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HRC Jet Kit for Street


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Skyntara

 
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HRC Jet Kit for Street

Sun Dec 13, 2009 6:11 am » Post: #1 » Download Post

Been trying to tune my carby a bit today and it's quite painful.

Just wondering if an HRC Jet kit is worthwhile for road use?

I found this Bakudan Kit on Yahoo Auctions http://page9.auctions.yahoo.co.jp/jp/auction/k117796189

Is it worse, better or equivalent to a real HRC kit.

MC21 btw.
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Hermit

 
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Sun Dec 13, 2009 7:14 am » Post: #2 » Download Post

the HRC kit is for use with pre-mix, blanked power jets, open carbs and presumably race pipes too. Therefore all the sizes are quite big - they provide you with main jet sizes from 180 to 210, some number 40 slow jets and a range of needles besides a few other bits and pieces.

If you are still using the 2T pump, standard airbox and exhausts then you'd be better off buying different jet sizes from an online shop or your local MX shop maybe? A bit of google searching will find you a Keihin dealer. I think i remember finding a shop called cycletreads here in NZ who can supply carb parts - so there must be a shop in Aus who can help you too.
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nsrdownunder

 
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Sun Dec 13, 2009 7:57 am » Post: #3 » Download Post

That kit looks like Hrc needles Hrc emulsion tubes and Bakudan Kit main jets. it`s a lot of money without the T and Y piece
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Skyntara

 
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Sun Dec 13, 2009 9:22 am » Post: #4 » Download Post

Yeah, I have every size between 150 and 162 (thanks Tyga).

But do main jets really affect power down low, off powerband?
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fontyyy

 
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Sun Dec 13, 2009 10:19 am » Post: #5 » Download Post

Yes they do.

You're a member have a look here, replies 2, 3 and the last one tell you your exact problem if you're trying to set it up a road going mc21 with 150-162 main jets.

A guys, just a reminder; no specific jet sizes in general please Wink
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Skyntara

 
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Sun Dec 13, 2009 10:54 am » Post: #6 » Download Post

Cheers,

I'll continue there.

Was really looking for a separate yes/no answer on the HRC jets.

Looks like it's a no for street use, thanks guy.
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Skyntara

 
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Sun Dec 13, 2009 12:41 pm » Post: #7 » Download Post

Well I started playing with my spare carbs on the bench and worked out how easy it is to get the needles out.

Standard B and C needles - No surprises there.

They had very thin sanded down washers under them - not sure if that's normal - definitely homemade.

With new found confidence I popped off the tank, Tyga tail and airbox and popped open the carbs on the bike to find....

Adjustable needles....

hrmmm...


I can make out J2BA on them.

Is this a good thing or a bad thing?

Anyway, I whacked the standard needles in since I had the standard emulsion tubes.

The emulsion tubes that go with the adjustable needles are about 41.5mm long and they had some dodgy no name brand 150 jets in them that were longer than stock honda ones.

The tubes have 16 holes, in 2 sets of 8 top and bottom.

The wierdo short SJs are genuine Keihin at least and are 24mm long.

What am I looking at here?
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Andy
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Mon Dec 14, 2009 5:12 am » Post: #8 » Download Post

Why don't you read the carb pages of the tuning section?

Even if I do say so myself, there are bloody good descriptions and diagrams of the HRC emulsion tubes and adjustable needles there. It should be blatently obvious what you have if you take the time to have a read through the vast reference that is the main site!

I would be extremely surprised to see it running "A" needles without HRC emusion tubes, unless they are on the bottom clip, and that would run so poorly I would be surprised if you could even pull away!

Anyone who's ridden mine in it's (sort of) finished form, or anyone else's that's been set up correctly, will tell you there's nothing wrong with running a full HRC jet kit on the street.
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Skyntara

 
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Mon Dec 14, 2009 6:27 am » Post: #9 » Download Post

Sorry Andy,

I've been reading the carb tuning and searching the threads but when I started this thread I didn't even know how to get needles out of the carbs.

There were no measurments on the site so all I knew was that I had two different sized emulsion tubes some wierd long jets and some wierd short slow jets.

I'm a bit of a n00b but I think I've got my head around it now. Much better with computers than bikes.

So the general consensus has shifted to the HRC kit being good for street?
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Andy
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Mon Dec 14, 2009 6:29 am » Post: #10 » Download Post

General consensus is that HRC kit is good full stop!*

*Except maybe the rear brake! Laughing
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Hermit

 
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Mon Dec 14, 2009 8:43 am » Post: #11 » Download Post

I wish i kept all my little HRC labelled bags...

God i LOVE HRC.
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fontyyy

 
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Mon Dec 14, 2009 10:30 am » Post: #12 » Download Post

How can a set of jets be either good or not good for road (or track)?

The "arguement" for not buying the jetkit if you've got a near stock motor is that you won't use 95% of it and you could get the exact same net result with a set of mains.
So that's spending about $10 rather than several hundred.

This is Steve's mc18 dyno graph from quite a while back.
That's just wiresplice, race pipes, modded airbox and a different main jet.
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Skyntara

 
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Mon Dec 14, 2009 11:35 am » Post: #13 » Download Post

O...K.... so no consensus then.

Since I'm running pretty well now and feel like I'm only one or two jetting iterations away from being good I might leave it be.

Although I do have a spare engine and carbs so it might be nice to build up an HRC carb.

Excellent points from both sides, I'll keep my eye out for a good deal on Yahoo Japan, but I won't break the bank for a set just yet.

Thanks for all the advice guys.
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Andy
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Tue Dec 15, 2009 7:38 am » Post: #14 » Download Post

fontyyy wrote:
How can a set of jets be either good or not good for road (or track)?

The "arguement" for not buying the jetkit if you've got a near stock motor is that you won't use 95% of it and you could get the exact same net result with a set of mains.
So that's spending about $10 rather than several hundred.

Bollox!

If you can find a jet kit, buy it! If you have anything other than a completely stock 45hp MC21, fit it and get it set up by someone who knows what they are doing. Simple.
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nsrdownunder

 
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Tue Dec 15, 2009 10:33 am » Post: #15 » Download Post

I agree Andy you cannot beat adjustability ,How can you get it right if you cannot adjust it ?
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