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Best guess for main jet size?
- Gary - K7GLD
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11 Jan 2012 02:09 #497504
by Gary - K7GLD
John Day area - Eastern Oregon
Restored 1983 Kawasaki 1100LTD
Best guess for main jet size? was created by Gary - K7GLD
Here's the deal:
On my '83 KZ1100LTD, I have a Kerker 4/1 exhaust setup
a set of PODs
Running 120 main jet
37.5 pilot jet
Air screws 1 3/4 out
synchronized carbs
Adjusted valves
Where I live, I'm operating at 3000 to 5500 feet elevation
Engine starts great, runs great, accelerates smoothly thru all RPM range, no sags, flat spots or hesitations.
BUT, the pulling power at full throttle from, say, 3500 RPM on up is rather mediocre - instead of WOWWWwww, it's HO-HUMMmmmm! I *know* this engine can pull stronger than this - the valves are adjusted properly, the compression is good, the engine has 27K miles, uses no oil, doesn't smoke, and sounds great mechanically.
I'm convinced I need a larger main jet than the 120's that are in there now, but don't have a "feel" for where to best go in a larger size for better fueling thru the midrange and upper RPM ranges - I'm thinking perhaps 140's, but need input from someone knowledgeable with setups like mine.
My plugs are reading right on for color, a very light tan, so really don't think I need to be looking at pilot jets or air adjustment - I have adjustable needles in the slides, and am running 3rd notch from the top - higher makes the plugs too lean - lower gets them sooty.
I'm open to other ideas from a knowledgeable perspective, but REALLY think my missing power is caused by too-small main jets - will someone edumacate me with informed input? :confused::confused::confused:
On my '83 KZ1100LTD, I have a Kerker 4/1 exhaust setup
a set of PODs
Running 120 main jet
37.5 pilot jet
Air screws 1 3/4 out
synchronized carbs
Adjusted valves
Where I live, I'm operating at 3000 to 5500 feet elevation
Engine starts great, runs great, accelerates smoothly thru all RPM range, no sags, flat spots or hesitations.
BUT, the pulling power at full throttle from, say, 3500 RPM on up is rather mediocre - instead of WOWWWwww, it's HO-HUMMmmmm! I *know* this engine can pull stronger than this - the valves are adjusted properly, the compression is good, the engine has 27K miles, uses no oil, doesn't smoke, and sounds great mechanically.
I'm convinced I need a larger main jet than the 120's that are in there now, but don't have a "feel" for where to best go in a larger size for better fueling thru the midrange and upper RPM ranges - I'm thinking perhaps 140's, but need input from someone knowledgeable with setups like mine.
My plugs are reading right on for color, a very light tan, so really don't think I need to be looking at pilot jets or air adjustment - I have adjustable needles in the slides, and am running 3rd notch from the top - higher makes the plugs too lean - lower gets them sooty.
I'm open to other ideas from a knowledgeable perspective, but REALLY think my missing power is caused by too-small main jets - will someone edumacate me with informed input? :confused::confused::confused:
John Day area - Eastern Oregon
Restored 1983 Kawasaki 1100LTD
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- andler2008
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11 Jan 2012 04:32 #497514
by andler2008
1980 KZ 1075
Mods? Pshh I have no idea right now
1981 Kz1000 CSR - Sold
Replied by andler2008 on topic Best guess for main jet size?
I have a 1000 and I run a 140/40 setup. It worked wonders for me. So I'm assuming maybe a 2 sizes up on the pilot and a few for main. I'm sure there's other guys that know more than me On here that'll have a good outlook on your situation.
1980 KZ 1075
Mods? Pshh I have no idea right now
1981 Kz1000 CSR - Sold
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- Gary - K7GLD
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12 Jan 2012 22:19 - 12 Jan 2012 22:22 #497825
by Gary - K7GLD
John Day area - Eastern Oregon
Restored 1983 Kawasaki 1100LTD
Replied by Gary - K7GLD on topic Best guess for main jet size?
Double post - sorry!
John Day area - Eastern Oregon
Restored 1983 Kawasaki 1100LTD
Last edit: 12 Jan 2012 22:22 by Gary - K7GLD.
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- Gary - K7GLD
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12 Jan 2012 22:21 #497827
by Gary - K7GLD
That's almost EXACTLY where I'm headed so far with my setup, allowing for our elevation that runs from 3000 to over 5000 feet, and dictates slightly smaller jet sizes - I tend to get sorta rankled with the guys who knock 4'1 pipe setups and PODS...
Fact is, the fuel induction systems on these bikes is hardly rocket science - nor are the Kawasaki designers and engineers any sort of "Gods", whose various systems cannot be modified, and possibly improved upon - and that includes the OEM airboxes and exhaust systems!
I have serious problem and disagreement with the notion that "PODS simply can NOT be made to function properly - and CERTAINLY not as well as the OEM setup"...
That's pure BS - and most likely all it takes is the proper mix of time, knowledge and resources to make them work, and most likely work BETTER than the OEM system they replace. And I sure hate to ashcan my own effort just because some pimply-faced high school kids with nothing more than a hammer and screwdriver weren't able to get it done!
John Day area - Eastern Oregon
Restored 1983 Kawasaki 1100LTD
Replied by Gary - K7GLD on topic Best guess for main jet size?
andler2008 wrote: I have a 1000 and I run a 140/40 setup. It worked wonders for me. So I'm assuming maybe a 2 sizes up on the pilot and a few for main. I'm sure there's other guys that know more than me On here that'll have a good outlook on your situation.
That's almost EXACTLY where I'm headed so far with my setup, allowing for our elevation that runs from 3000 to over 5000 feet, and dictates slightly smaller jet sizes - I tend to get sorta rankled with the guys who knock 4'1 pipe setups and PODS...
Fact is, the fuel induction systems on these bikes is hardly rocket science - nor are the Kawasaki designers and engineers any sort of "Gods", whose various systems cannot be modified, and possibly improved upon - and that includes the OEM airboxes and exhaust systems!
I have serious problem and disagreement with the notion that "PODS simply can NOT be made to function properly - and CERTAINLY not as well as the OEM setup"...
That's pure BS - and most likely all it takes is the proper mix of time, knowledge and resources to make them work, and most likely work BETTER than the OEM system they replace. And I sure hate to ashcan my own effort just because some pimply-faced high school kids with nothing more than a hammer and screwdriver weren't able to get it done!
John Day area - Eastern Oregon
Restored 1983 Kawasaki 1100LTD
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