missing and shots a blue flame out the pipe

[kev1981]

i just got a 1994 gsx600f katana and it's missing i put new plugs in and drain the crabs but if u hold it at about 5 grand it misses and shots a 6" blue flame out the pipe and it sounds like it backfires through the carb any ideas? i'm thinking on crab isn't getting the right amount of fuel to the bike (not sure though) if anyone has any idea it would be great thanks so much kevin...

[md86]

Ever been jetted ? Maybe it wasn't done right .

[kev1981]

yeah, the guy how sold it to me said it was jetted!!
so how would i fix the problem? thanks kevin

[md86]

Well , I'm thinking a few things .....
Maybe the emulsion tubes are worn . Older bike , it could happen . Or the needles are way off . SOUNDS like it's getting too much fuel somewhere .

[The CyberPoet]

There are two ways to get it back to "reliable" that I know of if you have bad jetting:

1. Return it to absolutely stock. Most people use this as their last fail-safe option. Running stock is an easy way to find a "known good" solution.

2. Tweak it to spec. Take it to a shop that has a Dyno with an exhaust analyzer and have them tune the carbs. This involves changing jets, clip settings, etc. until it is fueling correctly across the whole range. The only problem with this is that if the problem is something else (debris in the carbs, bad spark, etc) it may not resolve your issue at all. If the only thing that's wrong is the jetting settings, this will cure it quickly and without heartache.

There are also ways of tuning it yourself, but it takes literally weeks or months of tweaking and can often cost you as much in spark plugs as you would have paid the shop in the first place (not to mention the hassles of repeatedly tearing your carbs down).

You haven't given us a lot of information to work with, so I won't assume it's necessarily just bad jetting without asking some questions:
(A) Have you check the gas tank for rust, old fuel?
(B) Drained the carb bowls?
(C) Replaced the spark plugs and fuel filter?
(D) Does the bike have aftermarket headers, muffler?
(E) Brand/type of air filter(s)?
(F) Has it ever run right for you in this RPM range?

Cheers,
=-= The CyberPoet

[ed]

6" blue flames?!?!? Wicked... why change that??

Just joking...sorry, I'm not helping. I hope what the guys told you helps.

[kev1981]

yeah i fixed it the carbs are all gumbed up from sitting for so long thanks guys for the help