Jetting a '99 400wr ??????

[wbbaz]

I need help with jetting on a '99 400wr. I live and ride at 5,000', but also go up to 7,500 or down to 3,000' Do I need to rejet at each altitude, and if so what jets must be changed. I have a factory manual, but not a clue as to which jets to alter. Any information would be greatly appreciated.

Thanks

Bill

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[Florida 393]

Bill,
I'd imagine the main jet and possibly the needle clip position. Lets see if Faded sees this thread and will reply. He is a stone jetting whiz on any brand bike and carburetor. Can you tell us what happens as far as popping on decel, backfireing or blubbering at the respective altitudes? That would help with knowing what you need. Thanks for reposting here.

Bill Barnard

[Keetoman393]

Bill, try looking at Garrett's website which has a wealth of information. There is a section in it that has an excel spreadsheet that calculates the jetting vs. altitude issue. I use it when I go to Colorado to ride and my bike has ran flawlessly every year. Good luck!

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[wbbaz]

Trouble sustaining idle. I'll try a main jet change and clip adj. Thanks for the help. Where would I find Garretts website, in ATM ?? I'll look for Faded as well.

Thanks for the help.

Bill

[Florida 393]

The link to Garrett's site is in Keeto's reply. ( [Only registered and activated users can see links. ] ) Garrett was a young rider from Houston, Tx. He was killed in 2002 and word was spread through Thumper Talk. A nenorial race was held in Houston on 1 Dec 02 and has been held in October every year since. Garrett was a brilliant young man that shared his knowledge with anyone that needed. Go to the Garrett M. Berg forums for the whole story and the background on key people for this site that followed Garrett's spirit and got this place going.

Faded is a member here, check these 4 stroke and 2 stroke forums for his replies (do a search or use the forum member guide link at the top of the pages. He is a sharp man with much tuning knowledge for any type of dirt bike.

Bill

[wbbaz]

Thanks to everyone for their help. I ended up going to my local Yam dealer for a valve adj. and asked them to install the main jet for the 5,000' altitude. It's been cold recently so I haven't had a chance to take it out to try it. I feel a little more confident about the jetting issues just from your replys.

I'm not sure how to copy everyone, so please don't be offended if i didn't reply personaly. Having a little trouble navigating the site.

Thanks again,

wbbaz

[Keetoman393]

Glad you got it sorted! Thank you for letting us know it is running better.