I'm stumped

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gebhardm

New Member
Jul 5, 2010
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Illinois
OK here is the story

In June I got an 80cc kit and mounted it on my bike. It ran very well for the first 2 tanks. I had the gas/oil mixture at 16/1 because that is what the literature that came with the bike recommended. Then about 2.5 weeks ago I noticed the bike was losing power. Really slightly at first.
1. My first attempt to fix the problem involved increasing the gas/oil ratio to 32/1. This had little or no effect.
2. Second attempt was to change the position of the "e" clip on the throttle assembly. I moved it to the top location after reading suggestions on this forum. Again little or no effect. Moved it back to its original location.
3. I then cleaned the carburetor and again nothing noticeable gained. As a matter of fact the engine seems to be slowly getting worse.
4. I thought it might be a bad needle valve in the carburetor because on two occasions the engine returned briefly to its powerful former self when I closed the fuel shut-off valve. So I ordered a new carburetor from DAX o
5. Installed the new carburetor and tested bike. Still no power
6. Tried a different CDI and plug wire and saw no noticeable difference in the performance of the engine.
6. So now I have decided that its not the fuel or carburetor but maybe the spark.
7. I disconnected the black wire from the "C" that surrounds the magnet and sanded the connection. Again no noticeable effect.

SO here are my questions.

1. I tested the spark by unscrewing the plug from the engine head but left it connected to the CDI. Upon pushing the bike with the plug resting on the engine I saw some small sparks (just barely noticeabler) jump at the plug. Is this normal? SHould they be loud and more energetic?
2. How can one test to see if the plug wire is OK?
3. Could my coil be bad? How can one tell?

I really am at wits end with this thing. It was running great and then wham, its performance has gone south in a big way. I am really open to suggestions. Thanks for your suggestions on my previous posts. Unfortunately they didn't help.

Mike
 
Goat Herder

Goat Herder

Gutter Rider
Apr 28, 2008
6,237
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Run it temporally with out the exhaust pipe attached. There have been reports of the cats clogging up these.
 
Bikeguy Joe

Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
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Check the plug first to see how the engine is burning....what did the old one look like when you changed the plug?

Air leak?

CDI/magnetos don't generally "lose power" or go bad slowly, they seem to work, then stop working.
 
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gebhardm

New Member
Jul 5, 2010
33
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Illinois
Bikejoe

The weak magneto idea does some sense. The motor never would idle without dying from the very first day it ran. I know the problem is not with the kill switch because completely disconnecting it has no effect. Does anyone know of a simple test to see if the coil is OK? Also, although I get a spark when pushing the bike its really weak but maybe that's simply because the magnet is not rotating very fast under these test conditions. I really have exhausted all my ideas on this thing. Nothing I do seems to matter. In general the engine runs like crap right now. I barely runs when coasting downhill. The plug is black (but it always was even when it was running well). I have not yet tried running the thing with the muffler removed because it is such a new motor I just can't believe its clogged. Also when I had the muffler off last week I blew through it and air flowed easily. I know something is wrong with the engine but as I say, I'm stumped.

sincerely
Mike
 
stevolandis

stevolandis

New Member
Feb 20, 2010
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NE Pennsylvania
I had a problem like this. It happened from putting too much squirt gasket on my exhaust pipe. The engine had low power, and would only go to half throttle. I blew compressed air and water from a hose through it, and everything seemed fine. I thought my pipe was good. But, it was actually clogged with gasket.
Moral of the story- just being able to blow through the muffler doesn't mean it's okay. I tried w/o the pipe, and my engine had a huge amount of power compared to the normal muffler.

If the problem turns out to be your muffler(probably the catalytic converter) you could cut it open at the base by cutting around the bottom(not through the pipe) and pull out the bottom. you can then try tearing out the cat. But make sure it's your pipe before trying all this. The pipe will need to be welded together again.

