Converting motorcycle throttle bodies

[Ben Andrews]

Hi all, i'm currently working though the build of my type 4 engine and am looking at the intake system.
i managed to pick up some throttle bodies off of a suzuki gsxr 1000 motorbike pretty cheaply and now need to see if i can get them to work.
They are 50mm on the intake which taper's down to 42mm at the butterfly.
The challenge's are that the centre to centre measurement differs to that of the idf type manifolds i have and the method of fitting the throttle body differ too.
Heres some pics illustrating:







To solve these problems the idea is to make a billet adapter to convert the IDF fixing method to something that would work with the motorcycle throttle bodies.
As can be seen from the illustrations below the adapter will essentially just bolt on to the IDF manifold, and offset the part for the throttle body. The throttle body will then be fixed on with a hose and clamp as used on turbo engines.







The sharp edges inside the adapter will be blended to provide as smooth a transition as possible.

My question is what do all you think of this solution, although the transition to the throttle body to manifold will be as smooth as possible it will still be quite a sharp bend for the air-fuel mixture to get though. Would this hinder performance or tuning?
Another idea is to create a adapter with no offset and hog out the manifold but im not sure there's enough material in the manifold to be able to do this.
I look forward to any thoughts you have on this be it good or bad.

[Kelley]

Your motorcycle t/bodies use a flexible rubber intake boot so that they have a good seal whem mounted on the motorcycle. Your idea is sound except for how your AL adaptors fitting on the intake side of the t/bodies. Metal-to-metal seals on a M/C's intake do not work. You might try some different sized motorcycle intake boots from a boneyard to size them since most have a two bolt fitting to hold the intakes to the head, they may bolt right to the AL intakes that you have, then when you find them, go buy some new ones. It's a good bet that boneyard intakes have some sort of dryrot.

[HotStreetVw]

you could always build a differnt intake from the head up.

[panel]

Have a look here http://www.msefi.com/viewtopic.php?t=6627

[Steve Arndt]

Go to hondatech.com and search for "ITB" or "motorcycle throttle bodies" or the like. There is a thread there where people have adapted many style of bike TBs to cars. Everything from GSXR, to Ninja, and all the sizes from small to big.

[raygreenwood]

Those look preety smooth on the inside. You could make that part out of Torlon plate or block. It machines like butter...slicker than Teflon, rigid like derin...good to constant 600+.Then.... Groove it for a viton 0-ring and be done with it. Very low heat exspansion.

[76bug]

how much did u pay for the throttle bodies? also wot type of injectors can u use with them?

[mschilling]

That's a good point about injectors. They may need to be machined to accept a regular sized injector where you can get your choice of sizes.

[76bug]

hmmm, well they look like a really nice TB, i cant actually see where the injectors seat, and another question did they come with a tps if not would u mount one?

[Steve Arndt]

I have seen complete sets with injectors, TPS, fuel rail, throttle bodies on ebay go for anywhere from 50 bucks to 250.

Just search ITB or individual throttle body or hayabusa or

[76bug]

ok thanx im very interested in trying this myself, are the TB's paired or did u have the cut them

[Guest]

this is a sweet set up we have use the bike TB's on lots of cars from honda to ford. The only problem with the type1 or type4 is the linkage but they do works well with the injectors that it come's with .we have six sets for sale if you need a set
from bug man nrg I can not log in
www.emeraldperfomance.com

[76bug]

um the link doesnt seem to work, wot impedance are the standard injectors and wot size are they in cc's, i will be using a michrotech

[Jerry D]

It would be easy enough to cut the flange off the manifold and reweld it on the correct centerline of the T/B then blend the manifold as needed.
Just a thought.
Jerry...

[Ben Andrews]

how much did u pay for the throttle bodies? also wot type of injectors can u use with them?

They cost me £80 from ebay
Not sure what type of injector they are, this is all new to me and is the first time ive built an engine let alone installed EFI. From the web page panel posted earlier they are 230cc/min if that helps.

mmm, well they look like a really nice TB, i cant actually see where the injectors seat, and another question did they come with a tps if not would u mount one?

The injectors are seated on the other side not visible in any of the pics. They did have a TPS. Also they had secondary set of butterflies which were operated by a stepper motor and had another tps sensor fitted. These i removed and dont inted to use, They were also troublesome when i tried to split the throttle bodies as the shaft for the butterflies is one peice accross all 4. This struck me as a bit strange as the primary throotle shaft is 2 peice... still im not gonna use them so doest really amtter.

you could always build a differnt intake from the head up.

It would be easy enough to cut the flange off the manifold and reweld it on the correct centerline of the T/B then blend the manifold as needed.
Just a thought.

As much as it would be better to fabricate a new manifold or modify the current ones my fabrication skills arnt really up to the task and to have a proffessional do it would probably too expensive. Having a simple adapter made will hopefully be the cheapest option.

Im trying to see how cost effective i can make this system for, Can it be done for less money than a pair of IDF's while at the same time perform better?.... thats what im aiming for.

And yes im a cheap bugger.

As for the Linkage that will certianly be a challenge but ill worry about that when the time comes.... not that im putting it off lol.

Thanks for all the comments so far, certainly some food for thought