MY ZX50 O.E.M CARB TUNING

[thebatman]

ok, im back, lets hope all you still here.  ok i tried to pull a zombie and make a jet with my microbits. i used the next size bit(no#),i got .838mm,.033in. opened it up a tad. i did a plug chop(indexed)with oem jet and one(indexing slightly off) with the bigger jet. my scooter must be smokin crack!!!   i think all have a gray look. the oem is alot lighter colored on the mix ring (which btw is the "colored ring" around the ceramic bottom portion of the shank but not dead down from top, slightly upward, correct??) anyway with the bigger jet it was virtually unchanged from oem(performance, responsivness), the mix ring was also a lighter color and thinner ring but looked gray to. seemed unchanged to me, well rpms did seem to drop a few hundred at take off, i could tell she wasnt starving as bad as with oem. took a short ride(w/a chop plug), that plug looks/has a VERY faint ring around it(dont look gray, light makes it disapper, the ceramic is started turning a brownish color w/13?mi ride..hmm?? must b the crack

[art]

It sounds like your close'be nice if you had a couple sizes larger to try.I'd rather be to rich than work down.

[thebatman]

thats my issue, cant find any jets for this dam thing yet, one more possibility tomorrow. how could i be close if its not better,but same(performance,response). i can drill out to next size..lmao, but i cant put the metal back in if to big..this first chop i done i could actually tell it was better, more pep, better response. some said wrong color yesterday,now i tapped it bigger and lost that pep..         so i should put the oem jet in, set my idle. the mix screw is 1-1/4 out right now....    dont know if i like the ngk boot w/ its hard ass plastic tho....

[art]

I miss read thought you said was better with bigger jet.Scratching my head now!I had to go from a #70 to a #90 open air and pipe,and still a hair lean http://www.dansmc.com/spark_plugs/spark_plugs_catalog.html  Have you looked at this yet

[thebatman]

no, not really, pretty much unchanged, lost a few rpm at take off and i can tell she isnt as thirsty but not peppy..   yeah ive seen that but they never say how many miles are on those plugs anywhere, my chop plugs look new except for mix ring, this plug with 13? miles started coloring some tho

[sidthesloth]

If you go to large just solder it up and drill it out to a smaller hole.

[thebatman]

ok, im back, lets hope all you still here. ok i tried to pull a zombie and make a jet with my microbits. i used the next size bit(no#),i got .838mm,.033in. opened it up a tad. i did a plug chop(indexed)with oem jet and one(indexing slightly off) with the bigger jet. my scooter must be smokin crack!!! i think all have a gray look. the oem is alot lighter colored on the mix ring (which btw is the "colored ring" around the ceramic bottom portion of the shank but not dead down from top, slightly upward, correct??) anyway with the bigger jet it was virtually unchanged from oem(performance, responsivness), the mix ring was also a lighter color and thinner ring but looked gray to. seemed unchanged to me, well rpms did seem to drop a few hundred at take off, i could tell she wasnt starving as bad as with oem. took a short ride(w/a chop plug), that plug looks/has a VERY faint ring around it(dont look gray, light makes it disapper)

[thebatman]

well i just went out and turned mix screw another 1/4 turn to 1-1/2 turns out, she seemed to respond better to that,(ran better, bit more pep) am i crazy or am i getting anywhere near spot??    my idle is taking a bit to come down tho, (which started when i redid my cvt last week), but may b a touch worse with this bigger jet in.. also seems to have altered cvt a slight touch, is this possible??   maybe 1/2g lighter roller??   

[zombie]

I'm even having a hard time here. Try this Batman... Run a NEW plug for 60 seconds at wot. Just post the result from that. Setting your idle mix for the highest rpms on the mix screw is still a touch too lean. You will need to get it to the highest rpm's, and then turn the screw 1/4 turn counter clockwise, that is the best setting. Once you have that use the slide adjustment screw to bring the idle to the desired rpm.

[art]

Hey learned something new again,I always set to to highest idle,That would explain why mine is raceing a bit at stops now.I'm a bit late to this thread do we know the carb model.If its the pb I found alot of info for it.

[thebatman]

what up zombie?  ok, even have a magnifying glass. with this bigger jet, it still looks grayish to me.it is a fainter, thinner ring than before tho, i put a light on it or in sun ring looks to dissappear. curved part, creamy. seems to run ok i think.. flatter than before till wot, cvt changed

[Shaka]

I've missed quite a bit on this and am a little lost.  You're saying it performed best with the oem 90 jet, correct?  When you opened the jet up a little the mix ring was lighter and you lost your performance?  Keep in mind the best performance is going to occur with a lean mix!  You don't necessarily want to tune by performance, but by what the plug tells you!  If you tune by performance your performance won't last long! 

I found it real difficult to distinguish between plug chops done with jet sizes very close to one another as well.  What I really ended up doing was running one I know was too big for awhile and getting some good color on the plug.  Then I would drop down one jet size and do the same until I ended up with a plug that was nicely browned after running for a couple days. 

[thebatman]

no, not really shaka. it runs ok with oem jet, just starving. this big jet she runs a bit better but the plug still grayish, even richened it a tad.idk size, noticeable difference in size, bit was .838mm. other things changed also(cvt,pipe sounds)

[zombie]

Try going up in size again. 85-87? I like shakas advice on going too big, and working back. It is alot safer that way. BUT you are soooo close to the right set up. I think you will find 86 will get it for you. Just work on the plug chops for now... forget the rest for a minute.

[Shaka]

I thought you started with a 90 jet.  Is that smaller than your 0.838mm bit?  Take Zombies advice about only changing the jets right now and focusing on the plug chops.  You don't need to readjust any of the screws for each jet.  Those screws only adjust the idle circuit and have no effect on your main jet/WOT plug chop!