Venture MP Belt Deflection/Secondary Sheave Offset

[Ryking93]

Hey Everyone,

I recently purchased a 2014 Yamaha Venture MP used with 2700km.. I did a oil change, oil filter change and gearbox oil change. typical maintenance; Along with this I installed a brand new OEM belt. I wanted to ensure everything was OK for when I started my riding season.

Last weekend I took a friends 2008ish Venture Lite for a little ride and notice that his clutch engaged significantly quicker than mine did and was more aggressive off the start. (Just seemed to have more torque) I attributed that to my belt deflection not being correct and possibly my sheave offset.

I know there is a difference for both, and I have read the service manual inside and out, I just don't know how to adjust the belt deflection if somebody could explain a little better in detail what to do. I've also read the forums and still have a little trouble understanding. also it seems that my new belt is sitting flush with the secondary instead of protruding a tiny bit out over and I'm hoping that's my issue

Also I did notice when accelerating that once I got a little speed I felt the clutch (almost feels like changing gears) and continue accelerating. Should I feel this shift as much as I do?

Thanks,

Ryan

 

[Mooseman]

Sheave offset is adjusted by moving or changing secondary clutch shaft shims. From what I can tell, belt deflection is not adjustable except by changing belt number. There is no spec in the manual for it AFAIK.

The MP is actually geared lower (higher numerically) so theoretically, should have a quicker takeoff than the Lite however, the MP has a wider track and more weight to move. The effect would also give the Lite a higher top speed theoretically and lower RPMs for the same speed. I've only ever been on my MP so I can't really say.

For the clutching, there are some differences between the two. The MP uses a primary blue-gold-blue spring while the Lite uses a yellow-blue-yellow. I have no idea how this affects primary engagement. Each also use different weights. So those are probably what you are feeling in the difference in clutch engagement. And for the secondary, you guessed it, each use different springs and helix.

For how to adjust the belt height in the sheave, that's done by taking the secondary apart and removing a shim to bring up the belt,add a shim to lower it. Manual says it should be 1.5mm above the sheave. I adjust it by having the lower part of the ribs on the back of the belt at the sheave level. So basically, the ribs are sticking out.

 

[Ryking93]

Sheave offset is adjusted by moving or changing secondary clutch shaft shims. From what I can tell, belt deflection is not adjustable except by changing belt number. There is no spec in the manual for it AFAIK.

The MP is actually geared lower (higher numerically) so theoretically, should have a quicker takeoff than the Lite however, the MP has a wider track and more weight to move. The effect would also give the Lite a higher top speed theoretically and lower RPMs for the same speed. I've only ever been on my MP so I can't really say.

For the clutching, there are some differences between the two. The MP uses a primary blue-gold-blue spring while the Lite uses a yellow-blue-yellow. I have no idea how this affects primary engagement. Each also use different weights. So those are probably what you are feeling in the difference in clutch engagement. And for the secondary, you guessed it, each use different springs and helix.

For how to adjust the belt height in the sheave, that's done by taking the secondary apart and removing a shim to bring up the belt,add a shim to lower it. Manual says it should be 1.5mm above the sheave. I adjust it by having the lower part of the ribs on the back of the belt at the sheave level. So basically, the ribs are sticking out.

Thanks for the info!!

So for yourself. What RPM do you see engagement and movement? I will be checking today to see exactly my engagement rpm. But his was significantly quicker with less throttle.

Like you said, this may be because of the wider track.

I don’t see my sheave offset being anything besides spec as the machine wasn’t driven hard and only has 27xxkms. But I could stand corrected.

I’m absolutely loving the machine, besides the tuner skis! Lol

 

[Mooseman]

After just adjusting the track last night, I the primary clutch started moving at about 2600-2700. I might be taking it out today after doing a bunch of things to it, namely enclosing the tunnel and maintenance. I'll try and get some specifics.

From what others have been saying, the Tuners are a hate-hate relationship on this sled. They might be good for trail riding but absolute garbage off trail, which is what this sled is supposed to be for. Although I use mine primarily on-trail, I have a set of Camoplast Cross-Terrain 7" wide with a set of Double Down carbides. Good combo but they're fat and ugly.

 

[Ryking93]

After just adjusting the track last night, I the primary clutch started moving at about 2600-2700. I might be taking it out today after doing a bunch of things to it, namely enclosing the tunnel and maintenance. I'll try and get some specifics.

