Do I need to re-jet my bike? - TwoWheelForum: Motorcycle and Sportbike forums
 
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post #1 of 13 (permalink) Old 05-28-2005, 03:53 AM Thread Starter
 
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Do I need to re-jet my bike?

I'm planning a trip out to Yellowstone this summer and I plan on riding through the surrounding mountains such as Big horn and the Teton's I'm not even totally sure what the elevations are for the mountains that I just listed but do I need to re-jet my bike for riding up in the mounain elevations? I have a 2002 FZ1 (carburated). Thanks
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post #2 of 13 (permalink) Old 05-28-2005, 07:50 AM
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Your bike will be fine! It may lean out a bit but to re-jet it for just that...

Then when you come down from the elevation your bike would start to run rich...




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post #3 of 13 (permalink) Old 05-28-2005, 08:41 AM
 
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Yup, you'll be fine... You may have to crank up your idle a bit as you go higher in elevation though.
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post #4 of 13 (permalink) Old 05-28-2005, 09:58 AM Thread Starter
 
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Cool, thanks guys, I can't wait to get out to the mountain roads, I've never been to the western part of Wyoming before, I hope there'a alot of twisty roads.
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post #5 of 13 (permalink) Old 05-28-2005, 10:47 AM
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Quote:
Originally Posted by Gas Man
Your bike will be fine! It may lean out a bit but to re-jet it for just that...

Then when you come down from the elevation your bike would start to run rich...
Actually, you have that backwards...it will run slightly rich at higher elevations (less air). However, I agree that it is not worth rejetting just for the trip...especially because CV carbs compensate for the amount of air flowing through the carbs.

Larry

Rarely is the question stupid, but sometimes the answer is you need to run everything you read online through your own personal BS meter to determine if it makes sense to you.

Last edited by larryg; 05-28-2005 at 10:50 AM.
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post #6 of 13 (permalink) Old 05-28-2005, 01:46 PM
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OMFG!!! It's Larry G checkin!!!!

FOr those newbies that just don't know... this guy in the tech guru of all!

Been along time Larry... glad to have you back!!




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post #7 of 13 (permalink) Old 05-28-2005, 06:12 PM
 
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Quote:
Originally Posted by Dayton1000
...do I need to re-jet my bike for riding up in the mounain elevations? I have a 2002 FZ1 (carburated). Thanks
It might run better. If you go over the Powder River Pass in the Bighorns, it's over 9,600 feet. You'll notice the decreased power, but you'll still be able to pass all those cages like they're stopped.
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post #8 of 13 (permalink) Old 05-29-2005, 06:17 AM
 
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Quote:
Originally Posted by larryg
Actually, you have that backwards...it will run slightly rich at higher elevations (less air). However, I agree that it is not worth rejetting just for the trip...especially because CV carbs compensate for the amount of air flowing through the carbs.

Larry
welcome back stranger...ive heard that before,(CV carbs can compensate for air) but how do they do that...is it the way the slides move with the diaphram????? cause everything else is sort of locked in (air jets , main jets etc)

and if it is the slides/diaphram then you would still be running rich at wot due to the main jet size etc....

Last edited by GsxrJack; 05-29-2005 at 06:19 AM.
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post #9 of 13 (permalink) Old 05-30-2005, 05:39 PM
 
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Quote:
Originally Posted by Dayton1000
...I plan on riding through the surrounding mountains such as Big horn and the Teton's
Hope you ain't going there today. Supposed to get 12-14 inches of snow in the Big Horns.
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post #10 of 13 (permalink) Old 05-30-2005, 10:20 PM
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post #11 of 13 (permalink) Old 05-30-2005, 11:17 PM
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Quote:
Originally Posted by GsxrJack
welcome back stranger...ive heard that before,(CV carbs can compensate for air) but how do they do that...is it the way the slides move with the diaphram????? cause everything else is sort of locked in (air jets , main jets etc)

and if it is the slides/diaphram then you would still be running rich at wot due to the main jet size etc....

Thanks, my life has taken an intersting twist lately. I should probably post something about that. Anyway, yes you are on the right track, CV carbs work on pressure differentials...based on the flow of air through the venturi, the needle is raised by the diaphragm and fuel is drawn out of the float bowl. This effectively compensates for having less air at higher altitudes while operating at less than ~7/8 throttle. If he was going to be WFO for extended periods (such as racing) I would say it is necessary to rejet because the fuel mixture at that point is based mostly on the main jet and the needle is no longer controlling mixture and able to compensate.

The reality is, he will feel that the bike is making less power (because it is) but the mixture won't be so far off that it is bad for the bike on a temporary basis.

Larry
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post #12 of 13 (permalink) Old 05-30-2005, 11:27 PM
 
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Nice to see you posting again Larry. Haven't seen you in a while. Do tell us about how everything is going.
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post #13 of 13 (permalink) Old 05-31-2005, 08:46 AM
 
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Quote:
Originally Posted by larryg
The reality is, he will feel that the bike is making less power (because it is) but the mixture won't be so far off that it is bad for the bike on a temporary basis.

Larry



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