Won't run without choke

[simmeth]

Ok. A little background information first. '93 Kat 600, under 12k miles, hasn't been ridden for a year or two. Gave bike an oil change (new filter) and new plugs. I also siphoned out the stale gas and put fresh gas in the tank. I can not get the bike to start unchoked. I took off the air filter and used some starting fluid to get it started at first while choke was on... and after a little bit of spraying, the bike stayed running on its own after a few stall outs also. If i take the choke off, it dies right away. Has anyone experienced this problem or know right off what it could be?

Thanks..

[suzukisportrider2004]

sounds like dirty carbs

[simmeth]

Anyone have any suggestions? Gonna try carb cleaner tomorrow, anyone tried that before? results?

[steves]

Probably junk in the idle circuit, maybe the idle is set too low.

[The CyberPoet]

Didn't I answer this question just a day or two ago?

First, let's look at what's going on:
At idle, the carbs are unable to pull sufficient fuel to keep the engine running by themselves; using the choke (actually an enricher circuit on the Kats) adds more fuel to the mixture from a secondary circuit and provides the engine the spare fuel it needs to run at idle.

Now let's diagnose the problem:
The idle jet passages are clogged (probably with dried fuel residues), thus preventing the carbs from pulling sufficient fuel up through those passages at the low vacuum level available at idle.

Now lets look at the fixes:
There are a couple fixes. The simpler one is to add a stout fuel system cleaner to the fuel, and run the engine to pull it into the carbs, then let it sit, followed by riding, followed by parking overnight, and then suck the rest through the next day by riding. Usually one tankful will give you either total relief, or at least significant improvements.

The second method is manually cleaning the same passages in the carbs, using a parts cleaner bath, spray carb cleaner, a nylon bristle (some older bike guys will say a piece of wire; I recommend stiff nylon because it will not scratch up the existing metals or deform the openings because it's simply not strong enough to do so). This is also the only fix that will work if there is physical debris in the carbs, such as rust particles from the gas tank.

Cheers,
=-= The CyberPoet

[md86]

Re: Won't run without choke

hasn't been ridden for a year or two.

Yeah , you'd be pretty lucky if an in-the-tank treatment works .....