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PIGDOG is working on a custom manifold for GSXR throtle bodies

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Check this link out, it's a guy locally that built his own ITB's for his GA14 Sentra. He used ITB's off a GPZ 1100 Kawazaki (35mm), it worked out quite well for him...

EDIT: Oops, forgot to post the link...

http://www.teamdragon.co.za/forum/viewtopic.php?t=714

I am setting up 4x32mms ex Suzuki GSX11GK. Most large bike carbs are vacuum operated. These ones are a manual type, they are much easier to balance and keep in tune. But they will all work very well. If you can get a 36mm Flat side setup they would be spectacular. I ran them on all my race bikes back in the good o'l days but very rare, very expensive.

Pretty much any size will work.

A better question is which are most optimum for an A12 engine with stock cam.

id say around 28-30 for a bog stock small block aseries
for the bigger motors and worked small blocks id say 32-38

1200GXman, fuel injection throttle body sizes and injectors are chosen to suit the horsepower target of the bike.

Bike engines make a lot more horspower per cc then pushrod dattos do, so if your motor is a fairly standard A14/15 or even a warm A12 then any FI setup from a 600cc bike engine will be fine.

If you have a worked A12 or mild A14/15 then look for a setup from a 750cc (ie GSXR) and for turbo application look for a setup from a 1000cc

ball park figures for late model unmodified fuel injected bikes are (roughly):

1000cc make around 145 rwhp (160 crank)
750cc make around 130 rwhp
600cc make around 110 rwhp

The keihin brand throttle bodies are used on nearly all brands of bike, yamaha, honda, suzuki, triumph etc.

Using a standalone fuel computer would probably be the best bet as I dont think the bike ones will be of any use to the average A series as the fuel maps would be for much higher RPMs

Again, sorry Bandit_blues for hijacking your thread.

To be more precise, I am planning first before I take up this project build which will be sometime in the future when I have money as the economy is on the bad side at the moment.
My plans are as follows:
A12 engine either bored one oversize (as I already have the one oversize pistons) or go larger to do what Dodgeman did and make it 1300cc engine.
Lightened A12 flywheel.
276 (Mild street) performance cam.
GX cylinder head with a very light port job, cleanup of intake ports and polish of exhaust ports.
A14 size valves.
4-2-1 GX extractor also polished as far as possible on the inside to prevent future carbon buildup.
Full balance.
Fuel injection using bike quad throttles and a computer only to handle fueling.Spark will be the normal A series stuff.

I have also leaned in the direction of a 600cc bike. Maybe 750cc then.
Now another question.What type of throttles. I read here that you get something like sliding type throttles and I can't remember the other type of throttle. Or is it the carbs that have a SU style sliding butterfly. Can someone help with this as I don't want to buy quad throttles and then see they are not the correct type.
Any info appreciated
datto12qld, it seems you are the bike expert here so maybe you can enlighten

When they are talking about Flat Slide it is a type of carb where there is a rectangle box sitting vertically inside the cavity of the carb.
(kind like a sliding door that goes up and down)

when you pull the accelerator cable it is lifted and opens up the 'throat' of the carb letting air in and also lifting the 'needle' which unblocks a jet at the bottom which lets fuel come up and mix with the air.

There is also 'smooth bore' and round type and also semi flat. All have different properties but work on same principle

In fuel injection you dont have slides you have butterfly valves that turn on a shaft the same as how car carbies work.

I think a setup from a gsxr 750 would go well in your application, just work out what hp you expect to make with your A12, then google the stats of different bikes.

They are all pretty close in power so it is ok to just stick to one manufacturer for comparisons.... ie, Suzuki GSXR 600/750/1000 you fill find the yamahas, hondas, kawasakis 600/750/1000's make about the same power for each model of the same size.

As for a computer you could probably go a microtech mt-4 or something similar but i would recommend you get a "microsquirt" they are VERY small compact fuel injection computers (about the size of a wallet) they have sh!tloads of functions, and are cheap.

You can use a microsquirt to control your ignition as well (with a couple of addons such as ignition pickup wheel & sensor etc)

Just keep in mind that the micro squirt does have limitations compared to a mega squirt or any other CAR ECU becasue they are meant for bikes.
For eg. They can only put out enough power to drive one coil, so if you want a 4 coil setup you need an extra device to power the coils.

But all in all, they are suited very well to the project your planning. Probably a bit trickier to set up at first, but a lot cheaper then anything comparable.

have a look at
http://www.microsquirt.info/

I will be using one of these for my bike EFI conversion onto A15.

Hope that helps mate!

bike carbs work, and they rule....
beeoneoneoh.wordpress.com

Is any issue regarding the position of the carbs? what i`m trying to say is if the carbs must be in a horizontal position or if they can sit in angle?