Carb Indexing

[Crashvr6]

This may sound strange, but I'm finding that if I install my Airstriker on my 2003 CR250 with the carb aligned with the air boot notch and my float level set at 16mm, it leaks fuel when on the pro-moto billet kickstand

When I lean the bike to the right, it can lean at a much greater angle without dumping fuel.

I was looking at the angle of the carb with it lined up to the notch and it is tilted quite a bit to the left side of the bike. My easy remedy would be to square up the carb and be done with it, but I'm wondering if there are some that might have an explanation as to why it would be tilted to the right.

I do not have the TMX to compare, so any guidance would be welcome.

[223hpyhooker]

Here you go I just happen to be working on my carb lol.

They look the same but internals are definitely different with the quadvent.

[RMmatt]

Mine will leak out of the overflow if I get the bike to far sideways

[223hpyhooker]

Also mine leaks barely leaning as well. If im riding and lean it against something I shut the fuel off I hope we can resolve this noise I thought I had a float level issue but it was at the 16mm as reccomended.

Edited June 9, 2014 by 223hpyhooker

[RMmatt]

Hpy what's the best carb to run on a 04 CR250? I know that people swap em out for a better one but what is it and what makes it better? Is there a noticeable difference when switching carbs?

[223hpyhooker]

I never ran my tmx with a fresh engine and I have a 03 but pretty close to the same as yours. I can tell you that the only performance mods I have done are a 36mm pwk and my head being cut and everything else rebuilt to stock and I am still dialing in the jets because I went with a 36mm and the jetting is a little weird compared to what others are reporting with the 38.

With that said the bike is has tons of power down low and I can just lug up hills very slowly and if I barely crack the throttle it will lift the front end up even being a little loaded up. I am still trying to get the main dialed in although I ride mostly 1/4 to 3/4 and like to short shift I am anal about my stuff operating as it should.

Edited June 9, 2014 by 223hpyhooker

[moto9]

I never ran my tmx with a fresh engine and I have a 03 but pretty close to the same as yours. I can tell you that the only performance mods I have done are a 36mm pwk and my head being cut and everything else rebuilt to stock and I am still dialing in the jets because I went with a 36mm and the jetting is a little weird compared to what others are reporting with the 38.

With that said the bike is has tons of power down low and I can just lug up hills very slowly and if I barely crack the throttle it will lift the front end up even being a little loaded up. I am still trying to get the main dialed in although I ride mostly 1/4 to 3/4 and like to short shift I am anal about my stuff operating as it should.

Im running a 36mm also, along with a moose intake spacer and a rad valve on my 01 woods bike.

I just installed a wing or divider on the engine side of the carb...picked it up from slavens.

What I did with the float level was....carb off the bike and hooked up to a fuel source...screws out of the float bowel.

I kept bending the float tab unti I could tilt the carb to about 2:00 without it leaking.

A few wide open tests to make sure it was getting enough fuel...all good.

I get pretty good fuel range on the stock tank, so I don't think I'm getting much drip on the trail.

Thinking about a head mod as my next upgrade.

[AXAxiom]

This may sound strange, but I'm finding that if I install my Airstriker on my 2003 CR250 with the carb aligned with the air boot notch and my float level set at 16mm, it leaks fuel when on the pro-moto billet kickstand

When I lean the bike to the right, it can lean at a much greater angle without dumping fuel.

I was looking at the angle of the carb with it lined up to the notch and it is tilted quite a bit to the left side of the bike. My easy remedy would be to square up the carb and be done with it, but I'm wondering if there are some that might have an explanation as to why it would be tilted to the right.

I do not have the TMX to compare, so any guidance would be welcome.

 

When I switched to the A/S

I put the bike on the stand and used a level to get a reference point with the bowl, with the angles coming out of the reed block it looks deceiving but I know its level with the bike upright

Edited June 9, 2014 by AXAxiom

[jeddclampette]

I never ran my tmx with a fresh engine and I have a 03 but pretty close to the same as yours. I can tell you that the only performance mods I have done are a 36mm pwk and my head being cut and everything else rebuilt to stock and I am still dialing in the jets because I went with a 36mm and the jetting is a little weird compared to what others are reporting with the 38.

 

. Agree, a 36 doesn't run as crisp if it uses the same jetting as that of a 38.

THe 36PWK on my '05 is using a DDK needle for woods riding. My pilot is 42 or 45, main is 165 or 168. 44:1, Klotz Techniplate TCW3 (low flashpoint oil). I ride at 700 ft ASL, 5000ft ASL, and 9500-12000ft ASL, all using the DDK and those size jets. My PWK is the late design that comes on the KTM. So the air slide is KTM specification, not Keihin

[Crashvr6]

When I switched to the A/S

I put the bike on the stand and used a level to get a reference point with the bowl, with the angles coming out of the reed block it looks deceiving but I know its level with the bike upright

I'll check for level this afternoon, but with the carb installed and viewing from the rear of the bike with the subframe removed, it was not level to the eye.

[AXAxiom]

I'll check for level this afternoon, but with the carb installed and viewing from the rear of the bike with the subframe removed, it was not level to the eye.

 

It may be just me, but if I view the carb from the rear and use parts of the engine or frame as a reference then the carb doesn’t appear level when it is level.

