1994 GSXF 600 carb balancing and idle tuning

[Omegasteve]

Hi all!

I'm very happy that I've managed to get the bike actually started and able to run to a degree. Now I've borrowed a CarbTune off of a very nice gent and set about balancing my carbs (GSXF600 1994). I have an issue that I can't seem to resolve though. I can get it to start (not reliably though) and then run but I cant get the idle below 2k rpm without it stalling. Each time it stalls it won't restart at all unless I use a very small spray of easy start.

Once it starts again it will once again happily run and rev, but only with the high idle.

Any tips on where to start?
____________________
1994 SUZUKI GSX600F project - 1997 Honda VFR 750

[stinkwheel]

It should start and idle acceptably well on standard settings and a static balance. The vacuum guages are for fine tuning.

Has it been off the road for a long time? Blocked pilot jets are a common issue. Latchy starting, and no low speed idle would be classic symptoms of one or more blocked slow running jets. They can even be dropping one or more cylinders at low idle.

I had the same on my VFR750 when I recomissioned it. Despite having meticulously cleaned the carbs and ultrasoniced/solvent cleaned and blown through the jets multiple times, it ran like a bagowank. Swapped in a new set of slow running jets and it fired up into a steady idle with a push of the button.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Omegasteve]

[stinkwheel]

https://www.cmsnl.com/suzuki-gsx600f-1994-r-e02-e21-e22-e25-e34-e53_model13665/jet-pilot325_0949232006/

https://www.ebay.co.uk/itm/275048108523

https://www.ebay.co.uk/itm/225023607860

https://www.ebay.co.uk/itm/311650848494

https://www.allensperformance.co.uk/carb-repair-kits-and-seal-kits-for-keihin-and-mikuni-carbs/
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[virus]

For the price of 4 brand new, unblocked and unworn pilot jets from allens performance its worth throwing some in just to KNOW its not that causing the problem.

Also when its running spray some wd40 etc on the carb to engine boots, if the idle lifts then you have an air leak on that boot. They can crack and deteriorate over time and an air leak would give you a high idle.
____________________
own: 81 xs1100g...
owned: 85 rat CG (sold), 91 GS500e (stolen), 84 gsx400f (scrapped), 81 z250 (siezed, siezed, scrapped), 83 cb250rs (sold), 84 gpz750r ratfighter (killed) 84gpz400 (sold), '80 cb650 ratfighter (wrote off) 95gsx6/12f ratfighter (killed) 91 xj900 (sold)
stinkwheel Well I just had my hands up a pigs fanny. Which makes your concerns pale into insignificance.

[jaffa90]

Have you tried restricting the airflow into the air box at the point off stalling to see if it makes any difference?
It`s the same as the old fashioned manual choke to speed up the air flow to pick up more fuel.

[Robby]

It certainly does sound the problem is too little fuel at idle. Have you messed around with the mixture control screws, because they should be what allows you to have a decent idle. On older vehicles it can help to give them an extra half turn out on top of whatever the manual recommends.

It is also old enough for rubber seals to start being a problem. Virus' suggestion of checking the inlet rubbers for leaks is a good one. Also worth checking around the throttle shaft seals. A butane pen torch can be more accurate than a can of WD40 for this diagnosis, and less messy.

If any of the rubbers are dry and expensive or impossible to buy, you can soak rubber parts in a 50/50 mix of wintergreen oil (an essential oil that also happens to have a real-world application) and alcohol. Makes them feel good as new.