Difference between 8GS and 8GK belts (Reverse Update)

[Mooseman]

Some have asked what the difference is between these two belts. The 8GS was the original belt used with 07 and 08 Venture Lite/MP and Phazers. The 8GK is the updated belt used on 09+ as well as those earlier sleds that were updated with a shim in the secondary.

The first pic is with both belts with the 8GS behind the 8GK. You can see that the inner ribs of the 8GK are squared off and shorter than on the 8GS, which are rounded and longer. You can also see the difference with the individual belts.

My own experience with each belt is that the 8GK was harder to shift however I had removed one shim because with both belts, it sat too low in the secondary sheaves. That was probably how Yamaha tried to fix this by reducing the drag on the secondary which would put too much tension on the dog gears in the reverse gear box.

 

[JetAv8r]

Mooseman,

Have you got a copy or a link of the Yamaha Technical Bulletin on the Secondary calling this out?

 

[Mooseman]

It's available here:
Technical Bulletin/Tech Exchange

 

[JetAv8r]

It's available here:
Technical Bulletin/Tech Exchange

Weird. All I get is this when I click on the Link, "
TY4stroke: Snowmobile Forum | Yamaha - 4 Stroke - Error
You do not have permission to view this page or perform this action."

 

[Mooseman]

My bad, it's only accessible to paying members.

 

[JetAv8r]

You ROCK! Might have throw some coins in the site Working this "Reverse" issue on my sled...I'll have quite the encompassing write-up when done!

 

[Mooseman]

If you do get it working right, it will be an accomplishment for you and sadly too late for me as I will be selling the ol' MP as I have moved on to an RS Venture GT. I never was able to get it working reliably. The most frustrating was the "push the button and nothing happens" problem. Check my threads here and others' in the Phazer section. As far as not wanting to shift into reverse, that is caused by too much tension on the secondary by the belt. Just taking some of that tension off with your foot a bit lets it shift.

Good luck.

 

[JetAv8r]

Roger that! Yea, I'm hoping I can get the reverse working smoothly. It is absolutely amazing how much info is out there on the "reverse" issue -- its just scattered all over. I've been going through everything step by step--I had more than one issue on mine (bad TPS etc). I think I have the Chain dialed in now. Next up will be accomplishing the S2009-004
Tech Bulletin above. Congrats on the RS Venture GT - nice upgrade!!! If you want to edit up my MS word.doc PM me with your e-mail and I'll zap you what I have and you can add/edit as you see fit.