another 26mm OKO and 155z noob please help me !!

[turbomini]

Hi guys long time reader first time poster.

basically i have a motovert rx with a stock pitster pro 155z motor with an aftermarket exhaust and a 26mm OKO flat slide carby it is the one with the swivel top cable outlet.

my problem is as follows.

the bike will cough and splutter through the rev range and up top while riding and also run rough when sitting at at steady throttle setting. however some times it seems to rev cleanly.

i have checked the following items.

checked for air leaks around the inlet manifold carby ect
checked and resealed exhaust to head
checked the valve clearances
checked the timing

i've also tried a new spark plug and checked all electrical connections on that side of things i dont think its spark related.

i purchased a jetting kit and i've tried using 96# 100# 102# 104#
the secondry jet is a #36 i have not touched this.

i have also tried the needle in all settings and have settled that it runs best one down from center.

and my air screw on the carby is at around 2 turns outwards and i have been playing with this i.e turning it in till the revs drop then backing it out till the revs peak and leaving it at that setting .

my OKO carby has the swivel style top where the cable exits the carby are these prone to leaking air around this area could this be a problem ??

oh and i'm located in adelaide.

any suggestions would be great awesome forum guys

i'm about to throw the towel in on the the oko and maybe just switch to a mikuni.. ??

 

[DHZ_XR8cing]

try #38 idle jet. where is your needle set? double check the o ring on the carbie manifold. dont over tighten it.

 

[pbk]

i find 36 pilot and 102 main works best, you should be able to rule jets out as your problem... re check your valves and timing

and e clip on either middle notch or one above

EDIT: check all breather hoses are not blocked.... i know it may sounds stupid but make sure your got enough petrol and your tap is on

 

[DHZ_XR8cing]

i find 36 pilot and 102 main works best, you should be able to rule jets out as your problem... re check your valves and timing

and e clip on either middle notch or one above

EDIT: check all breather hoses are not blocked.... i know it may sounds stupid but make sure your got enough petrol and your tap is on

The fuel tap is a great 1.on my bike with the fuel tap when its turned on only dribbles out.. enough for it to run but rough.

 

[thump*140]

The 155 will actually be happier with a 40 pilot over the 36. 36 is a bit lean for this particular motor so i've found.
Don't turf the oko for a mikuni, it's like taking a backwards step in evolution...
I'm in Adelaide, have tuned "one or two" okos, if u want some help, pm me, can probably sort u out

 

[pbk]

The 155 will actually be happier with a 40 pilot over the 36. 36 is a bit lean for this particular motor so i've found.
Don't turf the oko for a mikuni, it's like taking a backwards step in evolution...
I'm in Adelaide, have tuned "one or two" okos, if u want some help, pm me, can probably sort u out

i have no clue how you run your oko's with 40 pilot jet..... it must have something to do with altitude cos i tried a 40 pilot and ran like shite and your honestly the only one that seems to run 40 pilot

your clearly different thump to us normal people

 

[thump*140]

nah, it only seems to be the 155z that has needed the 40 pilot PBK...
The 150 lifans and 160 yx's i've helped tune over this way have been happy on 36-38 pilots... but yeah, the 155z in the miniblitz was severely unhappy with anything smaller than a 40 pilot, was backfiring pretty badly on deceleration...

 

[pbk]

hmm very weird it must have something to do with being in another state

 

[sean01]

hey thump, can you verify what brands pilot jets your using? the ones from the revmx kit? keihin? or dhz?

reason i ask is that i have come across a few pilot jets now of different brands and have found them all to be different sizes tho there marked the same number.. IE: a keihin 35 was same as a no brand 39 (checking with jet drills)

ok back on topic...

i cant comment on the 26 oko on a 155 as iv only used the 28mm but it should share the same pilot..
we found it would run fine with a 36 or a 38 we also found a 40 to be way off, but as above it would depend on the jet brand.

also i would recommend that you strip the carby and clean/blow it out as it may have something floating around in it..

also can you verify the needle part number, it should be a JJH but i have seen others..
also is the same with and without an air cleaner?
may pay to check the ignition pickup to magneto tab clearance.

also a video of it running would help..

