Jetting down procedure?

Madman · Post by **Madman** » Mon Apr 30, 2012 10:17 pm

Ok just breaking in my new build, started with jets 52/150!
Starts right up and revs a bit choppy then smooth through pilot then Boggs at main, how many steps down should I go to begin with?
I'm thinking 50/145 to reduce the choppy low revs and the bog into main.

And lowering the needle (or raising the clip) makes the mix leaner?

bakaracer · Post by **bakaracer** » Mon Apr 30, 2012 10:25 pm

Madman wrote:Ok just breaking in my new build, started with jets 52/150!
Starts right up and revs a bit choppy then smooth through pilot then Boggs at main, how many steps down should I go to begin with?
I'm thinking 50/145 to reduce the choppy low revs and the bog into main.

And lowering the needle (or raising the clip) makes the mix leaner?

for a 21mm carb those are really big jets. you should be in the 45 pilot 115main then go from there. 52/150 is more a 28mm/30mm carb setting in hawaii setting

Madman · Post by **Madman** » Mon Apr 30, 2012 11:26 pm

Cheers man, I was following advice from another forum member he may have assumed that I had a 28mm carb! great ill go from there I was a little scared that my fuel consumption would go crazy from there!

Madman · Post by **Madman** » Mon Apr 30, 2012 11:27 pm

Do they use the 28 mm carb in Hawaii because of the
Clean crisp air?

bakaracer · Post by **bakaracer** » Mon Apr 30, 2012 11:29 pm

Madman wrote:Do they use the 28 mm carb in Hawaii because of the
Clean crisp air?

no its a fad that started back in the mid to late 90's. believe it or not the air there is not that crisp. in fact the humidity is usually high there since they are surrounded by water and they get every once in a while south western winds which they call vog or volcanic haze mixed with warm southern air. it sucks when there is that type of weather.

Madman · Post by **Madman** » Tue May 01, 2012 11:47 am

I didnt have any 115 jets at home so I swapped in a 28mm carb to check! wow the jeting at 52/150 was super for a short ride but im going to get some more jets tommorow and swap back in my 21mm carb as I think the 28mm is overkill and I dont have a 24mm carb which I am led to belive is perfect!

veedubh20 · Post by **veedubh20** » Wed May 02, 2012 1:20 am

you need to keep the eye open on the jetting 115 is small or will make hole on piston.

go down on the pilot 48/50 and main jet 140 raise the clip 1 up from the middle is lean, one and half turn out on air fuel screw.

japan climate are much differ than hawaii.

72cc polini contesta, 8.4 gear, 1 k center spring only. stock goshi pipe.

ct /24 oko filter 48-135.

21mm is small mouth than 24mm oko.

with the pilot jet that you have, If the motor bog on idle to take off speed. need to down size pilot jet. example 50 , down to 48. Once the bog goes away on riding stop and go or waiting on the red light stop. leave the pilot jet when bog goes away. should be fine. Main jet you need to worry. plug should be golden brown color.. Carry extra plugs with you riding.

just ride for 3 minutes on cruz speed 55 kph and check and change the main jets look at the plug colors it white/ grey tip end plug is lean on the main jet. need to go little bigger. repeat all the step on themain jets.

if you change pipe any brand,, all must be tunes on grams, jetting, springs, gonna do that all on time to tune.

Madman · Post by **Madman** » Wed May 02, 2012 1:37 am

veedubh20 wrote:you need to keep the eye open on the jetting 115 is small or will make hole on piston.

go down on the pilot 48/50 and main jet 140 raise the clip 1 up from the middle is lean, one and half turn out on air fuel screw.

japan climate are much differ than hawaii.

72cc polini contesta, 8.4 gear, 1 k center spring only. stock goshi pipe.

ct /24 oko filter 48-135.

21mm is small mouth than 24mm oko.

with the pilot jet that you have, If the motor bog on idle to take off speed. need to down size pilot jet. example 50 , down to 48. Once the bog goes away on riding stop and go or waiting on the red light stop. leave the pilot jet when bog goes away. should be fine. Main jet you need to worry. plug should be golden brown color.. Carry extra plugs with you riding.

just ride for 3 minutes on cruz speed 55 kph and check and change the main jets look at the plug colors it white/ grey tip end plug is lean on the main jet. need to go little bigger. repeat all the step on themain jets.

if you change pipe any brand,, all must be tunes on grams, jetting, springs, gonna do that all on time to tune.

thanks man I'll give it a try. I'm swapping back in the 21mm tonight and have all the jets I need. I'm gonna drop the pilot down to 50 and the main to about 145 to try, don't wanna burn a hole in the piston!

bakaracer · Post by **bakaracer** » Wed May 02, 2012 2:26 am

what size jets do you have to play with?

Madman · Post by **Madman** » Wed May 02, 2012 2:31 am

bakaracer wrote:what size jets do you have to play with?

From 28 to 54 pilot and 70-158 main

I have more than what's in the photo!

bakaracer · Post by **bakaracer** » Wed May 02, 2012 2:35 am

But you don't have a 115 main. What size is the next closest to 115 you have?

Madman · Post by **Madman** » Wed May 02, 2012 2:36 am

bakaracer wrote:what size jets do you have to play with?

I know you guys have a lot of experience and I welcome and thank you for any advice and help!

Madman · Post by **Madman** » Wed May 02, 2012 2:37 am

bakaracer wrote:But you don't have a 115 main. What size is the next closest to 115 you have?

Have one now I picked up a set from 115 to 128 this morning!

Madman · Post by **Madman** » Wed May 02, 2012 2:40 am

Was going to test out the 115 tonight but was worried after veedub said about holes in pistons!

Bear45-70 · Post by **Bear45-70** » Wed May 02, 2012 3:13 am

Listen to baka. Veedub doesn't know half what baka knows.

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