost:Free) This will improve the back shift but it will require more rivet weight to prevent over revving. I know that Yamaha does not make a heavier clutch arm rivet than what you have. Remove the end rivet and replace it with a button head bolt and nut. (Cost:$12) See the photo in my post here: https://ty4stroke.com/threads/srviper-mtx-top-speed-seems-slow.131829/

Depending on your track lug height, you may have to go to a multi angle helix to straighten the shift curve to prevent an initial over rev, but try the cheap fixes first. -PeeWee

 

[yamahaguy]

If you have a MTX I assume you love to boondock so if that's the case don't cut the track you have one of the best tracks out there for off trail. My advice is to call Thunder Products and talk to Tim or Terry they can get you set up with a proper low elevation clutch kit that actually works.

Also if you can make it out to one of the TY rides you'll have the opportunity to ride with guys running TP clutch kits not to mention having a awesome time just riding with a good group of folks!

 

[Ben T]

Planning on keeping the lugs for off trail. 70 miles total on the sled. Are these break in periods a defined via ECM?

Talked with Tim and went with their kit for starting out and picked up a 43 helix on ebay. Really liked their adjustable arms for tuning.

Slightly hesitant to gear up yet. Just simply on the belief I loved gearing down my prior sleds. Good tip will see as I get more seat time.

 

[Thunder Products]

Planning on keeping the lugs for off trail. 70 miles total on the sled. Are these break in periods a defined via ECM?

Talked with Tim and went with their kit for starting out and picked up a 43 helix on ebay. Really liked their adjustable arms for tuning.

Slightly hesitant to gear up yet. Just simply on the belief I loved gearing down my prior sleds. Good tip will see as I get more seat time.

Thank you so much for your order Ben!

Happy to hear you picked up a helix so you get the best performance out of your Viper.

As to the miles, the 4 stroke engine takes a little more break in time. It's not in the ECU, but just the components of the engine loosening up.

 

[Ben T]

Wanted to post follow up on my experience with the clutching. Maybe 200 miles last winter on the 43 helix and thunder products kit. Extremely pleased with the setup. Got clutching extremely close. Night and day difference on upshift and back shift.

top end is not my thing so happy with the gearing setup but if top end is your thing as Others have said this sled needs taller gearing.

Also found my center spring soft upgrade to 160 very pleased.

 

[Adam Nelson]

Wanted to post follow up on my experience with the clutching. Maybe 200 miles last winter on the 43 helix and thunder products kit. Extremely pleased with the setup. Got clutching extremely close. Night and day difference on upshift and back shift.

top end is not my thing so happy with the gearing setup but if top end is your thing as Others have said this sled needs taller gearing.

Also found my center spring soft upgrade to 160 very pleased.

Your dealer shouldve installed a 42 degree helix if you are at low elevation. Mine did the same thing to me. I ended up with a 50r42 helix and love it. I have a 162x3" track.