Howdy all,

I have been having issues with my GS not wanting to cold start. The choke appears to be useless and does nothing to aid starting. This issue has been with the bike since I inherited it a couple of months ago. Once running the engine starts and stops as normal, but if left overnight the bike takes forever to get started again.

I have removed the carbs, cleaned them out and replaced the needles, main jet, pilot jet, idle air screws and the needle and seat in the float bowl.

Main Jet = 140
Pilot jet = 40
Needle has 1 washer under E clip
Idle air screw was trialled at 2 turns out didn't start at all
Idle air screw was trialled at 3 turns out eventually starts and runs
Idle air screw was trialled at 4 turns out eventually starts took longer than 3 turns out and runs fine.
I have also fitted the K&N lunchbox pod filter, I put the original airbox back on and it made no difference to the starting.
The only other mod I have completed is the ignition advancer, but it makes no difference to the starting when I return the advance to standard.
I have fitted a carby balancer and adjusted the carbs to be within sync.

I am in Brisbane Australia not that much higher than sea level.
I was wondering if there was something else I could check?
Does anyone know of an issue with the choke circuit on the early BST33SS Mikuni carbs?

Once the bike is even mildly warm the engine starts and stops normally. Engine idles smoothly at approximately 1200rpm and the engine note sounds crisp and direct when warmed up. Exhaust temps are still a little bit out LH side 280 deg Celcius and the RH side is 270 deg Celcius. But still close enough that it should start and run when cold.

Cheers
Rufftoy

Stock pipe and K&N is a disaster, but your starting issue isn't the pipe. I'd check float height and check if the pilot is clogged again. The modern gas makes all these things clog up easily.

Cool.
Buddha.

Cheers Budda, will recheck float hights.
Have you ever disassembled the choke circuit?
Is there a way to strip those parts as well?
I have access to an ultrasonic parts cleaner should I strip the carbs and clean them in that? will it hurt anything?

Cheers mate

The choke plungers can be removed, but likely isnt your problem. Choke closes off 1 air passage and makes the bike suck through another which directly leads to the pilot jet. Air passages getting clogged happen when your bike or carbs are left in a pile of mud (dont laugh, I've cleaned atleast 1 carb that was) Not when it was just parked. The clean with some type of solvent cleaner is usually a recipe to get dirt out of one spot and into another sometimes. If you have cleaned it already, just open and look in the pilot jet. The dumbest thing suzuki did was the 3 jet carbs, those were fitted with even smaller pilots like WTH, we clog a 40 pilot sitting higher up in the float so much, they decided to put a smaller 20 in and sat it deeper down. Sorry 37.5 and 17.5 but same deal.
Cool.
Buddha.

hows the sparkplugs? what type are they, it could be them or float height..

Spark plugs are about 2000kms old. I have made sure the gaps are within spec. Plugs are DPR8EA NGK. Plugs are quite clean not fouled and don't appear to be getting too hot. Float height was 14.1mm from where gasket seats to to of float on both.
Cheers
Eddie

No point unless you've checked exhaust valve clearance.

Ok, thanks all for the assistance. I finally got the carbs cleaned in an ultrasonic cleaner and back together. I noticed prior to cleaning that there was a blockage in the orifice at the base of the float assembly. I suspect that this blockage was the cause of the choke not working on cold starting. Once cleaned the bike now starts with full choke and once warm idles as it should.