Slick motorcycle ITB mounts for IDF manifolds

[aircooledtechguy]

Long story short:

I was at a friends house that is really into motorcycles. He’s got moto parts around his garage like I have VW/Porsche parts around mine. I see a rubber carb flange that looks interesting and ask about it. I find out that it is for a Mikuni carb to mount onto the engine. . . The flanges have a metal base flange that has rubber cast around it. It’s really a nice design and seems to work fantastic. Hmmmm. . .

So after I return home I google them. Find they come is a bunch of sizes. I take some key measurements off a set of IDF manifolds and a set of VFR800 Interceptor ITBs I have (36mm butterflies) that I would like to use on my 2.0L in my bus. I found the size I would need w/ Mikuni P/N. . .

I found a retailer in eBay that sells them cheap and order a set of four. I had to modify the bolt pattern to fit the IDF manifold slightly (about 2mm total). They fit perfectly!! Now I can directly mount most motorcycle ITBs directly to my VW IDF manifolds!!





As you can see, the ITBs fit perfectly. The rubber base even has the correct male groove to match the female groove in the ITB for a solid fit that won’t pop-off. With shipping, I have just under $100 in this entire set-up of TBs and mounts. I will be converting from Dellorto carbs to MS2 w/ ITBs and EDIS on the T-4 motor in my ’66 E-Z Camper this winter.

I have no doubts that these same Mikuni carb mounts could be used for GSXR ITBs and a host of others out there as well. Hope this give some of you another avenue to go MS and ITB.

[Piledriver]

Cool, what part# did you end up with?

Several folks have tried similar and found they don't quite seal up with the common GXSR TBs.
The issue with the GSXRs is they are IIRC ~75mm c/c, and don't line up well vs ~90mm IDF.
(insufficient overlap to the bore in the manifolds, due to the offset)

What's the center/center spacing in the Interceptor TBs?

The ones you found appear to be a near perfect fit and ~near same spacing as IDFs.

Devastator is working on some machined/bolt together adapters to deal with the GXSR vs. IDF offset issue.

[aircooledtechguy]

I used P/N 07-100-15 which is for the 40-44mm Mikuni carb base.

The VFR 800 TBs are 2mm wider than the IDF openings, but with these rubber bases, that's nothing (1mm each side is nothing to write home about). They fit perfect.

[Slamd72btl]

Not sure if it helps anyone or not, but it looks like the ITB's on the 2006-2009 VFR800 are the same as the 2004-2007 CBR1000RR. They share the same injectors, according to p/n, and they look to be identical, just mounted in a different configuration, although I could be wrong. FWIW. Nice find

Upon further research, it looks like the CBR1000RR's are 44mm vs the the VFR800's ~34-36mm

[Piledriver]

Slick, good info.

If you have injector flow# and or dead time#s, please update the thread on msextra.

[Slamd72btl]

Not sure if it helps anyone or not, but it looks like the ITB's on the 2006-2009 VFR800 are the same as the 2004-2007 CBR1000RR. They share the same injectors, according to p/n, and they look to be identical, just mounted in a different configuration, although I could be wrong. FWIW. Nice find

Upon further research, it looks like the CBR1000RR's are 44mm vs the the VFR800's ~34-36mm

In the unlikely event that anyone paid attention to my post, disregard it - the CBR's seem to have a different C-C spacing

[Devastator]

In the unlikely event that anyone paid attention to my post, disregard it - the CBR's seem to have a different C-C spacing

We're reading your posts, just don't always have something to say.

Several folks have tried similar and found they don't quite seal up with the common GXSR TBs.
The issue with the GSXRs is they are IIRC ~75mm c/c, and don't line up well vs ~90mm IDF.
(insufficient overlap to the bore in the manifolds, due to the offset)

I have a set of GSXR600's that have a 71mm. bore spacing, and another that has 75mm. spacing. They are different year TB's. Those CBR TB's look like a nice fit.
Keep up the good work.

[jhilverda]

I've also bought some VFR800 TB's and Mikuni (07-474) flanges. Looks nice and they also almost fit at once.









I have turned one shaft around so the throttle piece is on the front. With rivets I have mounted the butterfly valves. I am planning to make an electronic gas pedal using an arduino with servo's on the TB's, but I have look into that.

Does anyone know the original injector size?

More pictures on my Flickr account.

[andy198712]

any more on these?

[antsu]

Hello.

First I would like to apologize for bad English in advance

And here is my Honda itb's which I try to install to my bug engine. I have a a slightly different technique for installation, it is a turbocharged engine and I am concerned that they jump out of their rubber seats because of pressure and vibration.. So I did a little bit welding..

I have not driven on this setup yet because the job has not been completed.. and there is snow on the ground.

Less talk and more photos, and please feel free to comment..

Here is the throttle body.

IMG_20161001_194719.jpg

Some flange manufacturing...

IMG_20161001_194708.jpg

Kopio IMG_20161001_201436.jpg

IMG_20161001_194805.jpg

At this point had to think about how I weld flanges in place because all rubber gasgets and etc will melt when the heat spreads in the throttle body. Butterfly screws has riveted heads so I did not want to get them out..

So I put TB:s in water and weld the flanges..

IMG_20161001_222653.jpg

This is the finished product. I did some weld bead sanding after..
Sitting nice and straight and bolts can be easily fitted.

IMG_20161001_212404.jpg

IMG_20161001_212437.jpg

IMG_20161001_212504.jpg

[andy198712]

Looks great!

[panel]

Pile , do you have the link ?

Slick, good info.

If you have injector flow# and or dead time#s, please update the thread on msextra.

[Piledriver]

Pile , do you have the link ?

Slick, good info.

If you have injector flow# and or dead time#s, please update the thread on msextra.

I can't find it, just post it up in a new thread.

[gearheadgreg]

Reviving this old thread.

What do most people do for air filters on this setup? Adapt simple IDF style ones, or is there a better one available?

I was thinking of using the VFR velocity stacks and making a base adapter to use some old IDF filters, but thought I'd ask first.

Thanks for all the great info here, btw.

[TZepeSH]

I am using these throttle bodies too. I will use IDF type K&N air filters and the VFR velocity stacks. I will just elongate the bottom holes in the filter bases to go around the "bosses" on top of the throttle bodies and drill new mounting holes where the VFR has them. Note that two sets of trumpets are needed, on a VFR two are taller and two shorter. I will use the long ones. They are 12$ a set, transport is more expensive.