Popping from exhaust, just on idle, runs great,

  • bountyhunter
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Re: Popping from exhaust, just on idle, runs great,

28 Sep 2012 22:06 - 28 Sep 2012 22:13
#551485
Patton wrote: If the clear-tube test shows fuel level within specs
That is the FIRST thing I would have checked. If the fuel level is even one mm too high, it will make the bike pop and sputter at idle.

Guess how I found that out.....

This part made me wonder:
I checked all my float heights and they are bang on from when I set them after I rebuilt the carbs a couple of years back.

Checked with clear tube or "bench set"? The latter method is useless.

IMPORTANT:

If this was a coil problem, you would very likely be fouling TWO plugs. The 1-4 plugs are in series on the output winding of one coil, the 2-3 plugs are in series on the other coil. Series means the same current usually through both plugs. When I see one plug running rich, carbs are the first tree to bark up until proven otherwise.
1979 KZ-750 Twin
Last edit: 28 Sep 2012 22:13 by bountyhunter.

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  • bloglos
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Re: Popping from exhaust, just on idle, runs great,

01 Oct 2012 12:44
#551834
Ah ok thanks, yes I purchased those coils from Z1 a year ago but took them off because my bike would be very difficult to start and seems to run completely different. Maybe I just got unlucky and received a defective set or coil.
Patton wrote: Am thinking that Kaws with points ignitions came with 4Ω coils (Ω = ohm), but am unaware of a source for good 4Ω coils with replaceable plug wires.

Would consider these 4Ω coils from Z1E:
www.z1enterprises.com/ItemDetails.aspx?i...cap&item=IM01143-55S
www.z1enterprises.com/ItemDetails.aspx?i...aps&item=IM01143-55L

Good Fortune! :)
78 KZ650 C2 - Runner
77 KZ650 B1 - Project

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Re: Popping from exhaust, just on idle, runs great,

01 Oct 2012 13:09
#551837
even a mm hey. It's probably 1-2mm high but at the top end of the float spec. Same as when I rebuilt them 2 years ago and it hasn't popped for 2 years. Anyways.. I'm going to pull them and give them little cleaning. Maybe adjust the heights a little.

bountyhunter wrote:
Patton wrote: If the clear-tube test shows fuel level within specs
That is the FIRST thing I would have checked. If the fuel level is even one mm too high, it will make the bike pop and sputter at idle.

Guess how I found that out.....

This part made me wonder:
I checked all my float heights and they are bang on from when I set them after I rebuilt the carbs a couple of years back.

Checked with clear tube or "bench set"? The latter method is useless.

IMPORTANT:

If this was a coil problem, you would very likely be fouling TWO plugs. The 1-4 plugs are in series on the output winding of one coil, the 2-3 plugs are in series on the other coil. Series means the same current usually through both plugs. When I see one plug running rich, carbs are the first tree to bark up until proven otherwise.
78 KZ650 C2 - Runner
77 KZ650 B1 - Project

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