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 Post subject: 74 CR125 air boot woes
PostPosted: Mon Jul 04, 2016 5:33 pm 
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Joined: Sat Jan 04, 2014 1:07 am
Posts: 19
Hello,

I bought a new Mikuni VM30-83, since the Mikuni carb that came on my bike was not responding as expected to jetting changes and had a 50mm inlet bell and poor fitting "straight" air boot (this boot lacked the height change from inlet bell to air filter cage). I am unable to mate the new carb-mating air boot to my air filter cage. The boot fits the 58mm carb inlet bell fine, but has a 78mm diameter where it meets the air filter cage. This is just small enough to not fit the 80mm air filter cage.

I have not yet tried a hair dryer to stretch the boot to the wider opening, although the boot is soft and pliable.

Have I got the wrong boot or a non-original air filter cage?

Can a dremmel tool be used to remove some carb boot rubber to make it fit?

UPDATE: the air filter cage opening of the boot that came on the bike as well as a new boot fitting a 26mm Mikuni (46mm air inlet bell) both measure 78mm. The new boot should stretch to fit the air cage.

Thank you,
Ben


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PostPosted: Mon Jul 04, 2016 7:36 pm 
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Joined: Sun Nov 30, 2008 12:10 pm
Posts: 1010
Location: Connecticut, USA
The CR125M air boots fit the air filter cage flange very tightly, by design. You will probably need heat and a fair amount of stretching to get the boot on the cage, but once it's on and the clamp's in place it's not going anywhere unless it rips.

The Honda 17253-400-000 and Suzuki 13881-41301 air boots both have 57mm carb-side and 76mm airbox-side openings and @ 75mm overall length, plus an upward offset from carb to airbox.

Ray

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'74 CR125M (175cc), '75 MR175, '82 RM250Z, '08 YZ250F, '14 Zero FX electric, '14 Zero MX electric, '18 Alta MXR electric


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PostPosted: Tue Jul 05, 2016 2:53 am 
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Joined: Sat Jan 04, 2014 1:07 am
Posts: 19
Thank you, Ray.


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