Leak Jet.

15 replies to this topic
  • xBRIANx

Posted February 28, 2008 - 08:09 AM


I went up to the local dealer to pick up my adjustable fuel screw. Well, while I was up there, I was just shootin the shit with the guy, and he told me about (sorry I cant remember the name) this Leak Jet aftermarker add-on thing, or some shit like that, anyways it was like 99.99 and it looked about .03 cents of material went into making it, but he told me it would give my wr the throttle response of a 2 stroke, meaning when I would snap the throttle back real fast, it wouldnt bog at all.

He also told me (he doesnt know however that I ride a wr with all the mods and shit done to it -free mods that is) that I really dont need to rejet it until I do something like exhaust to it. The reason that Im wanting to rejet, and maybe Ive misunderstood, is for the simple fact that when I sling the throttle back, it sometimes just completely stalls. Which is a pain in the ass on the trails, especially when you need a quick shot of power, and instead it stalls:banghead: :) :smirk:

Also, My stock fuelscrew (hopefully this sounds somewhat normal) Was screwed all the way in, becuase I know how your supposed to count the turns in, so you can set your new one at, or around the same level, but yeah, my stock was all the way in. Does that sound right? And as far as adjusting it goes, I havent noticed a difference in anything at all.. I can have it all the way screwed in, and backed out about 3 whole turns, and not notice a difference.. also, is that normal? <-----NOOBIE!! Again guys, you've been a huge help thus far, I appriciate everything you guys do to help a fellow rider, thats why I like this site so much.

  • WR450RICKO

Posted February 28, 2008 - 09:56 AM


what year bike?

  • kskyles

Posted February 28, 2008 - 10:04 AM


So, which year is your WR?

I don't think there is anything in this world that you can bolt on to our bikes to make them feel as snappy as a 2-stroke.

If you can turn your fuel screw all the way in without making your bike cough and stall, then you probably have too big of a pilot jet. Take a look through the jetting database and see what guys at your elevation and temp are running. It will get rid of the stalling.

If you've got $70 lying around, the JD Jetting kit did wonders for my '05.

  • William1

Posted February 28, 2008 - 10:16 AM


The JD jetting kit along with the correct leak jet (a 40, 45, 50 depending) will make you bike respond like a 2S. The adjustable leak jet, although pricey, does work and is worth the money if you have an alloy frame as pulling the carb on them is a pain. Adjustment takes mere seconds. James Dean can hook you up on both items.

  • xBRIANx

Posted February 28, 2008 - 10:47 AM


yeah im sorry, its an 06 WR450. So, should i suppose the question now is, rejetting, ive heard people say you should definatly rejet, after you do all the free mods to the wr, which all ive done was the baffle, grey wire, and throttle screw. Does that deserve to be rejetted? Either way it sounds like I will need at least a new pilot, since the throttle screw isnt doing anything. But if I decide to get the pilot, I wouldnt more than likely have to change the Main as well, correct?

  • William1

Posted February 28, 2008 - 11:57 AM


Being the WR is a 'green sticker' bike, it has to conform to the EPA. Because of this, stock jetting is the pits.

You could do the pilot, you might need to do the main, but not because of the pilot, but because at WOT, the jetting is off possibly. That said, the mid range is possibly off and many of the needles in the WR's are not adjustable.

Buy a James Dean kit, follow his instructions to the "T". Make sure you keep good note of what jets (Main, Pilot, Leak) and needle, clip position. Install the JD kit. Test by riding a fully warmed bike. You may need a tiny bit of final tweaking to get it right, but James does a real good job with his kits and you may find it is perfect. When I did my bike, I used an O2 sensor to confirm the jetting. Installed his kit exactly per his instructions and it was jetted perfectly. No changes needed.

  • xBRIANx

Posted February 28, 2008 - 12:07 PM


Okay, Ill definatly give that a shot probably sometime this weekend, payday.. thanks william

  • kskyles

Posted February 28, 2008 - 12:28 PM


You've probably done this already, but-

Check out the perfomance index and read through this tutorial:

It's a great write-up that's taken the fear out of jetting for a lot of people in this forum.

Good Luck!

