KB Jet exchange

**Racey Rider** · 15th December 2005, 20:19

When going to a different track us two stroke owners need to think about jetting for the altitude of that track.

I'm thinking it would be handy to have access to a range of jets to test with.
Jets for my bike are close to $15 each, and when I only need to try a size to see if it's right for a certain track, it's a bit of a waste of it turns out I need another size.

So I'm willing to lend out my jets to others when I'm not useing them. Maybe we can organize a 'Jet borrowing list' It's only like 50c to post them around. But could be very helpful.

I have a KR150 with a Keihin PWK 28mm carb.
Jets are N424-36 in size 138 & 132
Would really like to try jets 135 & 130 if anyone has them.

The idea may not work,, but,,
just trying to save a dollar!

Cheers.
RAcey.

**Ivan** · 15th December 2005, 20:24

the best way is leave the jets stock, I left the RG standered and it did good at Taupo and Manfield with a small bike like that you dont even need to change em it aint like the motor is high performance but good idea any ways could work out

**White trash** · 15th December 2005, 20:40

I've got a clapped out Harrier. I'm looking for a hoon in an F-18 Hornet.

Anyone keen for a swap this weekend?

**Racey Rider** · 16th December 2005, 06:58

I would disagree Ivan. To my why of thinking, the smaller the motor, the bigger the need to get the jetting just right for any given alitiude.

You may have a jetting setting that works ok at any track, but that must be a compromise setting that is not giving you the best power at one particalar track. Raceing at Taupo is a lot higher altitude than Manfield. Dave (old KB member) used to go down two jet sizes on his RS125 for taupo.
I've yet to test the theroy but it sounds right to me.

And how could they not include the F14 TOMCAT in the top 10 last night?

**Sketchy_Racer** · 16th December 2005, 08:47

Ivan your right but also wrong. all engines need jetting to compensate for different air humidity and heat etc etc, a standard 150cc 2 stroke would need to be jetted, only if the air was extramly different than normal (being higher, lower etc) but a 125gp would need jet changes for every tiny little air difference, due to the fact that they are allways trying to run as lean as possible, but not so lean it blows up, like yours did ivan.

and racey,

i have read that you have removed you air filter?? am i correct?

now if so did you change the jetting when you did this to suit more air flow?? if not this would explain whay you bike has seized on (how many times, i dont know ????) so yes you definantly need to change your jet, providing you havnt already.

sooooo

ill go look in my jet box and see what i can do for you

Glenn

**Sketchy_Racer** · 16th December 2005, 08:48

oh and you should only ever go up one jet change at a time

**Ivan** · 16th December 2005, 08:50

Originally Posted by Racey Rider

I would disagree Ivan. To my why of thinking, the smaller the motor, the bigger the need to get the jetting just right for any given alitiude.

You may have a jetting setting that works ok at any track, but that must be a compromise setting that is not giving you the best power at one particalar track. Raceing at Taupo is a lot higher altitude than Manfield. Dave (old KB member) used to go down two jet sizes on his RS125 for taupo.
I've yet to test the theroy but it sounds right to me.

And how could they not include the F14 TOMCAT in the top 10 last night?

Nah that is actually an idea at Taupo with the RS I will be going down more than 2 jet sizes because it is so cold there

**Sketchy_Racer** · 16th December 2005, 08:52

sorry no can do, the largest i have is a 120,
good luck though

:

**Ivan** · 16th December 2005, 08:52

Originally Posted by RG100!!

oh and you should only ever go up one jet change at a time

ah get stuffed use a humidity gauge and then it tells you what size jet to use with the humidity if you get a jet chart lol

**Sketchy_Racer** · 16th December 2005, 08:59

ok, thats if you a rich prick with all the fangdangled thingymybops, for us hillbillys, its one jet chande at a time, then a plug shoot

**Eurodave** · 16th December 2005, 09:08

The RNZAF just exchanged their old Skyhawks for a nice wad of cash, I bet well never see it though, prolly go to all the bloody dole bludgers
On a more serious note, Ive got a good range of Dellorto jets for sale if anyone needs some

**Ivan** · 16th December 2005, 10:43

a humidity gauge is 40 bucks and I aint rich I sacrtifice to race I am struggling I need a job next year to pay for my racing

**sAsLEX** · 16th December 2005, 11:10

Originally Posted by Racey Rider

And how could they not include the F14 TOMCAT in the top 10 last night?

or the HUrricane!

**Racey Rider** · 16th December 2005, 17:35

Originally Posted by RG100!!

and racey, i have read that you have removed you air filter?? am i correct?
now if so did you change the jetting when you did this to suit more air flow?? if not this would explain whay you bike has seized on (how many times, i dont know ????) so yes you definantly need to change your jet, providing you havnt already. sooooo
ill go look in my jet box and see what i can do for you

Glenn

Thanks. I removed the air filter one time at Manfeild as the bike was running very rich, and the plan was to allow more airflow through to correct the mixture. But in removeing the air filter, it allowed too much extra air through, which caused detionation in that instance. Learn as you go.