engine not running right. Possibly leaning out

S

Simonator

Guest
My engine was running great until one day. I was out riding in the rain, and the engine died. It would not start back up or fire at all. I tried it again a few days later with no luck. The engine was getting fuel, spark, and compression. Clutch was not slipping either. I found a spare coil layin around, so i swapped that one on. It fired right up. I was like WEEEEEEEEEE! Until I hit about 20 mph (where the powerband usually starts). It started sputtering and would not go any faster. It also sputters under a load. It is not acting like it has an air leak. It idles down real fast when i disengage the clutch. It runs worse when I play with the choke. Before when i had an air leak, it ran good with the choke half open. It doesnt even like to start with teh choke. It fires right up with the choke off..... weird... I checked the spark plug. It is a light tan color and dry. The carb was adjusted the 3rd spot down on the pin. I went to the 4th (richest) setting. It ran worse. I pulled the plug right after that, and it was still the same.
I bought a multimeter so I can test the magneto. I just haven't figured out how to use it. Can someone explain this to me, or link me to a thread that explains it?
I also checked the compression. I did it when the engine was cold. It is at 70 psi. Seems a little low, but maybe it is because the engine is cold? Even if it is a little low, the engine should still run ok. I would like to check it again when the engien is warm, but I do not have the gauge handy.

Any ideas?
 


B

BSA

Guest
Very odd, try running on the second slot. Can you give us a rough idea of how high you are above sea level. I think that you may be running to rich, if you were too lean the choke would improve the situation no make it worse. Try the second slot on the needle, and if that doesn't work try the 1st slot. A good way to test if you are running two lean is to wait for the engine to warm up and then engage full choke; it should kill the engine instantly.

BSA
 
S

Simonator

Guest
Very odd, try running on the second slot. Can you give us a rough idea of how high you are above sea level. I think that you may be running to rich, if you were too lean the choke would improve the situation no make it worse. Try the second slot on the needle, and if that doesn't work try the 1st slot. A good way to test if you are running two lean is to wait for the engine to warm up and then engage full choke; it should kill the engine instantly.

BSA
I am at about 600 feet above sea level.
I am running the 2nd slot right now. It is Still running the same. Full choke at idle speed never kills the engine instantly. It always takes a few seconds. My carb is O ringed. Before I O ringed it, there was a leak. I sprayed brake cleaner where the carb clamps to the intake. That slowed down the idle. Now if i spray brake cleaner there or around the intake gasket, the idle does not change at all. I don't think there is an air leak. I am at about 600 feet above sea level.
 
D

Demosthenese

Guest
could be your electrics somehow. I know that just replacing the wire and plug socket that comes out of my cdi, my bike works WAY better now. If you're getting spark it could still be a poor connection leading to a weak spark, or you're cdi could be damaged or something. You said you replaced the coil; what did you mean?
 
S

Simonator

Guest
I just ran my finger on the muffler outlet. It is a little moist. Does that automatically mean I am rich? Or is this normal for a 2 stroke?
 
S

Simonator

Guest
could be your electrics somehow. I know that just replacing the wire and plug socket that comes out of my cdi, my bike works WAY better now. If you're getting spark it could still be a poor connection leading to a weak spark, or you're cdi could be damaged or something. You said you replaced the coil; what did you mean?
I used my spare CDI from my last motor.
 

sparky

Active Member
Joined
Mar 19, 2008
Messages
1,429
could be your electrics somehow. I know that just replacing the wire and plug socket that comes out of my cdi, my bike works WAY better now. If you're getting spark it could still be a poor connection leading to a weak spark, or you're cdi could be damaged or something. You said you replaced the coil; what did you mean?
I think this is my problem... my plug wire looks terrible & I've only been running this thing for a month, not even everyday.
 
S

Simonator

Guest
I think i figured out the problem. I finally removed the magneto cover and looked inside. It turns out that there is some trapped water in there. Time to let it dry out and see what happens. I'm going to order a new magneto just in case this doesn't work. Why did I wait so long to remove the magneto cover?! DEE DEE DEE!
 
S

Simonator

Guest
Well the magneto tested good.

I just came up with another idea. When I couldnt get it to run, I removed the head, not knowing that those studs and nuts hold the whole cylinder on. maybe I broke the seal on the gasket at the bottom of the cylinder? If so maybe it is leaking the compressed air/fuel which is causing it to sputter when Im going more than 1/4 throttle?
 
D

Demosthenese

Guest
the gasket is a metal one, so it can't be torn, i think the head bolts are just supposed to be torqued down to form the seal. I know that i've removed my head and i just put everything back and retightened the bolts and it works fine.
 
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