too lean or not too lean?

[AntNZ]

Hi, i have finally got my z155/160ho stock engine running good, ended up with 39pilot and 105 main, clip in middle position, I think it might still be running bit lean but not too sure. Have attached photos of plug after a chop. Please advise..Thanks

 

[AntNZ]

Sorry, photos not that clear, will get more if needed.

 

[my67xr]

Yeah could be a bit lean still.
When you blip rev it off idle is there any hesitation, or even from 1/4 or 1/2 throttle when you go quickly to wot ?
Do you have a decent oiled foam filter on it

 

[motorman]

Yeah looks lean to me.

I would bump the main up to 110 and possible the pilot to 40.

 

[AntNZ]

Yeah could be a bit lean still.
When you blip rev it off idle is there any hesitation, or even from 1/4 or 1/2 throttle when you go quickly to wot ?
Do you have a decent oiled foam filter on it

No hesitation at any throttle position, revs clean all the way to top. I have uni pod filter and yes it is oiled, can you put to much oil on them? Carb is oko26 flatslide, I havnt heard of anyone on here with jetting this high with this carb/engine combo.

 

[gottagetacheaperhobby]

Try a 108 main jet, and double check for any airleaks around inlet manifold. It would be more likely you havent oiled the filter enough rather than to much if its lean, as less oil in the filter will allow more air flow. You can also try putting the clip on the bottom and doing another plug chop, if it looks better go up to the 108, return the clip to middle and do another plug chop.

Sent from my SM-T110 using Tapatalk

 

[AntNZ]

Try a 108 main jet, and double check for any airleaks around inlet manifold. It would be more likely you havent oiled the filter enough rather than to much if its lean, as less oil in the filter will allow more air flow. You can also try putting the clip on the bottom and doing another plug chop, if it looks better go up to the 108, return the clip to middle and do another plug chop.

Sent from my SM-T110 using Tapatalk

Thanks, i will try that in next couple of days and see how it goes. Raining here at the moment.

 

[AntNZ]

Sooo, i dropped the needle clip one notch, and bike wouldnt start, getting too much fuel, plug was absolutely saturated! I put clip back in middle and away it went. Now bike has started hesitating bout 1/4 throttle if i rev quickly, but once i get past that point it revs clean through to top.
I have a 39 pilot in it, wondering if i drop that back to a 38 will it fix the problem?
Last 2 weeks here have been uncharacteristically muggy/humid.
Or should i just play with air screw see if that fixes it?

 

[B3RG]

Hey AntNZ.
Ive got the same engine with the same carby.
I'm also having a few problems with mine dont know if its the heat in Sydney at the moment or what?

I've got a 102 main and 39 pilot
fuel screw is 1/2 turn out.
the needle clip hasnt changed so what ever it is out of the factory

Ive noticed that when I do a chop the plug is just black not too wet though.

it will start fine cold and does lag a bit off the mark.

when the bike is hot, I cant even get it to start

I also have a spare 100/m and 36/pilot

any suggestions?

 

[my67xr]

Hey AntNZ.
Ive got the same engine with the same carby.
I'm also having a few problems with mine dont know if its the heat in Sydney at the moment or what?

I've got a 102 main and 39 pilot
fuel screw is 1/2 turn out.
the needle clip hasnt changed so what ever it is out of the factory

Ive noticed that when I do a chop the plug is just black not too wet though.

it will start fine cold and does lag a bit off the mark.

when the bike is hot, I cant even get it to start

I also have a spare 100/m and 36/pilot

any suggestions?

When you do a plug chop, did you warm up the bike and run it up a slight incline held at wot in 3rd or 4th for 10 to 20 second's.
Then you turn the engine off (while holding it wot still) and bring the bike to a stop, now pull the plug out and check the colour.

Berg why are you running the mixture screw so rich at 1/2 turn out ?

 

[my67xr]

Sooo, i dropped the needle clip one notch, and bike wouldnt start, getting too much fuel, plug was absolutely saturated! I put clip back in middle and away it went. Now bike has started hesitating bout 1/4 throttle if i rev quickly, but once i get past that point it revs clean through to top.
I have a 39 pilot in it, wondering if i drop that back to a 38 will it fix the problem?
Last 2 weeks here have been uncharacteristically muggy/humid.
Or should i just play with air screw see if that fixes it?

Raise the needle clip to the second from top, then raise the idle speed and readjust the mixture screw to suit

 

[B3RG]

When you do a plug chop, did you warm up the bike and run it up a slight incline held at wot in 3rd or 4th for 10 to 20 second's.
Then you turn the engine off (while holding it wot still) and bring the bike to a stop, now pull the plug out and check the colour.

Berg why are you running the mixture screw so rich at 1/2 turn out ?

So the bike was hot going slight incline only 2nd gear and 1/2 the revs.

I read somewhere that with this setup with the air screw I should turn it all the way in the 1/2 a turn back (counterclockwise)
Could this be the reason its hard to start when warm?
it seems fine when its running but maybe it needs to be fixed and its going to be even better?

 

[AntNZ]

Hey AntNZ.
Ive got the same engine with the same carby.
I'm also having a few problems with mine dont know if its the heat in Sydney at the moment or what?

I've got a 102 main and 39 pilot
fuel screw is 1/2 turn out.
the needle clip hasnt changed so what ever it is out of the factory

Ive noticed that when I do a chop the plug is just black not too wet though.

it will start fine cold and does lag a bit off the mark.

when the bike is hot, I cant even get it to start

I also have a spare 100/m and 36/pilot

any suggestions?

