Carb Issues

[SteveD]

Hey guys - throttle adjust screw is on the bottom - I was right about that one. Can't see it in your picture. I can see the vacuum take off screw (just a blanking screw), the mixture adjustment jet/screw, the pilot jet/screw and the main jet. The throttle arm is there, but I can't see an adjuster screw underneath the carb. I was confused about the idle stop - it is at the end of the cable linkage (duh!) on the inside (engine side) of the carb facing upwards. I have the 32mm flattop. It reads like you're calling the throttle adjust screw the idle stop? Is this just a difference in naming of the parts?

Anyway, I've gotten the left side working nicely. The right side is running okay with the choke set, but as I slowly let the choke out it starts to backfire and die. It even wants to backfire once warmed up with choke on. What gives?

Have a read here...http://rossmz.blogspot.com.au/2008/12/t ... r-bmw.html including the comments at the end re free play. I hope it helps. It should essentially be the same despite 32 v 40 and the flat v domed tops.

[barryh]

Hey guys - throttle adjust screw is on the bottom - I was right about that one. I was confused about the idle stop - it is at the end of the cable linkage (duh!) on the inside (engine side) of the carb facing upwards. I have the 32mm flattop.

Anyway, I've gotten the left side working nicely. The right side is running okay with the choke set, but as I slowly let the choke out it starts to backfire and die. It even wants to backfire once warmed up with choke on. What gives?

I'm confused about where you found the throttle stop screw but as long as you found it that's all that matters.

Don't expect the chokes (enrichers) to work flawlessly on 79 flatops. They can be OK for a cold start but not much use when the engine is running. If yours haven't already been done there was a service bulletin modification which makes them work better either by replacing the disc with a later type or modifying the existing one to drill a 4th fuel hole and to enlarge the counterbores on each of the 4 holes. It's a tricky job though involving a 0.6mm drill bit that is so small you can hardly see it. Made a huge difference to my enrichers so highly recommended if it needs doing.

Enricher disc mod.png (103.22 KiB) Viewed 888 times