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Discussion Starter #1
Guys,

My 1991 has a Yoshimura carbon fiber street system and a stock air cleaner.
Main jets are 140 Keihin. Pilot jets are 38. Jet needle is a NU60. All stock. Jet needle has 2 shims. Mixture screws 2.5 out Bike gets great MPG the way I ride it. Pulls nice and hard wide open. In fact in lower gears it pulls even harder after 10,000 to 11,000.
Bone stock you would think it would flatten out after 10,000. Idles great. Bottom line I think it's carbed fine. This year I switched to a K&N. Think I'll have to re jet?

Thanks,
Joe
 

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Main Jets should be at LEAST a 2 size bump up, if not 3..... better fouled plugs, then a burned piston...

Let me guess, you have NEVER checked the color of your plugs, have you? :rolleyes
 

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Discussion Starter #3 (Edited)
Ya I have checked them.Looked normal with stock air filter. Sometimes slightly sooty. Ride pretty conservatively. Wind it up sometimes, mostly in lower gears. I'm in my 60s. Been riding since 1965
 

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Ya I have checked them. Looked normal with stock air filter. Sometimes slightly sooty. Ride pretty conservatively. Wind it up sometimes, mostly in lower gears. I'm in my 60s. Been riding since 1965
In fact in lower gears it pulls even harder after 10,000 to 11,000.
Really? You ride conservatively do ya now?? :squint :rolleyes :rofl

Im 57 and I havent hit 10-11k on my ZX11 yet..... (you looking to blow a rod or suck a valve first?), and my plugs arent sooty, they are TAN and Im running 160/162 Kehin main jets..... w/the jet needle raised 2 notches from bottom, (1 clip below middle).

The main jet size numbers vary with brand, though.. My pilots are also 38s with air screws out to 2.5 as well. STOCK EXHAUST. Drop in the K&N, which I am also running. Me thinks that will be close to the final touch to balance out the jetting, but it is a process of trail and error with each engine...
 

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Discussion Starter #6 (Edited)
Normal meaning yes they are mostly tan. When I say sooty, I mean mainly from just putt putting around, or long idling.I synchronize the carbs once a year in the spring. Idles pretty long when doing that. Last set of NGK CR9E plugs I ran about 20,000 miles. Looked normal. When I say normal I mean a glaze of tan on the insulator. Only adjusted one valve in that mileage. Exhaust valve was slightly tight at .178mm. Put it in the center with a 2.25 shim.Yea I rev it up ONCE in a while. I almost think the machine was designed to do that.
On a side note, the 1991 C2 run 140 Keihins per the Kawasaki service manual. All other C models run 155s or 152s. Got me. Blaine, what year is yours?

Cheers,
Joe
 

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Discussion Starter #7
Normal meaning yes they are mostly tan. When I say sooty, I mean mainly from just putt putting around, or long idling.I synchronize the carbs once a year in the spring. Idles pretty long when doing that. Last set of NGK CR9E plugs I ran about 20,000 miles. Looked normal. When I say normal I mean a glaze of tan on the insulator. Only adjusted one valve in that mileage. Exhaust valve was slightly tight at .178mm. Put it in the center with a 2.25 shim.Yea I rev it up ONCE in a while. I almost think the machine was designed to do that.

Cheers,
Joe
 

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D model has bigger main jets than C model. Mine is totally stock, and has 160/158 (center carbs)
Yeah, so with my 93D Im running 162/160s, with stock exhaust and a K&N filter.

The aftermarket pipe DEFINITELY means bigger main jets, IMHO....
 

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Mine I have a micron exhaust k&n filter +2 advance CA emission delete 164 out 162 in stock pilot 2.5 on the mixture screws 15mm on the the floats runs great till last weekend took my wife for her first ride on a bike. so was way low in the rpm band stoped to for a break was idling really low and low end thorttle reaponse wasnt there think a plugs fouled I haven't had time to look into it yet project for this weekend
 

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Mine I have a micron exhaust k&n filter +2 advance CA emission delete 164 out 162 in stock pilot 2.5 on the mixture screws 15mm on the the floats runs great till last weekend took my wife for her first ride on a bike. so was way low in the rpm band stoped to for a break was idling really low and low end thorttle reaponse wasnt there think a plugs fouled I haven't had time to look into it yet project for this weekend
Jso, My setup is similar to yours except for the MJs, exhaust & and float level.... Also have the 2 degree advancer, (pretty beotchin isnt it?), but left my float level stock..... maybe thats where the issue is at....move the float down 1-2mm.

Quoting Factory Pros purple tuning specs sheet, Every ZX11 sample config that has an advancer on it, +4, has a 15mm float level, the stock air cleaner combo is the only one that uses a 17mm float level with 160 MJs. Every config, also uses the dual snorkel pipes all the way to the carbs.

I also noticed that when I installed the advancer, my idle went to a throatier loping rumble......
 

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i did it all at the same time just keep buying one thing there and here when the wife wasn't looking lol. so never heard it with just the exhaust and stock timing wheel. Kiss ass mid corner off pulls like a raped ape. have a cool idea with mine i want to try looking to try to get the weight down to around 450 wet have a new pile of parts started...
 

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Yeah, so with my 93D Im running 162/160s, with stock exhaust and a K&N filter.

The aftermarket pipe DEFINITELY means bigger main jets, IMHO....
I have the K&N filter too, and the sparks color is perfect.
And yes, a 4 in 1 exhaust means bigger jets. I remember my lovely MkII 1000, when I've replaced the stock exhaust, I've jumped from 110 to 115 (and the engine took much more time to reach working temperature...)
 

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Discussion Starter #16
Exhaust

My 4 into 1 system is the street version. Vary quiet.When the engine is at song, you'll hear it, but even then it's sooo much more quiet than a Muzzy etc. I'll ride it and observe. Then adjust if need be. Make sense? It would be nice if I could have the AF ratio tested through out the RPM range like on a dyno.

Cheers
 

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Found the problem the vacuum plug on the number three intake manifold from when I deleted the smog stuff came off. So rode it around for a hour in the hills with new plugs back to light tan. Then went to my friends dyno a/f spot on and made 145HP at the wheel
 

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Discussion Starter #18
I've got another question for anybody. The Kawasaki C model manual supplement states the main jet size for the ZX1100-C2 is Keihin 140 but the high altitude size is [152]. Other C models are 155 and [152] for high alt. These are all sizes for US models. My C2 has the 140s. Pretty sure they are Keihin got a star like symbol on the side. If the 140s are normal altitude how can 152s be high alt? I'm a little confused. I saw a chart stating the 140s are .0540 inch. May I can inside Vernier caliper measure a jet.

Joe
 

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From 1990 to 1991½, MJ were 140 Keihin.
From 1991½ to 1993, MJ were 155.
Some other changes (needles I think but a negligeable one) also has been made to go along with the 155 MJ. Most important one has been the lenght of the inlet tube that pressurise carbs bowls at the ramair intake.

The 152 MJ for altitude you wrote about is for 199½ and later C model.
 
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