Is anyone using motorcycle carbs?
Turbo Mini Forums

I read an article that was linked on another forum (http://www.v-performance.com/products/air_fuel.html) where the claim was that motorcycle carbs are vastly superior to our beloved SU carbs, providing better fuel atomization, leading to better power and mpg. I also recall a forum member who was running a motorcycle throttle body on his turbo Mini and was making pretty big power there.

The article recommends the 45mm Mikuni, but I found a cheap four-carb setup, locally, that included the injectors. I was wondering if anyone's taken this approach (with probably larger fuel injectors).

What's the experience out there with motorcycle carbs (one, two, or four)?

**************************************
1967 Cooper 's' Turbo build @ www.drjing.com

Now that's weird I have read the same link tonight. It talks specifically about the mikuni hsr range. They even have a mini plate made up to fit a standard manifold.


Nothing is mentioned about boost so I doubt they can be sealed without some serious thinking.

So only good for NA and evil suck throught like mine.

I run a bike carb but was looking for a larger size hence the research. I'm just not sure on the flat slide style you would need some work on the low throttle side which they mention. So you don't lean out if you boot it from low revs.

Edited by gr4h4m on 2nd Apr, 2012.

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

Last year I had a set on my racecar. Its not a A-serie thou


This year I upgrade to a 1242 FIRE, also on carbs

Edited by vegar on 2nd Apr, 2012.

www.shag.no

Vegar are they r1 40mm choke?

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

The one on pics are 40mm Kehins. Not sure what bike thy are from.
This year I gone use a set of 38 mm Mikuni from a Kawa 600RRRsuperduperNinja. They are not on the pics as thats just a mock-up :) The Kawa have 118 bhp (I know we are using bananas on this forum, but this is claimed by Kawa ) and my engine should be in the same region of power. I have purchased a set of needles to get it all tuned on the dyno :)

www.shag.no

You could box them in for use under boost? Not so tidy but it's an easy way to make carbs work under presure.

www.topcatcustom.co.uk

Nice, Vegard!

gr4h4m, good point on the sealing for turbo pressure. Hmm... Need to give that some thought.

**************************************
1967 Cooper 's' Turbo build @ www.drjing.com

how about placing the whole carb settup in the plenum, no need to seal the carbs then

vegar, what engine is that? looks quite compact

Edited by Brett on 3rd Apr, 2012.

Yes i moved to the darkside

Instagram @jdm_brett

The first is a 1050cc Abarth engine from my Autobianchi A112 Abarth. It made about 110 bananas with that 8-port setup.

The other is a 1242 FIRE engine wich will run a ported head, 306 deg cam, KMS ignition etc. Hope this will make over 115 bananas :)

www.shag.no

´,m running 40 mm flatslides with asjustable powerjets, very drivable and good power

internationally known as "big" swede

from mikuni factory:) the are aftermarket flatslide carbs "mikuni rs 40"

internationally known as "big" swede

I'll be interested in seeing what the Fire engine makes, from what Ive read you should be able to make your target easily,

I sure hope so. As far as I can see the biggest limiting factor is the small and they are located way out from each other so it is not possible to get very much bigger. I recon maybe 1 mm bigger valves are max before it reaches the bore

Edited by vegar on 5th Apr, 2012.

www.shag.no

alot of the bike carbs can be used for boost with a little re plumbing. There was a site which explained how but lost the link when my laptop died. will see if i can find it again. Robert has done this to his bike

Edit found it on the left there is a button pressurise carb it explains there.
http://www.turbo-bike.net/

Edited by jlay on 5th Apr, 2012.

My small bore turbo project http://www.turbominis.co.uk/forums/index.php?p=vt&tid=473901

surely you can find some Tbs for use under boost as some bikes are turboed and supercharged

noticed this little set up currently for sale on ebay at the moment http://www.ebay.co.uk/itm/classic-mini-man...b#ht_500wt_1287

one day boost will be mine!

oops cant get link to work sorry

Edited by jlay on 5th Apr, 2012.

My small bore turbo project http://www.turbominis.co.uk/forums/index.php?p=vt&tid=473901

thought id sort the link for you

Edited by wez on 5th Apr, 2012.

one day boost will be mine!

cheers

My small bore turbo project http://www.turbominis.co.uk/forums/index.php?p=vt&tid=473901

I looked at using bike carbs on my K head at first. From what I read you just have to pressurise the top chamber in the carb and the float bowl. (just take a feed off the plenum).

Here's a link to a helpful site.

http://www.turbo-bike.net/Pressurize%20carbs.htm

EDIT: like this

Edited by matty on 5th Apr, 2012.

https://www.facebook.com/pages/Fusion-Fabri..._homepage_panel

www.fusionfabs.co.uk



1/4mile in 13.2sec @ 111 terminal on 15psi