Bike won’t start. I’m about to cry

[MikeyVeitch]

I can’t get my 1100 swapped bandit to start. Just to start I’d say there’s nothing wrong with the motor. Because it was running lovely 2 hours ago. 
CDI is good. 
coils are wired in correctly. 
got fuel. 
got spark. 
Turns over more than fast enough. 
Just no bang

Honestly any suggestion would be a great help because I really have no clue anymore. Some days I press the button and it starts. Some days I have to bump start it. Some days that won’t even work.  

[TonyGee]

fit new plugs

[MikeyVeitch]

Got new plugs today

still no luck 

Edited March 6, 2023 by MikeyVeitch

[TonyGee]

5 minutes ago, MikeyVeitch said:

Got new plugs today

still no luck 

are the plugs getting wet ?

[MikeyVeitch]

Yeah new plugs are getting wet

Nothing wrong with the carbs balanced them last time it was running but I’ve got 45 pilots 145 main jets mikuni bst36 carbs, k&n pod filters and an 1127cc block

[TonyGee]

I'd be checking the airbox if it has one ? found a rag in a customers airbox once 

must learn to read better !!!!  it hasn't got an airbox 

Edited March 6, 2023 by TonyGee

[no class]

plug wires on the proper plugs 1-4/2-3 ? how about the petcock ? diaphram good ? needle and seats ?  float height ?  how many plugs are wet ? 

Edited March 6, 2023 by no class

[inmate]

Had a similar problem with my old Gs, sometimes would start on the button, sometimes had to bump it, mostly wouldn’t start. turned out to be a knackered starter motor magnets, replaced with a second hand starter and all good so far. Oh, and an extra earth lead.

[davecara]

Have you changed your ignition barrel?

[Dezza]

Could some cack have made its way into the carbs and then clogged up any of the choke circuits?

[TonyGee]

or has it been in the rain and water has got into the tank ? 

[Rijko]

15 hours ago, MikeyVeitch said:

 Some days I press the button and it starts. Some days I have to bump start it. Some days that won’t even work.  

This issue needs to be sorted : you may solve your current issue doing so ..

That's not a wise crack - the GS family is known to have bad connections.
Low voltage due to bad connections does impact power supply to igniter and coils.
The issue is really common ... you should really check your connections.

If the starter relais and starter engine do not engage when pressing the button, you may have dirt or corrosion
inside the RH handlebar switch.
12V to igniter and coils also come from that switch.
 

[MikeyVeitch]

Tank has been completely flushed. Carbs have been professionally restored. 
new spark plugs and coils wired in and plugged in correctly. 
Stator is working as it should. 
exhaust has no blockage. 
Engine ground cables have been replaced. 
Ignition barrel has not been replaced since well before the problems started. 

[davecara]

Little things like the ignition pickup (little red plug) not been rewired on bullet connectors and connected back to front?

If youve got spark and the leads etc are good it must be fuel related. Will it fire on brake cleaner/carb cleaner/lynx africa?

[MikeyVeitch]

I’ll try a bit of brake cleaner tonight. The confusion to me is that I’m certain it’s wired correctly because I just started it and it ran 10000% perfect. But now when I try to start it it’s just cranking over. 
Probably a fuelling issue.

[davecara]

Sounds very much like a fuelling issue, possibly your plugs have gotten wet, in which case you'll want to leave them a while to flash off, also a possibility the tap isnt providing fuel to the carbs? tap set to PRIME or ON? I've had a tap close itself under vacuum before now

[Dezza]

2 hours ago, davecara said:

Little things like the ignition pickup (little red plug) not been rewired on bullet connectors and connected back to front?

If youve got spark and the leads etc are good it must be fuel related. Will it fire on brake cleaner/carb cleaner/lynx africa?

I did not know Lynx Africa and carb cleaner were interchangable. I'll tell my son when he comes home as the carb cleaner smells a whole lot better.

 

Try drying the plugs with a blow torch and putting them back if possible when they're still warm, hot even (takes practice).

[davecara]

7 minutes ago, Dezza said:

I did not know Lynx Africa and carb cleaner were interchangable. I'll tell my son when he comes home as the carb cleaner smells a whole lot better.

I normally have a few kicking around after the festive period, smells awful but cleans stuff quite well!

[no class]

easy stuff first !  unplug the fuel hose from the petcock ( while in the ON position)  if it leaks …. diaphram and spring kit .  if the needles and seats are worn and leak …. it will gradually let fuel into the intake tract and into the motor . pop off the oil filler cap … put your nosey by the fill hole and get a good sniff …. if you smell petrol …. you have a problem . 

[Joseph]

has the vacuum pipe to the petcock been pinched/partially pinched by any chance ? 

[bluedog59]

If I've got this correct,

It always spins over on the button , sometimes it starts, sometimes not. Bumping it gives the same results.

It always shows a good spark when you test it.

When it does start it runs fine.

I'd be looking at the fuel systems that are in use at starting rpm. Airscrew settings, everything involved in the choke circuit and float height.

Edited March 7, 2023 by bluedog59
Typo.