Sputters from 3 to 6000

[scp616]

I traded a friend a fourwheeler for a 96 GSX 600F that hadn't been run in 2 years and I just got it running on all 4 cylinders. It's been fighting me the whole way but after completely disassembling the carbs and sonic bathing all the pieces it idles at an even temperature on all 4 cylinders. When it's below 3000 or above 6000 rpms it runs great, but it sputters and barely makes it from 3 to 6. It's got good spark and new spark plugs and 160psi compression on all 4 cylinders.
Any clue as to why it's acting the way it is?

Thanks,
Scott

[Kreylyn]

I traded a friend a fourwheeler for a 96 GSX 600F that hadn't been run in 2 years and I just got it running on all 4 cylinders. It's been fighting me the whole way but after completely disassembling the carbs and sonic bathing all the pieces it idles at an even temperature on all 4 cylinders. When it's below 3000 or above 6000 rpms it runs great, but it sputters and barely makes it from 3 to 6. It's got good spark and new spark plugs and 160psi compression on all 4 cylinders.
Any clue as to why it's acting the way it is?

Thanks,
Scott

3-6k is the transition with the needles, and heavily reliant upon the good and proper working condition of the emulsion tubes. Improper needle position settings, worn/damaged needles, worn/clogged emulsion tubes, incorrect float heights could all cause issues along those RPMs for your bike. If it's specific to an RPM range, and repetative, I doubt it's an issue with anything but the carb settings.

Any noticeable change between hot or cold running engine, or it just does it all the time?

Krey

[scp616]

Sorry about not replying sooner, It didn't email me to say there had been a new post.
I checked everything in the carbs, cleaned everything, replaced all the o-rings, and the float level appears to be fine. At that rpm range do you think it could need larger jets? It does have a K&N filter and a pipe.
It idles a little rougher when it's cold, but once it warms up it runs fine. As far as the 3000 to 6000 problem, temperature does not seem to affect it much.

Thanks for the reply,
Scott

[Kreylyn]

Sorry about not replying sooner, It didn't email me to say there had been a new post.
I checked everything in the carbs, cleaned everything, replaced all the o-rings, and the float level appears to be fine. At that rpm range do you think it could need larger jets? It does have a K&N filter and a pipe.
It idles a little rougher when it's cold, but once it warms up it runs fine. As far as the 3000 to 6000 problem, temperature does not seem to affect it much.

Thanks for the reply,
Scott

I would check this....

http://www.factorypro.com/tech/needle_jet_wear.html

Krey

[Pacerman]

I had the same issue on my 01 Kat 750. R2 K and N with stock air filter... Problem solved. Also you need to ensure proper carb settings and ensure they are synced.

My bike ran like crap(sorta) and was extremely cold natured until I put the stock air filter back in.

[scp616]

Found out what was wrong. Guess it was just running lean. Before I ordered a jet kit I made spacers to shim the needles up and it ran a whole lot better. So I ordered a jet kit today, hopefully that'll fix all the problems.

Thanks for the help,
Scott