From what others have been saying, the Tuners are a hate-hate relationship on this sled. They might be good for trail riding but absolute garbage off trail, which is what this sled is supposed to be for. Although I use mine primarily on-trail, I have a set of Camoplast Cross-Terrain 7" wide with a set of Double Down carbides. Good combo but they're fat and ugly.

Awesome thanks!

I’ll have to check my track also and see what it’s like, I know after this season I will be replacing my slides. Seems the previous owner may have done a bit of hard packed/ ice riding. They’re worn right in the bend where the track meets the slide. Nbd.

I do not like them whatsoever. So far even on trail, whether hard packed or freshly groomed I still find them darting sometimes to the point where I’m not expecting it and it almost throws me off the machine. I can handle a non responsive machine. I’m 25yrs old, 290lbs and 6’4” so I have no issue throwing it around when need be.

Over the next couple weeks I’ll be taking them off and buying a used pair off a lite and replacing them because I want to put on a 8” set of skins for better floatation.

 

[Mooseman]

When I bought mine with 800km, the slides were worn at the same spot. I added low snow wheels there and they've helped a lot. I also replaced all the wheels with 135mm. Excell has nice wheels with good bearings. Kimpex also has some that look like the stock wheels but have cheapo bearings. I just replaced my slides and this are my third pair. Put in white ones as they supposedly last longer.

Adjust the track a bit on the looser side than the manual says. I run mine with just a bit of droop in the middle. I also run a fully clipped track. Is yours still only half clipped? That was one thing my stock track had and I added all the missing clips, which I also think helped with slide longevity. I now have another track, a 15" wide Crossover, which is also fully clipped.

I'm also 6'2", 340lbs. One thing you'll notice sitting on it is that damned plastic in the back of the seat that will kill your tail bone. I did this to it.
Why our MP/Lite butts hurt and the fix

 

[Ryking93]

When I bought mine with 800km, the slides were worn at the same spot. I added low snow wheels there and they've helped a lot. I also replaced all the wheels with 135mm. Excell has nice wheels with good bearings. Kimpex also has some that look like the stock wheels but have cheapo bearings. I just replaced my slides and this are my third pair. Put in white ones as they supposedly last longer.

Adjust the track a bit on the looser side than the manual says. I run mine with just a bit of droop in the middle. I also run a fully clipped track. Is yours still only half clipped? That was one thing my stock track had and I added all the missing clips, which I also think helped with slide longevity. I now have another track, a 15" wide Crossover, which is also fully clipped.

I'm also 6'2", 340lbs. One thing you'll notice sitting on it is that damned plastic in the back of the seat that will kill your tail bone. I did this to it.
Why our MP/Lite butts hurt and the fix

I’ll have to start doing modifications. I’d say I’ll end up replacing all wheels and slides this summer and adding the low snow wheels. I’ve heard the DuPont slides are the best but don’t know for sure.

I will check the track tonight and adjust like you say! Not sure what you mean by half clipped/fully clipped.


I know the plastic piece your referring too but I find I sit great in the seat, but after a while of riding my knees are seized up solid. I’ll have a look and do that!!

 

[Mooseman]

The metal clips in the track, mine only had half of them. Bought and clipped all the missing ones.

The DuPonts are expensive and not necessary if you use bigger wheels. Some have had the inserts fall out after they overheated and melted the plastic around them. Plain white slides are supposed to last longer because they are pure plastic. There are some with graphite too. I think any would be fine. Mine lasted a long time with the bigger wheels and low snow wheels up front. This was one of the first mods I did using SkiDoo wheels because there weren't any others available at the time. Now there are bigger wheels that are a direct swap.

I didn't get a chance to check clutch engagement. Was working on the trailer wiring since it was so mild today.

 

[Ryking93]

The metal clips in the track, mine only had half of them. Bought and clipped all the missing ones.

The DuPonts are expensive and not necessary if you use bigger wheels. Some have had the inserts fall out after they overheated and melted the plastic around them. Plain white slides are supposed to last longer because they are pure plastic. There are some with graphite too. I think any would be fine. Mine lasted a long time with the bigger wheels and low snow wheels up front. This was one of the first mods I did using SkiDoo wheels because there weren't any others available at the time. Now there are bigger wheels that are a direct swap.

I didn't get a chance to check clutch engagement. Was working on the trailer wiring since it was so mild today.

Didn't even know that was possible I will have to check my track!


