atomik 125cc OWNERS OPINION

[zwebx]

hey man thanks for the info. the cdi that you mentioned, does it only increase the rev range? (sorry this may be a silly question but hey im still learning). i have rimlocks on my rims (igot them off a cheap bike i got for 30 off an idiot at school and i also ripped the forks out and i've got em on my bike now) and a gpx 125 motor sounds like a good option, but i hav a limited budget, but is 125 my limit? are there any other bigger sizs i could fit? and my carb is a mikuni 'racing carb' at 25mm and my rear shock is quite adjustable. and my spark plug is a ngk, but it probably needs replacing by now.

the plugs last a long time dw about replacing it till it breaks (prolly 1000 hours of life in them just guessing) 125 is no limit, just thought if you did not want to go larger then gpx is the go.. thats $400 new and there is not much second hand market for them (i could be wrong) but keep a keen eye out for a yx 160 or a zongshen 155 (also called a 155z and pitster pro 155) s/hand and even get it if its smokey (if its cheap) and then maybe save a little bit and rebuild it. your frame will fit any "pitbike" style engine that are the same size (some are a little longer and whatnot) as the ct 110 bikes (postie bikes) but they all have the same mounting points..
you could replace your carby to a oko carb 26mm but im not sure what the power difference would be..

my advice as to this engine.. (if you are not already happy with the power) ride it and ride it hard till it blows up and while riding her get some cash under your belt for a nice larger engine..
i dunno maybe im just being a power freak (its a addiction once you start)

 

[Blender]

the plugs last a long time dw about replacing it till it breaks (prolly 1000 hours of life in them just guessing) 125 is no limit, just thought if you did not want to go larger then gpx is the go.. thats $400 new and there is not much second hand market for them (i could be wrong) but keep a keen eye out for a yx 160 or a zongshen 155 (also called a 155z and pitster pro 155) s/hand and even get it if its smokey (if its cheap) and then maybe save a little bit and rebuild it. your frame will fit any "pitbike" style engine that are the same size (some are a little longer and whatnot) as the ct 110 bikes (postie bikes) but they all have the same mounting points..
you could replace your carby to a oko carb 26mm but im not sure what the power difference would be..

my advice as to this engine.. (if you are not already happy with the power) ride it and ride it hard till it blows up and while riding her get some cash under your belt for a nice larger engine..
i dunno maybe im just being a power freak (its a addiction once you start)

thanks for the answer man (and sorry for my horrible typing) im going to check my plug today and see whether its running lean/rich or hopefully perfect. the zongshen engines sound good, but i cant find any around, so i dont know there price. so i was wondering what you think i should do if im to replace my engine with either the zongshen or the gpx. in my opinion the gpx sounds like the better option, but i have limited experience with mods to this degree and would like to know what you thought. Cheers jack

 

[Blender]

i just pulled my plug out and found it was running a little rich. i've got another bike under the house that im not sure what brand it is. i found most of the stuff on it can be used on my atomik. i pulled the forks, wheels, sprockets, rear shock, carb and the ignition system. i'll put some photos up of it soon so uyou fellas can hopefully tell me if a better engine/what size it is and so on. i also pulled the plu out of it and found that it is the same plug as my atomik has got. a ngk c7hsa, that was running a little lean. i'll try and get some pics of both bike soon.

 

[zwebx]

thanks for the answer man (and sorry for my horrible typing) im going to check my plug today and see whether its running lean/rich or hopefully perfect. the zongshen engines sound good, but i cant find any around, so i dont know there price. so i was wondering what you think i should do if im to replace my engine with either the zongshen or the gpx. in my opinion the gpx sounds like the better option, but i have limited experience with mods to this degree and would like to know what you thought. Cheers jack

nothing to be worried about doing anything to the engines, i could train a monkey to do it its simple its just not forgetting things that is hard (lol like a rocker adjuster) its hard to get the 2nd hand zongshens and yx's because people with a keen eye snatch them up really quick
if you post a pic of your carb it will be better to identify
if its the one im thinking of then on the bottom towards the front is the air fuel mixture adjustment screw you may be able to make it better with that?

