This cb125 is going to be the death of me
- Thread starter swizbee42
- Start date
swizbee42 said:
Ok what is going on here. You guys are talking about a condenser, he's got fuel pissing out the back of the carb. We need to fix this first.
Do you mean the bike is backfiring, or its literally dripping out the air intake side of the carb?
Please address one thing at a time. Its impossible to diagnose things when you're talking about electrical issues one second and then we just glance over the fact that you have fuel coming out of where its not supposed to.
Post a video of the bike running or you trying to start it or something. Is it even running at this point?
advCo said:
It is running. It starts no problems and idles all day. Ot does not like anything above 1/3-1/2 throttle. The fuel is not pissing out, its blowing backwards out of the intake side of the carb behind the slide. I'm talking about fuel and electrical because I think they are related. Like I said before when there is any electrical load on it it gets worse
Here is a video of the carb
https://youtu.be/ayP7bmJFinE
That's with a 90 main jet and the needle in its lowest position no electrical load
https://youtu.be/CygzVbBxd6Q this was with the old battery and rectifier. Since been changed it has made 0 difference
Ok. Videos are helpful. The first video sounds like a classic lean condition caused by a vacuum leak. Your idle is way too high and bogging when you rev = vacuum leak is the first place I'm looking. Idle should be at 1200 RPM.
Spray starting fluid or something all around the intake manifold where it connects to the carb, and where the intake connects to the head. If your Idle changes at all (it will likely surge), then you need to address that first.
The fuel coming out of the air intake side of the carb ain't right. Check your float height and see if that fixes that issue, my guess is that your float height is set too low and filling the bowl too high with fuel or a leaky needle and seat inside the carb that's allowing too much fuel in.
Your charging system seems fine. 7v while idling should be more than enough on a 6v system. Lets get the thing running right and then get into the electrical. I think you have 2 separate issues here and trying to fix them both at the same time is confusing for everyone.
Spray starting fluid or something all around the intake manifold where it connects to the carb, and where the intake connects to the head. If your Idle changes at all (it will likely surge), then you need to address that first.
The fuel coming out of the air intake side of the carb ain't right. Check your float height and see if that fixes that issue, my guess is that your float height is set too low and filling the bowl too high with fuel or a leaky needle and seat inside the carb that's allowing too much fuel in.
Your charging system seems fine. 7v while idling should be more than enough on a 6v system. Lets get the thing running right and then get into the electrical. I think you have 2 separate issues here and trying to fix them both at the same time is confusing for everyone.
advCo said:
I will try both of those tonight and report back. Although I have tried the float height multiple times. Everything I have read says 21mm is what it should be set to. But I have not tried to see if there is a vacuum leak yet. I know the idle was too high and I was kind of doing it for video sake to measure voltage with 1 hand.
Ok interesting turn of events. Set floats to 22mm and wont start. Leak down test .....100% leak down. But pressure coming out of exhaust, which either means a smoked valve or off timing. Yes it was at TDC on compression stroke. Now here is my question
Is it possible to have all the timing marks lined up but have the cam bolted in 180° out? And if it is possible would it run?
Because if it is off time that way. That would explain the pressure at the carb.
About 1 step away from throwing a match at it
Is it possible to have all the timing marks lined up but have the cam bolted in 180° out? And if it is possible would it run?
Because if it is off time that way. That would explain the pressure at the carb.
About 1 step away from throwing a match at it
I don't believe it can be 180 out, its a 4 stroke.
My 360 would bog exactly the same, because it was too rich, try smallest main jet and lowest needle.
Its been too long and I don't recall what main jet I have in Piglet.
What does the manual say for float height?
My 360 would bog exactly the same, because it was too rich, try smallest main jet and lowest needle.
Its been too long and I don't recall what main jet I have in Piglet.
What does the manual say for float height?
There is always some reversion, but that is off the charts. Try a smaller main jet and see if it makes any difference.
I would also check teh main air jet and passage to the needle jet (emulsion tube) to be sure that air is getting through. The main air jet is really small on those carbs - something like 0.5mm diameter (20 thou). If it's blocked, the carb is drawing in raw fuel instead of tiny droplets.
I would also check teh main air jet and passage to the needle jet (emulsion tube) to be sure that air is getting through. The main air jet is really small on those carbs - something like 0.5mm diameter (20 thou). If it's blocked, the carb is drawing in raw fuel instead of tiny droplets.
