So ill preface this by saying that this isnt strictly bike motivated but i need some help from the people who do know bike

What im looking to do is mate a set of K series throttle bodies to car engine to craft myself an inexpensive quad throttle body setup. My research has lead me here and specifically to the K1100 set of throttle bodies that ive seen a few different post of people using on their K100 bikes. They certainly seem the way to go for what im hoping to achieve as theyre simple enough, look robust, have the right size etc etc but before i was prepared to take the plunge and buy a set of ebay or some such i need to get some measurements and because im planning to use them outside their intended design there isnt any information on things i need to know(that i can find) and i havent been able to find a wrecking locally with any that i can eyeball.

So i was kind of hoping someone on here might have a set sitting around and a few minutes with a set of vernier to spare.

The measurements im looking for are

Internal Diameter at the butterfly
External Diameter (both ends if theyre different)
Length of the body (ie barrel length)
Spacing centre to centre (and need to know if theyre uniform)
Overall length of all 4 when mounted on the rail

I also wouldnt mind a bit more info on their construction like whether the throttle cable is the centre mounted cable or the end mounted (near the TPS) and if the 2 ports out are both vacuum.

Now that ive typed it all out i feel like im asking for quite a bit of information   maybe if someone has a blue print it might save me some time! 


Hopefully someone can help me out, or atleast point me in a direction i can find out

Thanks guys and gals

You do realize that we are going to want to see pictures of this vehicle and the engine you're working on.   There are a lot of voyeuristic busybodies on this forum.

There are pictures of the throttle bodies in here in a number of threads, just check out the search engine up the top of the page. So we would like to know what type of car engine its going on, will it be direct mounted or are you planning a manifold? Is the car injected or is that something you are going to do to it. In this section on about page 5 is K1100 throttle bodies to K100 with 3 pages of chatta. Then on page 6 fettling my K100 following conversion to K1100 throttle bodies.
So further down in the "your own renovation/custom you will find Two Wheels Better did a fantastic job with plenty of piccies on an upgrade of his bike, All of that should give you plenty of detail and understanding of how to fit it and what to expect when you do.

Naturally i will provide some pics once the project gets off the ground.

The engine ill be using is a Toyota 4E-FE thats commonly found in Starlets. Now why use this you might think? Im currently using the car in Kharnacross and Rally Sprint in SA and its relatively low cost, dependabilty and availability make it very reliable and easy to fix. The quad throttle side of the project comes from the ever present desire for more power and throttle response. Now some among you may know that these engines did come out turbo charged but that doesnt work for me as any form of forced induction moves the car into a different (and much higher contested) class.

I have seen most of the posts that you refered to K75cster and i think ive got a good overall idea of whats on offer, the specific measurements are what i really need so i can see just how much custom work i will need to do and what sizes some of the parts i need. The plan is to use the existing manifold but cut it down to fit the ITBs and bridge the gap using silicon hose sections. that way i can tweak the lenght for different results and take up any minor divergences where the two meet.

Hope that answers a few more questions that you had

This may be a start:

https://www.k100-forum.com/t1944-k1100-throttle-bodies-on-a-k100

Internal Diameter at the butterfly  = 34mm
External Diameter (both ends if theyre different) = 40mm both ends
Length of the body (ie barrel length) = 64.5mm
Spacing centre to centre (and need to know if theyre uniform) =  76.5mm uniform
Overall length of all 4 when mounted on the rail = 275mm for K75 (sorry, don't have K100)


The throttle for K100 and K1100 is always between TB2 and TB3.

Overall length of all 4 when mounted on the rail = 28.57 cm/ 285.75 mm (K100)
This includes the TPS mount, which bumps out a smidgen.

I say Galvanic, this reminds me of upping the oomph on older Ford Cortina's and Austin's by using four Amal Carbies. The Toyota is a carby engine or a single point throttle body fuel injected unit from the late 90's isn't it? I think someplace in here was a discussion on our local fuel injector modules and the likelihood of them being used by us. Micro squirt was one name bandied about. Hope thing work out.

Thanks a bunch for the measurements rob mack and kyle things are starting to look promising, the od of the stock pipes is roughly 42mm but very rough, bit of clean up is going to be needed to make a sound sealing surface but Atleast I shouldn't need to step up the joining hose.

The engine is factory efi and curiously a big helper here is that the injectors are mounted directly into the head, not the intake manifold. So the manifold can be removed entirely but still have the injectors there. I'm hoping this will make it a bit easier to do any match porting too

Need to take a few measurements on my end but looks like I'm going to go ahead at this stage, I'll post up some pics once I've got some pics to post.

Thanks again guys.

You're most welcome. Looking forward to the pics. 
After reading your post I did an image search for what you are describing;  actually a heluva lot of people utilize K100 t.b.'s for upping the HP on various engines.  Some stunning craftsmanship. 
Best of outcomes on this project.