OKO 30mm tuning

[Madass140]

well I have my Skyteam Ace 125 pretty well all sorted and its running beautiful with the Koso 26mm, the engine is a CG125 based engine 5 speed with counterbalancer and elec/kick start, mods I've done include, 150cc,different head with bigger valves, very nice porting job, big cam,26mm Koso, nice exhaust, new CDI unit, new Coil, I've yet to get around to fit my new speedo and Tach to get some figures ,

 

[rotn50]

Pics mate please. All sounds great, any vids also.

 

[Madass140]

Pics mate please. All sounds great, any vids also.

 

[my67xr]

i like your work madass140,

lots of attention to detail there, i like the TLS cross vented drum front.
and how you line up the heads of each screw and bolt, even the bolts holding the clutch cover on !!!
although i spotted one bolt head thats not perfectly aligned, the top bolt holding the clutch cover plate ?

 

[my67xr]

the OKOs' seem to differ a fair bit in jetting sizes too, depending if it is setup for a 2 stroke or a 4 stroke motor.
some of the 26mm OKOs i've seen come with a 95 main jet, and others with up to a 125 main jet, the latter obviously being for the 2 stroke bikes.


what pilot is your Koso running? im pretty sure my 24mm OKO Powerjet carb was supplied with a 50 pilot
i agree on the Koso being a better build quality too,
some i've seen have a polished, or at least a machined intake side, this gets rid of the lip where the intake bore steps down to the slide, creating less turbulence and a more atomised fuel/air mix.


another couple of things i found while tuning them
some of them can run a bit lean if you dont have a rubber boot where the throttle cable meets the adjuster on the top of the carby.
you can check this by running some insulation tape over the join and giving it another run.
if it runs a bit richer, then there is a vacuum leak there.
you can make it a more permanent fix by using the correct throttle cable boot, or by using some heat shrink tubing over the join to help it seal.
the mixture screw will need adjusting/resetting then too, once that problem has been sorted.


and finally with the carby problem of it not idling, that one is easy enough to solve too.
the genuine Keihin PJ carbys use a choke knob that is adjustable, the PWK choke knob isnt adjustable.
fit a Keihin PJ choke knob onto your OKO,
then turning the choke knob anticlockwise will richen the idle, and visa-versa, clockwise will lean the idle.

otherwise, just be happy with your MX style throttle, and keep having to blip it to keep the bike running.

 

[Madass140]

the OKOs' seem to differ a fair bit in jetting sizes too, depending if it is setup for a 2 stroke or a 4 stroke motor.
some of the 26mm OKOs i've seen come with a 95 main jet, and others with up to a 125 main jet, the latter obviously being for the 2 stroke bikes.


what pilot is your Koso running? im pretty sure my 24mm OKO Powerjet carb was supplied with a 50 pilot
i agree on the Koso being a better build quality too,
some i've seen have a polished, or at least a machined intake side, this gets rid of the lip where the intake bore steps down to the slide, creating less turbulence and a more atomised fuel/air mix.


another couple of things i found while tuning them
some of them can run a bit lean if you dont have a rubber boot where the throttle cable meets the adjuster on the top of the carby.
you can check this by running some insulation tape over the join and giving it another run.
if it runs a bit richer, then there is a vacuum leak there.
you can make it a more permanent fix by using the correct throttle cable boot, or by using some heat shrink tubing over the join to help it seal.
the mixture screw will need adjusting/resetting then too, once that problem has been sorted.


and finally with the carby problem of it not idling, that one is easy enough to solve too.
the genuine Keihin PJ carbys use a choke knob that is adjustable, the PWK choke knob isnt adjustable.
fit a Keihin PJ choke knob onto your OKO,
then turning the choke knob anticlockwise will richen the idle, and visa-versa, clockwise will lean the idle.

otherwise, just be happy with your MX style throttle, and keep having to blip it to keep the bike running.

I'm still interested to try a 30mm carb, the inlet valve is 30mm, I have ported it 30mm,
I tried the OKO 30mm with not much success, maybe I should try a 30mm Koso with powerjet, just looking for any possible increase in power, the 26 works great.
I now have my new Koso speedo fitted so I'll do some test runs to see how I'm going, the Tachometer I fitted at the same time seems a bit eratic, no instructions on where I should connect the pickup wire to.

 

[my67xr]

i have seen the pickup wire for the tacho wrapped around the spark plug lead before.
i've also heard there is another box that you can buy for wiring the tacho up to electronic systems, not sure if they mean computerised systems or not though?

how much did you speedo cost? and did you buy it locally?
was it the RX1N?

 

[Madass140]

i have seen the pickup wire for the tacho wrapped around the spark plug lead before.
i've also heard there is another box that you can buy for wiring the tacho up to electronic systems, not sure if they mean computerised systems or not though?

how much did you speedo cost? and did you buy it locally?
was it the RX1N?

Speedo is Ebay item No,
271038974458

 

[my67xr]

ok, the classic style, it suits the bike well

here is a Koso 30mm Powerjet carby you may be interested in?
http://www.aliexpress.com/item/KOSO...SR50-NSR80-Dirt-Pit-bike-Parts/751225374.html