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Wheel

Anyone else? '03-'06 YZF's

13 posts in this topic

The band that clamps the air filter mount into the boot broke yesterday on our '06, leaving the air filter and mount laying in the bottom of the box. Of course, it sucked a bunch of dirt. I've never had this happen on previous year bikes. According to Yamaha 's parts catalog, this clamp is the same on YZ250F's and 450F's from 03 through 06. Upon inspection, it appears that this clamp was overtightened and twisted, probably causing this failure. I have never tightened or had this apart, so it had to have happened before it left the factory, or before I recieved it from the dealer.

Once any damage is corrected, you can be sure that I will silicone the mount and boot together, as well as safety wire aroung the clamp to prevent this from happening again. Our 06 250F will get the same treatment.

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I am confused - are you talking about the band that tightens the airboot to the carb? These will bend very easy if overtightened. I replace the screw with a allenhead. This is much better for adjusting on my 03. The boot is attached to the rest of the airbox...I have not removed it yet from my 06.

Who rejetted you bike - they may be the culprit to overtightening this :applause:

I have never heard of the airfiler just falling down inside the airbox...weird

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The boot is not attached to the air box. It goes into the airbox and into the filter mount. There is a band that holds these together, similar to the band that clamps the boot to the carb, but much larger. It is this clamp that broke, which allowed the filter mount and filter to fall out of the boot. If you look under the intake section of the online parts catalog, it gives a breakdown of the airbox and filter system. If you remove the seat on your bike, you can see this band in the front of the airbox.

I always thought that this system was flawless because it limits the possibility of leaks. I never dreamed that this clamp could fail.

I do almost all my own mechanical work. I am the only one who has done any re-jetting on this bike. My rider does do basic air filter service and oil changes, but that does not involve removing this clamp. In fact, there is no reason to ever loosen or retighten this clamp unless one of the airbox components got damaged and required replacement. At least that is what I thought. Dealing with this potential problem as per my original post will now become part of my new bike prep in the future.

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The band that clamps the air filter mount into the boot broke yesterday on our '06, leaving the air filter and mount laying in the bottom of the box. Of course, it sucked a bunch of dirt. I've never had this happen on previous year bikes. According to Yamaha 's parts catalog, this clamp is the same on YZ250F's and 450F's from 03 through 06. Upon inspection, it appears that this clamp was overtightened and twisted, probably causing this failure. I have never tightened or had this apart, so it had to have happened before it left the factory, or before I recieved it from the dealer.

Once any damage is corrected, you can be sure that I will silicone the mount and boot together, as well as safety wire aroung the clamp to prevent this from happening again. Our 06 250F will get the same treatment.

Now that's messed up. I had never heard of this until it happened to me almost two weeks ago. Wheel , you were the first to reply to my post http://www.thumpertalk.com/forum/showthread.php?t=377034&highlight=Air+filter+disaster My bike is still in pieces. Twin Air makes a seal ring kit that should prevent that from happening again. Do you have it apart yet? What is the extent of the damage?

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Sand. There were traces of it all the way through the intake valves, on top of the piston, and in the exhaust valves. None in the header or can. The piston is fine, the rings are still in spec, the cylinder is not worn or scratched, and the valves are still in spec. It must not have run long and/or be more durable than I thought. I did a leak test on the valves and the intake ones were leaking just a bit. I used compressed air and solvent to flush the sand out and now they don't leak at all. So now I'm hoping to just buy some gaskets and put it back together. I will put some new rings in as well. What do you think? Also, would you take the carb apart and clean it? I'm unsure on how that exactly works :applause:

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Sounds like you should be ok. I would also clean the carb. At the very least, blow out the rear passages, the throat and slide while making sure that the slide operates smoothly and no debris remains, remove the bowl plug and blow through the pilot and main. Check for debris in the bowl plug and then decide if you should disassemble any further.

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Sounds like you should be ok. I would also clean the carb. At the very least, blow out the rear passages, the throat and slide while making sure that the slide operates smoothly and no debris remains, remove the bowl plug and blow through the pilot and main. Check for debris in the bowl plug and then decide if you should disassemble any further.

Thanks for the advice. What are the "rear passages" you are reffering to?

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Twin Air makes a seal ring kit that should prevent that from happening again.

Correction. I need to do some more searching but I have not found this kit for Yamahas. Apparently the 2002 CRs have a design flaw with the air box that has warranted aftermarket companies to produce a sealing kit. I also saw them for Kawis. Take into consideration the concept and I'm sure something could be made in the shop. Now to call the patent office :applause:

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Just realized that I'm logged in under my brother's account. The previous two posts were by "XT2YZ".

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What are the "rear passages" you are reffering to?

At the bottom rear throat of the carb is a small passage with an air jet installed that leads to the slow speed circuit of the carb. It supplies air to the slow speed circuit and works in conjunction with the pilot jet to provide the proper mixture at idle and just off idle. This can become easily plugged by any debris entering the carb. The best way to clean is to blow any debris away with carb cleaner or compressed air, and finish by blowing through the pilot jet to flush any dirt that may have entered back out.

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