I have seen a ton of post on this subject but here is a question for all that have had problems. I myself have not had any problems with the tranny on my 01 raptor. What gearing are you all using ? I am using stock rear and a 12 tooth front. (this is just a little research of the curious kind)

 

I ran a 12/40 then 12/42 and settled with 13/42 on one of my Raptors. I am sticking with the 13/42 for trails and dune running. It has better all around feel with the 13/42. 13/40 works great for other fun as well as 14/40 if you have the mods to pull it.

 

All you guys bi@%#ed about your tranny failing but no one remembers the gearing ? Looking for a little info here.

 

Never had a problem with my transmission yet. Ran 13/40, 12/40, and now 13/42.

You don't need to search for a solution though. The engineers have already figured it out and made the appropriate changes to the cogs on the gears.

/NotuRaptor

 

I have had no problems with my tranny either just looking for some info for a theory im working on.

 

A better theory might be to check how many people run their Raptors at full bore on the pavement instead of dirt. This is the reason many of Yamaha's street transmissions fail - too much traction and power for the weak cogs on the gears. The shift from 1st to 2nd puts an incredible amount of stress on the transmission. I ride fast on the street but I take it easy when shifting from gear to gear. I never do a burnout on the pavement nor do I ever spin the tires when going from 1st to 2nd on pavement.

/NotuRaptor

 

my raptor was completely stock, and my tranny has gone 2 times...it is apart in my basement now

 

If your quad has the gearing setup for more low end rather than top speed it will take some stress off the tranny and place more ont eh rear end. This is pure physics and is applied by drag racers all the time. Powershifting will greatly increase the chances of breaking the cogs, especially if the tires grip rather than spin.

 

<< if your quad has the gearing setup for more low end rather than top speed it will take some stress off the tranny >>


This is wrong. Setting the gearing for more low end (example 12/40) multiplies more torque....adding more stress to the transmission.

 

I just put a set of Fortin gears in a Raptor today. I was surprized to see the basic design of the gears was identical, but two key differances. The Fortin gears are forged instead of cast, and some of the dogs are just slightly &quot;back cut&quot;. They looked much better than the stock gears[due to forging], but it shows that the design was OK, Yamaha just went cheap on the material. Watch for a feature on this on Off-road.com. The bike belongs to them.