I just bought a YFZ450 quad and put all the GYTR stuff on it. This included: pipe, header, intake with the led pulled off the air box, and I advanced the exhaust cam. I am running a 178 main jet, and I’m having symptoms of lean condition. I am told that the fact that the header and pipe turning blue is normal!!! I’ve been building V8’s for a long time, and this is not OK in the V8 world. Plus it back fires a bit when I let off the gas, this is also a sign that the bike is border line lean! I was going to try a 183 main, but a tech at Yamaha said that it would be too rich. This is also the same guy that told me that the entire pipe being blue was normal! When I got the GYTR goodies it came with needle and jets. I put in the biggest jets and set the needle on the seventh position to make it as fat as possible. Hell I even had to grind off the top portion of the needle stem so it would fit in the carb in that position. This pulled the needle up as far as it could go. Does anyone have a suggestion on jet sizing??

I got the Alba kit in mine, header, pipe, K&N, and did the cam thing, yes every bike I have seen out there, the head pipe glows at idle, but cools down when riding around, it has been awhile but I believe I have a 45 pilot, 175 main, I have the NVCQ needle, it is on the 4th clip and the bike straight up hauls A$$, doesnt pop when letting off the gas, my only problem is that it doesnt want to idle. hope this helps.

Don't get me wrong... This is the badest bike I've ever owned!!! The YFZ450 is incredably easy to ride considering how nimble and freakin fast it is. I out wheigh a friend by 50 pounds. He has a Banshee with a Trinity stage four kit on it. He can not out pull me. After he talked all the trash, he rode my bike, dusted every one up Olds with it that day. Guess who's Banshee's in the Trader... There is a third jet in the carb that is just for idel. You may need to incress it for more fuel at idle. There is also a screw on the front/bottom of the carb that you should unscrew about half a turn. I would adjust it in quater turn incremints and run the bike for about 30 seconds at a moderate RPM. This is what I did to get my bike to idel. I think I am going to try the 183 main.. I'll keep you posted on the out come!

I forgot to mention, I did install the new air mixture screw so that I can adjust it by hand and dont need a screwdriver, I got that at alba too, might want to look into one, albaaction.com.

Cool, that mix screw is a B%t*H to get at... Thanks for the heads up!

You guys should be careful with those air/fuel adjusters, they don't seal nearly as good as the stock ones do and I've seen more than a few leak. And with a little bit of air leaking through there your lean problem just gets worse along with the decel popping.

If you are going to go bigger than a 178 main, only go to a 180, I've run a 178 in a bike I race and it works great. The needle could be where your problem is in my opinion, I don't know the number off hand but I do know you have to run the same needle that comes stock on the YZ 450.

It's true that the whole system will turn blue, especially if its Ti. But if you keep the bike movin you should be just fine.

Dustin

I was told to run some C4 gas with a plug change to check proper plug coloration. The suposed reason was that pump gas is dirty and may give you the wrong reading. Is this true? Your just checking fuel burn, how far off could it be?

I don't agree with the race gas thing. If you're going to do a plug check it should be with the gas you are running on a normal basis. Unless you are running a high compression piston or have had some motor work done there is no reason to run anything but 91.