I'd bet my money on a restrictive airbox/exhaust causing the rev limits. Try to pull the core from your exhaust system and re-run the testing.

 

I tend to think that it's #2. If it were speed limited then it would run the same speed in 4th or 5th. It's not like the ignition starts cutting out to limit it. It just quickly tapers off as the rpms get high. I think it is a very sneakily designed rev limiter in that makes you THINK it's just running out of power. I bet if I put a tach on it and pick the tires off the ground that it'll turn a different rpm in different gears.

So yes, I believe that it's going to turn the same rpm in 5th regardless of the sprocket.

I haven't checked the speed in the other gears to see what rpm it pulls in them. I should have and I will.

 

We'll find out for sure soon but as I said before, I think that if the rpms were limited only as a result of inadequate power to pull the rpms that it would go faster down a hill than up it. Think about it. Doesn't that make sense?

 

Yes, if it was toping out at 74 on a level grade due to HP, no limiter, then yes, it would go faster downhill.

 

Make no mistake about it, the Raptor is geared way, way, way, way too tall! I posted some gearing info in the thread on 12-tooth sprockets. I think the tall gearing is unnecessarily killing the available G's in 4th and 5th. By gearing down one tooth minimum on the countershaft, you should pull higher RPMs in 4th and 5th, but may still not reach 9000RPM because 12 teeth is still fairly tall gearing. See my post in the other thread...

 

HMMMMM??? It kind of sounds like the same thing that Suzuki did with the 2000 GSXR1300 Hayabusa, it was slower than the 1999, and when Kawasaki released their ZX-12, the horsepower, gearing and speeds just didn't add up. Its in the electrics, I havn't got mine yet, so you guys need to buy a service manual and do some wire chasing!!!

 

Wow! This is one of the most exciting post that I've read on it. I agree, they have some how limited it, but don't have a clue as to how. I would think that an electronic limiter would be easy to "feel", instead of taper off. I'm sure if that's the case, there's an aftermarket co. working on it right now. It will be a while before mine is broken in, but when it is, I'll take mine to a dyno.

I would tend to believe that they have limited it with a combination of the gearing and exhaust, but I could be wrong and that doesn't make sense considering your GPS readings.

Keep us posted, and be sure and give us some readings on max speed/rpm in the other gears when you get that info.

 

Wow, that is incredible. I wonder where a speed sensor would be placed? Any Yamaha Employee's out there who want to "Anonymously" answer this question?????

One question, if you run it flat out in 4th gear to the limiter, what is the speed of that run? If you shift into fifth, and lose speed, or the engine just drops RPM's than something is fishy.

Where can you get a reliable, accurate Tach for one of these things? Where would the sensor go?

 

This may be a mute point but, there is some sort of limiter behind the throttle. I thought it said in the owners manual you could limit maximum speed. It's just a screw on the backside of the throttle and can be seen obviously. I have not topped my Raptor out yet but will be very dissapointed if "the goods were not sold as billed". It say's right here in the Raptor brochure that this thing rev's to 9000 rpm.

 

In the 2000 Yamaha ATV brochure they have a Tach\Hour meter for their four stroke ATV's. I assume this would work on the Raptor.