Same Keihin jets fit '05 and '06?

[red7]

I have a JD jet kit for '05s and someone told me that the needles won't work on an '06 but I was wondering if the main and pilot jets changed as well? I just got a '06 YZ450 and still have a bunch different size jets from my '04 WR. Can I use them on that or do I need to get specific ones to fit the '06?

[mtrdrms]

You can use the same jets just do a search here and make sure you put the right sizes in for optimum performance.?

[Ranger18]

All kehein FCR jets are the same. The needles might apear to fit, but they may be shaped different. If I were you I would sell the JD needles, and instructions on ebay.

I have an 06 450 and run a 45 pilot 168 main currently. I just picked up an NFLR needle (factory needle for an 07) and a 170 main. This should help out alot. I might also go up to a 48 pilot.

I think for winter a 48 pilot 170 main

and for summer a 45 pilot and 168 main should work great.?

[red7]

All kehein FCR jets are the same. The needles might apear to fit, but they may be shaped different. If I were you I would sell the JD needles, and instructions on ebay.

I have an 06 450 and run a 45 pilot 168 main currently. I just picked up an NFLR needle (factory needle for an 07) and a 170 main. This should help out alot. I might also go up to a 48 pilot.

I think for winter a 48 pilot 170 main

and for summer a 45 pilot and 168 main should work great.?

Are you at sea level ranger? That's exactly what I'm thinking when I pick up my YZ on the 2nd of January. 170 main, 48 pilot with the NFLR needle. Talking to burned, he thinks I could run this all year here in Mazatlan. It doesn't get much over 90 here in the summer but is way humid (hence, I surf more and ride a little less).

BTW- can someone explain to me how humidity effects jetting?

[Ranger18]

Are you at sea level ranger? That's exactly what I'm thinking when I pick up my YZ on the 2nd of January. 170 main, 48 pilot with the NFLR needle. Talking to burned, he thinks I could run this all year here in Mazatlan. It doesn't get much over 90 here in the summer but is way humid (hence, I surf more and ride a little less).

BTW- can someone explain to me how humidity effects jetting?

I ride at about 2000', but live at 500' I can ride around my house and the bike feels great, and when I ride desert it feels great also. I'm switching to the 170 main forsure because I get some hesitation on my top end. My low end is good with a 45 but a 48 is great. I think you could ride all year with the 170, 48 especially at sea level, but if you notice a little decrease in power I'd switch to a 168, 45. As far as humidity I have no idea how it effects jetting, but I do think it would help cool the charge(cause the gas to be more dense) which is a good thing.

[grayracer513]

Humidity occupies space within the air mass, and in doing so, displaces oxygen from the air, so higher humidity requires leaner jetting, just as do higher temps and altitude.

[red7]

Grayracer, how much difference does humidity make? Is there a recommendation chart like there is for temperature and altitude? Do you think a 48 170 will work all year or will I have to drop to a 168 when the temperature hits 90 and the humidity is high as well? To be honest, I try to only ride in the morning when it's cooler (maybe 80) 'cuz I'm soaking wet if I ride at mid day.

I'm just curious if 20% to 80% humidity equates to a jet size and also which jets.

[grayracer513]

I don't think it affects things as much as temp and altitude, except at the extremes, but then where I am the humidity usually doesn't swing much, and it conveniently runs opposite the altitudes I ride at somewhat, so I more or less ignore it.