Sudden bogging/stalling after 120 miles - Motomax 250

[ADKRider]

Thursday after getting home from work, I went for a short ride and I had a sudden loss of power under throttle. Ever since then, it will idle fine at first, cut out under throttle and then won't even idle properly once warm. I have since cleaned the carb, cleaned the fuel filter, drained the gas (concerned about water), and replaced the spark plug. I am at a loss as I'm not exactly experienced with small motors or carburetors.

The picture of the fuel filter is before I cleaned it out. I got out every little bit of that black shit by blowing with my mouth back through backwards after everything was dried out.

Edit:

[Bruces]

What specs are your valves adjusted at ?

[dirtbkr188]

Did you check the jet needle to make sure it is secure under the "A-clip" and spring in the throttle slide?

[Crossbar]

What dirtbkr188 said. That acts like a lack of fuel. I'd also pull the fuel line at the carb and check you're getting adequate flow from the tank.

[ADKRider]

Valves adjusted to 0.05mm both sides. When I took apart the carb, the the needle seemed secure, but I didn't inspect it closely. Unhooked fuel line and there is a steady flow of fuel.

What is the A-Clip supposed to look like?

[Bill Hilly]

Originally Posted by ADKRider

Valves adjusted to 0.05mm both sides. When I took apart the carb, the the needle seemed secure, but I didn't inspect it closely. Unhooked fuel line and there is a steady flow of fuel.

What is the A-Clip supposed to look like?

You may have picked up a little spec of something it the main jet. I had sudden trouble out of my TBR7 one day. It was not what I would call a bog, but it wanted to cut out, land act up on anything higher than mid throttle. I ran it home on back roads, drained the carb, and some of the gas from the petcock while on reserve, because I know water goes to the bottom. I tried it out, and it still acted up. I asked about it here at ChinaRiders, and got some gas related responses ,and also was told that it may be a loose connection in wiring, or the coil may have a loose ground. I didn't see any loose wires, but I did clean some dried mud off the coil, and unhook the ground, and clean the grounding surface good, and something I did took care of the problem, and it never gave me trouble again. . I did order a coil for it, and did put it on, but my old one was working good in the mean time.
I forget about it, but my Brozz had ,and probably your MotoMax does too have a lot of pollution stuff. I unhooked, and got rid of mine, but I remember a vacuum hose that ran directly to the intake manifold, and I can't remember exactly were the other end ran, but it would have had to be some sort of check valve, or PVC valve. I would check that line, or plug it off.

[ADKRider]

Originally Posted by Bill Hilly

You may have picked up a little spec of something it the main jet. I had sudden trouble out of my TBR7 one day. It was not what I would call a bog, but it wanted to cut out, land act up on anything higher than mid throttle. I ran it home on back roads, drained the carb, and some of the gas from the petcock while on reserve, because I know water goes to the bottom. I tried it out, and it still acted up. I asked about it here at ChinaRiders, and got some gas related responses ,and also was told that it may be a loose connection in wiring, or the coil may have a loose ground. I didn't see any loose wires, but I did clean some dried mud off the coil, and unhook the ground, and clean the grounding surface good, and something I did took care of the problem, and it never gave me trouble again. . I did order a coil for it, and did put it on, but my old one was working good in the mean time.
I forget about it, but my Brozz had ,and probably your MotoMax does too have a lot of pollution stuff. I unhooked, and got rid of mine, but I remember a vacuum hose that ran directly to the intake manifold, and I can't remember exactly were the other end ran, but it would have had to be some sort of check valve, or PVC valve. I would check that line, or plug it off.

I tried cleaning my carb already, but didnt remove the jets and spray through them. I also saw a post on another forum that describes 3 symptoms of a bad coil and mine seems to be doing them. Tomorrow I'm going to try to clean the jets even better and order a replacement coil.

Anyone have advice on a coil to order? Saw amazon has Nibbi coils too, but the one I looked at was too short for Motomax.

[dirtbkr188]

The A-clip is part #7 shown in the diagram below.

[ADKRider]

Originally Posted by dirtbkr188

The A-clip is part #7 shown in the diagram below.

Yes, that whole assembly seemed secure, although I will double check tomorrow when I remove the carb again.