Topic: 400 trouble

[Fred T]

Hello, Im having an issue while ridding the bike, after about 10min the engine seems to flood or feels as it is running on two cylinders for about 30 seconds and then it will run fine again. This failure happens many times while ridding.
Any idea what could be causing this before I disassemble the carbs? I have drained the bowls and fuel seems fine, petcock filter is clean and also used sea foam to clean any possible dirt.

[denward17]

Are you sure it is flooding?  See any signs of leaks or overflow?

Check your fuel tank vent, check your spark plug color.
Getting spark to all 4 plugs?

[Fred T]

No leaks or overflows, the bike runs great until that happens. Will check later the tank vent and spark plugs.
Thanks

[bryanj]

More likely electrical than carbs from description

[Tim2005]

Are you running points or electronic ignition? I have had similar problems with electronic ignitions in the past

[HondaMan]

To check if the fuel tank's air vent is [rusted] closed or nearly so, just pop the gas cap loose every few minutes while riding and then close it again. If this stops the trouble, then the little air vent in the gas cap is rusty and sticking closed a little bit. A new gas cap (or a complete refurbish, though without the right tools) will fix it.

[Fred T]

Are you running points or electronic ignition? I have had similar problems with electronic ignitions in the past

Running with Dyna S electronic ignition

[Fred T]

Are you running points or electronic ignition? I have had similar problems with electronic ignitions in the past

Running with Dyna S electronic ignition

Will try thanks

[Fred T]

To check if the fuel tank's air vent is [rusted] closed or nearly so, just pop the gas cap loose every few minutes while riding and then close it again. If this stops the trouble, then the little air vent in the gas cap is rusty and sticking closed a little bit. A new gas cap (or a complete refurbish, though without the right tools) will fix it.

👍

[HondaMan]

Are you running points or electronic ignition? I have had similar problems with electronic ignitions in the past

Running with Dyna S electronic ignition

Argh...try taking off the points cover and taking it for a ride. If the Dyna triggers are dying (like both of my old Dyna S units did) they act much like that. If taking the cover off lets you ride just fine, or a lot further before acting up, they are in trouble.

[scottly]

 check your spark plug color.

1+

[bryanj]

I have read on here of several dynas failing that way

[Fred T]

Crédit to Hondaman and bryanj, right on the money with the Dyna S , went to the old points and problem resolved.

[newday777]

Crédit to Hondaman and bryanj, right on the money with the Dyna S , went to the old points and problem resolved.

👍

[scottly]

Hey Fred, what are you going to do with the dead Dyna S ignition? I could use it for a science experiment.