I do think it has something to do with the compound angles coming off the cylinder, I don’t understand it, but that’s what I came up with

[223hpyhooker]

. Agree, a 36 doesn't run as crisp if it uses the same jetting as that of a 38.

THe 36PWK on my '05 is using a DDK needle for woods riding. My pilot is 42 or 45, main is 165 or 168. 44:1, Klotz Techniplate TCW3 (low flashpoint oil). I ride at 700 ft ASL, 5000ft ASL, and 9500-12000ft ASL, all using the DDK and those size jets. My PWK is the late design that comes on the KTM. So the air slide is KTM specification, not Keihin

Yeah I am using a CEK needle in 3rd clip with a #7 slide and had a 175 main which i dropped to a 172 along with dropping the pilot to a 40 but this made things way worse. I am going back to a 42 pilot and going to give the bike more air screw to hopefully get my main dialed in. The carb was running a lot better at 30 degrees cooler.

I am using yamalube 2R with sonoco supreme 112. Also just checked compression and it was 250PSI with a nearly new mac gauge which was 10psi higher right after break in. I checked my piston and it looks good with a very slight carbon build up because I was thinking that with my silencer being soaked that maybe the bump in compression was due to carbon build up but i had no signs of this maybe it wasnt. I feel like I am getting close and should have some more results soon. I like the ktm 6.5 slide that is on the 250sx because of the notch in the middle seems to make the bike idle nice for the woods without loading up to much but when I priced one it was over 100 dollars.

[223hpyhooker]

Here is my angle as well I tried to take the picture parallel with the frame and shock to give a idea. I think technically I could give the carb 0 lean because it doesn't go in far enough to notch, but I don't know of the consequences of this and being the tmx has the same angle maybe they are built this way for a reason. Anybody play with the angle and have insight to this please chime in. I do know that the 2000 cr had the head reed design so it probably had less angle due to sitting higher but I dont know if it still had this big of a lean.

I know most dirt bikes will leak if leaned but when on the side stand it isn't that much and tells me it leaks whenever i turn left and I don't want to lower the float from the 16mm because it may make it run lean especially with right side of the float bowl being up higher then the left.

Edited June 10, 2014 by 223hpyhooker

[AXAxiom]

Here is my angle as well I tried to take the picture parallel with the frame and shock to give a idea. I think technically I could give the carb 0 lean because it doesn't go in far enough to notch, but I don't know of the consequences of this and being the tmx has the same angle maybe they are built this way for a reason. Anybody play with the angle and have insight to this please chime in. I do know that the 2000 cr had the head reed design so it probably had less angle due to sitting higher but I dont know if it still had this big of a lean.

I know most dirt bikes will leak if leaned but when on the side stand it isn't that much and tells me it leaks whenever i turn left and I don't want to lower the float from the 16mm because it may make it run lean especially with right side of the float bowl being up higher then the left.

 

Did you hold a level up to and parallel to the bowl gasket with the bike level on the stand?

Edited June 10, 2014 by AXAxiom

[223hpyhooker]

No I can do that when I get back home but I can tell its at a angle just by eyeballing it. I dont think its a huge deal because the stock carb was designed at this angle.

[223hpyhooker]

After getting my level out and getting my bike level this is tge amount I had to go over to make the float bowl level although it doest seam like a lot it is very noticeable.

[wykyd450r]

After getting my level out and getting my bike level this is tge amount I had to go over to make the float bowl level although it doest seam like a lot it is very noticeable.

I been having the same issue with a new PWK A/S from JDJetting on my 03 cr250.  I bought the same carb for my previous 02, and had zero issues.  Did you ever figure this issue out?

[223hpyhooker]

I just turned the carb clockwise in the boot, but it wouldn't allow the notch in the boot to be utilized. I have also heard of people lowering the float height a mm or 2 but I didn't want to risk any lean issues . This did keep fuel from flowing out until it was at a really good angle, before it would flow even leaning against a tree at a small angle.

[wykyd450r]

I just turned the carb clockwise in the boot, but it wouldn't allow the notch in the boot to be utilized. I have also heard of people lowering the float height a mm or 2 but I didn't want to risk any lean issues . This did keep fuel from flowing out until it was at a really good angle, before it would flow even leaning against a tree at a small angle.

Thanks!! I appreciate it.  I actually started a thread about the leaking issue a few days ago, so its a few pages back now. I been into the carb a few times now, and made sure the height is 16mm, no debris, etc. Same end result. The solution sounds like it'd help for sure.  Those 2 tabs on the manifold/insulator don't do anything for the pwk anyways, so it should still be mounted just as secure.  As I said in my thread, it runs great, that's why I didnt want to bother moving the float height or anything.   Thanks again!!

[Rywi24]

Here is my angle as well I tried to take the picture parallel with the frame and shock to give a idea. I think technically I could give the carb 0 lean because it doesn't go in far enough to notch, but I don't know of the consequences of this and being the tmx has the same angle maybe they are built this way for a reason. Anybody play with the angle and have insight to this please chime in. I do know that the 2000 cr had the head reed design so it probably had less angle due to sitting higher but I dont know if it still had this big of a lean.

I know most dirt bikes will leak if leaned but when on the side stand it isn't that much and tells me it leaks whenever i turn left and I don't want to lower the float from the 16mm because it may make it run lean especially with right side of the float bowl being up higher then the left.