I have just spent the best part of a week running and testing/adjusting jets and we all know how fun it is to change raptor jets. When I get a gain here I lose it there and visa-versaI am going mad!
I have a total of eight 1/4" holes drilled in the lower part of my airbox in splash safe places I also have the usual snorkle mods done on the lid. My mods are listed at the bottom of the page. Here is my dilema:

When I remove the airbox lid and run the recomended 170/175 jet I have a large gain at full throttle when I nail it from about 1/2 throttle to wide open. However if I am low in the rpms and go wide open it bogs down and even dies. I have also lost my low end torque in third gear and up.

With the airbox lid on and 146/148 jets it runs fine (not great) throughout the low and mid rpm range but then starts to drop off quickly at the higher end.

I have to run with the lid on most of the time because of the wet conditions I ride in, however a couple of times a year I get the luxury of running no lid so I want to know what jets and screw positions you other rappy owners run with the lid on and off so I can stop screwing with these damn carbs. Any help would be great as I have to drive 20 miles every time to test it too




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I have found that running with no lid is really hard to get the jetting down

its all trial and error

lid on 148/150
no lid 165/170 2nd clip

still not perfect[img]i/expressions/face-icon-small-disgusted.gif[/img]

 

Do you know what your mixture screws are at? I am on the third clip on both carbs with dyno jets needles, does that sound right?

 

I am shocked that with the GYT-R pipe, you din't opt for their jet kit as well. I too found that not running a lid makes jetting a pain. I too change between running a lid, and not running it. I have a K&N, with 5 1/2" holes drilled in the lid directly above the filter. This makes for optimal protection while increasing air.

Judging by your description, with the 170 175 jets you are way too rich. That's why you're getting a gain on top and have almost nothing on the bottom. There's too much fuel getting to the cylinder for it to use up. Right now, because of the colder weather staying right around freezing, I am jetted at 160/165 with no lid. But I'm only running in dry conditions and in an unheated, indoor motocross track. My clip is on the third position.

I would definitely jet down if I were you. I'm not sure how much warmer it is in Delaware, but you might want to run leaner than 160/165. You'll have to change again in the summer time, though. As far as running 146/148 jets with your lid on, this is too lean. With the modified lid you have substantially increased your airflow. You need to increase the fuel as well. I would try running 150/155 with your lid on, and see how that runs.

 

Weather here is around 40-45 degrees on the days we have rode. The GYTR jet kits are on back order through yamaha until May or I would have them instead. I bought a set of genuine Mikuni jets sized at 2 1/2 intervals from 150 to 170

I am going to put in 152.5 and 155 jets on clip position 3 with my lid back on and see how that runs this weekend. I get too much water splash up on top of my airbox to drill holes where you have them, my holes are all in the bottom of the box in the corners of the rinforcing plates.

Still have not heard what mixture screw settings you guys use and they are equally hard to get to with a hot engine.

How about Lid off??? what jets and clip/screw settings should I try?

 

I have an 01, with a full FMF system, and Dyno-Jet recommends 146-148, 3rd clip, 3 turns out, and the fins trimmed from the snorkle. Runs perfect. By the way, im in St. louis and the elevation is around 600 ft.

 

That is the exact spec I was running before removing the lid and it just seemed to drop off a little at the top end. I will let you know how my latest mods work out.

 

Ok I am back and all seems better, but not quite perfect I have the needle clip at 3rd position, 152.5 and 155 main jets and screws 3 turns out each. It is hard to say if anything is wrong just dosn't seem right on from the bottom to 3/4 throttle..

I added 5 new 1/2" holes in the top of the lid right above the filter so that makes a total of five 1/2" and six 1/4" holes in my box. I had all kinds of suggestions today to change the stock 22 pilot jets with 25, move the clip to position four and so on... I have no motor mods at all and just a full pipe and proflow k+n kit running on 92 gas. I am at about 1000ft elavation...anyone else have a different setup that seems to be spot on???

 

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No more raptor jetting guru's want to through in some set up that came to them while meditating??? Anyone?[img]i/expressions/face-icon-small-shocked.gif[/img]