Hi Berg, my bike was running fine 2 weeks ago with 39p and 105m, just got alot hotter and very muggy here lately.
Pretty sure your needle will be in middle position(out of 5 possible notches) if you havnt changed since you bought it.
My bike still going good just hesitates all of a sudden bout 1/4 throttle, put it down to heat/humidity.
If i roll on throttle slowly i dont notice any hesitation, only if i grab a hand full quickly do i notice it.
Im not the man to ask advice from, can only tell you what i have experienced myself.

It was fine before this heat wave so just guessing that it will only take minor tweaking to get it back to normal.

I thought my bike was running lean looking at plug, but it would seem i wasnt doing plug chops properly.

my67xr is the man to get your answers from, he seems to be a wealth of knowledge! Just post a question and he will answer, he cant help himself....haha

Thank god for people like him!!
If you see this my67xr (Craig), would dropping my pilot to a 38 from 39 help my 1/4 throttle hesitation?

 

[my67xr]

So the bike was hot going slight incline only 2nd gear and 1/2 the revs.

I read somewhere that with this setup with the air screw I should turn it all the way in the 1/2 a turn back (counterclockwise)
Could this be the reason its hard to start when warm?
it seems fine when its running but maybe it needs to be fixed and its going to be even better?

Can't tell much without running it at full throttle for 10-20 second's.
It takes a little while for the spark plug to get to it's self clean temperature

Start the air screw at 1.5 - 1.75 full turn's out, then tune it from there

 

[my67xr]

Hi Berg, my bike was running fine 2 weeks ago with 39p and 105m, just got alot hotter and very muggy here lately.
Pretty sure your needle will be in middle position(out of 5 possible notches) if you havnt changed since you bought it.
My bike still going good just hesitates all of a sudden bout 1/4 throttle, put it down to heat/humidity.
If i roll on throttle slowly i dont notice any hesitation, only if i grab a hand full quickly do i notice it.
Im not the man to ask advice from, can only tell you what i have experienced myself.

It was fine before this heat wave so just guessing that it will only take minor tweaking to get it back to normal.

I thought my bike was running lean looking at plug, but it would seem i wasnt doing plug chops properly.

my67xr is the man to get your answers from, he seems to be a wealth of knowledge! Just post a question and he will answer, he cant help himself....haha

Thank god for people like him!!
If you see this my67xr (Craig), would dropping my pilot to a 38 from 39 help my 1/4 throttle hesitation?

By slight hesitation do you mean like a stutter ? (the engine sound's a bit rough at 1/4 throttle)
I would suggest you try moving the needle clip up one notch, to the 2nd notch down from top

 

[AntNZ]

By slight hesitation do you mean like a stutter ? (the engine sound's a bit rough at 1/4 throttle)
I would suggest you try moving the needle clip up one notch, to the 2nd notch down from top

Im gonna try that right now, let you know in 20 min, i just get my bike out of the shed and have couple thou acres to roam......yeah I know, nobody likes a skite, Tracks are where i get my enjoyment from.....SooooN

 

[AntNZ]

O.k, So raised needle clip, worse than before, I now think that spark might be my problem...Plug is perfect colour(coffee tan).
pulled plug out and attached to plug lead, earthed it out on engine,frame and everything else i could reach with length of plug lead.. Couldnt get a spark from it no matter how hard i tried!! Dont know how the bike started at all!!
i will try new plug and keep you posted..
Could be a week or more before i get new plug.....

Is the NGK CR7HIX iridium plug sutible for this engine? 155/160ho

 

[my67xr]

Yeah, i'd be using that Irridium plug if i was you.
Might pay to test you stator and coil while you're at it too.
http://www.miniriders.com/electrica...urce-coil-pulse-coil-regulator-rectifier.html


Did you try checking for spark with the kill switch disconnected ?
Sometime's the wire's come loose inside and can short it out killing the spark.

Check your earth's are all good too, nice clean bare metal is best, with a thin smear of grease to stop it rusting.
Coil to frame, main harness to frame and engine mount's to frame too
And check all the join's from plug's to socket's are clean inside, and that the wire's havent come loose and pop out the back of the plug/socket.

 

[AntNZ]

Yeah, i'd be using that Irridium plug if i was you.
Might pay to test you stator and coil while you're at it too.
http://www.miniriders.com/electrica...urce-coil-pulse-coil-regulator-rectifier.html


Did you try checking for spark with the kill switch disconnected ?
Sometime's the wire's come loose inside and can short it out killing the spark.

Check your earth's are all good too, nice clean bare metal is best, with a thin smear of grease to stop it rusting.
Coil to frame, main harness to frame and engine mount's to frame too
And check all the join's from plug's to socket's are clean inside, and that the wire's havent come loose and pop out the back of the plug/socket.

Cheers mate, i'll check all that out tomorrow.

 

[AntNZ]

Yeah, i'd be using that Irridium plug if i was you.
Might pay to test you stator and coil while you're at it too.
http://www.miniriders.com/electrica...urce-coil-pulse-coil-regulator-rectifier.html


Did you try checking for spark with the kill switch disconnected ?
Sometime's the wire's come loose inside and can short it out killing the spark.

Check your earth's are all good too, nice clean bare metal is best, with a thin smear of grease to stop it rusting.
Coil to frame, main harness to frame and engine mount's to frame too
And check all the join's from plug's to socket's are clean inside, and that the wire's havent come loose and pop out the back of the plug/socket.

So that irridium plug you mention, is it the NGK CR7HIX?