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • xBRIANx

Posted February 28, 2008 - 03:04 PM


Wow, yeah I was really dreding replacing the main and the pilot, and until now, along with the leak jet as well, that guide makes it awesome to rejet it, the only thing I'm worried about, is when the float bowl is drained, i heard there was a certain way to had to adjust the pin inside it or something like that when you drain the gas out. But yeah, this makes it alot easier to understand. Okay lemme get this straight-

Replace Pilot, and Main jet, and Im assuming you only adjust the pilot and main with the size of the jet, you dont have to worry about screwing it in to far or not to far as opposed to the Adjustable fuel screw? Assuming that assumption is correct- when I buy the JD jet kit, am I going to be purchasing certain sized jets? Or is it kinda like a 1 size fits all type of deal? I ride in Ohio, so, I would assume 0-4500 ft. elevation would be the correct elevation setting. And the temperature that I prefer to ride in would be anywhere from 50-however hot it gets here sometimes, so we'll say 95 give or take a few degrees ºF.

As well as that leak jet thing The guy at the bike shop told me about, does it sound like a stupid purchase? Will I notice more of a throttle response as opposed to not having it? Also, rejetting it right now, with just the free mods done, is it necessary? Nothing else has been done to the bike, except for the fact that I just put in the adjustable fuel screw.

Another thing in the link given above, the forgive me, I forget what it was called something about a needle in the top of the carb, getting/replacing one of those, another thing I should consider? What should I look for in that? Basically Id like to get everything done with the carb kinda, at once so I dont have to go back to it, yet it wouldnt be that big of a deal becuase nothing looks too complicated so far. AGAIN THANK YOU GUYS FOR THE HELP!!

  • kskyles

Posted February 28, 2008 - 08:07 PM


the jets don't need to be adjusted. they just come in different sizes. you just unscrew the old one, and put in the new one.

the needle is accessed through the top of the carb. you can see it in the tutorial.

the JD Jetting Kit will come with two needles, and some main jets. you will probably have to buy a couple of pilot jets, and a couple of leak jets.

if you are going to get the JD kit, i would order that, then look in the WR Perfomance Index - and look in the jetting database. you'll find the right sizes and needle settings in there. or you follow the JD instructions.

i wouldn't buy the adjustable leak jet thingy from the dealer. i'd find the right size that you need in the Jetting database, and buy that one - it'll be 4$ vs. 90$.

  • dazzabb

Posted February 28, 2008 - 09:44 PM


the jets don't need to be adjusted. they just come in different sizes. you just unscrew the old one, and put in the new one.

i wouldn't buy the adjustable leak jet thingy from the dealer. i'd find the right size that you need in the Jetting database, and buy that one - it'll be 4$ vs. 90$.

The jetting database, although helpful, is not got be the same for every bike even if all the same year with the same mods, its surprsing how many jetting variations there can be in similar set up bikes.

By buying the adjustable LJ you will be able to set it up for the perfect leak jet size.

If you have more than one bike, take off the adjustable LJ and fit the correct size actual LJ that can be determined from how many turns out the adjustable LJ is.
Even if you sell the bike you can keep the adjustable LJ which will fit on any Keihin FCR carb so other WRs / CRFs would also accept it.

Yeah it's gonna be more expensive but you will likely get the jetting right first time and not need to keep changing LJ until you get the correct size.

I got bored of changing jets on my WR, so i went the whole hog and got the Power Bowl, but this will be overkill for some.

  • rbn14

Posted February 28, 2008 - 10:31 PM


The merge racing ALJ requires some drilling so once it is on a bike it cant be transfered to another bike. The r&d power pump on the other hand can be, it seems to be kind of a mix of a ALJ and a Quickshot.

  • Holigan

Posted February 29, 2008 - 07:43 AM


The merge racing ALJ requires some drilling so once it is on a bike it cant be transfered to another bike. The r&d power pump on the other hand can be, it seems to be kind of a mix of a ALJ and a Quickshot.

Jason Raines will be running the Merge ALJ on his WR in this weekend's GNCC in Florida and for the remainder of the '08 season. The reason that pros choose to run our ALJ is the product design allows for fuel to flow in a circular path, one hole in and one hole out.


  • xBRIANx

Posted February 29, 2008 - 10:14 AM


So, Main jets - If i get the kit, will come in a few differenet sizes, then Ill probably need to buy a few pilots. Also- The float bowl, I heard something like that has to have gas in it, or you will have to reset the pin, or needle or watever it is inside it. Assuming thats true, what would re setting that consist of?

  • rbn14

Posted February 29, 2008 - 10:43 AM


The JD kit comes with a pilot (at least the one for the 07 does). Just give them a call to clarify.

  • xBRIANx

Posted March 01, 2008 - 09:23 AM


Okay, so, about the float bowl? How do I reset that once I drain all the gas out?


Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.