Jet Kit Availability?

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Jet Kit Availability?

05 Nov 2014 19:08 - 05 Nov 2014 19:08
#652986
Is there anyplace that one can buy a Stage 3 jet kit for a KZ900? My bike has a Kerker 4-1 and pod K&N's and has been jetted up some by the previous owner, but I would like to just install a new kit into it and then get down to tuning, main jets on down to pilots.

Any help would be appreciated. I tried to search but didn't come up with much...
Last edit: 05 Nov 2014 19:08 by OutsiderKZ900A4.

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  • Patton
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Re: Jet Kit Availability?

05 Nov 2014 20:10
#652996
Could inquire of Z1E as to the feasibility of using a KZ1000 Dynojet kit.

www.z1enterprises.com/ItemDetails.aspx?i...+1977-80&item=DJ2304

The jet needle is particularly important to performance throughout mid-range.of the carb.

Good Fortune! :)
1973 Z1
KZ900 LTD

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Re: Jetting Recommendations Needed

07 Nov 2014 05:21
#653128
Well, I have tried searching here and online for a Stage 3 type jet kit for my bike but have not had much success. There are some no name kits on Ebay that I don't really like the looks of. I would like to find a Dyno Jet or Factory Pro type kit but they don't seem to be out there either, so I am going to ask the knowledgable people at KZRider for their recommendations.

The bike is a 1976 KZ900A4, it has a Kerker 4 into 1 exahust, K&N Pod filters and a Dyna ignition system on it. What would you recommend as a good starting point for jetting, Main Jet and Pilot Jet. I am not sure if the needles are adjustable in these or not but if it is like my triples of the similar vintage they should be?

Any help would be appreciated, thank you.

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Re: Jetting Recommendations Needed

07 Nov 2014 06:00
#653130
www.kzrider.com/forum/3-carburetor/59638...-availability#652996

Any advice from the folks at Z1E?

Good Fortune! :)
1973 Z1
KZ900 LTD

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Re: Jetting Recommendations Needed

07 Nov 2014 06:22 - 07 Nov 2014 06:26
#653132
Stock KZ900 carbs are very accommodating and not overly lean with original jettings and jet needle middle-clip positions.

With non-carb components near-perfect (compression; valve clearances; ignition; fuel supply) and carb in as-new condition, would first test ride Kerker and pods with stock carbs (stock jets and settings), as these bikes performed very well in such configuration when relatively new, even with over-bores up to 1100.

If roadside plug readings incident to throttle-chop testing indicates lean mixture at WOT, could go one size larger main jet.

So long as low rpm is steady, with strong pull-away from idle, there's imo no real need for larger pilot jets.

It's doubtful imo that a different jet needle clip position would be needed.

Remember that carbs should not be used in attempting to offset deficiencies in non-carb related components.

Good Fortune! :)
1973 Z1
KZ900 LTD
Last edit: 07 Nov 2014 06:26 by Patton.

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Re: Jetting Recommendations Needed

07 Nov 2014 08:18
#653140
Dynojet Jet Kit - none available - and as Patton said, you really don't need one - and that's likely why they don't make one.

The KZ900 tended to be a rich setup to start with, so I would probably only go to 120 or 122.5 main and 20 pilot jets, then raise the needle (lower the clip) one notch.
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  • OutsiderKZ900A4
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Re: Jetting Recommendations Needed

07 Nov 2014 17:06
#653178
Patton wrote: Stock KZ900 carbs are very accommodating and not overly lean with original jettings and jet needle middle-clip positions.

With non-carb components near-perfect (compression; valve clearances; ignition; fuel supply) and carb in as-new condition, would first test ride Kerker and pods with stock carbs (stock jets and settings), as these bikes performed very well in such configuration when relatively new, even with over-bores up to 1100.

If roadside plug readings incident to throttle-chop testing indicates lean mixture at WOT, could go one size larger main jet.

So long as low rpm is steady, with strong pull-away from idle, there's imo no real need for larger pilot jets.

It's doubtful imo that a different jet needle clip position would be needed.

Remember that carbs should not be used in attempting to offset deficiencies in non-carb related components.

Good Fortune! :)

The biggest issue the bike seems to have is it is lean on idle. The previous owner turned the air screws in almost all the way to make it want to idle right. This leads me to believe that the pilot jets need to be bigger. My Dad ran into a similar issue on his modified S3 (400 triple) that ended up being mostly taken care of with H2 pilot jets. I have 20 and 22.5 pilot jets ordered from Z1E. It runs good from mid range on up.

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Re: Jetting Recommendations Needed

07 Nov 2014 19:05
#653183
OutsiderKZ900A4 wrote: ...The biggest issue the bike seems to have is it is lean on idle. The previous owner turned the air screws in almost all the way to make it want to idle right. This leads me to believe that the pilot jets need to be bigger... I have 20 and 22.5 pilot jets ordered from Z1E. It runs good from mid range on up.

Would also consider possibility of an imperfectly clean pilot circuit. For instance, perhaps the orifice is partially obstructed where the pilot circuit mixture enters the main carb bore (see #6 in the following illustration.




Good Fortune! :)
1973 Z1
KZ900 LTD

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Re: Re:Re: Jetting Recommendations Needed

07 Nov 2014 19:14
#653186
Patton wrote:
OutsiderKZ900A4 wrote: ...The biggest issue the bike seems to have is it is lean on idle. The previous owner turned the air screws in almost all the way to make it want to idle right. This leads me to believe that the pilot jets need to be bigger... I have 20 and 22.5 pilot jets ordered from Z1E. It runs good from mid range on up.

Would also consider possibility of an imperfectly clean pilot circuit. For instance, perhaps the orifice is partially obstructed where the pilot circuit mixture enters the main carb bore (see #6 in the following illustration.




Good Fortune! :)
When I pull the carbs, I am going to clean them. I can't see all 4 carbs having the exact lean issue but they will definitely be cleaned.

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Re: Re:Re: Jetting Recommendations Needed

07 Nov 2014 19:39
#653188
If not already done, would also assure via the clear-tube test that the fuel levels are within spec, as too low fuel level could result in too lean pilot mixture.

And assure that the pointed tips of the pilot screws are in good condition, and that the pilot screw o'rings are present and correct and in good condition.

Presumably, the pilot screws are the correct pilot screws for the carbs at hand, and haven't been unknowingly replaced by similar pilot screws from different model carbs.

Good Fortune! :)
1973 Z1
KZ900 LTD

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Re: Re:Jet Kit Availability?

07 Feb 2015 14:26
#660862
Well, here is where I am at. Pulled the carbs, cleaned them, put in the 20 pilot jets and put it back together. When I start it, you can hear and feel that it isn't running on all cylinders. 3 and 4 (2 passenger side cylinders) are firing and the pipes heat up quick. 1 and 2 9n the other hand, are not. Pulling the plugs find them covered in fuel. It had spark. I am baffled at 1 and 2 acting the same. Letting the motor cool down before popping the carbs back off.

Any suggestions where to start?

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Re: Re:Jet Kit Availability?

07 Feb 2015 14:34
#660863
One other thing, when I took the bike apart, I found these open ports on carbs 2 and 4, which were open. What do these do? The service manual is not real helpful on this...

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