I have a raptor that I put a yoshi full titanium exhaust, prodesign adaptor w/ kn filter, with know airbox lid. I am using dyno jet kit mains are at 148-150 and up one on needle from stock. Three turns out on mixture screw. I am at about 1000ft. The probelem I have is that the header pipe is glowing red right away. The bike idle fine and has power though out the whole throttle everything runs great. I did think I would have more power( I get the front wheels off the ground sometimes in third gear).
Any help would be great.....jessie james

 

Sound like you are way lean you need to bump the pilot jet up by one or two size up. Also the main jet of 148 might need to bump up too.

Also you might want to call Yoshi and find out what they got to say about that.

That what I would do.

Bill

 

I have a blaster and my pipe was glowing red the other day. I have a DG pipe/silencer and I was reving the gas pretty good. I changed the spark plug 30minutes prior to riding. Then my pipe was smoking pretty bad, I got off and looked in the silencer. It was red! It hasn't been red since because I don't rev my engine as much, I wish I knew what the problem was as well. :-\

 

desracers
What is the stock pilot screw size I have to place a order for my kid and I thought I could get the pilot scews from them. I was going to order through denniskirk any one know if this is the right part number 17-64 plus jet size

 

Jessiejames
The stock pilot is 25, might bump to 27.5 size.
I don't know about the part number from denniskirk.

Hope that will help.

also have you had the chance to call yoshi?

 

do both carbs have a pilot jet? and are they the same size. could someone pm me the link to alba

 

My '02 YZ 426F's header glows red at an idle too & it's completly stock. I think if your stock headers weren't painted black that they would have glowed too. This is common on all 4-stroke dirt bikes I have been around.

 

Bansheesand

If your pipe is glowing red at idle, it mean you are too lean. Either the air screw need to rich it up or a next size of pilot jet.

You got to remember all new bike tend to run a little lean in order to please the EPA of US Govt.

So you got to rich it up a little bit.

 

No...the 426 has spot-on jetting & these bikes aren't subjected to the EPA run em lean crap like the WR 426 & XR's are. A 4-stroke will glow the head pipe at an idle IF the header is UNPAINTED. My bike has perfect jetting...plug reads fine & at sea-level here & I'm running the same jetting as MXA magazine...stock. If I was lean..believe me..I would know it. Bike runs perfect.

 

Oh yeah...the thickness of the header also has something to do with the glowing. The 426's have thin header pipes....my 2000 model did the same thing too. That titanium header could be thinner than the painted stock header. Later....