Fuel, Spark, and one grown man crying.....

H

hombremosqa

Member
I ride my bike everywhere. And i do mean EVERYWHERE. its my primary form of transportation and since i live in the city, its very useful and cost effective for me.

some of you saw the frame from my last build, how it cracked the lower tube at the head tube, but i have since purchased a new bike, and now i have a MB again.

SO, in light of this, i have come across a problem. I run 32:1 fuel @ 87 Oc in my engine. and it works just fine, but i have been having trouble starting it recently.

I find that my spark plug is getting wet with fuel when it doesnt fire right away.(which is what it had been doing before) not only that, it takes almost 15 min to get it started.

the new frame is a bit longer than the old one, and i had to prop up the rear of the engine using a wooden block, which leads me to think that the carb is not sitting at the right angle?

i use the fuel line shut off valve when i park the bike at the end of each ride, but like i said, when i go to start it, it acts up until i take out the plug and clean it and dry it off.

I'm running everything stock. any suggestions? my legs are tired and muscley.
 
With out pics it's hard to say if the carb angle is the problem. I would clean the carb, it could be your slide is sticking open. You may want too adjust your float level if all else fails and you can't level the carb.
 
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Shadeslay said:
With out pics it's hard to say if the carb angle is the problem. I would clean the carb, if your plug is wet after a few attempts it could be your slide is sticking open.
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when you say slide, do you mean inside the carb? i dunno why, but i call it a thimble. and it doesnt stick at all. how open should it be to get it started? also, how open should it be to keep the engine at idle?
 
hombremosqa said:
when you say slide, do you mean inside the carb? i dunno why, but i call it a thimble. and it doesnt stick at all. how open should it be to get it started? also, how open should it be to keep the engine at idle?
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Yes inside the carb. It really doesn't need to be open very much to get it started, because of how the slide is designed. Idle varies depending on different circumstances, I keep mine pretty low just above stalling out.
 
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Start with the simple things first. With the plug out and grounded to the cylinder head, wire connected, of course, try rotating the rear wheel, clutch engaged, and check for a good spark. If it is weak or erratic try a new plug and check all of your wiring connections, especially where the plug wire screws into the CDI.. If you can rule out an ignition problem then it might be time to check the float level in the carb. Heavy bumps or vibration can alter it over time. A high float level can cause flooding which sounds like part of your problem. Check Norman's threads on carb service and rebuilding. Give these things a try and come back with your results.
Tom
 
I'll bet it's your float. But get the simple stuff out of the way first. 32:1 oil will be just fine, certainly won't effect starting.

I say get a new plug, remove the head or otherwise get the excess fuel out, make sure your carb is level and not causing the float bowl to be over full (and you may need to bend the arms down just a hair)
 
_MG_2659.jpg


this is a pic of the bike in question. i had to raise the rear of the engine using a wood block to clear teh chain on the right side of the bike. it wasnt much, but because the frame itself is a bit longer, it changed the geometry of project a tad.

i did clean out teh plug and the cyl head, and it fired right up, but a while later after it had cooled and i tried to start it, it had difficulty doing so until i pedaled fast. seems like a fuel surplus prob.
 
At that angle you shouldn't have much trouble with the carb. But it maybe enough, that you'll want to adjust the float. Make sure your air filter is clean, that can sometimes cause a difficult start.
 
I agree. Not much angle there. So, when you do get it started and ride it hot for a good while - what does the plug look like?

AND how old is the fuel mix?
 
I would check the spark plug gap I run about 0.020 gap try a new plug gaped to that setting and see if it don't start better.
Norman
 
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Hombre,
Pablo is right. The carb angle isn't enough to cause the problems you're having. I see you're using the kit supplied spark plug connector and boot. They are known for causing some trouble but I don't believe that is the problem. I still lean toward the float level being too high. Did you check Norman's thread on carbs? He gives some detailed info on setting the float level. As for your engine mount, the wood might work for a while but I'd keep my eye on it for cracks. The reason Pablo asked about your fuel mix age is because mixed 2 cycle fuel has a relatively short shelf life compared to unmixed gasoline. A couple of weeks or more and you should mix a new batch. Keep us informed of where you're at.
Tom
 
well, the gas is only about 2 weeks old, and is still good. if i dont use 2 gallons after 3 weeks, i usually pour it into my wife's car to burn it.

i did just rebuild the carb yesterday and cut new seals from the gasket material you find at checker. so far no leaks.

to answer a few other questions:

once i finally do get it started, and i run it for a while (about 4 to 5 miles) it looks like a dry and slightly tan color. looks normal.

what i have been doing recently to get it started is this:
if is doesnt start up after about 1/4 mile, i stop, take out the plug (I usually dry it off since its covered in gas) re screw it, and go again. usually by this time, it fires up.

i'm noticing that when i take it out, like i said, its doused in gas. thats what has led me to think its a faulty carb setting or something along those lines.
 
So you have eliminated a float set too high?? That's all that is sticking in my craw, right now.
 
Pablo said:
So you have eliminated a float set too high?? That's all that is sticking in my craw, right now.
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i think so. the problem is that without an actual measurement, its kind of hard to be sure. and the fact that it didnt have this problem before puzzles me
 
well, after much deliberation, and much speculation about the carb and the float, i adjusted it again, and put it back on, it sputtered but didnt fire. again with the wet plug.

i got to thinking, and decided to take off the cyl head. I found the problem. it was compression. after getting off all the crusties off teh piston and the cyl head cover, and spraying the gasket with the copper spray a gasket stuff, it fired up like it was almost brand new. OH HAPPY DAY!!!
 
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hombremosqa said:
i got to thinking, and decided to take off the cyl head. I found the problem. it was compression. after getting off all the crusties off teh piston and the cyl head cover, and spraying the gasket with the copper spray a gasket stuff, it fired up like it was almost brand new. OH HAPPY DAY!!!
Click to expand...

well, maybe not, its doing it again. ....... any bright ideas?
 
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after almost two weeks of having type A flu, im getting anxious to get back to work on my little thumper.

i am already thinking of changing the plug, but i dont know how effective that will be in light of the following


1.) I have already adjusted the carb float to ensure that i am not flooding the cylinder with fuel,

2.) I have also inspected the float itself with a magnifying glass and found no leaks in the ring float

3.) The metering needle is sitting with the clip at the stock location (2nd notch from the top)

4.) CLEANED the CRAP out of the piston head and the cylinder head cover

5.) Made sure the engine is getting good compression by spraying the cylinder head gasket with some Copper Spray-a-gasket


At one point the engine was working fine, but when i installed it on the second frame, it seems like everything just went to ****.

a friend of mine told me that its possible that the magneto could be out of adjustment and it could affect the timing? i want to tear into this engine because of another reason too, but am a bit hesitant to do it since i dont have engine schematics. any help here would be awesome guys
 
Well, an expert on bike fixing I'm not, but here's a schematic of the engine that came with my kit (click for larger image):

 
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