maybe a vacleak?

[gsxkat1100]

Seems like I may have seen the answer before, but I can't find it on here. 90 kat 1100. Stock carbs and airbox. Fresh rebuild on the carbs and bumped pilots up to mik 50s. Yosh exhaust uni filter

For some reason, between 2&4k, the bike stumbles fairly badly and stalls. Got it out and couldn't get out of first. Any ideas?

[KAT TOY]

try a stock air filter

[gsxkat1100]

Unifilter would cause that much issue?

[gsxkat1100]

Holy camel toe Batman! $70 for a stock filter and $26 for a uni?

[DClark]

Unifilter would cause that much issue?

The UNI filter (I have an old one on the shelf somewhere) has a one big flaw- sealing. It uses a very narrow ring of foam to seal and it so narrow that it opens up the possibility of leaking. Doesn't matter how well it flows or if the carbs like or dislike it; that bad seal is enough to make me take it out and say "don't buy a UNI!".

[gsxkat1100]

Stock filter did nothing. Is there any way to sync a set of carbs without pulling the plugs on the carbs? Mine are seized up.

[KAT TOY]

sounds like a dirty pilot circuit. unless you can sync using a stethoscope you have to remove the caps. the stock air filter allows the proper restriction needed for the CV carbs.

[Wild-Bill]

I'd be pulling the carbs, cleaning them and taking a vise-grips to those sync plug screws. Agreed that a UNI filter isn't going to be well liked by the engine but even replacing that won't do you much good if the carbs aren't synced and the pilot circuit isn't clean.

[gsxkat1100]

I just pulled the carbs, dipped them in the good chemical dip, and cleaned the crap out of the pilot orifices. Also installed new pilot jets I guess a good sync is the only option.

[DClark]

Not to sound too obvious, but take the pilot jets, eyeball them to make sure you see daylight through them, blow through them if necessary- these suckers need to be totally clean and open.

[Dr. Acula]

Pilots?

But by 2000-4000 rpm's wouldn't he be pulling through the mains? My first thought was to recheck all my work to see if I hadn't pinched something or pulled it loose.

[DClark]

But by 2000-4000 rpm's wouldn't he be pulling through the mains? My first thought was to recheck all my work to see if I hadn't pinched something or pulled it loose.

Somewhere in there will be the transition from pilot to main/needle. Somewhere above 5,000 rpm will be all mains. I forgot the ranges in the FP diagram, but they are not exact for all carbs, just approximate.
Also, pilot are always in play, just their % of play decreases in the upper range.

[Dr. Acula]

Are they?

Once the throttle plate moves away from the bore I would think that you would draw zero from that circuit as in any idle / off-idle circuit. He did not mention if he had just added that exhaust. He may have to play with main jet, needle clip slots etc...No?

[gsxkat1100]

Needles are in slot 3 for all 4, should I move them up or down? Never had to mess with that stuff. Maybe this is why the bike sat abandoned for 5 years before I got it.

[Dr. Acula]

What happened when?

When did the Yoshi exhaust come into the picture? Did you just add it and that's when the problems started? You want to move the needle up, luckily that can be done without a lot of bloodshed. Perhaps you could contact Yoshimura and see what their recommendations were for jetting when adding that exhaust. I guess that's maybe the only thing nice about the modern stuff is changing things with just key strokes, rather than taking things apart a dozen times before you get the scratch itched. But if you're on here you probably love the old stuff, it's an illness we share.