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CB350/400 / Still carb troubles
« on: September 04, 2023, 06:15:31 PM »
Back in February I posted saying I think I'd sorted my troubles with carbs not shutting down . In April I went for a Boyer electronic ignition complete with micro coils and I still have the same problem with the carbs !
There's quite a long time between posts because my wife was very ill with lung cancer and sadly passed on 30th June , so shed time was the last thing on my mind!
However one of her last wishes was "Get that bl##dy bike sorted!" So I'm now back in the mood to try and sort it.
From the top :-
Boyer fitted and bike starts/runs. Using a timing light its correct.
Tappets adjusted.
Have to fiddle with idle adjuster to set at 1200rpm .
Idle mixture screw set at 2 turns out.
Plugs very sooty
Open throttle and revs soar and doesn't drop back to 1200rpm when released. Have to fiddle with idle adjuster to bring back down.
Sprayed carb manifold connectors to barrels with Carb cleaner and no effect , so not drawing in air, better not they're new - good
Remove carb tops and sprayed carb cleaner in but slides don't appear to be sticking either.
I've noticed that if you press the top of brass hexagonal nut on the carbs this will reduce the revs but too hard and it stalls FWIW.
Prior all carbs stripped, ultrasonic cleaned, carb cleaner on jets with jet brushes etc etc retaining original brass and new seals from NJ.
Bench synced at least twice.
Standard air box and new air filter
I've no idea what to do next! I have an old lawn mower, never serviced, starts first time every spring, think I'll put engine from that in instead.
To me it's pretty obviously carb related, (I think ) as there is good spark and timing is ok. Not got to the stage with setting Boyer to full advance yet which requires 4500rpm as revs all over the place.
Cheers peeps!
There's quite a long time between posts because my wife was very ill with lung cancer and sadly passed on 30th June , so shed time was the last thing on my mind!
However one of her last wishes was "Get that bl##dy bike sorted!" So I'm now back in the mood to try and sort it.
From the top :-
Boyer fitted and bike starts/runs. Using a timing light its correct.
Tappets adjusted.
Have to fiddle with idle adjuster to set at 1200rpm .
Idle mixture screw set at 2 turns out.
Plugs very sooty
Open throttle and revs soar and doesn't drop back to 1200rpm when released. Have to fiddle with idle adjuster to bring back down.
Sprayed carb manifold connectors to barrels with Carb cleaner and no effect , so not drawing in air, better not they're new - good
Remove carb tops and sprayed carb cleaner in but slides don't appear to be sticking either.
I've noticed that if you press the top of brass hexagonal nut on the carbs this will reduce the revs but too hard and it stalls FWIW.
Prior all carbs stripped, ultrasonic cleaned, carb cleaner on jets with jet brushes etc etc retaining original brass and new seals from NJ.
Bench synced at least twice.
Standard air box and new air filter
I've no idea what to do next! I have an old lawn mower, never serviced, starts first time every spring, think I'll put engine from that in instead.
To me it's pretty obviously carb related, (I think ) as there is good spark and timing is ok. Not got to the stage with setting Boyer to full advance yet which requires 4500rpm as revs all over the place.
Cheers peeps!