I already have an outer wears lid, hasn't helped or hurt, actually think it probaly hurts since air is sucked through tiny holes all over the place instead of from one big gapping hole, not sure? I've been thinking about the PVC thing for a while, the tough part is making the intake boot/filter connection, do they sell PVC in flat sheets? That would do it, just need some cutting & glueing.
Jackal, I could make several end caps with different sized holes drilled out of them, one with a small hole for good low end/woods riding, a larger hole for good all around trail riding, & leave it open for all out top end, then I could mass produce it, ya that's it, that's the ticket. I guess I could let you in on a little piece of the action, LOL.....
Turbo charge it, hmmm, very interesting, but $$$$ I bet, the possibilities are endless....
For flat out trail riding the jetting is awesome, its only when it comes to hill climbing & you're approaching the top of the mountain & you need to slow down to avoid flipping over or jumping off the other side, if you don't fan the hell out of the clutch to keep the rpm's up, then she'll hit that low rpm bog/turbulence problem & she'll start to bog & sputter & it scares the hell out of me. Just flipped it because of that, actually it flipped several times but that's another story.
Maybe I just can't have the best of both worlds?

 

I'm using a foam filter with billet plate. I am not having trouble climbing hills in general, I am having trouble around 1/4-1/2 throttle & if I am climbing a big hill & I slow down to that throttle range then it creates a problem. As I said before, a solution to this is fanning the clutch but its tricky. Also, checked float levels many times & they are fine, been there done that. Thanks for asking.

 

What other motor mods do you have?

I am running a single K&N with dual inlets on an aluminum adaptor with no air box. I still use the factory rubber tubes to attach the carbs to the adaptor plate. I am using 190-195 mains, 27.5 pilots, and dyna jet needles on the 4th clip. I have absolutly no studders or hesitations at any RPM's.

 

Whaaa!

I think you need to collumnize the air further back in the filter before it enters the boots to the carbs.. I bet an aftermarket airbox will help tons.

 

I was having fits with 1/4 to 3/4 throttle also. After much trail and error I found that getting the top end right caused a very rich 1/4 to 3/4 and the higher up you went up the worse it got....above 5,000 ft. changing only the Jets just doesn't cut it anymore! I think it's because DJ builds and tests their needles at sea level. It would sure be nice if someone built some high altitude needles.

FYI...When I was at Glamis last year using the DJ kit specs...my Raptor would beat all the other Piped/Jetted Raptors and DS's but at 9,000 ft I couldn't get it tuned correct and regularly got beat by several well running 400ex's.

So one weekend I played and played until I came up with the following higher altitude setup....

- set screws at 2.75
- go big with the main and get the top end dead on. (1/4 to 3/4 way rich)
- then lower the needles until the rich 1/4 to 1/2 problem disappears and the plug shows a little lean across the board.
- next go one step bigger with the mains to get the top end dead on in the new needle position.
- 1/4 to 1/2 will still show a little rich on the plug but it should drive fine.
- everything I read says that the stock pilots are fine until you start doing major motor work.

At 8000ft...I think I ended with a DJ148/146 (two larger then recommended) and the needle three notches lower then recommended.

Next summer I'm going to play around with the stock needles and see if they handle the altitude changes any better then the DJ needles. I might even buy some of the new TI needles.

Has anyone tried tuning a raptor with an O2 sensor and gauge? It might take out a lot of guess work.

I wish someone would build a Tuned Port Fuel Injection system for the Raptor!

 

TriRap, you are jetted rich big time but I guess that is because of all the motor work you had done.
I have a stock sized 11:1 Wiseco piston & Stage I hotcam. I just received new needles from CT racing, they obvioulsy listened to us or they are smart enough to figure it out themselves but they copied the Mikuni needle where the clip postions are & then they copied the Dyno jet needle taper, finally somebody got it right! I will try their needles with diff combos & see how it goes. I had the jetting real close in the summer but am having a little more trouble with the colder weather, I will let everybody know if/when I get it right for winter riding. I may also splurge for the two into one after market aluminum airbox.

 

Chimmer,

I had this problem with two Raptors. I'm sure your tired of hearing all the fix's, but I haven't seen this one mentioned and it cured my problem that sounds identical to yours. ( stutters at tops of hills when slowing, stutters when climbing slow rocky hills, even can feel it when playing around going from open throttle back to 1/2 to 1/4. ) The float level was to high, and the recommended .510 in. is too low! At wide open throttle for more then 400-500 feet it will run out of gas on a motor with mods. I found that .425-.430 in. works on mine with 180 185 jets. This is measuring it from the bottom with the carbs upside down as the book shows. Hope this helps, if not sorry to bother you.

 

2stroke... you read my mind, I was thinking about that too. I remember when I had a broken needle valve on the right carb & I would always smell gas especially after going up/down hills. Basically the right carb was constantly overflowing & never running out of gas since it was coming out the overflow tube on the bottom of the carb. Anyway, I don't remember having any of the bogging problems with this condition, I could be wrong, for some reason it never seems that simple though, I'll try it, couldn't hurt!
Thanks for the specs, I'll just bend the tang a little to allow more gas to fill up in the bowl & see what happens.
I am going to experiment with the new CT's needles I just got & see if they make a difference too. Their taper is the same as Dyno jet's needles so you would think you should use Dyno jet mains but CT racing says to use Mikuni mains 170-175, sounds rich for skinny needles but we'll see. I have an assortment of both Mikuni's & Dyno jet mains so we'll see what works best. I've rejetted so much I wore out one of the fuel screws & will be replacing them as well, jetting hell here I come!