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870 Views 8 Replies 7 Participants Last post by  TGrizzly2014
Hey Grizzly fans: Have a question regarding our '14 Grizz 450. What kind of altitude can you achieve with the carbeurated 450? We are considering Colorado this year but want to know how high this beast will take us without rejetting. Thanks!
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I don't know anything specific about the Yamaha Grizzly 450 but here are a few tips. Newer carbureted toys run lean at sea level due to smog regulations. Our California XR400R dirt bikes ran fairly well up to 13,000 feet in Colorado with a few slight modifications but no jetting changes. There was a low speed fuel screw on the carburetor which I leaned out a bit. I removed an intake restrictor piece that was present. There was also a quiet core piece in the exhaust which my boys removed (I did not). Anything to increase the air flow will lean it out a bit. You might have to crack the throttle a bit to start it at high altitude. The only jet you might have to replace is the main jet. This can be easily done with a couple of tools. (A wrench to remove the big (17 mm?) bolt at the bottom of the carburetor bowl and a special little main jet tool to remove and replace the jet) You can use the altitude-jetting tables from Yamaha to find out what main jet is appropriate for your trip. I carried smaller main jets but never had to use them.

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My 2003 Artic Cat TRV was a 500 and when we went to Colorado I swapped out the main jet for one for 9,000 feet. Took about 10 minutes. Ran perfect up until about the top of Antero at 13,000 plus. Then it popped mildly and such but still runs fine. Swap it back when you get home.

I've taken my old DRZ to the Black Hills without jetting and at 6,000 plus feet it's performance sucked big time. Popped and hesitated, very annoying.

I wouldn't risk a fun vacation if all it takes is a quick jet swap to eliminate that potential issue. Bought a 2016 700 Grizzly last year so no more jetting!

We stay at Taylor Park and Pitkin area most of the time we go.
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I run a 660 and changing the jet was the wrong thing to do. I increased the air by drilling holes in the air filter box, which can be covered with tape for high water crossings. I also learned that raising the pulley ratio freed up the engine for great performance.
The 660 needs the gas to make power, so cutting the gas didn't work.
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WOW again!

Man these posters know a thing or two about the Grizz! Thank you gentlemen for your assistance with my questions! Very valuable info!

Tim :grin2:
Ridgway is the only one that I know of that believes that jetting is not important at altitude. Each to their own. Will it run with out re-jetting, yes. Will it run better if you re-jet, yes.
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Anything I've ever owned that had a carburetor on it ran better when it was jetted correctly (per the manufacturer) for the altitude that it was used at.

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Here's my take,
I've landed over the river from Council Bluffs many, many times. I've been all over Nebraska and met more great people in that state than all states combined, however the landscape leaves much to be desired. Go to Colorado on the Rockies, take your camera and ride as high as that 450 will take you. When it peters out, eat a sandwich, soak the views in, take a thousand pictures and you'll wonder why you don't live closer.
You should be able to cover the mountain without many sandwich breaks.
I'll leave jetting up to others, however I will say, pack your bags and go, Colorado is Gods Country for landscape, (sorry WV).
Good luck and safe travels.
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Hey thanks Hammerhead for the advice and suggestions. My fellow Nebraskan's can be a friendly bunch but the scenery her beckons for more. We have been to Colorado many times on our GoldWing and I often wonder what it would be like off-roading there. Hmmmm....
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