Problem reconnecting airbox to carby. Any tricks or advice?

G'day all,

I've just bought myself a 2009 WR 450F and i'm giving it a service and checking all's ok before i go ride it. The last bike i owned had a faulty carby pump so i decided to check if the one on my WR was working ok or not. To get at the carby i removed the two lower rear sub-frame bolts and flipped it up to get a look into the throat of the carby as i twisted the throttle and yep, the pump works fine and the jet squirts fuel nicely. The problem now is that when i flip the rear sub-frame back down i cant get the rubber airbox manifold to fit back on to the back of the carby. I've tried for hours and even when i think the rubber may be over the lip of the very back of the carby it doesnt seem to want to push all the way back on, even though the carby itself was not loosened or moved in any way and is in the exact same postion it was originally. It's just so hard to see the back of the carby and trying to get my hands in there to push the manifold about is impossible as there's just no room at all. I tried greasing the rubber too and still i cant get it on (or forward enough).

So here are my questions: Is there a trick or a common technique that's used to get the rubber airbox manifold to slip back over the back of the carby when the rear sub-frame is flipped back down? And if it does go over the rear of the carby, is there a way to get it pushed all the way forward enough? Should the clamp be fitted to the manifold before i flip the sub-frams back down, or put on after i finally get the airbox manifold pushed back onto the back of the carby? Are there any special tool/s needed etc?

I'm pulling my hair out with this and i cant get it back on which means i cant ride my new bike! Please help!!

Ta heaps,

I use a little WD-40 to lube up the rubber.

Usually pulling the air filter allows either your hand or another tool to snake into the intake tract and help. Not sure how different an 07 up is but that's what I did with my 04 if I remember right. It's been a while, however and I work on lots of bikes.

You may simply want to remove that pivot bolt and come at it straight on as well. It should go on, don't remember anyone specifically having issues with this not did I. The one "trick" I've always done is work them on from the hard to reach/see areas and then work forward, that may help too.

Edited by miweber929

I agree, remove the pivot and come at it straight on. You may have to wiggle the carb a little as well.

I've never had to remove the top subframe bolt to get the airboot back on the carb of any of my WRs or YZs (99, 03 07, 08, 09 or 2012). I'd recommend leaving it in place as it creates the perfect alignment between the carb and airboot.

As another mentioned a little lubricant insde the airboot where it contacts the carb bell will work wonders. I personally use silicon spray as it doesn't attract dirt like most other lubricants.

Flash light

A very light coating of lubricant will make your life significantly better. Can be said for various issues you may be having, bike related or not.

Grease the boot, keep the subframe loose, and push on the bottom/back of the air boot.

Use a blunt instrument to push the boot into place from either side of the bike (I use a extremely long screwdriver with a rubber foot slipped over the end) and push against the bottom of the boot if it's not quite there.

You can also use nylon twine and wrap it around the neck of the boot, and pull it on from both sides.


Thanks to all those that replied, and here's how after over two hours of messing about i ended up getting the airbox boot to fit back onto the back of the carby:

- I lubricated the back of the carby and the rubber airbox boot with silocon spray.

- I loosened the carby at the inlet manifold, which allowed the carby to pushed and pulled up, down, forwards, backwards, left and right so as to better position the back of the carby to where it needed to mate with the airbox boot.

- I removed the two engine mounts above the carby so as to give me more space to get my hand on the carby to do all the re-positioning as and when needed.

- I noticed that whenever i swung the rear sub-frame back down and the airbox boot pushed and squeezed between the shock spring and the bike's frame that the metal airbox boot clamp became deformed, becoming oval shaped rather than remaining round. This meant i was trying to get something oval shaped to fit over something round in shape. To avoid this i pushed the airbox boot up as it passed between the shock spring and the frame when i swung the rear sub-frame down, as higher up the space between the shock spring and bike frame is larger. This allowed the clamp to remain round in shape, which meant the rubber airbox boot remained the correct round shape as it met up with the back of the carby.

- I used a long flat srcew driver to run round the inside lip of the rubber airbox boot to lift it over the back of the carby where it still refused to go on.

Hope this helps anyone else who has to get at the carby for what ever reason. What a pain in the arse this thing is to work on!


Honda z50

Honda XR75

Scorpa SY250

Kawasaki KLX 250 (with 351 big bore kit)

Yamaha WR 450F

Suzuki DR600

Suzuki GR650

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