 

[my67xr]

the carby could probably benefit from a bigger pilot jet too, a #20 ?

 

[Blender]

hey guys http://www.google.com.au/search?hl=...A%2F%2Fwww.mytrailbuddy.com%2F19.html;432;324 a link to my carb. its not the EXACT one of my bike, but its the one that came with it.

 

[zwebx]

yeah, looking at the photo the air fuel adjustment is on the bottom (you can see it its the flat head one)

 

[Blender]

yeah, looking at the photo the air fuel adjustment is on the bottom (you can see it its the flat head one)

so how should i adjust it..or should i? do i tighteb it or loosen? sorry im pretty clueless, but dont be afraid to tell me everything u kno lol.

 

[Rodney68]

Screw it in lightly until it stops turning but only lightly as you can damage the screw then undo it 1 1/2 turns out and start from there you may have to turn it in or out from this setting. Best to use the search button at the top of this page and type in Mikuni tuning and you will find everything you need to know mate.

 

[zwebx]

so how should i adjust it..or should i? do i tighteb it or loosen? sorry im pretty clueless, but dont be afraid to tell me everything u kno lol.

im pretty sure this is the correct way around, but loosen it and it will make the main jet a little ritcher (not so loose that air can get around it) tighten it and it will lean out...
the best way to do this is to buy http://tboltusa.com/store/flex-jet-p-1063.html
(bending a screwdriver prolly wont work... it dident with mine)
get the bike to a high idle and then turn the screw in and out untill you get the highest rpm out of the idle (w/o touching the idle screw) for a steady ammount of time (so go in untill the rpm drops.. go out untill the rpm drops counting the number of turns and then go to the middle) and it should be able to idle steady without stagering and whatnot and she should be good

 

[Blender]

im pretty sure this is the correct way around, but loosen it and it will make the main jet a little ritcher (not so loose that air can get around it) tighten it and it will lean out...
the best way to do this is to buy http://tboltusa.com/store/flex-jet-p-1063.html
(bending a screwdriver prolly wont work... it dident with mine)
get the bike to a high idle and then turn the screw in and out untill you get the highest rpm out of the idle (w/o touching the idle screw) for a steady ammount of time (so go in untill the rpm drops.. go out untill the rpm drops counting the number of turns and then go to the middle) and it should be able to idle steady without stagering and whatnot and she should be good

thanks man that really helpful. my bike was running a little rich so this can kill 2 birds with 1 stone! so u HAVE to take the carby off to do this? by the looks of it i think you do but just wanna be sure. cheers jack

 

[zwebx]

thanks man that really helpful. my bike was running a little rich so this can kill 2 birds with 1 stone! so u HAVE to take the carby off to do this? by the looks of it i think you do but just wanna be sure. cheers jack

if you get the flexi jet installed then you dont..
thing is to do it properly you have to have the bike running.. so you could take the carby off and turn it and hope its better but it will never be exact unless you adjust it while its running

also a quick tip.. undo the bolt closest to you back off the one farthest from you (the carby mounting bolts) and then you might be able to adjust the air/fuel screw without taking the carby off
its in a prick of a spot.. thats the reason i went to a cheap moklt because the adjuster screw is where it should be, on the left up and in view... easy to get to (not on my frame so much though lol

 

[my67xr]

if you are lucky, sometimes you can adjust that screw with a small flat screwdriver bit.
like the one on the left, watch you dont burn your hands on the barrel too.



you need to have the bike running and warm when you go to set/adjust the mixtures.
turn the idle speed screw in .5 - 1 turn to raise the idle a bit.
then adjust the fuel mixture screw so that the engine runs at the smoothest/fastest speed.
once you are happy with that, then drop the idle speed back down so it happily idles by itself.

then take the bike out for a ride and see how it goes, it may need a little tweeking on the mixture screw to get it right.

i'm pretty sure you will need a bigger pilot jet for it too.
when the bike is warm, and you have it idling, give it a blip on the throttle, does it hesitate a bit, then go to rev?
if so then the pilot jet needs to go up a size or 2.
DHZ and most good bike shops will sell you a replacement jet for about $8 - $10
you need to take the carby off, re,move the fuel bowl and then swap the new jet in.
the old one will most likely be a #15 or possibly a #17.5
i would try a #20 pilot jet, i have found this size works well with the 125's.