Hope that helps!
 
corgi1

corgi1

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Aug 13, 2009
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and 16-1 oil is too much oil ,24-1 break in mix ,, is the c -clip on the 2nd notch on the top needle in the carb,,,black plug is too much fuel/oil or needle valve in the float bowl has dirt in it and flooding,,, the plug may need replaced (highly reccomended),,,,,is the float got a crack or hole in it and sunk in the bowl,fairly common prob. and that will cause flooding
 
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gebhardm

New Member
Jul 5, 2010
33
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Illinois
I just got done running the bike with the muffler off and WOW what a difference in power. Thanks to everyone for the help. I just couldn't believe the catalytic converter could be plugged after only approximately 120 miles but I was breaking the engine in on 16/1 gas to oil (non synthetic) so that will build up gunk fast. Also the gas had alcohol in it at 10% but I'm not sure that matters. So I hope this thread helps people who may have a similar problem. Now is there any advice out there for cleaning a muffler?
 
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fm2200

New Member
Nov 16, 2008
258
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new york city
I would try changing the carb, they are 25 bucks at most places. If your plug is light brown then the fuel mixture is probably right. If it's almost white or only slightly brown your fuel mixture is too lean. A darker plug means excessive fuel mixture. Also try cleaning the air cleaner or running it with no filter to see if it performs better.
 
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fm2200

New Member
Nov 16, 2008
258
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new york city
The fuel mixture is way to rich that's why the exhaust is fouled with unspent fuel. I would opt for another carb. Your spark plug tells the story it's not suppose to be dark.
 
BarelyAWake

BarelyAWake

New Member
Jul 21, 2009
7,194
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Um... why would you change a carb if it's an oil/fuel mix and an exhaust problem?

I figure jus' runnin 32:1 w/a quality oil & a decent expansion chamber setup outa fix him up right... even just a kit pipe w/o a cat *shrug*
 
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fm2200

New Member
Nov 16, 2008
258
1
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new york city
The primary problem is that his plug is fouling, not having a cat would probably help too. The color of the plug is paramount to performance, leaving a rich mixture will surely be an ongoing problem. The replacement of the carb is a cheap fix, these mass produced engines are pretty crude in a fundamental way of design.
 
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bairdco

bairdco

a guy who makes cool bikes
Aug 18, 2009
6,537
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living the dream in southern california
i agree with Barely Awake, the carb's not the problem, it's what's going through the carb and coming out the back end.

fuel.

from everything you described, from 16:1 mix, black plug, and the bike running better (briefly) with the petcock shut off, it's been running too rich, which probably fouled your cat in the exhaust.

i dunno how exactly to clean one,but first, but you could try getting a can of carb cleaner, take the cap off the bottom of the exhaust, hold the exhaust over a trash can, stick the carb cleaner tube up in the main pipe (the skinny one, not the whole muffler, it's where the bolt hole is on most pipes) and spray the whole thing in. hopefully, all the built up crap will come out.

edit 1)be careful of the carb cleaner shooting back at you. it's great for cleaning grease, but not so good on the eyes.

edit2) hopefully, everything you did that wasn't related hasn't compounded the original problem.
 
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BarelyAWake

BarelyAWake

New Member
Jul 21, 2009
7,194
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Maine
Yes, you're absolutely right fm... but unless the carb is defective in some fashion it's easy enough to adjust, as he's done. I would suspect the fouling to be a result of the 16:1 fuel/oil, made worse by a catalytic converter - as evidenced by the following;

gebhardm said:
I just got done running the bike with the muffler off and WOW what a difference in power. Thanks to everyone for the help. I just couldn't believe the catalytic converter could be plugged after only approximately 120 miles but I was breaking the engine in on 16/1 gas to oil (non synthetic) so that will build up gunk fast...
Click to expand...
While it's true most of these engines run on the rich side, the clip second notch frm the top on the needle works for most folks... provided their exhaust isn't stuffed up w/oil lol
 
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