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Discussion Starter · #1 ·
Trying to be as brief as possible. SSR Lazer 5 moped. Damn thing starts and runs like a champ in the early morning, but only for about 10 to 20 minutes. There’s always an unpredictable moment when it has a sudden and near total loss of power and I have to limp it back home at about 2 or 3 miles an hour with the engine running just fast enough to engage the centrifugal clutch. After that it’s like that for the rest of the day.
I have replaced the battery, the ignition coil, the CDI, the voltage regulator, the magneto. All the components are generic and I have traced every single wire the bike has from one end to the other. That’s all the electronic components there are.
Anybody know a good exorcist in the Los Angeles area?
 

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What makes you think its electrical?... when you say it loses power I assumed you meant it has no engine power and may not be specifically electrical. Since you have replaced the entire electrical system I would be checking fuel delivery to and from the carb. Fuel tank for venting. Fuel level in the carb. exhaust for any blockage....esp at the muffler and the exhaust port and any air leaks and/or air flow restrictions.

good luck
 

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Yes, what he said.
And fuel filter if it has one.
Emphasis on the tank vent.

Any modifications to the intake or exhaust ?
The fuel mixture in those tiny engines is sometimes more dependent on the intake and exhaust flow than it is on the actual carb itself.
 

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Discussion Starter · #4 · (Edited)
Well the carburetor, fuel filter, and fuel lines were the first thing I replaced. I cleaned out the fuel valve and filter under the gas tank. Plus the fact that it appears to be so completely dependent on temperature, i figure it must be electrical. Today I started it up for the first time about noon, it ran 20 miles an hour for a minute and then crapped out and I limped it back at 3 miles an hour.
Everything on the bike is stock, and no i haven't checked the exhaust pipe. Is it possible that the heat is causing it to clog up?
Another thing is that while it's running, the instant I try to choke it up it dies. If I spray even a drop of starter fluid into the air cleaner it instantly dies. Also it seems to me that if it was starving i would see a bubble in the inline fuel filter, and I'm not.
I did discover another very strange symptom today. When I disengage the centrifugal clutch, the engine, unloaded, revs up quite normally. Then when I re-engage the clutch and try to get it to move, it will just barely budge up to maybe 3 or 4 mph at full throttle. I don't know what that means, but maybe you guys do. I believe it has a CVT transmission. Maybe the tranny is locking up? the belt is getting stuck?
Thanx
 

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These bikes have a simple centrifugal clutch that operates by rpm so its unlikely to be that and if the transmission were to be faulty it would fail straight away. Since adding starting fluid or choke seems to make it worse I wonder if its getting too much fuel what does the spark plug look like.

Heat would not cause the exhaust to clog up. It would be worthwhile undoing the header pipe when it does it to see if it is this.

What air filter does it have and is the pipe from it good....sometimes they can soften and then collapse causing a severe restriction this will be supported by a spark plug that is very dark to black in appearance. Did you open the tank cap when it does this....it may be a simple vacuum in the tank.

One last couple of things... what are the wheel bearings and brakes like....as they heat up bearings that are no good will become very stiff and brake linings can drag then heat up enough to become very stiff.
 

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Discussion Starter · #6 ·
... it would fail straight away.
Well that's good i don't really wanna go diggin' into the tranny. And yeah the spark plug is black as soot, that's at least one thing that I can fix fairly easily. And I can pull the exhaust. As for the wheels, no, the rolling resistance is perfectly normal, I've checked many times. But I have not thought to open the gas tank.
Anyway, I've given up tryin to figure out these bizarre symptoms. At least there are some things that I can try, although right now I'm sicker than the damn bike. We'll see tomorrow.
Thanx :)
 

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So now it sounds like it is running WAY too rich.......and not too lean as the original guess was.

Are you sure that you understand the operation of the choke ?
That is, which position is ON (closed) and which is OFF (open) ?
 

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Discussion Starter · #8 · (Edited)
which position is ON (closed) and which is OFF (open) ?
well yeah what i meant to say was that i initially reacted by closing it, which only made it worse, so I gave up on that. Then later on i decided to double check by spraying some start fluid, and the same thing happened.
The part i still can't figure out, and never will, is that it's intermittent. It will run ok for a minute or two, then presto, in an instant the power drops out and it will barely crawl back to the house.
First time it happened, i gone about a mile when it died. i parked it in the shade, sat on the sidewalk for half an hour, started her up again and it got me halfway home before crappin out again. I did that four times in a row, each time making less progress than the last.
The message was clear and unequivocal: ELECTRICAL! But now I've replaced every electrical component except the flywheel. If the flywheel is heating up and losing it's magnetism, it's time find a priest.
 

