Fitting Motorcycle carbs to valver..

Hi.

Haven't posted for a while. Been a busy little engineering student.

Anyway, I'm thinking of fitting carbs from a large capacity motorcycle engine to my ABF engine'd mark 2 valver. The standard system is getting a little tired and under fuels the 2 litre anyway so I am considering fitting 40mm carbs from one of the large capacity bike engines, such as the YZF R1 or something similar.

Think about it. These carbs are ideal. They are extremely well developed, fitted to engines that often make 175 brake, they are simple, easy to fit (they often hold on with flexible tubing) require little maintenance etc etc..

Before anyone says "they are for small engines and wont be suitable" think about the volume of air they have to flow in a 160 brake 12 000 rpm engine. They can be re-jetted to suit cars and with a choke size of 40mm should be more than up to the job.

I could also use them as the trhottle bodies if I later convert to megasquirt injection.

What I'm after guys is your input on this matter..Potential pitfalls, information and advice.

Wouldn't mind doing this conversion. The manifold will be the most time consuming job and getting them re-jetted and rolling roaded the most expensive.

If I can get this right I can see it being an excellent conversion for us valver boys sick of K jet...

Jai

 

If you haven't already - Buy the Dec 04 Retro cars, there's an article about this.

Company in Yorkshire specialise in this conversion, interesting stuff. They say it's sadly not just a case of just bolt on some 30 smashed up R1 carbs and off you go, they need serious re-jetting for car applications. They can re-jet them on their rollers and they mention that unlike a manky old set of Webers they rarely go out of tune.



They get a gasket flange laser cut then usually weld 4x40mm tubes to the flange so it mates up to the original flanges of the bike carbs, so usually no need to seperate the bike throttle linkages which makes it a lot easier.

In the article it says they've fitted them to all sorts from a Micra 1300 16v To a set of 6!!! on a Triumph TR6, Do a lot of Pinto's/CVH's in kit-cars, Vauxhall 16v (1600 and 2 litre)





Edited by: GVK

 

Yeah, it's a good read. I don't have it here, but don't they say about 5-600 to convert and set up?

 

does it say how much a rejet is? in the end they are still carbs so will be less accurate than any kind of injection, i'd get your engine set up at stealth first just to see what the k-jet can really do.

If using the carbs look at the bore spacing of the original bike engine, match it to a vw bore spacing and they should line up with the manifold, then just hack it off radius the inside edge and use the rubber tubes to connect the carbs. will need a chunky mounting bracket too

 

what you have to weigh up is how much is gonna cost to how much or a performance enhancement you are going to get.

if its going to cost you 5-600 and your getting an extra 5 bhp whats the point....

i could understand if there was a world shortage or kjet parts, just seems like a lot of hassle

 

Considering a k-jet car is capable of 200bhp with the standard 50mm inlet manifold, I would work on all other aspects 1st.

 

Didnt they say? or maybe i heard it else where that if you had it setup by them they would guarantee an increase in power over your current setup.

 

be good to see some graphs, i can't see how they can guarantee an increase, bit of a brave statement

 

i'd rather have the bike engine attached as well, megabusa style

 

There's a guy on Scoobynet doing this to his Mi16 engined 205. Using TBs from a GSXR750 (whatever one of those is ). There are a few useful links in that thread too. Interesting ...

 

Yes this is what you want, the Powertech macro V8 version 30hr rebuilds might be a problem though

/Had to change the link the forum code keeps changing superb!tch in the address to superfemale dog which doesn't exist
Edited by: Finite

 

Didn't someone spend 2000+ on a set of DTH throttle bodies and DTA to end up with more or less the same top end power as it was on K-jet? [:^(]

Ok driveablility was improved.....

In the article it states that they mostly see gains of 30bhp compared to a factory EFI system and their bike carbs will improve response and driveability over a Weber DCOE set up.
They say that in most cases the whole conversion including rolling road set up for re-jetting will be 500-600

Some of us have spent 400+ on a pair of cams in the past and seen no gains
Edited by: G_V_K

 

Like a pair of Schrick cams maybe?

 

. You still got those schrick sticks?

 

Nah, they were sold the moment they were removed from the car

 

What can stealth do for my newly recon kr 16v? It has new injection bit. I took it to awesome and a guy there just tested the co and declared it ok. 35 later I am not totally convinved

 

there is ALOT of info on vw vortex about fitting bike ITB's to 8v and 16v engines, running cheap engine managment like megasquirt etc...

a few vids flying about on there too.

was gunna do the same, but couldnt be arsed. still got the GXSR 43mm throttle bodies sitting in my garage if anyone is interested in doing this conversion.

just search on vortex for ITB

 

I wouldn`t go down the bike carb route, don`t think it would be easy to convert them to throttlebodies really, bike throttlebodies and megasquirt however would be worthwhile. Must need some seriously big main jets to power a car and same goes for the pilot jets.

 

We're getting confused with ITBs (injection) and carbs (not injection)

Dodger, Stealth rolling road tune including warm up regulator mod will do wonders for your KR.

 

What will they do to my warm up regulator? Don't tell me I will need a new one!