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01 CR250 Carb swap - intake boot size?

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I have an 01 CR250, those came with the mikuni carbs. I just chunked my Mikuni and bought a new PWK 38mm, basically the 2000 CR250 OEM carb.

My issue? Intake manifold on my 01 is too small for the 38mm Keihin Carb.

Does anyone know which intake part number is the right one? When I check OEM fiche, the years all have several part numbers, Which could lead to buying the wrong one?

Any specific info toward the issue would be much appreciated.

Thank you.

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2000 cr250 uses this:

INSULATOR, CARB

16221-KZ3-J20

The 2000 came with the Kehin carb.

2001 OEM number is:

INSULATOR, CARB

16221-KZ3-L10

more than likely since they are the same size carbs, you can use some silicone spray and it will go into the boot. If not a heat gun will help make the boot more pliable and then insert the carb. The reed block has the same mounting pattern 86-01 so you can swap the 00 and 01 boots. Angle may varry slightly .

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Tried the silicone. No love. Have a feeling it may melt before it fits. The Keihin is just a bit larger.

You sure about the part numbers?

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came right off service honda's website. If you want to double check, try Motosport and central cycle sports to check the numbers.

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those are correct part numbers. the problem with trying to stick a kehien onto a mikuni air boot is, the lips are different shape. if i remember right, the mikuni is a half moon shape while the kehien is more of a peaked type. it can be made to fit with some trimming, but to make it perfect, its better to just order the 2000 air boot, so you dont run the risk of a leak.

are you positive that you bought a 38mm PWK? the size difference was very slight when i was doing my conversion. later i found an old PWK boot i had and used it instead, but the kehien popped right in without any trouble.

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I put the 38mm PWK into the intake on my 94CR125 which normally has a 36mm carb. Stretched it but I didn't have much trouble getting it on. Not sure why your Keihin won't go into the 38mm boot on your 2001. Doesn't make sense.

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anyway. iv never heared anybody complaining about needing a new boot for the keihin swap in that PWK coversion swap for 01-up bikes.

Well now you have.

Not sure why your Keihin won't go into the 38mm boot on your 2001. Doesn't make sense.

You're telling me!

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Welcome to the incomplete world of internet recommended mods.

Chances are, you really need a '00 intake if you want to run a '00 carb because the O.D. of the PWK intake is 2mm larger than the TMX.

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Like hardhitwarrior, I havn't heard of this before either. Are you saying you can't get the carb started into the boot or that it doesn't go in as far as you'd like it to? kuritaro9 is correct in that the carb inlets are different in design regarding the grove as is CamP about the size difference, however the carb went into my 01' boot and I ran it that way for some time before switching to the 00' insulator. I wouldn't say you need the the 00' insulator but it does provide a much better fit. I posted pic's of the issue in more than one thread around here. This one shows the difference in the carb inlets as well as the fit when installed in the 01' insulator. http://www.thumpertalk.com/forum/showthread.php?p=9725792#post9725792

Could be that you may have to losen your insulator clamp completely to get the carb to go into the 01' insulator.

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I have an 02 and was able to put the 38 in my intake boot ok. It was tight but it fit.I also changed the rear boot to a 1999 model but it is causing my float bowl to slightly rub the top of the case. I filed down the bowl nut a little and it helped but I think I need to try a different boot. Maybe the 2000 is is higher? does anyone know about that?

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I have an 02 and was able to put the 38 in my intake boot ok. It was tight but it fit.I also changed the rear boot to a 1999 model but it is causing my float bowl to slightly rub the top of the case. I filed down the bowl nut a little and it helped but I think I need to try a different boot. Maybe the 2000 is is higher? does anyone know about that?

Did you try it at all with 02 rear intake boot?

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I have a 38mm keihin, a 36mm keihin, a 38mm mikuni from a 02, a 38mm from a 05, a 02 cr250 engine intake boot, and a 05 cr250 engine intake boot.

Dont remember why I was trying different fitments, but I do remember, the 36 & 38mm keihin fits fairly easily into the intake boot of the 05 which had the later model mikuni (with TPS). The keihin carbs were a lot tougher if not impossible to get into the intake boot of the 02 which had the older version mikuni (without TPS). The intake boot of the 01 and 02 probably have the same inlet diameter since they both use the same mikuni carb (without TPS).

If I were you, I would just get a 00 intake boot as it was made for the Keihin carb.

Even the fitment of the keihins into my 05 boot is not that great, I ended up modifiying the carb slightly to make it fit better.

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Chances are, you really need a '00 intake if you want to run a '00 carb because the O.D. of the PWK intake is 2mm larger than the TMX.

Yes. That is the case. But after checking Ron Ayers, fiche, and a few others, I noticed each year listed several of the same part #s. Wanted to check if anyone knew from experience, which was the right one. Of course, that was the queue for such gems of englightment as, "sure you got the right end going into the right direction?" etc,.

If I were you, I would just get a 00 intake boot as it was made for the Keihin carb.

Yep, that's the plan.

Could be that you may have to losen your insulator clamp completely to get the carb to go into the 01' insulator.

I couldn't get the sticken thing to go in without a clamp whatsoever. It simply would not fit.

Thanks for all the input.

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Not sure if you meant me but the 00 intake won't bolt up to a 02 case.

Nope, directed to the guy putting the 00 carb on the 01.

Mounting the keihin on the 02 might work better though with the 05+ intake boot. I distinctly remember trying to put the keihin into the 02 intake when both were off the bike and it did not want to go at all. On the 05 it was much easier.

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Did you try it at all with 02 rear intake boot?

Yeah it would have worked fine with that boot actually, but I modified my box to get a better seal at the boot box connection. I may just get another 02 box and install the MX bones kit to seal it better. Unless I can find a boot that will fit my current box.

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