So I am currently knee's deep in a secondary clutch... After a little bit of reading I've discovered that apparently there are 3 screws in the back of the secondary sheave, which you can add shims to tighten the sheaves, and remove shims to widen the sheaves. I have added a single 1.5mm shim (Washer) to the rear of the secondary sheave. I tried placing a belt on it but notice no difference so I'm going to reinstall on the machine and see if gravity will assist.

https://imgur.com/a/cvhVQhG

 

[Mooseman]

AFAIK, those three screws, one of them we see in that pic, hold that bushing for the helix in place. You have to add/remove shims inside between the sheaves, which means you have to take the clutch apart. If you do that, you MUST use a new C-Clip (the one we also see in the pic) and install it correctly or it WILL self destruct. This is well documented for our sleds and Phazers.

 

[Ryking93]

AFAIK, those three screws, one of them we see in that pic, hold that bushing for the helix in place. You have to add/remove shims inside between the sheaves, which means you have to take the clutch apart. If you do that, you MUST use a new C-Clip (the one we also see in the pic) and install it correctly or it WILL self destruct. This is well documented for our sleds and Phazers.

Ahh you are right then. Just wasted an hour or so fooling with those screws. It doesn't have the engagement that I'd prefer, however does engage at approximately 3,100rpm (within spec.) maybe next time I'll try a different belt size or something. but nothing ventured nothing gained. I'm definitely not comfortable disassembling the clutch unless I absolutely have to.

 

[Mooseman]

You'll probably have to modify the primary for that if you really don't like the engagement RPM. I'm not very well versed on clutch tuning. There is a kit out there called the Comfort Clutch Kit. I think @BombaPolaYama installed it and liked it on his Lite. I might even add that to my mod list next although I like not having to use the brake too much at all right now. Also comes with the Quiet Clutch kit.
http://www.schmidtbrosmotorsports.com/yamaha-phazer-clutch-kits/

I'm giving you lots of ideas to keep you busy this summer

 

[Ryking93]

You'll probably have to modify the primary for that if you really don't like the engagement RPM. I'm not very well versed on clutch tuning. There is a kit out there called the Comfort Clutch Kit. I think @BombaPolaYama installed it and liked it on his Lite. I might even add that to my mod list next although I like not having to use the brake too much at all right now. Also comes with the Quiet Clutch kit.
http://www.schmidtbrosmotorsports.com/yamaha-phazer-clutch-kits/

I'm giving you lots of ideas to keep you busy this summer

Lol keeping my wallet busy! I seem to have a love hate with the engine breaking. Never touch the break but cannot let off the throttle while standing or I nose dive over the handlebars lol

My main concern is the skis, Which I have the solution for just need the time to complete it. As I do a lot of off-trail/trail breaking the float skis are a must.

Everything else I am quite happy with this snow machine, well worth it

 

[Mooseman]

I finally got the sled out around the yard after all the work. It's ready and waiting for the snow. We have a bit but not enough to open the trails.

So for yourself. What RPM do you see engagement and movement? I will be checking today to see exactly my engagement rpm. But his was significantly quicker with less throttle.

Mine started moving the sled around 3500, which is according to spec. This is that I found in the manual for the different models:



So in reality, the Lite (VT) has a higher RPM engagement. It could have been offset by its 20 tooth top gear vs. the MP's 19, which gives it a higher gear ratio.

My son's Phazer FX has bad engine braking and was actually thrown off once while he was standing. I think his clutching is also way off as he often hits the rev limiter at like 13 000 RPM and blows belts. His sled is in the garage now so we'll be going over it.

 

[Ryking93]

I finally got the sled out around the yard after all the work. It's ready and waiting for the snow. We have a bit but not enough to open the trails.



Mine started moving the sled around 3500, which is according to spec. This is that I found in the manual for the different models:

View attachment 144672

So in reality, the Lite (VT) has a higher RPM engagement. It could have been offset by its 20 tooth top gear vs. the MP's 19, which gives it a higher gear ratio.

My son's Phazer FX has bad engine braking and was actually thrown off once while he was standing. I think his clutching is also way off as he often hits the rev limiter at like 13 000 RPM and blows belts. His sled is in the garage now so we'll be going over it.

I appreciate you checking, thanks!

I’m satisfied with mine at 3,100 approx. within spec.

The engine break is nice because you don’t have to always hit the break, it does it for you. However sometimes it’s agressive. I can live with it though

Getting the suspension set up for me and my girlfriend will be key now, and replacing my slides.