Thunderbird Frame Hole Help

72Combat · Aug 11, 2014

I have a non Thunderbird frame that does not have the hole for the SU carb.
Its unlikely I'll find a frame here so might just convert the one I have.
Would anyone have one that they could give me the measurements and or a copy of a tracing?
Exhibit A:

Exhibit B is the bike:

Picked it up as an unfinished project, mostly there except the outer chain case, the SU carb. Its a 1953.
Motor is usual " was rebuilt but no docs"
Cheers John

Matt Spencer · Aug 26, 2014

Just fit a Dual Carb Head . :wink:

originality at the price of degressin isnt worth pusueing . A T - bird should be a 100 mph road bike .

Who Cares , as long as its got a Air Filter , like a K&N or whatever . Seeing You Asked . dont mess with a running piece , its Stronger perhaps as is . not worth the hassle Its How it GOES that Counts . Its a TRIUMPH . not a vase
or something .

Triton Thrasher · Aug 27, 2014

I've never heard of anyone wanting to do that.

SU carburettors are nice, but not worth re-engineering your frame for.

Tim_S · Sep 16, 2014

Better late than never I suppose ........I measured the outside diameter of my rubber hose to the vokes air box at 42mm OD.

Tim_S

grandpaul · Sep 17, 2014

Many single carbs will still fit without the hole in the frame (bad idea from the start)

grandpaul · Sep 17, 2014

This is a '53 with the hole, but I bypassed it using a modern JRC superior carb.

72Combat · Oct 9, 2014

Thanks for the comments.
I placed an add in the Vintage Car Club mag, see if I can get a frame.
Failing that , just put it together as it.

acotrel · Jan 11, 2015

It would be very difficult to re-engineer the frame in a way which would not be visually detectable and I would have thought the reason for using the SU carburettor is to keep originality. You might be better to simply fit the Type 6 Amal carburettor which was used on many Thunderbirds.

72Combat · Jan 12, 2015

Probably, I'm not in a hurry as the Commando ticks the Brit bike box and having too much fun riding my 900ss and BMW's.
I might put a Bing carb on it :lol: