Temp Altitude Humidity Effects on Jetting

Now that the temp here in AZ has cooled down significantly, off to the bike salvage yard (ZX636 Clutch Perch) yesterday for morning temp @ 73 degrees... Nice.....

I noticed some real minor popping during deceleration...
AT a stop light, noticed she was stumbling a tad at idle...

hmmm, ok so what have I learned in jetting....
Higher altitude equates to less air more gas so leaner is required...

Cooler air equates to density change so more air less gas... Richer is required...

Out with the long blade screw driver I have tucked in the tail section, tweak the slow jets 1/8th turn for richer setting...

All better..... See even an old fart can learn.... :blush: :laugh:

Possibly a needle clip position change (Richer) as it gets cooler here is required....

For those interested, nice write up here....
www.justkdx.dirtrider.net/printcarbtuning.html

One of the things I've learned is that if you jet for the best power when the bike is fully warmed up, you actually end up pretty lean for most other conditions.

If you want the most drivability, you will end up jetting a little richer than you want for best power. This means the bike will actually feel a little sluggish on really hot days when the bike is warmed up all the way.

As with most things, there must be some tradeoff. I usually jet somewhere between best power and best drivability, but that means I tend to stay on the choke a lot longer on cold days.

Choke... Pretty weird where these CR's they don't like choke at all.... If choke any and I mean any amount ~ 1-2mm pull on is about it.... :huh:

So off to mi amigo experts to find out more info... Keihin CR's are known for this... Ahhhhhhhhhhh... I see....

Granted, AZ cold is a hell of a lot different then up North/Back East cold so have to consider that as well....

As previously mentioned due to AZ heat index, I run a tad more on the rich ~ 13.8-14.1 Stoich on the A/F ratios.... Power and cooling effects...

I've encountered this same scenario on North mountain runs 1500 ft elevation changes where even in the summer months, higher elevations, had to lean out for better idle - 1/4 throttle/rpm ranges.... Just the way it works out....

All good....

Yeah, the TK-22 chokes are literal chokes. They are a plate that slides down over the intake. There are little flaps that open up if the engine vacuum is pulling too much. Crude, but effective. You have to play with the lever if you want to get on and ride right away.

Enricher type chokes seem to be a lot less finicky.

loudhvx wrote:

Yeah, the TK-22 chokes are literal chokes. They are a plate that slides down over the intake. There are little flaps that open up if the engine vacuum is pulling too much. Crude, but effective. You have to play with the lever if you want to get on and ride right away.

Enricher type chokes seem to be a lot less finicky.

You're probably aware of this but those TK choke plates had a nasty habit of fall off and getting sucked through the engine....

larrycavan wrote:

loudhvx wrote:

Yeah, the TK-22 chokes are literal chokes. They are a plate that slides down over the intake. There are little flaps that open up if the engine vacuum is pulling too much. Crude, but effective. You have to play with the lever if you want to get on and ride right away.

Enricher type chokes seem to be a lot less finicky.

You're probably aware of this but those TK choke plates had a nasty habit of fall off and getting sucked through the engine....

Yeah I have a few write ups here on how to prevent that. Just basic inspection really. The pins walk out from vibration, but you can put them back and re-peen them or glue them so they don't walk out.

However, I would prefer a solid plate and have been mulling over some ideas on that. Or at least simple ways of doing that and adding more "click" positions to the choke lever.

One of these days i hope to finish a TK-22 website.