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The message was clear and unequivocal: ELECTRICAL!
No it isn't......and never WAS.

Your diagnostic skills are seriously lacking.
IF you can manage to accept that, then you might be able to find the real trouble.

You didn't say that you did any real testing with the fuel system.
Did you pop the cap on the tank when it fails to see if that helps ?
Have you considered vapor lock ? That is, a part of the fuel line is getting so hot that the fuel is boiling inside of it.
How about a gasket leaking when it gets HOT ? Either manifold or in the carb.
Fuel line blockages can be "intermittent" too. Rubber hoses become softer when HOT and a bend might close up.
 

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Discussion Starter · #10 ·
But I've seen vapor lock, and vacuum leaks, and leaky gaskets. I know what to look for. Like it's 72 degrees here, nowhere near hot enough to cause vapor lock. And if the manifold was leaking it would be too lean, choking it up would show that. And with a brand new carb, n fuel lines n air filter there shouldn't be bad gaskets.
And the way it goes from normal power to near death in the blink of an eye. After running less than 2 minutes when it's still cold.
The fuel line is about 5" long, brand new. And the brand new inline fuel filter is transparent plastic. If something was wrong with that all I have to do is look at it and see.
And I've repaired enough cars n bikes to know when I've encountered something that defies typical explanation.
Anyway, today I'm gonna pull the carb and tune it. That way i can at least eliminate one more thing.
Thanx
 

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Your carb may be flooding causing a very rich situation which in turn will cause the engine to bog down. The black plug condition supports this.

I would be checking the float is working properly is set to the correct level and the float needle is clean and in good condition....a light line around the tip indicates wear which leads to it not sealing properly.

Also pop the tank to allow any vacuum to escape....ditto the exhaust header...you would be surprised how easy a single will bog down if it cant exhaust properly and it would act in exactly the way you describe with any of these problems
 

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Discussion Starter · #13 · (Edited)
Also pop the tank to allow any vacuum to escape.
Yeah i did that yesterday and no it made no difference, but then I already knew that. As you no doubt know, a starving carburetor is readily observable in several ways, like the distinctive way the engine stalls or stumbles when you hit the gas, or if you see a bubble in the fuel filter, or if it revives when you choke it up, revives when you spray start fluid, all of which i have done countless times in the past while working on vehicles.
And, of course, if the spark plug is black as soot, or if it immediately dies when you choke it up, if it instantly dies when you spray start fluid, then it's a good bet that no, it's not starving.
But you know that too. And you also probably know that working on cars, every once in a great while you run into something that's truly bizarre, that defies a simple or common answer, like I have done in this case. That's why I said, half joking, that it was cursed.
Well, last night i found the curse, or was it a joke?
It all started with the new carb i got from Amazon. It came with a new fuel filter, which I plumbed into the fuel line. It also came with a new air filter which goes right onto the throat opening. And last night I pulled the air cleaner back off and rattle rattle, there was a foreign object inside. I looked and there was a second new fuel filter that had been included with the new carb, sitting inside the air filter. It was bouncing and getting sucked and lodged into the throat opening only to fall back out when the engine shut off.
I guess my diagnostic skills are seriously lacking, cause I sure as **** can't figure out how an inanimate piece of plastic managed to perfectly mimic the syndrome of an electrical fault. At least in the beginning it sure did. It ran perfectly fine at first, to the store, the pharmacy, Burger King. Next day it started fine, went about a mile and a half, and crap, it's dead. I waited half an hour in the shade, started and ran a half mile, and crap again. The third time it went about six blocks, then three, and I was home.
Saturday I replaced the coil. Sunday morning it was 65 degrees. It ran 5 miles to church like a champ. At noon it started, made 2 blocks n crap. In my book, and maybe yours too, that's electrical. Either that or a fuel filter rattling around in the air box.
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You were so stuck on your original "diagnosis" that you overlooked the CRITICAL clue:
That is, the introduction of additional fuel caused it to fail........because there already was an obstruction in the intake causing it to run rich all the time.

So if you REALLY stretch the point, the plug that was collecting carbon because of the rich mixture likely was the cause of it running really bad after a while and that could be called an "electrical fault" maybe.

The lesson here should be that you need to keep an open mind.
And still check things that you KNOW could not be causing the problem.........because sometimes they DO.
 

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I sometimes get so focused on something the obvious gets overlooked but an extra filter getting sucked into the inlet manifold is one I would've had a hard time guessing. Guess that why pilots have check lists.
 
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