Katana carburator questions

[robinjo]

Had the bike on the Dyno bench the other day just for fun. Turns out it has 87.6 HP at the rear wheel but at about 7k rpm instead of 8500rpm as by factory specifications, after that it drops down to about 60hp at redline, operator says it's running rich at the topend and probably is jetted for a 4 into 1 pipe.

1981 Katana 1100 with stock Mikuni 34mm vacuum carbs, (black chrome) exhausts, box and filter. I have the carbs apart for cleaning and adjusting and it has 107.5 main jets, not sure if these are the correct ones, sounds small to me. Don't have a way of measuring them but they seem to be bored out to a larger size. Will replace them to be absolutely sure.

Anybody has a manual with the jet sizes and float hights?

I know I'm doing things backwards, tearing into the bike without a manual but it started with taking of the fairing to get to the little nut to attach my new "winglet" that I recieved and ended up with my carbs in a million pieces on the table 8O :roll: Manual is on order, don't know how long it will take to get here...

[daveo]

No problem Robin,
main jet- 107.5
float height- .88" +/- .04"
main air jet- 1.2 mm
jet needle- 5D58
needle jet- X-1
pilot jet- #45
starter jet- #32.5

[robinjo]

Thanks Dave! \/

This is what is meant by main air jet right? Mines are stamped with 160 so that means they are 1.6mm. Could this be (part of) my problem with a erratic idle? Doesn't idle when cold and wonders around when warm.



I'm in the proces of cleaning them right now, including all the little passages with carb cleaner, gotta find something to poke through some little holes though.

[daveo]

Thanks Dave! \/

This is what is meant by main air jet right? Mines are stamped with 160 so that means they are 1.6mm. Could this be (part of) my problem with a erratic idle? Doesn't idle when cold and wonders around when warm.
I'm in the proces of cleaning them right now, including all the little passages with carb cleaner, gotta find something to poke through some little holes though.

Yes, that could be the problem, try using a piece of nylon fishing line or leader, or maybe a hair brush bristle, just don't use anything harder than the jet itself, as you don't want to booger it up