CBR250R heart transplant, now won't run

[nodrog:Me]

how do you know the transplant motor is good?

[nzspokes]

how do you know the transplant motor is good?

How do know its not?

[kiwi-on-wheels]

Tried start yah bastard, no joy.
Firing order is correct, coils are good.
Plugs were dry, will try a bit of fuel down the neck Sunday.

The frustrating thing is that it ran fine before it came out of the old frame. Started easily, revved clean, fuel is fairly fresh, line filter is clean and can confirm theres plenty of flow, theres good spark, and atm im cranking it from a car battery, so that takes care of the weak start, its a 550cca grunter with a solid charge on it.

[nodrog:Me]

How do know its not?

well it doesn't fuckin work for one.

[kiwi-on-wheels]

Both motors start and run. The motor that came out had a toasted head gasket, the one gone in is a minter. Nice and quiet too. Had it running, took it for a ride before the swap, felt a lot happier than the one its replacing

[nodrog:Me]

Both motors start and run.

no they don't.

[kiwi-on-wheels]

They did before they were removed from the frames.

Which is why I dont get it, both motors were in running condition before they were swapped between frames, why the hell arent they working now

[nzspokes]

Have you ensured fuel flow to the carbs? Is the choke stuck open? How have you proven spark?

[kiwi-on-wheels]

Yep confirmed fuel flow to carbs, refills the float chambers happily. Needles are clean, smooth operation. Jets are clean.

Choke operates smoothly

Spark proven by holding a spark plug in each lead against the head, every lead and every plug has spark. Not a big fat blue one, more a softer yellow arc.

More earthing / more robust path to earth required perhaps?

[eldog]

Yep confirmed fuel flow to carbs, refills the float chambers happily. Needles are clean, smooth operation. Jets are clean.

Choke operates smoothly

Spark proven by holding a spark plug in each lead against the head, every lead and every plug has spark. Not a big fat blue one, more a softer yellow arc.

More earthing / more robust path to earth required perhaps?

Earth via frame? Or direct.
fuel in cyl not just carb.
air flow? Should have some air/fuel mix when turning over when plug out
Timing?
just thinking of things you might have dislodged/loosened when you installed it into bike.

[kiwi-on-wheels]

Earth via frame? Or direct.
fuel in cyl not just carb.
air flow? Should have some air/fuel mix when turning over when plug out
Timing?
just thinking of things you might have dislodged/loosened when you installed it into bike.

Earthed to engine casing. Which is Earthed to the battery through the starter motor earth.
Fuel is in cylinder as the plugs had a touch of wet when I pulled them out.

However, if I hold my hand over the spark plug hole and crank the bike, I dont get any fuel out of the hole.

Timing is via a cdi trigger wheel which has a keyway attachment to the end of the crank, no way it can be out.

[nzspokes]

Fuel is in cylinder as the plugs had a touch of wet when I pulled them out I dont get any fuel out of the hole.

Thats a problem. On a cold start it should be well wet. When turning over there should be a good mist coming out the plug hole.

Again try fuel down the plug hole.

[tigertim20]

Tried start yah bastard, no joy.
Firing order is correct, coils are good.
Plugs were dry, will try a bit of fuel down the neck Sunday.

The frustrating thing is that it ran fine before it came out of the old frame. Started easily, revved clean, fuel is fairly fresh, line filter is clean and can confirm theres plenty of flow, theres good spark, and atm im cranking it from a car battery, so that takes care of the weak start, its a 550cca grunter with a solid charge on it.

how can you confirm plenty of flow if the plugs are dry?.

[eldog]

Flow into carb not necessarily into engine

[kiwi-on-wheels]

What would prevent flow from carb to motor? Jets are clear, plenty of vacuum.

Will drop thimble of petrol down each throttle body and try that way.

Definately not getting a fine mist

I do however have the carb boot rings loose as the carbs have been on and off so much, might tighten those up and give that a go