Hello Guys,

I just got my Yoshi full pipe today and I put it on. I rejetted to 150/155 main with lid on with 3 one inches holes. The headpipe glows red when it idles but when you are riding it doesn't glow so I took the lid off and tried it to see what happens but it still glows so what's the problem? Is it too rich? I haven't turn the fuel mixture screw. I just change the jets that's all. Yoshi paper tells me that I have to turn the fuel mixture screw out by 1 and 1/2 out. Where are the fuel mixture screw are?? Please tell me where they are. When I test drove and the power was really awesome and it sounds great but little bit too loud for my parents! hehe [img]i/expressions/face-icon-small-smile.gif[/img] Please help me out to stop the glowing red. I don't want to ruin my engine.
Thanks for the help!
See ya
Dusty

 

Sound like you are lean on the bottom
Two things, one you might need to bump up the pilot jets up one size or two size
low main jet might need up one size
150 to up one more I think is 152.5.

The air screw is bottom the carb either you take it out and do it or have a special screwdriver with 90 degree bend to get it.

Also for the loud issue see if they have the sliencer core and that will reduce the db to make your parent happy.

Good luck

 

Come on guys!
Help me out! I really want to ride my Raptor so bad but i have to get this problem fixed! I will give you more details about it. When I am riding and when I let off the gas and it back fires couple of times. Thank you desracers I will try to do your way to see if it works. Any Yoshi pipe owners out there that can help me!? Please reply and don't be nervous to answer!
I really need your help
Thank you very much
See ya,
Dusty

 

(When I am riding and when I let off the gas and it back fires couple of times.)

Sound like you are lean when that happen. Basically you need to rich it up more, have you bump up the pilot jets yet and loose the air screw yet? That should solve the issue that you are having.....

Bill

 

I am RapYosi's neigbor. He is running a yoshi full system and the air box has the snorkle removed and the lid has 3 1 inch uni air vents. We put in the 150-155 jets and put it back together and started it up and after a few minutes the head pipes turned red at idle but turned to normal when being ridden. Then we took the whole air box off and the headpipes did not turn red until he went for a ride and it backfired once in a while and was shooting a flame right through the spark arrester.

 

RapYosi,

I have the Yoshi full pipe on my raptor. Your too lean at idle. Turn your fuel mixture screws out 3 turns. When I tried the 1 1/2 recommendations my head pipe would turn very blue and purple (but not glowing red). At three turns out the first part of the head pipes nearest the motor are a bit purple and the rest is a golden color...I think I'm good now. Some other guys here have posted that 3 turns out is the way to go, but if you have to go to 4 turns out you probably will need to go to the next larger pilots (25's I believe) and then adjust your fuel mxture screws accordingly. Here's a website with photos so you can locate the fuel mixture screws.

Raptor Jetting Photos[b]

 

Thanks "klj"

I was going to shoot him a link to my photos page but you beat me to it. [img]i/expressions/face-icon-small-happy.gif[/img]

Hopefully it helped you out "RapYosi".

1) Try 3 turns out on your main and 2-3/4 turns on the other carb.

2) Make VERY sure that your head pipes are securely seated in the head.

3) CRITICAL - Make sure that you re-inserted the head pipe gaskets.

Good Luck

 

The air screw needs to be where Yoshi tells you. Your pilot or (slow) jet IS the problem. If you have too turn your air screw past where Yoshi tells you (out) too make engine run smoothest at 1/4 throtle, you need a larger pilot jet. If it runs smoother before you get it that far out at 1/4 throtle, you need a smaller pilot jet. I kinda get confused about the larger & smaller deal & don't have my book in front of me, but this is the correct formula. TO be safe, ALWAYS start with a larger jet & work your way down. A good motorcycle shop will swop out pilot jets with you until you reach success!
good luck

 

run 160/165 with the airbox open & a k&n with outerwear
2 turn out on right & 2&3/4 turns out on left
yamaha jet kit has everything you need
mine runns great at sealevel & at 4k feet of sand mountain nv i just adjust left mixture out a little

 

Hey guys,
I just want to thank you for your help! it really helps me alot! I rode my Raptor today and it runs very good but when I let off the thottle and it back fires pretty much. I haven't adjust the screws yet but I will soon because I don't have the tools but my dad is making it one so that I can turn it when the carb is on the engine. Today I put the lid on and I put the snorkle back on and it was little bit better but it still glows red when it's idling but not as fast as before. My headpipe is very purple! I mean really purple! The low and mid is improved but the top end is the same? I drag race my buddy with his stock 400ex and I can beat him pretty good but i thought it would do better and with my stock Raptor it would slowy beat him. At 5th gear half thottle I would let my buddy go by me slowly and then hit the gas full and it would slowy catch up and go by him but I thought it would go right by him. Yoshi owners what are your results with stock 400ex drag races?? I don't feel any top end improvement. I don't want any bigger jets because I want to keep the good gas mileage. Well this is all I have to say. You can help me more if you want to or is there anything in your head you can always tell me.
Goodnight guys
P.s. Thanks for your helps again!
Dusty