Overdrive on quads??

[Timberjack]

Firstly, I know that belt driven ATVs don't have gears per se, but here is my quandary: I have a belt driven Yamaha Bruin 350 that tops out at about 50 km an hour on a flat mainline logging road. The trouble is, at that speed it revs pretty high, and if it had another "gear" it sure would be nice to be able to cruise at that speed but at a lower RPM. One day I plan to upgrade to a newer and maybe slightly bigger quad.

The question for you guys is are there quads out there that will travel at a reasonably fast speed along the mainline without revving so high? Does getting a quad with a larger engine necessarily equate to faster speeds at a lower RPMs? I'm thinking a grizzly or can-am 650. Oh, and are there mods that can be easily done to change the rpm without buggering up slow speed performance?

Thanks!
TJ

[landphil]

I've personally exceeded 100 kph on a Polaris Big Boss 6x6 800 twin, belt driven, they can really wind up on a long straightaway. It had high and low range, which I'd say would be more of a factor in it's ability to do well at both ends of the speed spectrum.

That Bruin doesn't have hi / low range, does it?

[Timberjack]

I've personally exceeded 100 kph on a Polaris Big Boss 6x6 800 twin, belt driven, they can really wind up on a long straightaway. It had high and low range, which I'd say would be more of a factor in it's ability to do well at both ends of the speed spectrum.

That Bruin doesn't have hi / low range, does it?

Ya thats right. No low range. On of the main reasons i would like to upgrade one day.

[BCBRAD]

Firstly, I know that belt driven ATVs don't have gears per se, but here is my quandary: I have a belt driven Yamaha Bruin 350 that tops out at about 50 km an hour on a flat mainline logging road. The trouble is, at that speed it revs pretty high, and if it had another "gear" it sure would be nice to be able to cruise at that speed but at a lower RPM. One day I plan to upgrade to a newer and maybe slightly bigger quad.

The question for you guys is are there quads out there that will travel at a reasonably fast speed along the mainline without revving so high? Does getting a quad with a larger engine necessarily equate to faster speeds at a lower RPMs? I'm thinking a grizzly or can-am 650. Oh, and are there mods that can be easily done to change the rpm without buggering up slow speed performance?

Thanks!
TJ

I am on my second Can Am 650, slow or moderate speed it revs ~3000 rpm , from 40 or so kph it runs 6000 rpm not much in between. Doesn't seem to effect longevity at all. Both get/got ~23 mpg cruising and will top out at 120 kph.

[Seth]

Firstly, I know that belt driven ATVs don't have gears per se, but here is my quandary: I have a belt driven Yamaha Bruin 350 that tops out at about 50 km an hour on a flat mainline logging road. The trouble is, at that speed it revs pretty high, and if it had another "gear" it sure would be nice to be able to cruise at that speed but at a lower RPM. One day I plan to upgrade to a newer and maybe slightly bigger quad.

The question for you guys is are there quads out there that will travel at a reasonably fast speed along the mainline without revving so high? Does getting a quad with a larger engine necessarily equate to faster speeds at a lower RPMs? I'm thinking a grizzly or can-am 650. Oh, and are there mods that can be easily done to change the rpm without buggering up slow speed performance?

Thanks!
TJ

Something doesn’t seam right. My brother has that exact same quad and he can easily keep pace with me and my buddies on mid size (450 & 500cc) quads when doing about 65 - 70 km per hour. Have you checked to see that the throttle limiter isn’t limiting your speed? There is a philips head screw on Yamaha’s on the front side of the recoil throttle housing mounted to the handle bars where the thumb throttle is. Make sure it is wound all the way out. Yamaha has that screw on there so that if a younger inexperienced rider is using the quad a parent can limit its top speed. If that screw was wound in even a bit you would experience exactly the condition you’ve described.

[Stroodle]

There are a number of things here - if you are not reaching speeds of similar machines, first check would be the belt - perhaps it is worn? When was the last time your clutches were serviced? There are modified clutches available that have been machined to allow higher speeds while maintaining a lower engine RPM. There are also clutch weights that can be changed to make changes in your performance also. Check the forums for your machine type and will find tons of information. Hope this helps a bit.

[MRP]

There are a number of things here - if you are not reaching speeds of similar machines, first check would be the belt - perhaps it is worn? When was the last time your clutches were serviced? There are modified clutches available that have been machined to allow higher speeds while maintaining a lower engine RPM. There are also clutch weights that can be changed to make changes in your performance also. Check the forums for your machine type and will find tons of information. Hope this helps a bit.

Yup my first thought. Worn thin belt or nylon clutch slider bushings on main or the drive. If there the same as the old sleds I had. 1/4inch difference is a big deal on the top end.

[Timberjack]

Something doesn’t seam right. My brother has that exact same quad and he can easily keep pace with me and my buddies on mid size (450 & 500cc) quads when doing about 65 - 70 km per hour. Have you checked to see that the throttle limiter isn’t limiting your speed? There is a philips head screw on Yamaha’s on the front side of the recoil throttle housing mounted to the handle bars where the thumb throttle is. Make sure it is wound all the way out. Yamaha has that screw on there so that if a younger inexperienced rider is using the quad a parent can limit its top speed. If that screw was wound in even a bit you would experience exactly the condition you’ve described.

Ahh - I should've been clearer. I can get mine up to 65km/hr on a long straight with no uphills, but it's revving high and not at a comfortable RPM being a single cylinder (vibration becomes unpleasant...) Just that under 50km/hr or so the engine's running at a much "happier" RPM. Ideally, I'd like to squeeze another 20km/hr our of it at the same "happy" rpm... I'll check the throttle limiter, but don't think that's an issue.

Cheers,
TJ

[Timberjack]

There are a number of things here - if you are not reaching speeds of similar machines, first check would be the belt - perhaps it is worn? When was the last time your clutches were serviced? There are modified clutches available that have been machined to allow higher speeds while maintaining a lower engine RPM. There are also clutch weights that can be changed to make changes in your performance also. Check the forums for your machine type and will find tons of information. Hope this helps a bit.

Thanks for the feedback MRP and stroodle... I'll look into the belt and bushings for sure, but it's the different clutch idea I was fishing for. I'm not a mechanic so didn't have the right words, but now I can do a search to see if there's a relatively cheap mod I could do to help. Though I don't suspect cheap will be part of that anything like that...

What about the relationship between a larger engine and faster cruising speeds? Do quads with larger motors tend to have different clutch assemblies that allow for faster speeds at lower rpm (nothwithstanding BCBrad's comment above about his can-am 650...)?

Cheers,
TJ

[MOUNTAIN MICKEY]

I rode my 2004 350 Bruin for 12 years and did not experience the issue you are having. Still had original belt on it when I sold it.