 

[Blender]

if you get the flexi jet installed then you dont..
thing is to do it properly you have to have the bike running.. so you could take the carby off and turn it and hope its better but it will never be exact unless you adjust it while its running

also a quick tip.. undo the bolt closest to you back off the one farthest from you (the carby mounting bolts) and then you might be able to adjust the air/fuel screw without taking the carby off
its in a prick of a spot.. thats the reason i went to a cheap moklt because the adjuster screw is where it should be, on the left up and in view... easy to get to (not on my frame so much though lol

thanks man. i have abosolutely NO money atm so im tryin to make it go with the stuff i already got. like i said i hav another bike under the house that i salvaged for spares, a 125cc prodeced by 'wu yian yu sports eqipment. the model is 'wyay' and it was made in 2008 and is the same size as my atomik. i've been meaning 2 get some pics in, but my camera died recenlty if any1 knows anythin about these bikes, feel free to share

 

[zwebx]

there is not really much more to say.. accept for ride the damn thing ignore the pilotjet for now and ride it till she smokes and claps (like a french woman) then turf it and get another

 

[Blender]

if you are lucky, sometimes you can adjust that screw with a small flat screwdriver bit.
like the one on the left, watch you dont burn your hands on the barrel too.



you need to have the bike running and warm when you go to set/adjust the mixtures.
turn the idle speed screw in .5 - 1 turn to raise the idle a bit.
then adjust the fuel mixture screw so that the engine runs at the smoothest/fastest speed.
once you are happy with that, then drop the idle speed back down so it happily idles by itself.

then take the bike out for a ride and see how it goes, it may need a little tweeking on the mixture screw to get it right.

i'm pretty sure you will need a bigger pilot jet for it too.
when the bike is warm, and you have it idling, give it a blip on the throttle, does it hesitate a bit, then go to rev?
if so then the pilot jet needs to go up a size or 2.
DHZ and most good bike shops will sell you a replacement jet for about $8 - $10
you need to take the carby off, re,move the fuel bowl and then swap the new jet in.
the old one will most likely be a #15 or possibly a #17.5
i would try a #20 pilot jet, i have found this size works well with the 125's.

cool man. i had a look on my carb and it seems the mixtuer screw is on the right side, facing me when i look at it. i've jsut put new oil in it (castrol magnatec 10w-40) and its running alot smoother. i had a look at my old oil....and i wish i hadnt lol. but i'll toy around with my carbie today. and would u know what the primary jet size is? cheers jack

 

[Blender]

there is not really much more to say.. accept for ride the damn thing ignore the pilotjet for now and ride it till she smokes and claps (like a french woman) then turf it and get another

when getting anew bike what do YOU think i should get. i want something bigger. not only engine-wise but also size wise.

 

[my67xr]

the main jets in the copy mikunis are normally pretty close, most use a #95,
you wont really know what main jet it needs until you get the pilot jet right, and adjust the mixture screw
then do a couple of WOT runs and check the colour of the spark plug.

 

[Oznewbie]

Do you mean pilot jet a little richer ?

... And The needle controls the main ?

 

[Oznewbie]

Above is In relation to this

im pretty sure this is the correct way around, but loosen it and it will make the main jet a little ritcher (not so loose that air can get around it) tighten it and it will lean out...
the best way to do this is to buy http://tboltusa.com/store/flex-jet-p-1063.html
(bending a screwdriver prolly wont work... it dident with mine)
get the bike to a high idle and then turn the screw in and out untill you get the highest rpm out of the idle (w/o touching the idle screw) for a steady ammount of time (so go in untill the rpm drops.. go out untill the rpm drops counting the number of turns and then go to the middle) and it should be able to idle steady without stagering and whatnot and she should be good