POS cb125 bucket

[wbks]

Hey Ixion.
The bowl does look like it has soot on it but it's not going to come off for a steel wire scotchbrite so it shouldn't be a factor in gas. Should there be more parts strewn all over the place or is that all there is to it? Just squirted carb-clean down the part that recieves the gas, and pretty much every where else and and sprayed it out with the air compressor. It did seem to slightly turn white when dry on some of the carb but for the most part it's a bit cleaner. Am I doing it right?

[Ixion]

Problem isn't the gunk in the float bowl, it's that if there is gunk there there will also be gunk in the internal passages., Where it a problem. LOTS of cleaning required. Not just the bowl, the little wee holes in the body.

[wbks]

Yea I'm going to get to that but are the parts on show there the only ones I need to remove? Otherwise I'm just going to use a cotton bud dipped in carb clean where possible and just spray the rest with carb clean through all the holes and hit it with the compressor?

[Ixion]

I'm looking for the main jet? Should be a little round screw about 6mm long and 4mm diameter or so. May be there, I can't spot it. Anyone, familiar with Keihins (IS it a Keihin? looks like it)

SL125 carb should look like attachment Main jet is #16

[wbks]

Well looking at it it looks like the float valve, throttle valve/jet/whatever, and slow valve is there but no little "main jet"? Unless, and sorry if this is a little stupid, but it looks like the Main jet goes on top of the throttle valve as pictured?

[Ixion]

Yep. that'll be it, still screwed in. All good. Just clean clean clean and then start all over again and clean some more. Lots more actually.

[wbks]

Took the mainvalve off and every bloody gap is clean as a whistle, air blows through it fine, and there is no gunk I can see but the bike still won't go. I don't really see what spraying more glorified paint thinner into it and hitting it with more compressed air is going to do...

[koba]

Took the mainvalve off and every bloody gap is clean as a whistle, air blows through it fine, and there is no gunk I can see but the bike still won't go. I don't really see what spraying more glorified paint thinner into it and hitting it with more compressed air is going to do...

yeah but its another thing to tick of the list for sure.

[wbks]

I think I've been "ticking it off the list" for two days while i've had it apart drenched in caberator cleaner. Can't really see what else to do to it? No visible dirt, no blockages, had it all apart, all put back together properly and tried the carb setting a turn differently about 5 times going a turn back from the stop every time

[koba]

I think I've been "ticking it off the list" for two days while i've had it apart drenched in caberator cleaner. Can't really see what else to do to it? No visible dirt, no blockages, had it all apart, all put back together properly and tried the carb setting a turn differently about 5 times going a turn back from the stop every time

Float level is another thing to check at this point.
You will need to find out what it should be for your bike/carb.
It prob won't help it start but it is somthing worth checking while you have it apart.

[koba]

Oh, to skip back a bit too...
To check condenser but a 6V battery across it for a few seconds, then pull it of, then touch the wire to the body and you should get a small spark.
Look closely.
If it is stuffed a condenser is a condenser so try find one that will fit in the gap but I think it can be installed anywhere between the points and coil.

[wbks]

It's getting a massive loud spark that will jump from the plug to the head almost 1cm away from it so the spark is fine.

[wbks]

And before I say anything else: If I sound a little negative and pessimistic, it doesn't mean I don't appreciate the bits of help some of you are giving me so keep it coming

[Ixion]

OK. Time to stand back a bit.

Three things required for an IC engine

Spark, at the right time
Fuel, in the right ratio
Compression

Given those three, and engine MUST fire. (assuming no massive mechanical dereangment)

So, you are lacking one of those. And you've gone through the book, so whatever is missing, it's going to be something you'll say "Nah, can't be that, cos... ".

Spark, per se, is sounding less and less likely.

Fuel, if the carb is clean , it can't be that much out, it should fire at least. maybe run rough, misfire, choke, blow smoke, but it should run. These are not fussy engines. Assuming there is not a honking big air leak where the carb goes onto the motor?

So, that leaves either compression, or timing. Are you sure you have compression ? Really sure? . Checking the timing isn't too hard, but it's one of those things that's real hard to describe. Is there someone could give you a pointer. Some of us will be fluffing around down southish at the weekend .

One last thought. You've checked the spark when the bike is stationary. But have you checked it when you are pushing it ? I've known stranger things. Secure the plug to an earthy point (bit of sellotape works). Push the bike along in gear (easy this time, with the plug out), see it it is sparking away.

Remember, when all else is eliminated, then whatever remains, however improbable may be the truth.

(Oh, I assume you have drained all the petrol out and replaced it with new stuff - always one of the first things to do. )

[wbks]

I mite take it down to the buckets at mt wellington on sat or sun if anyone thinks they can help out. The tank and cap is absolutely f'd at the moment and puts a cup of gas on the tank and down to the pipe every 5-6 pushes unless you stuff a rag across the tank and put the cap down so I don't think anyone but me will go near it haha.

Compression seems pretty stong but I haven't done a proper test or anything.
I could try the spark while moving tomorrow.