AIS removal and jetting

9 replies to this topic
  • lisato

Posted March 01, 2010 - 06:42 PM


just bought a brand new 08 wr450f. i've been searching for typical mods and have done the simple stuff like the gray wire, air box and exhaust restrictions with incredible results. next step i guess is the ais removal kit. what exactly does this improve and is it worth my time and money?

  • onearmbandit

Posted March 01, 2010 - 10:49 PM


I just bought a 08' WR450 about three weeks ago. When i first rode the bike it wouldnt idle more than 10 seconds or so without bogging down and eventually dying. When i would pull in the clutch to come to a stop it would start bogging very quickly so I would have to feather the throttle when stopping. It was also very hard to start with the Estart even when warm.

I installed the GYTR AIS removal kit, did the exaust baffle removal, throttle stop, grey wire, and air box mod and these are the differences I have noticed....

Starts much easier(usually first kick) and it all but removed the off idle bog. i say first kick because I only use estart after its warm and it fires up right away then. I can let it idle pretty much indefinately and it wont bog down and die. It seems to rev much faster. It has made the bike much more fun to start and ride. Obviously with the new throttle stop I get much higher RPMs which is nice.

The GYTR kit came when new main, pilot and needle jet. I also bought a Pilot screw so I can adjust the pilot jet by hand. When I installed that I adjusted it to exactly 2 turns out from lightly seated( as recommended in the GYTR instructions) and it was perfect.

To put it simply, after the mods I did, it ran like I would invision a brand new bike to run, wheras when I first got him home, it was a piece if S$%@ in my opinion.

You wont regret the GYTR kit. The installation isnt that bad but you dont need to take things apart to the extent recommended by GYTR.

Remove the battery, take the lower bolts out of the subframe and then Loosen the top bolt. After you do this you can lift the Subframe upward out of the way and tie it off to your handle bars without disconnecting all of the wiring and and radiator overflow tank. This with give you open access to the rear shock. After you remove the rear shock you will have access to the carburator.

The hardest thing about this process is getting tools to the bolts/screws/nuts you need to get too but if you have a little patience you will get it easy enough. I am not sure how it would have ran had I only done the mods you listed but I think the biggest part of it running so much better for me can be attributed in big part to the new jets. I have heard that just doing to AIS removal itself doesnt help that much....but if you are gonna have the carb out anyway.....



  • cherrymx

Posted March 02, 2010 - 10:18 AM


I just finished pulling the gray wire, installing the GYTR AIS removal kit, GYTR performance exhaust tip, and a fuel screw to mine. HUGE difference. The thing is a rocket now. The 50-75 bucks youll spend on a kit and a fuel screw is a lot of bang for the buck.

  • Cobalt650

Posted March 03, 2010 - 06:35 AM


Are you guys getting pretty good prices on the 2008's?

  • lisato

Posted March 03, 2010 - 06:46 AM


the prices i have found at least in the idaho-utah area are running 1500-2000 less than an '09 but they are getting pretty scarce

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  • ericahearn

Posted March 03, 2010 - 11:57 AM


I paid 5400 OTD at Specialty recreation in cda, idaho 2 weeks ago. I think they still have a couple left.

  • ericahearn

Posted March 03, 2010 - 08:40 PM


Just finished the AIS removal tonight. All the free mods have been done, as well as the o-ring mod and gytr exhasut tip. The bike ran like a** when I first got it a few weeks ago. Was incredibly hard to start, and did not like to stay running.:ride: Doing the Ais, jetting, and mods was an incredible difference. Bike now runs like it should have from day one.:lol: In my opinion the Ais and jetting is mandatory to have the bike run correctly. FYI: I used a 168 main and 48 pilot indtead of the ones supplied with the kit. All other jetting specs in the instructions were followed. Hope this helps.:thumbsup:

  • William1

Posted March 04, 2010 - 01:50 AM


AIS removal does nothing to change the way the bike runs. Removal may reduce decel poopping and it does lighten the bike by a few ounces. That and one less peice on complexity is about it.
The other jetting you do at the same time is what does it.

  • el bud

Posted August 10, 2010 - 01:23 PM


Right you are "un-braso".I just have to add one point that I've not seen covered.
the hardest part about jetting ,to me was to reinstall air box to carb as you pivot
tail section back down.After many attempts and alot of sweat,What worked well
was to set rear shock in place,but do not place bolts.shock can move around just
enough to let your fingertips help allign boot. Also when you bring tail sec down,
steady it, and replace top bolt with thin long shank driver (I used T25 as drift).That
lets you wobble your tail.I did solo all the way...PITA..But if you set out all tools,
plan your work and work your plan , You can do it.

  • tweav

Posted August 10, 2010 - 11:57 PM


AIS removal does nothing to change the way the bike runs. Removal may reduce decel poopping and it does lighten the bike by a few ounces. That and one less peice on complexity is about it.
The other jetting you do at the same time is what does it.

thank you for posting it before I went on an insane rant on it myself .:banana:


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