need help fast on jetting

[tjrap350]

ok I got down to jetting my 2007 raptor 350 with hmf and no airbox lid, The exaust calls for the e-clip to be lowerd to the 3rd notch but there is only one notch to begin with. I called the dealership and the place I got the bike from and they act like they have know idea what i'm talking about. please help

also called hmf and they said my jet kit should of come with an adjustable needle but it didn't. I got the gyr-t kit so what do I do?

 

[madcow]

If you have the right size jets you shouldn't have to move the needle, unless that exhaust flows much more of less air at full throttle compared to any other position. The needle affects 1/4 to 3/4 throttle, but the main jet affects 1/4 to full throttle. There was a really good post of jetting somewhere in these forums, explained everything you need to know. I'll try to find it.

 

[tjrap350]

ok found the pilot screw and screwed it in then backed off 3 turns and it won't even idle now no matter where I put it and blows black smoke do I need to change the pilot jet, I need to get this thing fixed.

 

[jasonp]

in your jet kit is there any instructions on what circuit to tune first and how to do so?

 

[jasonp]

also dyno jet kits and yamaha are going to be different. Some have adjustable needles and others don't. Personally I think the stock needle is just fine and just tune the main and pilot circuit and most of the time the middle will be right on so you may not have to worry about the clip position. Some times though with out and air box this will effect cv type carburators with vaccum slides because they are calibrated (diaphram spring and air inlet) with an air box hooked to them. So this is where you may have to play with needles and springs to get the mixture just right in the middle.
If you need tips on jetting look in your other thread or do a search.. I've posted a ton of info out there.

 

[tjrap350]

ok I got it all back right, now just to get the jetting right, what does the pilot jet do exactly? I have a 25 pilot jet, 155 main and 2.5 screws out on pilot screw, it seems ok no popping or anything just seems to lack a lil power in mid-top end, where should I go from here? sorry if I seem not to keen on all this, but I would rather learn to do it on my own instead of paying 150+ to get it done.

 

[madcow]

Pilot screw pretty much adjust idle mixture, too lean or rich and it won't idle. Lacking power doesn't describe the problem very well. Does it stutter at high rpms? Also, ride it for a while and check the plug, if it's black it's too rich, white and it's too lean. It should be brownish.

Don't worry, I had to go through the exact same thing with my Warrior, once you understand what you're doing everything's a piece of cake.

 

[Guest]

When you say pilot screw do you mean the back of the pilot jet or is there another screw youre talking about. The instuctions with the GYTR kit and the owners manual dont agree, and my needle doesnt have more than one setting. Thanks.

 

[madcow]

i can't say for the raptor because the carb is different, but on the warrior it's a screw outside of the float bowl cover, right beside it.

 

[jasonp]

When you say pilot screw do you mean the back of the pilot jet or is there another screw youre talking about. The instuctions with the GYTR kit and the owners manual dont agree, and my needle doesnt have more than one setting. Thanks.

I see there is a lot of confusion and that's ok because this is why I call the pilot screw the fuel screw.
Pilot circuit adjust the fuel mixture from 0 to 1/4 throttle postion.
The pilot JET is in the float bowl of the carb and has to be tight or seated (not to hard). The fuel SCREW or pilot screw is on the out side of the carburator just ahead of the float bowl. The new raptors may have a plug or something covering this that you have to drill out or take off.
To tune this circuit you adjust you idle speed up to about 1800-2000 rpm and start turning. Very lightly seat the screw and slowly turn out 1/2 turn at a time after the bike has warmed up. (You may want to put a fan on the engine as it might overheat and then you won't get a good reading). You will soon get to the point that rpm's reach there max and as you are turning out the rpm's will fall back down again. Stop, turn the screw back. Make sure and count your turns out. No more then 3 1/2 turns out if so bigger pilot jet and restart test. No more then 1/4 in if so smaller pilot jet.
If you within that range your ok. You might still have a little poping on deccel and have to turn the screw out another 1/4 to 1/2, that's ok.
Some needles don't have other settings and you'll just not have to worry about it.. so just worry about getting the pilot and main right on and you'll be great.
Make sure and see where you are on the throttle postion if your having a problem... this will tell you what circuit you are on.

 

[madcow]

Also, don't get the dynojet kit, it'll be annoying in the long run, trust me. The needle sucks and tends to richen the mixture alot at mid throttle, and the jets aren't the same sizes as stock, it makes everything really confusing.

 

[tjrap350]

what I meant about lacking power is around 1/4 through about 1/2 or a lil more its kinda doggy, kinda fat sounding, do you guys think its cuz I can't move the needle jet clip up or down or can the mixture screw have something to do with this the plug looks perfect but thats after just riding around a lil, I guess I need to do the plug check like marking the throttle and running it at diffrent throttle positions and then killing it and checking the plug but do you need a different plug for each test or can you just use your plug that you always run?

 

[madcow]

You have to run for a while to change the plug, at least 30 minutes I would think.