TOPIC:

Updating my setup. It runs so good with this setup and needle change I cant hardly stand it.

air filters K&N RU-0984 (pods)
Pilots 40 1.5 turns out
Mains 135 (cylinders 2 and 3)
Mains 132.5 (cylinders 1 and 4)
Needles 5ix11 set on clip 2 from the top (these are readily available and have 5 clip positions)
elevation 500 ft.

getting the carbs synced is no minor task but well worth spending time to get it right. FYI I worked down from a rich condition on Pilots (started at 45) and Mains (started at 140) and worked the stutter out of the WOT.

The yamaha 5ix11 needles IMO are definitely the ticket. Started on clip 3 from top and moved to 2 from the top. This needle is very close to the 5GX29 a 5 clip adjustable needle used in the KZ1100-A non-US models. The 5ix11 is readily available where the 5GX29 is not.

I post this info in case it helps someone else. My bike is the 83 KZ1100 Spectre with the original carbs. I will take it to the dyno soon to determine how close it is.

G'day,

Have just spent the last couple of day trying to resolve a major problem with a customer's GSX1100.

It idled nicely and pulled hard through the mid-range but WOT made it run rich enough to spit black smoke like a diesel truck. We tried main jets from 112.5 down to 90s but there was no difference.

The stock Suzuki BS34 carbs were NOT fitted with the pilot jet plugs when the bike got to me. When I eventually got hold of a set of the plugs and fitted them, the GSX ran perfectly.

After what I've just seen, it'd be pretty obvious if the pilot jet plugs were required but missing.

Wondering if the bike was set up with a non Mikuni set of jets,like Dyno-Jet, which uses a completely different # for flow rate? This might explain both the adjustable needles and the larger # for mains.
Be sure the bike is not starving for fuel at WOT, filters, petcock screen, screen above float valve, tank vent, float height/ fuel level as well as float drop.
then there is always the ignition, be sure of the quality there, measure the spark, how far will it jump a gap etc. Timing and advance is correct. Make sure that you Don't have resistor plugs, and only resistor caps, no suppression wires with caps.

Nitro Mick wrote: G'day,

Have just spent the last couple of day trying to resolve a major problem with a customer's GSX1100.

It idled nicely and pulled hard through the mid-range but WOT made it run rich enough to spit black smoke like a diesel truck. We tried main jets from 112.5 down to 90s but there was no difference.

The stock Suzuki BS34 carbs were NOT fitted with the pilot jet plugs when the bike got to me. When I eventually got hold of a set of the plugs and fitted them, the GSX ran perfectly.

After what I've just seen, it'd be pretty obvious if the pilot jet plugs were required but missing.

Over at GS Resources site this very same topic has been discussed many times, and they share your same outcome, if you don't have those pilot plugs installed the engine won't run correctly. It's funny how so many people focus on selecting a correct main jet, when in my experiences it's the pilot jet and needle clip position that far more important for crisp street performance...

I asked the question over there but no one had the correct answer...

Working on Suzukis is a bit different to real bikes, ha ha