MGB-GT Bike carbs on MGB GT Anyone?

[78redmgbgt]

Hi There, new chap just joining here? steveb from glasgow, scotland, if all goes well ill be new owner of a 78 mgb gt this saturday,,

Im interested in tuning it, after a comprehensive engine rebuild, has anyone out there any input on putting bike carbs on these engines, sure way of improving carburation, performance and possibly economy.

Been in press recetly for kit cars,,,,SB

 

[piman]

Hello SB,

British Leyland used Amal carburettors on their 8 (or was it 7) port mini heads. There is no other type of carburettor that can flow the same amount of air. Relatively simple to tune but I don't know of any used on MGB's. Worth playing with I would guess if you do a lot of other modifications but without them I wouldn't think it would be worth it.

Alec

 

[jgbowman1]

A friend of mine has a harley carb with a turbo. Here it is:

https://www.britcars.net/Seats1.html

 

[Nunyas]

whoa... correct me if I'm wrong here, but it looks like he started with the stock manifold. I can't tell from the pictures very well, but it looks like the turbo is being driven by the 4th cylinder exhaust port only. It certianly looks neat. I'd like to know more on how the manifold was modified to drive the turbo, and how well it's working...

I don't think I'd ever be able to do it to my car since I live in Cali, but I still find it interesting to learn about.

 

[jsneddon]

take a look at https://www.prirace.com/induction.htm

They seem to be doing some crazy stuff with Keihin and Mikuni bike carbs.

For what it is worth I have a buddy with a Honda motorcycle that uses the Keihin and we were talking about this upgrade.
His exact quote about them was "the Keihin carbs on the HONDA use the Stromberg-style vacuum-piston with the stupid diaphragm on the top, made of some pliable material that disintegrates if you park the machine in the dark for more than a month at a time. replacement cost: $80 per slider per carb"

Just for fun he has an old Suzuki RE-5 bike with a wankel rotary engine and I just rebuilt one of my extra SU H6 carbs from my TR3 for him. He's going to hook it up in a couple of weeks.

Talk about going full circle /ubbthreads/images/graemlins/smile.gif

 

[78redmgbgt]

I fancy putting 2 x 900cc bike carbs on each manifold, via adaptors and experimenting from there,,, inlet setup on mgb 1800 is rather contrived, again i get my car this weekend so i'll have a closer look then, each port could get its solution effectively, possibly via a custom bodie, dont know of modern bike carbs that feed a 900 cc pot at moment, recognise that each pot on the mgb is 440 cc, but the inlet is twinned , any ideas out there, y adaptors etc?? SB

 

[piman]

Hello SB,
what size are these carburettors? If their choke is smaller than 1 1\2" then there is not a lot of point. Doubling up will lose a lot of the potential. and you would be better going up to 1 3\4" S.U.'s, otherwise fit an aluminium head and get four inlet ports.

Alec.

 

[78redmgbgt]

i like the idea of individual ports, aka 16 valve head, 4 x ducati 900 v twin carbs would do, or similar cc bike, would all be relaively easy, but sounds expensive,,

Are these 16v heads plentful , ie 2nd hand,,,

 

[piman]

Hello SB,

they are made currently, but have been around for 20 or 30 years so it may be possible to find a second hand one, but they are not common. You could try E-Bay. They are, however, eight valve, not sixteen.

Alec

 

[aeronca65t]

I'm running a single S&S Super G carb (normally used on Harleys) on my 1500 race-Spridget. I'm limited to single carb for my car under our club rules. Homebuilt adapter and modded manifold.
It comes with an adjustable idle mix, and adjustable acel-pump and can be fitted with an adjustable main jet. Simple butterfly with minimum venturi restriction gives over 2" of straight-through barrel diameter. Around $200 USD. I can get it to idle sort of OK, but it's really good at higher speeds. My car rarely runs under 5000 RPM, so low-end power doesn't matter.
The first picture shows the result of a loose stud in practice. For the subsequent race, I had to use a vise-grips to hold everything together (safety-wired or course). The second picture shows the complete kit (I only bought the carb).

 

[Ab Crevoiserat]

You might want to take a look at this web page https://www.prirace.com/homepromo2.htm I know he is into Triumphs but he could have some helpful info for you