Carb Wize?

[Dale]

It used to run fine. Then it doesn't and you discover that the slide was installed upside down and the cable stopper is missing. Cable stopper is not found in the inlet.

Given these facts, is the inlet big enough for the cable stopper to pass? I believe that it is and therefore the stopper may have passed into the cylinder, did some damage and then passed out the exhaust port.

What Clarence said, check compression...

[Bullfrog]

How long would it take to install and test a richer main jet while agonizing about the mystery of what changed? It just might be a very educational effort.
Ed

[viclioce]

It’s just been quite a conundrum. No other mechanic. It has fresh gas in it. He left the petcocks open at one point and it leaked out all over the garage floor. Good thing I keep cat litter on hand.

The issue started before he put the slide in upside down. I think he put it in upside down when we were checking it the first time. That’s why it’s so mysterious to me. Everything I can think to check has been checked & confirmed.

I read thru the 125 manual again today. Like it says there’s serveral ways to configure it and make it run right. The question is, what could change in its own? Tomorrow, I’m going to pull the spark plug and change it to a fresh one. Maybe it’s border line fouled but still firing?

The grandson has a tendency to run it at too low rpms. I keep telling him he needs to “get it up in the pipe” and run at higher engine revs, and I frequently demonstrate that to him, when it will actually do it.

I’ll pull the spark plug and take a pic & post it, and see if a fresh one changes things. Probably the only thing left I haven’t touched... Or maybe I did & just don’t remember. Victor

[viclioce]

Ed. I’ll have to check & see what I have left. Not sure I have many bigger mains. Thought I would never use them and sent them to Danny Cook.

Would you suggest a 190? 200? Bigger? Just asking for advise! Victor

[viclioce]

Dale. The cable stop may fit into the intake manifold but wouldn’t clear the intake port. It’s divided just like a Road Toad exhaust port. I was envisioning the cable stop being inside the manifold, blocking air/fuel flow. But no sign of it having passed into it. That was just a far fetched guess, trying to eliminate all possibilities. If I decide to pull the motor out of the frame, I’ll check the exhaust pipe. But, it would need to be folded in half before entering the intake manifold to clear the intake port, and there’s nothing there which could do that to a cable stop. Victor

[viclioce]

Matt. The best gas I can get here is ethanol free 90 octane. Only one place on the entire city sells it & I always buy my gas for the bikes there. It’s only about 2-2.5 miles away and is a fill station for commercial vehicles. Always mix at 32:1 & I even rinse the measuring bottle eat time with a bit of new fuel before filling my gas can. I use 8 ounces of Yamaha 2R and mix 2 gallons at a time. I’ve never used anything else.

As far as the air cleaner goes, it just got oiled for the first time yesterday. I didn’t have any filter oil but I bought some Uni filter oil & it came in. Haven’t put the filter assembly back on yet. Was repairing the boot because it was cracking. So no chance it wasn’t getting enough air thru. The carb was open to the outside air, or pulling thru a dry filter at best. Victor

[matt glascock]

Rats Victor! I was really hoping something simple would turn the trick. Then again, a basic principle for troubleshooting is the systematic elimination of "the usual suspects".

[Joe Ormonde]

About a year ago I was sorting my main jets by size. Then , I found one stamped 190. I knew right away something was wrong because I had several 190 main jets. It turned out to be a 90 main jet that was stamped 190. CLEARLY stamped 190. First time I ever saw that. Joe.

[Dale]

Dale. The cable stop may fit into the intake manifold but wouldn’t clear the intake port. It’s divided just like a Road Toad exhaust port. I was envisioning the cable stop being inside the manifold, blocking air/fuel flow. But no sign of it having passed into it. That was just a far fetched guess, trying to eliminate all possibilities. If I decide to pull the motor out of the frame, I’ll check the exhaust pipe. But, it would need to be folded in half before entering the intake manifold to clear the intake port, and there’s nothing there which could do that to a cable stop. Victor

Victor,
You said that this is a combo Wombat, Combat motor. Which cylinder does it have? I ask because the cable stop will not pass through a model 94 cylinder (unless the intake has been enlarged) but it certainly will pass through a model 95 cylinder.

[viclioce]

Well, it’s supposed to be a Combat Wombat Cylinder. But I’m not 100% sure. I think it has a V port. But inspection showed that placing a spare cable stop up to the intake that it wouldn’t clear the intake port without some kind of bending. Victor

[Dale]

Well, it’s supposed to be a Combat Wombat Cylinder. But I’m not 100% sure. I think it has a V port. But inspection showed that placing a spare cable stop up to the intake that it wouldn’t clear the intake port without some kind of bending. Victor

I bench tested it with a cable stop from a 24mm carb and two different model 95 cylinders. It will pass through...
I hope, of course, that my suspicion proves to be wrong.

