Red 125 wkn

[Sly93]

Red 125 wont start ??? Help Please !!!

I have a little red 125 not sure what brand of bike it is but it is electric start i would like to keep the electric start but it wont work witch i think the battery is stuffed so for now i am just focusing on getting the engine started just by kicking it then figure out the electrics . But the engine wont fire it has plenty of spark and the carby is fine well it seems fine if you release the drain screw from the bottom of the carb it has plenty of fuel there witch is right true ? But the spark plug is bone dry ? Mag is fine wires look fine so what would be the problem? I have changed they key cause it was stuffed would that be a problem but carnt you just unplug them and it should still kick over ? My next step is to tighten the valves cause there extremely loose maby that's part of the problem ? Just waiting on the tools and then my next thought was to unplug the kill switch incase the contacts are playing up but then there wouldnt be spark would there ? Hope someone can help me out so i can learn why it isnt working and so i can learn to fix it .
Really appreciate any type of help .
Cheers, Kurt

 

[my67xr]

it sounds like the Pilot Jet is blocked up in the bottom of the carby.
the Pilot Jet supplys the fuel to the engine from idle up to 1/4 throttle.

pull the carby off, and the fuel bowl off
dry the rubber bowl seal so it doesn't expand.
then you will see the central main jet , right in the middle of the carby base.
slightly closer to the manifold side of the carby will be the Pilot Jet, unscrew it and hold it up to the light.
you should be able to see through the middle of it.
these carby have a tiny hole, poke a strand of fine wire through it to try and unblock it.
a strand from some copper wire etc
and check the holes that go across the jet too, if they are blocked it wont get the correct amount of air to mix with the fuel for idle.
once the jet is clear, look into the bottom of the carby where the jet come from.
hold the intake manifold side up towards the light, and look through the bottom of the thread where that Pilot Jet screws into, you should be able to see light through into the carbys' main bore.
if that hole is blocked, the bike wont start

 

[Sly93]

Ok no worries thanks heaps i will give it ago when i get home thank you. But im still wondering there is fuel in the bottom of the bowl but that dosnt matter if that centre jet is incorrect is that right ? Thanks again , Kurt

 

[my67xr]

it will be the jet that is next to the Centre jet, the smaller Pilot Jet that is blocked
if it is, it wont let the fuel from in the carby bowl, be drawn into the engine when the bike starts up and idles,

the Pilot Jet is the one on the left in this picture




this is where you need to be able to see light through into the carby bore with the jet removed

 

[Sly93]

Ok no worries thanks mate your a legend carnt wait to get home and see how it goes
Thanks again mate .

 

[Sly93]

I have done what you said mate and the plug is still dry ? What else could be rong ?
Cheers, Kurt

 

[my67xr]

do you have a compressor??

you'll need to pull the carby off again, and remove the fuel bowl
take the Pilot Jet out, and the central Main Jet, also the small brass mixture screw and spring from the side of the carby (not the bigger idle speed screw with the visible spring)
then on the air filter side of the carby there are 2 or 3 small holes, you'll need to blow compressed air through them one at a time
and check that you can feel it coming out one of the holes on the bottom of the carby

 

[Sly93]

Yea there is air coming out of there now what do i do ?
Cheers, Kurt

 

[GooseMan]

do you feel air blowing through all of the holes he^ mentioned, if so that is a good sign. if you have a strong spark then electrics are not at fault. What do you mean when you say your valves are loose though??

Do you have some way of towing the bike, is so then tow it about 3rd gear with the clutch out, sometimes this gets the bike going if it has been sitting for a while. I believe it must flush any sh*t in the carby out.

 

[my67xr]

so when you put compressed air into one small hole, you can feel it coming out the main jet hole in the bottom of the carby.
then you blow it through the other hole on the air filter side and it comes out the pilot jet hole


reassemble the carby and screw the mixture screw all the way in, then turn it back out 1.5 full turns.
this will give you a good enough fuel/air mixture to be able to start the bike

have you checked that the slide sits almost at the bottom of the carby bore ?
if not adjust the idle speed screw so it lifts the slide a couple of mm up from the bottom.

 

[Sly93]

Yea air goes through all holes the carb was on another engine i had sitting on the ground that i got going sitting on the ground so Im starting to think its not the carb or am i rong ? And there is plenty of spark. And when i say valves i mean exhaust valves and inlet valves witch i adjusted them today to 0.04 mm for the inlet and 0.06 mm for the exhaust and yea i guess i could but thats not really how i wanna start it all the time lol .
Cheers, Kurt

 

[my67xr]

you might want to readjust your valves then, .08mm for the inlet and .1mm for the exhaust


is the slide sitting close on the bottom of the carby bore?

are you using choke ?

 

[my67xr]

you only need spark, fuel and air for an engine to run, and you say you have all 3.
but we need to work out the reason the spark plug is not getting wet


do you have a spacer/insulator fitted between the carby and the manifold

 

[Sly93]

Yes that is correct air blew through freely .
Ok well i will reassemble it tomorrow after work and try it but as i said to goose man i had that carb in another bike that i got running thats why i dont understand why its not working on this engine and maby its not the carb but i will do what you said tomorrow and see how i go.
And when you say the slide what exactly do you mean maby you could post a photo of what you mean please ?
And im sorry about all the questions i just really wanna get these bikes going and im that keen to learn at the sane time hope we can work this out thanks again .
Cheers, Kurt

 

[my67xr]

the slide is the cylinder that moves up and down in the carby when you move the throttle

and you'll need to try and answer my other questions too, this will help me work out what is wrong


can you post a couple of pictures of the carby on from the side, and one looking inside it from the air filter side (with the filter removed)

 

[GooseMan]

When you try to start it do you use the choke? Or any throttle? Kick it over at full throttle a few times, check the plug and it should be wet for sure. If not then something is stopping fuel from getting from the carby through the manifold. Maybe even an air leak.

 

[Sly93]

the slide is the cylinder that moves up and down in the carby when you move the throttle

and you'll need to try and answer my other questions too, this will help me work out what is wrong


can you post a couple of pictures of the carby on from the side, and one looking inside it from the air filter side (with the filter removed)

Ok ill check when i get home and what Questions haven't i answered i think some of my replies get de-laid and come up after you reply to me sorry about that and i will check the slide when i get home i will adjust the the mixture screws and yes i have a spacer between the carb and manifold and yes i do yous the chock whats better half open, full open or closed ?
Hope i have answered all your questions .
Cheers, Kurt

 

[GooseMan]

I just mean open the throttle full this once to see if fuel is getting into the cylinder. Normally it should start with no throttle or just a bit.

 

[Sly93]

I just mean open the throttle full this once to see if fuel is getting into the cylinder. Normally it should start with no throttle or just a bit.

Yea i understand what you mean once i throw it back together ill give it a try just to see if it will wet the plug thanks GooseMan.

 

[stoozo]

you can try putting your hand over the intake side of the carby to block it off, then kick it over a couple of times.
then try restarting it, no throttle no choke etc

it will take a couple of kicks, then might fire up


let us know how it goes