First long run, ends in confusing. (carbs)

[jimbob35]

Only been riding a week or two, bikes been running good. Today I did my first long run (for me!) which was about 100 miles, at the end of the journey the bikes idle was extremely low and after a few seconds it would stall.

I increased the idle screw which kinda fixed it, it was ideling ok but if i revved the engine it would hang at 2k for about 20 seconds then return to ~1k idle.

i increased the screw again and it would hang at 4-5k for about 20 seconds then return to -1.5k idle.

if i reduce the screw it begins to stall...

I've got redex fuel treatment in the tank, at the stated dosage.

Any ideas oh wise ones?

[kevin2502000]

You may have just gotten some bad gas. I would run the next tank with some seafoam and hope that clears it up. Otherwise you may need a carb cleaning. I think when you increase your idle and it "hangs" there, that is the actual rpm if your idle circuit was clean. I bet its dirty so in actuality you are setting your idle too high but it is only registering after you rev it.

[The CyberPoet]

Hanging idle can be:
an overly tight throttle cable (with the engine off, turn the bars all the way to the right, open the throttle wide and release -- did you hear a distinctive click? If not, the cable(s) are too tight).
A minor vacuum leak (when it does idle down, is the idle perfectly stable, or does the needle bounce over a 25+ RPM range?).
Bike overheated. As the fuel gets too hot, it vaporizes (boils) in the fuel bowls, esp. once you're standing still. If it doesn't do it after the bike cools off, you've found your culprit.

Cheers,
=-= The CyberPoet

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[jimbob35]

Thanks for the replies, i'll do some checks tomorrow..

If overheating is the problem, how exactly do i remedy this? It has plenty of oil, there was no waiting in traffic and ambient temp was ~18oC

[The CyberPoet]

Combating overheating Kat engines:

(1) Highest gear feasible, move over 20 mph, keep moving -- i.e. 40 mph in 5th or 6th instead of 3rd will cool the engine down better. This is especially true if you have the five degree ignition advancer installed (which really boosts heat production in 1st through 3rd gears).

(2) Higher vapor-temp oils. Mobil 1 motorcycle products have the highest vapor temp of any motorcycle oil I've ever found (above 500 degrees F).

(3) Increase your oil volume to the maximum permitted (more oil = more time before any specific bit of oil goes back up to the head again to get cooked again). Also clean and check your oil cooler, make sure the fins are straight for good air flow & not covered with grime/dirt/debris/bugs that can reduce the efficiency. Optionally, upgrade to a bigger oil cooler.

(4) Richen up the carb mixtures by increasing the pilot screw settings & shimming the needle or installing a jetkit (like an Ivan's). A richer engine runs cooler than a lean one by a wide margin.

Cheers,
=-= The CyberPoet

______________________
CyberPoet's KR Specials
SuzukiStratosphere.com - 6 Cylinders, wet dreams...
The Best Motorcycle Tire Valves in the World, plus lots of motorcycle & Katana (GSX600F / GSX750F) specific help files.

[jimbob35]

Changed the oil and filter earlier, used castrol 1 fully synth for superbikes. (expensive!!) Worked a treat, i did the same journey again but this time with no problems!

It must of been overheating with the cheapy basic oil from the garage it got serviced in last.