WOW!!!! I have been searching for an ATV forum for quite awhile, and the ones that I have found only have posts on them every couple weeks. This looks like an awesome place. Glad I found you'all.

I've recently done some work to my 2001 660 Raptor. I added the GYT-R jet kit, K&N air filter, and FMF Header w/ slip on.

I did all modifications at one time, so pin pointing the problem makes it a little bit more difficult.

I'll first start with explaining the problem:
When I first start the bike it runs great, seems very responsive. But, only after a minute or 2, it starts to bog when I gas it up, and doesn't seem to be hitting right. Then it stalls, and won't start again till it cools down. Now, I don't know what's normal with this header, but that thing gets HOT!, I swear it almost looked like it started to glow red, is that normal?

1st problem is, while removing the carb, the Choke plunger assembly was stuck, and would not come out. While trying to take it apart I broke it off inside the carb. If this link works, it is part # 43 in the diagram:
http://www.yamaha-motor.com/sport/parts/home.aspx

So, I proceeded with jetting the carbs, and followed the instructions to the exact. There was plastic washers on the needled that i removed, but did not put the plastic washer back on the new needles, just put the clips in the 3rd groove down from the top, like the instructions said. Should that plastic washer should have gone back on the new needle?

Everything is back together but the choke. The cable is broke, and the plunger assembly broke off inside the carb. I have ordered the replacement parts, but won't have them till tomorrow. So, the choke is stuck on right now.

I trying to deteremine if the problem is likely the choke, jetting, or combination of both. I have been searching online, and read nightmare stories about people trying to get the jetting right. I really don't want to be one of those people. I am very hopeful that the problem is the choke. What really concerns me is that header gets so dang hot, if that is abnormal, then would that indicate a jetting problem, or could the choke cause that as well.


Thanks for any advice at all!!



Early bird gets the worm, but the second mouse gets the cheese.

 

you do need those plastic washers with them missing they will mess up the jetting alot i has a friend that is having the same problem as you are but with a z 400 he left the washers and the plastic washer out and it ran like crap just put the washers and plastic washer back in like it should go and i think it should be ok. then again i have never messed with any jet kits i always bought jets and just put them in leaving everything else alone. needless to say i had alot of trouble with mine but it was just from the floats not the actual jets.

 

you need to assemble the new needles exaclty how the old ones were, washers and all. the only thing that is being swaped is the needle itself. ALL the washers need to go back in the orriginal place!!! Also, what did you jet the bike out? Also, my bikes choke allways got stuck on the full on position so i just took out the cable, and wedged the choke mechanizem so its allways off. i rarely need it anyway.

 

Thanks for the help guys.

I wish I had the Gyt-r instructions here with me, but I used what they recommended for after market exhaust and air lid off. I think it was L/M160 and R/M165, in that order. I read in your signature you have them at 160/155. I really do not want to pull this carb out 3-4 times till I get it right, it's a real pain in the ****.

 

lol, ya, if you think a rappy is hard to work on, try a yfz... its a bit tighter, then again, dual carbs, 2x the fun!!! lol, carb jetting is always an issue that takes a long time...

 

Like others have said you need the washers. It sounds like most of the problem is that the choke is partly on. I don't agree with the GYT-R instructions on the mixture screw settings, set them both about 2 3/4 turns out.Good luck!

 

I have a similar problem with my choke plunger. It is stuck in the carb, only instead of breaking it or forcing it back in, I simply screwed it back in and went riding Sunday to see how much of a problem it would be. The bike runs like $#!* on the bottom of first gear, but clears out and runs ok. It just won't idle and wants to die in corners. I just need to get back into the carbs and free it up or replace it.

Here's another problem. When going into a corner in 4th gear, I would tap the shifter to go to 3rd and it would either go to 2nd or 1st. The clutch only has about 8 hours on it. Is my tranny junk?! It's an '02, but I ride mostly motocross. It's not the shifter, but the linkage feels a little sloppy coming out of the case. What's up?

 

Thanks everyone for the advice.

Just picked up my parts from the dealer, and will likely be up late working on the bike in the garage. Unfortnately I wont get home from work til around 9pm. I'm not quite sure I'll be in the right frame of mind to deal with the aggrevation I have in front of me. :-)

 

UGH!!!!

Was up til 3am last night cussing at my bike. I pulled the carb back out, and had a hell of a time getting the choke plunger out. It was stuck in there so good, I had to drill it out. Got it all back together none the less, and put the spacers back on the needles. Hoping everything would be perfect, I went to start it this morning, and nothing. I sprayed starting fluid in the carb, and it started right up,.....for about 5 seconds. Then would not start again. I only had a few minutes to play with it this morning as I was leaving for work. I am hoping that what ever the problem is, it is correcting itself today while I'm at work. :-)

I pulled the plug, and it was black(Carbon). I just put that plug in 2 weeks ago.

Now if it won't run right, I'm not sure if it's still a problem with the choke, or related to the way it's jetted.
I'm seriously starting to regret doing this mod. But, I sad badly wanted to put that FMF header on the bike.

If it will run on the starting fluid, only briefly, then that would indicate a fuel problem. So, what ever the cause is probably then related to the jetting. Would you'all agree with that?

Thanks

 

Fellas, correct me if I am wrong but, is it possible he has the carbs jetted backwards? Above, he wrote 160/155. Shouldn't it be 155/160? Left carb is supposed to have the leaner jet, correct?

Have a nice day.