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MC21 or MC28 carbs - that is the question....


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geckoracing1

 
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MC21 or MC28 carbs - that is the question....

Sat Feb 24, 2007 9:09 am » Post: #1 » Download Post

Anyone have a view on which are better, the MC21 or MC28 carbs? Both are 32mm, however the bore shapes are different.

I'm looking for outright power & performance as the bike is destined for the track. Any help or advise appreciated.

Thanks

Dan
07919 303762
dan.williams@s-n.com
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Dave Ett
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Sun Feb 25, 2007 12:19 am » Post: #2 » Download Post

From everything I know, the 21's produce more power. The 28's are tuned for power lower down the rev range.
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Matt@TYGA
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Mon Feb 26, 2007 6:07 am » Post: #3 » Download Post

The 28's are shorter, so "should" give more top end.

However, I haven't back to backed them on the brake.

A job for Stephen methinks
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StephenRC45
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Mon Feb 26, 2007 8:45 am » Post: #4 » Download Post

I'd rather change needle postion on a '21 carb any day over the '28....
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Mon Feb 26, 2007 9:01 am » Post: #5 » Download Post

Come on Steve...It only takes a day on the 28!
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fontyyy

 
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Mon Feb 26, 2007 11:44 am » Post: #6 » Download Post

They're only bad if you try to do it in the same fashion as you'd do a '21 - in situ is not a good idea, it's easier to get the carbs totally off and get the needle holders out, you need to undo the link between them and twiddle the adjuster right in to make enough room on the front cylinder carb.

So the length of the job is dependent on how easily you can get the carbs off.
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StephenRC45
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Mon Feb 26, 2007 11:46 am » Post: #7 » Download Post

So '21 it is then as you dont even need to remove the carbs Wink
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fontyyy

 
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Mon Feb 26, 2007 11:58 am » Post: #8 » Download Post

Steve, surely not - you must love taking carbs off....

you do it so often!
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StephenRC45
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Mon Feb 26, 2007 3:47 pm » Post: #9 » Download Post

You know I can't stand something that doesn't carburate perfectly, which I admit means re-jetting almost every day to keep it just where I want it lol
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Mon Feb 26, 2007 4:02 pm » Post: #10 » Download Post

Steve loves jetting so much that we had to beat him off of Paul's 21 with a stick 'cos he just couldn't leave it alone.

Or maybe it was Paul's amazing ability to feel when the jetting's an 1/8 of a jet out.

Now you know how I feel Steve. Wink
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StephenRC45
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Mon Feb 26, 2007 4:53 pm » Post: #11 » Download Post

I know how you feel Matt.

I do get alittle bored on holiday so the chance to play with some carbs was very welcome.

Going back to the topic though, I think as '21 carbs are so much nicer to work on I would choose them over '28's.
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Tue Feb 27, 2007 1:30 am » Post: #12 » Download Post

Have to agree there of course. MC21 carbs are a breeze to work on. I always used to have a quick groan when I needed to change the needle, or move a clip on my 28 race bike. Carbs off, pull 'em to pieces, blah blah blah. Not exactly something you'd want to do half way through qualifying or something. MC21 much quicker. Whip off the tank, yank off the cover and you're straight in there.

Proper PJ/PWK carbs are even better. If you're lazy you can even change a needle without pulling the tank off.
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