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Wanted mc21 air correction parts.


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Tt64rc45

 
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Wanted mc21 air correction parts.

Tue Nov 03, 2020 8:01 pm » Post: #1 » Download Post

Can anyone help with the X joiner in the air correction system?
My recently bought bike ( needed some work) has all the symptoms of a plumbing issue and a cobbled together x connector I think is to blame.
Otherwise, does anyone know the jet size in the X part and if the Y piece is restricted also.
Thanks.
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Andy
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Wed Nov 04, 2020 5:51 pm » Post: #2 » Download Post

I've got a little box of X and Y pieces somewhere, and I spent best part of an hour out in the shed looking for them, but I can't find them I'm afraid.

Not what you want to hear, but I expect Yahoo! Auctions is going to be your best bet.

Or, maybe 3D print some. I've just asked Matt@TYGA to check the STD. MC21 jet sizes for me, and he says he'll look when he gets to work in the morning.
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Tt64rc45

 
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Wed Nov 04, 2020 6:08 pm » Post: #3 » Download Post

Thanks, Andy. Much appreciated.
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Max
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Wed Nov 04, 2020 7:05 pm » Post: #4 » Download Post

https://www.jap4performance.com/product/carburettor-4-way-tubing-joint-cross-type/

Tyga US might have some, Mayne Matt can access them?
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Andy
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Wed Nov 04, 2020 10:15 pm » Post: #5 » Download Post

Well, it would appear that CMSNL have a Y-piece, so between them and Jap4, if you act fast, you could have the pair for about £50.
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Andy
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Thu Nov 05, 2020 2:28 pm » Post: #6 » Download Post


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Tt64rc45

 
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Thu Nov 05, 2020 6:05 pm » Post: #7 » Download Post

That’s brilliant, Andy thanks. I can make them in lockdown, save myself 50 quid...
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Andy
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Thu Nov 05, 2020 6:16 pm » Post: #8 » Download Post

You'll have to excuse the big silly watermark, but people steal content from here and plagiarise it as their own elsewhere! Wink

The HRC X and Y-pieces have different sizes, and there are also very small variations across the MC21 and MC28 years, but these are the most common dimensions. If you're making them yourself, and you're really fussy, you could make different sizes to really fine tune the air correction, but you'd need to be (a) really anal, or (b) really bored! Laughing
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Max
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Thu Nov 05, 2020 7:04 pm » Post: #9 » Download Post

Not sure why the originals have a brass turned jet inset into the plastic pieces to meter the airflow...cant see why they can't be solid plastic really (or solid brass)

Do you have access to a 3D printer then?
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Andy
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Thu Nov 05, 2020 11:02 pm » Post: #10 » Download Post

The brass jet is most likely a tolerance thing. You can't guarantee a 0.05mm tolerance (possibly even tighter) in plastic, and maintain it over a wide range of temperatures and conditions. Cost would preclude mass producing the parts in solid brass.

Also, off the top of my head, there are three different (STD.) Y pieces... and don't forget there's also HRC variants, that are different again! It's much simpler to have a generic plastic housing with consistently accurate jets pressed in. The numbers in the diagram above are the most common, and will work across the board for standard MC21s and MC28s.
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