I swear I just read someone was doing this due to larger secondaries or something on the fd tb. I can't remeber where or I saw or read it , or even if I did for that matter. Am I high? Just need to have this settled.
thx

 

Your are not mistaken, I am using my 13b TB w/ a 4mm bore

 

the bolt patterns are the same, the bac passage is slightly different, and needs to be blocked or something.

mike

 

Is that a 13bt or 13brew tb, and would you two care to elaborate more on the details/differnences.
thx again

 

I thought the FD TB didn't have the front set of butterfly plates like the FC and cosmo motors?
I just stuck with the 20B TB and did the TB mod to it.

 

20B one is larger. (slightly)

Looked both just a moment ago to compare.....

 

20B primary bore is slightly larger, but the primary throttle plate is identical in dimesions as the FD 13B-REW primary throttle plate.

I measured with a caliper myself.



-Ted

 

So are the secondaries larger also. I would assume so, but I do not have a 13brew tb to compare with.

 

Yet another bit to add to my list for my conversion.

The list is growning faster than I'm getting parts for it