Kiss my Keyster (carb kit needles)

Hotshoe · Post by **Hotshoe** » Wed Jan 05, 2011 12:38 am

Had an interesting carb tuning experience over the Holidays I thought I'd share.
I was retuning after installing some 140 main jets with good results overall but the engine was still a little weak around 3/4 throttle and the plug color had been a little uneven with dark spots on the electrode tips I didn't like.
I remembered the Forum posts about the Keyster CL carb rebuild kit needles being questionable so I swapped them out with some OS Honda needles.
After two runs, the engine now pulls strong all the way through the RPM range and the dark spots have disappeared.
Since nothing else was changed but the needles (cleaned D8HA plugs each run and 140 mains with both sets of needles set 2nd notch up from the bottom), I can verify that the Keyster CL needles make good tooth picks.
Attached are pics of one set of plugs run with kit needles and one set run with OS needles.
Once again, the Forum comes through!

cyclon36 · Post by **cyclon36** » Wed Jan 05, 2011 9:19 am

I see the problem, your needles are shaped like spark plugs :-)

davomoto · Post by **davomoto** » Wed Jan 05, 2011 9:57 am

Yeah, I've gone through that myself, and use OEM needles whenever possible.

Davo

brewsky · Post by **brewsky** » Wed Jan 05, 2011 11:11 am

cyclon36 wrote:I see the problem, your needles are shaped like spark plugs :-)

Your killing me!!!

Hotshoe · Post by **Hotshoe** » Wed Jan 05, 2011 11:11 am

Davo, with your experience in these matters what do you think of the plug color?
I'm burning Shell Premium from a high volume station which I think is about as good as it gets for pump gas.
I think the electrode looks a shade lean and the base looks a shade rich.
I'm looking for a set of 145's to try for the electrode and I'll go out a little on the air jet to see if that cleans up the base of the plug.

Are you trying to needle me Cyclon? ;-))

e3steve · Post by **e3steve** » Wed Jan 05, 2011 11:36 am

Breaker on the side: my own personal experience tells me they're both a touch lean. I judge the combustion quality from the colour of the earth electrode; yours, there, are grey -- they should be a sandy tan-colour. JMO....

Combustion doesn't take place around the plug body (only between the electrodes) so I'd expect to see the bottom of the threaded portion slightly blackened in comparison to the electrodes.

The idle jet air-screw only affects the mixture @ <¼-throttle.

davomoto · Post by **davomoto** » Wed Jan 05, 2011 12:32 pm

They look a touch lean to me as well. Are you doing throttle chop readings, or just a generic reading?

Davo