My uncle has a stock yamaha grizzly 660 and he wants to know how to get the top speed to
a level where he can hang with sport quads such as modified 400ex's. Any information
would be very helpful

 

Aren't you the one with the 770 stroker Grizzly??? [img]i/expressions/face-icon-small-wink.gif[/img] If so, you should be able to help him, but otherwise get a good pipe, filter, an jet it properly.

 

You ask wayyyy to many question about grizzlys and keeping up with sport quads! If they want to keep up with a sport quad then buy one. Grizzlys arn't made to be fast they are made for torque and to be work horses. If you want to "keep up" with the 400 just go buy a Raptor [img]i/expressions/face-icon-small-wink.gif[/img]

 

Man that was one hilarious reply. "Hey, aren't you the one with the 770 stroker kit?" I was laughing my ace off after that.

 

Hey Andy I was wondering how much top speed you lost with your 27" tires on your Grizzly? Also do you have any other mods on it?

 

The best way to get more power in a Grizzly, is to put a Prairie 650 motor in it.........[img]i/expressions/face-icon-small-happy.gif[/img]

 

I seriously don't have a clue. If I had a GPS, I would run some tests both ways to find out the difference. Back not long after I bought the Grizzly, I bought a GPS to test it with, and then returned it to Wal-Mart the next day (couldn't see dropping $180 on something I really had no use for). That Magellan 315 said I was doing 60 when the speedo said 65. Thats the only time I've ever tested.

I know that the speedometer is affected by the tire size in what its reading will show though. But I really don't know how much the actual speed is affected. On a big downhill with stock tires, I can nail the rev limiter and get 69 (for just a second) but it usually stops at 68. I haven't done it for a while with the 27" on, but seems like it was just a hair over 60 on the speedo doing this same thing.

Main place I notice the loss with the tires is acceleration. Nowhere near as quick, but it will still stomp a hole is smaller bikes like Rubicons and stuff. Modification is an HMF pipe with the jet kit and filter. If you don't mind the noise (cause it is very very very loud), its a hell of noticable performance gain for about $300 total. Pulls the big tires pretty fast, and absolutely screams with the stock tires on. Oh, and what I said about it running off and leaving the smaller quads, that was back when it was still stock with the 27's on.

 

Hey Andy, im seeing about the same (65 mph) with the 27's on my Grizz. I havent clocked it with a GPS yet. From what I've seen on my other bud's 660's with same size treads, the speeds match. If you want some more on acceleration, getcha a clutch kit...it will wake it up![img]i/expressions/face-icon-small-wink.gif[/img]