Hi All,
Previously I had some backfires through the exhaust when I eased up on power or was going down through the gears. I sorted this out with retarding the timing.....or so I thought.
Recently on a drive the car started misfiring, down on power, bucking ect and when that cleared I was back to the backfires.
I quickly redid static timing, going to have a look at this again as it was a bit rushed with the time I had. I'm going to try and move the coil as it's in the firing line of the thermostat opening and it does get hot. Method used was per the 126 Haynes manual, rotor pointed at the engine for cylinder one, 13mm before tdc on the timing marks.
I also noticed fuel bubbling at the base of the carb once I'd shut down the engine, I have a new bakelite spacer to go on it so I'll fit this also. I sprayed some starter fluid at the base and the engine didn't rev up so I don't think air is being pulled in at the base.
So, what else could be causing the backfires on deceleration? Points gap perhaps?
How tight should the 10mm nuts at the bottom of the carb be and after a couple of heat cycles should these be tightened down again?
It's a 650 with a 28 carb running condenser and points and an old Bosch Blue Coil, I've read some horror stories about newer coils so I'm going to try and continue with the old one as it seems good.
I did notice some carbon burns on the centre of the rotor in the cap so I'm thinking my over all issue is spark/ignition. I am lacking a timing light so I'd be heavily reliant on static timing. Car is running and idling perfectly but it's when it's out on a run and things get hot that the issue becomes apparent.
Thanks all!
Gavin
Previously I had some backfires through the exhaust when I eased up on power or was going down through the gears. I sorted this out with retarding the timing.....or so I thought.
Recently on a drive the car started misfiring, down on power, bucking ect and when that cleared I was back to the backfires.
I quickly redid static timing, going to have a look at this again as it was a bit rushed with the time I had. I'm going to try and move the coil as it's in the firing line of the thermostat opening and it does get hot. Method used was per the 126 Haynes manual, rotor pointed at the engine for cylinder one, 13mm before tdc on the timing marks.
I also noticed fuel bubbling at the base of the carb once I'd shut down the engine, I have a new bakelite spacer to go on it so I'll fit this also. I sprayed some starter fluid at the base and the engine didn't rev up so I don't think air is being pulled in at the base.
So, what else could be causing the backfires on deceleration? Points gap perhaps?
How tight should the 10mm nuts at the bottom of the carb be and after a couple of heat cycles should these be tightened down again?
It's a 650 with a 28 carb running condenser and points and an old Bosch Blue Coil, I've read some horror stories about newer coils so I'm going to try and continue with the old one as it seems good.
I did notice some carbon burns on the centre of the rotor in the cap so I'm thinking my over all issue is spark/ignition. I am lacking a timing light so I'd be heavily reliant on static timing. Car is running and idling perfectly but it's when it's out on a run and things get hot that the issue becomes apparent.
Thanks all!
Gavin