Mk2 8v on Bike Carbs, annoying problem.

[DreXeL]

Ok, I've just finished my build, basic spec is:

2E 2.0 bottom end
Crossflow head (with necessary mods)
Newman 272 camshaft
Home made inlet manifold
R1 Carbs with 165 jets to start with (have 170s and 175s if required) fed by an R1 fuel pump.

Basically the engine will start and run, but after it's warmed up a bit it'll just cut out. I can then start it again and it'll run for like 10-20secs then die again. It doesn't splutter or cough, it just dies completely.

Any ideas?

[DreXeL]

Forgot to mention, the problem seem unrelated to the choke as it does it weather the choke is engaged or not.

[DreXeL]

Anybody have any ideas?

To feed the carbs I have the stock fuel feed and return in the engine bay connected to a t-piece, which in turn is connected to the R1 pump. The car is a k-jet, I'm not entirely sure how the standard setup works but it's acting as if the stock fuel pump is shutting off, perhaps this is because the k-jet system has been removed and it's not getting any 'feedback'? How can I 'trick' the stock fuel pump to never shut off if that the case? Or am I barking up the wrong tree? 

[Wayne]

I don't think the stock fuel pump will work, I would say you need to swich to a standard electric pump from someone like facet.

[DreXeL]

There's no reason it shouldn't work though, carbs don't need anywhere near the pressure of fuel injection, hence the t-piece setup. I just want to know if the stock fuel pump switches on and off as needed with the standard k-jet setup, and if it does how can I make it stay on all the time?

[danny_p]

loose the injection pump you only need the lift pump,   t off that line to feed the carbs but place a restriction in the return line to the ank so you get a couple of psi at the carbs.

if you think it's a fuel pump run issue  just take the relay out and bridge the contact terminals  with a short pice of wire with a spade connector at ether end pushed in  to the fuse box.

[bvr]

Bike carbs can only handle up to 3 psi of fuel pressure, so are better off run with only the standard bike fuel pump, which itself pushes fuel better than it pulls, so should ideally be mounted close to the fuel tank. ( Fraid im no expert, this info is shamelessly stolen out of an article in Classic Ford!!)

[mwep201081]

Ok, I've just finished my build, basic spec is:

2E 2.0 bottom end
Crossflow head (with necessary mods)
Newman 272 camshaft
Home made inlet manifold
R1 Carbs with 165 jets to start with (have 170s and 175s if required) fed by an R1 fuel pump.

Basically the engine will start and run, but after it's warmed up a bit it'll just cut out. I can then start it again and it'll run for like 10-20secs then die again. It doesn't splutter or cough, it just dies completely.

Any ideas?

How long do you have to leave it before you can start it back up after it has cut out? Sounds electrical to me.

[danny_p]

Bike carbs can only handle up to 3 psi of fuel pressure, so are better off run with only the standard bike fuel pump, which itself pushes fuel better than it pulls, so should ideally be mounted close to the fuel tank. ( Fraid im no expert, this info is shamelessly stolen out of an article in Classic Ford!!)

thats why you use the std fuel lift pump out of the car. with a return line thats slightly restricted, or remove the gti lift pump and fit one from a carbed car  then the fuel pump from the bike can be used  but somtimes they refuse to lift fuel when the tank is low as they themselves are soposed to be fed fuel under gravity

[DreXeL]

Bike carbs can only handle up to 3 psi of fuel pressure, so are better off run with only the standard bike fuel pump, which itself pushes fuel better than it pulls, so should ideally be mounted close to the fuel tank. ( Fraid im no expert, this info is shamelessly stolen out of an article in Classic Ford!!)

I'm using the standard R1 pump for exactly that reason, the standard GTI pumps are feeding the R1 pump through the t-piece.

How long do you have to leave it before you can start it back up after it has cut out? Sounds electrical to me.

It'll start straight back up then run for a bit then die again. It runs for a shorter amount of time before cutting out each time I re-start it until it won't start at all. I then have to leave it for a while before it'll start again.