o.k. today i put my air box lid back on and cut two holes.... one in the top (3 1/2 x 2) and one on the back (2 x 2). i covered the top with one layer of foam home a/c filter and the rear with 4 layers. jetted 160/165. stock filter.
here comes the confusion (drum roll) this thing has more low end power than it has ever had. i thought removing the lid was supposed to be the way to go.
no matter how i jetted and adjusted fuel screws with the lid off i always had lag and other weird stuff going on. my yard is small so until i'm able to get out into the country and really open up i can't say about top end. although a high speed police chase could wake up a sleepy sunday night. haha.
the only thing i can come up with is that the air has less turbulence or something. i really don't have a clue. this thing just really rips down low now. feels like a whole new bike.
any ideas what happened????

 

Long time, sounds weird. For what you do why not get rid of the whole air box, it worked GREAT for me. Take her down the street real quick to see how the top end is, a good police chase gets the blood pumping.

 

Where's it cutting out at?

 

Hey Richie,

It seems to me that you were jetting too lean. Too much air and not enough gas.

When you put the lid back on that restricted some of the air and now you have a better ratio of fuel and air.

If you remember, when we went riding this past Spring at Kilgore Hills, I had to duct tape a portion of the airbox top on the 250X because it was acting the same way. I re-jetted it the following week and it straightened out.

A guy in Calhoun Citty bought that quad from me not long after that and he still has had no problems with it.

I think you just need to richen it up a bit on the main with the air box lid removed. [Only if the "miss" was on the top end] Richen the pilot jet if the "miss" was in the lower range]

Patrick

 

hey guys, what's been happening? if you remember my post "my raptor's possessed" it explained everything that was happening. the stumble is when the quad is very slowly pulling itself along with no throttle from me, then i peg it and it will "pull, cut, pull, cut, pull, then keep pulling. it all last about 2 seconds. it's still doing it but not as bad.
i've tried every combination i know. i've jetted all the way up to 180/190 with no lid and it was so rich it was puffing smoke and i was getting killed by my buddies banshee, which never happens. so i worked my way down and adjusted air/fuel screws. it got back to running fast. but it just never got rid of that stumble and it never seemed to pull as hard on the low side.
so today i put the lid on rejetted and it really pulling. i would remove the box but the lake will be dropping in a month or two and that's where we ride.
could the floats have gotten out of adjustment?? when that happens how does the quad act? i just don't think it's a lean condition because i've replaced the lid even with larger jets and i get the same cutting. and i have used the 27.5 with no improvement.
i like it like this. i feel safer with the lid on for the type of riding that is about to insue.
this is a question i need to know....just how many jets are there? i know there are the 160/165. those are main jets right? 27.5 is called the pilots right? are there any more that may need to be changed?
finally, when the lake goes down it is a blast to ride. so anyone that wants to come just let me know. you can ride all day.

 

Was this stumbling and bumbling present before you put in a piston and cam? If the answer is no, everything was fine then, prehaps the cam timing is off 1 tooth. Would this maybe cause this? Just a question, not real sure about what problems that would cause but, it seems you've tried everything else.

 

Good assumtion but I would think that it would cause more problems that he would notice.
RRR if it is worth the drive, the shop down here has an air/fuel meter to check jetting so you could rule that out. I am not saying they would do it right but it might make you feel better.

 

hey richie, what's your altitude? that effects mixture. if you're up there a ways you may be chasin your tail.
i'm at 4000' and put on fmf pc4 slip on, and cut a hole in the airbox the size of a strip of duct tape. went down one countershaft, then added holeshot xct's.... wanna race? talk about guts! you may have hit a lucky combination!
keep any eye on that plug tho. and like powroll says, 'dont overtune it'

 

wshrdskin, everything was fine before and after. the problem started when i removed the lid and had it jetted.
o.k. this is the beginning. i had my mechanic jet it according to a recomendation from someone on this forum. it was 180/190. my mechanic had my air/fuel mixture turned all the way in just to get it to run. and run was all it did. it was very slow. after adjusting the air fuel screw my plug was jet black and wet. so the next time i rejetted it myself and that's when i noticed the cutting. i never drove it the way i described earlier when it was 180/190 so i don't know if it was doing it then or not. regardless, it's doing it now.
ward, give me a little more input, like price and what all it will tell me.
raptor8, the altitude here is 100ft. sounds like a good set-up you got. and yes, yes i would like to race.
so can anyone tell me about the floats??

 

Ok heres the skinny. Laurel Yamaha has a fuel air meter, it tells you the ratio of fuel/air comming out of your pipe. It will do this at any RPM so you can jet accordingly at any throtle position. This machine will give you the info to get it jetted RIGHT.

The only problem I have with this is the shop where it is, I personaly have had alot of problems with them in the past. That is not to say that I absolutly would not go up there, actualy I might in a few weeks, but I would have to be at the end of my rope, you sound close to the end of yours.

Price, I don't know for sure but it is probably around $40 an hour since the mech. do the work. It should be just like any other work from them, price wise.

Talk to KNOWSALOT about the shop I am talking about, even ask him if he knows where another meter might be closer to you.