[viclioce]

Dale. The more I think about it, the more I conclude it would be pretty hard to turn the slide upside down and attach the cable to it without dropping the cable stop and being aware that you dropped it, even if you were as inexperienced as my grandson. So at this point, I’m not going to consider that the slide made it into the carb with the cable stop in place. It just doesn’t make sense to me. I’m thinking at this point I was just drawing for straws, so to speak.

I’m going to pull the spark plug & check it as I mentioned last evening. We will see what condition it’s in. I’ll report back and post a photo of the plug. Victor

[viclioce]

Pulled the plug. Here’s what it looked like. Putting new plug in now and will start & see what happens. Victor

[Bullfrog]

Plug change was a good idea.

On the main jet change - you are at 140 now. A change to 160 or bigger would be good. We are looking for ONE thing to be changed (main jet only - no changes to air cleaner, etc.) so we can analyze whether or not that ONE thing made things better or worse.

Ed

[viclioce]

No Ed. The main jet isn’t a 140, it’s a 180. See my very first post on how she’s configured.

I looked at my extra main jets today. I have a 160, 170, a 190 and a 210. Those are the closest jets I have to a 180. I may have a 200, but I have to finish reading some more jets with a magnifying glass because the finishes with aren’t bright like new jets. Victor

[Bullfrog]

DOH! I guess I was thinking of the Model 94 Wombat (140 or 160 main jet in a 24mm carb). Sorry about that mis-statement.

Ennnneywayeeeee, you are at 180. Try something 2 (or 3) sizes richer. You have a 210, give it a try. Let us know whether things get better or worse.

Ed

[viclioce]

OK. Will probably try it later today. It’s been snowing & cold. But it finally stopped & the roads are clear but wet. Soon as they dry out.

At a Dr. appt. now. So in a while. Victor

[viclioce]

First report. Change in spark plug gave some improvement in power, even cold as it it’s today, without a proper warm up. Pilot change next. Going to change to a 200 as I found one. Will report difference after wasting up bike. I’m lucky. I have two main jet banjo bolts, so I can change out main jets quickly! Victor

[viclioce]

OK. With the 200 main in it, she sputters more. I’m going to try a 160 main & report back, again. Of course, now I’m dealing with much colder, denser air. It snowed today and it’s only 43*F now. It was 58*F yesterday. Best that in mind. Victor

[viclioce]

OK. She ran better with a 160, but still not getting close to full revs. Dropped to a 140 and she screamed!!! It m going to try a 150, just to see if it isn’t too rich. May have it zeroed in momentarily!!! She was definitely too rich with the 180, & even with the 160! Victor

[viclioce]

Didn’t have a 150, but I had a 155. Seems like 155 is too close to 160. But it may still want the 140 when I put the air box back on. We will see what happens. Looks like it’s going to be between a 140 & 150. Maybe a 145??? More to come.

[viclioce]

Went back to the 140 main. Was running without the air box on it so it was running a little bit leaner with the air box off.

Put the air box on, opened the choke, started first kick. Ran her about a mile around the subdivision & turned turned the choke off. Ran her down the street and back, about a quarter mile. SWEET!!!!! The 140 main turns out to be perfect! Just like it’s supposed to be! I’m happy!!!

Can’t for the life of me figure out how it ran OK before. But I’m going to leave it alone at 140!

Thanks again to everyone for their guidance & suggestions! She really rips! Hmmmm....makes me wonder what she would do if I took out the 94 piston & put in a 95 piston to actually use the piston port features of this cylinder? More to come on that, down the road. Oh Terry..... LOL!!! Victor

[Bullfrog]

Good to hear there was progress.
Ed

[Bullfrog]

[ossa95d]

Congratulations on being able to jet around whatever the problem was/is. Like you I'm still wondering why the bike used to run well with the jetting as it was and now needed such a substantial change. The discussion was a lot of fun though. I hope you're starting to develop an ear for what an engine sounds like when it's running rich as opposed to a very different sound when it is lean or starving. Also it's a distinctly different sound when it is breaking down due to an electrical abnormality. Over time you will develop an ear for these sorts of things and it will help immensely with the diagnosis of problems. Happy motoring!