 

[fane]

just incase it helps

i put an OKO flatside 26mm on my stock dhz dpro160 aka 155z on the weekend with a 36 and 100 with needle on middle clip and it pulls cleanly all the way through the rev range

 

[thump*140]

hey thump, can you verify what brands pilot jets your using? the ones from the revmx kit? keihin? or dhz?

reason i ask is that i have come across a few pilot jets now of different brands and have found them all to be different sizes tho there marked the same number.. IE: a keihin 35 was same as a no brand 39 (checking with jet drills)

ok back on topic...

i cant comment on the 26 oko on a 155 as iv only used the 28mm but it should share the same pilot..
we found it would run fine with a 36 or a 38 we also found a 40 to be way off, but as above it would depend on the jet brand.

also i would recommend that you strip the carby and clean/blow it out as it may have something floating around in it..

also can you verify the needle part number, it should be a JJH but i have seen others..
also is the same with and without an air cleaner?
may pay to check the ignition pickup to magneto tab clearance.

also a video of it running would help..

Seano you talking about seeing a vid of my bike running with the 40 pilot??
the pilots i'm using are, i believe, from the Revmx kit.... so who knows how they compare to a size 40 Keihin... I tried basically every jet in my arsenal, and the 40 was the best of the lot... runs the same with and without the air cleaner, but i dont run filter oil on my pods, never have... Needle is a JJH, on the middle clip..and yeah, the carby is spotless, they always are... fiddly bloody things pitbikes are...

 

[sean01]

hey thump, can you verify what brands pilot jets your using? the ones from the revmx kit? keihin? or dhz?

reason i ask is that i have come across a few pilot jets now of different brands and have found them all to be different sizes tho there marked the same number.. IE: a keihin 35 was same as a no brand 39 (checking with jet drills)

ok back on topic...

i cant comment on the 26 oko on a 155 as iv only used the 28mm but it should share the same pilot..
we found it would run fine with a 36 or a 38 we also found a 40 to be way off, but as above it would depend on the jet brand.

also i would recommend that you strip the carby and clean/blow it out as it may have something floating around in it..

also can you verify the needle part number, it should be a JJH but i have seen others..
also is the same with and without an air cleaner?
may pay to check the ignition pickup to magneto tab clearance.

also a video of it running would help..

Seano you talking about seeing a vid of my bike running with the 40 pilot??
the pilots i'm using are, i believe, from the Revmx kit.... so who knows how they compare to a size 40 Keihin... I tried basically every jet in my arsenal, and the 40 was the best of the lot... runs the same with and without the air cleaner, but i dont run filter oil on my pods, never have... Needle is a JJH, on the middle clip..and yeah, the carby is spotless, they always are... fiddly bloody things pitbikes are...

above in bold is directed to you thump, and i dont doubt that your jetting is correct, its just everything iv tried a 40 pilot in falls over(except sht carbies).

the rest is directed to the thread owner..

 

[travishawton]

Thump*140 im running a 39 pilot and 102 main on my 155z with v2 head on it, I still think ill have to go to a 40 or bigger to stop mine from backfiring on decelaration its only half a turn out on the air screw and running a bit lean going by the colour of the plug.

 

[thump*140]

yeah backfiring on deceleration is usually a lean pilot... try going to a 40 or 42, open up your air screw a tad, that will soon tell you which pilot is the winner...

 

[turbomini]

thanks heaps to everyone for their ideas on this one espically Thump*140 who discovered what my actual problem was. which was a dodgy stator. at least i've learnt a lot about jetting and such now.

my next question is. where can i get an outer rotor kit to suit xy160 with charging circuit as DHZ are currently out of stock... ?

 

[thump*140]

Jr motorsports in china sell them. I'm pretty sure I've linked them in a thread about eBay pit bike suppliers. Might be in the tech section???