Bike turns off after taking off choke / intermittent starting issues

[divlukic]

My electric start has been finicky so I've been using the kickstart primarily, my usual start-up procedure is to turn the gas on, turn the choke on, turn the ignition, turn the killswitch and then kick it over. It usually turns over in 1-2 kicks and then I'll disengage the choke after a few seconds, maybe turn up the idle screw a little if it's a little low and then ease it back out as the bike warms up.

The other night it turned on as usual, but would immediately die after disengaging the choke. I tried turning up the idle screw and then it'd idle very high with the choke on but still die immediately with the choke off. Then, it wouldn't start up even with the choke on for 10-15 minutes of kicking, eventually I let it idle long enough with the choke on and then disengaged and it stayed on long enough for me to get home. When it did start up again, I did hear some backfiring as well. Does anyone have experience with an issue like this or would have any idea how to begin diagnosing/fixing this issue?

 

[gggGary]

Drain the float bowls into a clean container.
If there's dirt, clean your pilots.

 

[Jan_P]

Electric starter problems can be weak power supply
No mention what year model ,or Ignition system
Some ignitions can behave randomly at voltage out of spec

I would start charge the battery and measure charging across battery once it has started
And measure battery voltage after a day or so. And after power up on switch how much it drops

 

[divlukic]

1978 650 special, stock ignition stock everything. I pulled the battery and charged it overnight and while it kicked over in much fewer kicks, it still needed to idle with the choke on for a few minutes and with the idle screw turned way up before it’d stay at a steady 1100ish rpm’s with the choke off instead of just flipping it off after a few seconds. Still heard some backfiring too

I just replaced the stator since I had issues with the battery not holding enough charge for more than a few days after a fresh charge and everything’s been fine in terms of ignition since replacing that a month or two ago up until last night when this problem started

 

[ThatXS650Guy]

If a bike won't run without choke I automatically pull the pilots and clean them. 99% of the time they are clogged.

 

[Jan_P]

A quick measurement of charging voltage across battery .Would be the first I did
I may be wrong here but it is very simple to do Can do it In a 3 piece suit and Not getting dirty hands
Just to be safe here

May well be the pilots .. but the CSF rule
Cheapest -- Simplest -- First

 

[divlukic]

A quick measurement of charging voltage across battery .Would be the first I did
I may be wrong here but it is very simple to do Can do it In a 3 piece suit and Not getting dirty hands
Just to be safe here

May well be the pilots .. but the CSF rule
Cheapest -- Simplest -- First

Can you elaborate a little on this? Are you saying I should charge the battery to full and measure it with the engine off and then with it on? What numbers should I be looking for, what will that indicate to fix? Thanks in advance for your help

 

[Jim]

A battery has no way of knowing if the choke's on or off.
It's been mentioned above... check your pilots.
If they're dirty (most likely), start backtracking and figure out where the debris is coming from.

 

[Jan_P]

A battery has no way of knowing if the choke's on or off.
It's been mentioned above... check your pilots.
If they're dirty (most likely), start backtracking and figure out where the debris is coming from.

Thank You Gentlemen.
That is true .but the mixture burns differently or not at all depending on if overly rich or lean.
A weak spark As in no charging ( and weak battery that comes with poor charging ) .May ignite one mixture and not ignite a richer one
Done it over the years .Out on the highway with no charging If careful with the throttle it can run a while on battery
Trying to give throttle it dies. I suppose by soot.

Maybe not read carefully
It may still be pilots Yes but is still very simple to measure charging across battery
Machine running . If measure please report the numbers at ca 2.5 k 3 k
Lights on.
The rotor or brushes can need service

 

[onkelheri]

Thank You Gentlemen.
That is true .but the mixture burns differently or not at all depending on if overly rich or lean.
A weak spark As in no charging ( and weak battery that comes with poor charging ) .May ignite one mixture and not ignite a richer one
Done it over the years .Out on the highway with no charging If careful with the throttle it can run a while on battery
Trying to give throttle it dies. I suppose by soot.

Maybe not read carefully
It may still be pilots Yes but is still very simple to measure charging across battery
Machine running . If measure please report the numbers at ca 2.5 k 3 k
Lights on.
The rotor or brushes can need service

if something like youre dicription happens suddenly, it cut be even loosing a manifoldsyncrocap, ift it is BS34 causes wrong air.
Bad Start after a breake might be condenswater get united to a little waterbubble wich hangs like a valveball in front of the nuzzleopening. Rinse the floatchamber with "white spirit" ... somtimes you also find a unscrewed Jet in the chamber ... ore if it is a BS38 the brassplugs at the chokehousing going lose!

greetz heri