struggling to make bike run

GoldenMotor.com

harzeeent

New Member
Nov 15, 2010
2
0
0
Australia
G'day from Oz
Recently I bought a second hand bike and all is sweet. My mates kid saw it and wanted one so I searched and found one for him. He rode for a while and now it doesn't work. His dad doesn't know which end of a screwdriver to use so it's come back onto me to fix it for him. The problem is you have to pedal like mad to get it to barely run and as soon as you pull in the clutch it dies. I pulled apart and cleaned the carby. No change. Pulled apart the fuel line. Cleaned off the debri around the tank filter. Blew out the fuel line, made sure filter wasn't blocked. No change. Took the carby off my bike which was running sweet. No change. Pulled the spark plug out, it was covered in oil. Cleaned it up and regapped it. Lifted the E clip on the needle to the top setting. No change. Pulled the bottom of the muffler out, cleaned out the oil. Ran the bike without the base in. Now have a little bit more power but bike still won't idle. Any less than 1/2 throttle with the clutch in and it dies. If you blow through the muffler it's clear. If you put the base back on it goes back to the way it was. I took the head off and had a quick peek to make sure there wasn't any huge scratches in the bore and all looks fine. when you pedal and dump the clutch there is definately compression. If you tape the spark plug to the side of the motor there is a spark. Put it all together and it still doesn't run. I have searched a lot of your threads and while they have been helpful in understanding how these cheap chinese motors work it still hasn't fixed the problem. I am starting to think it's more to do with the CDI or magneto. The CDI looks like it's had an upgrade compared to mine. It has a quality cable and spark plug and all connections are soldered and heatshrunk so there doesn't seem to be anything adjustable or fixable just replacing the entire thing. Where the cable comes through the casing to the magneto there are only two wires. Other threads I have read say there are three. I don't know if that's a problem because the bike runs without a baffled exhaust albeit with low power. So what do I try next besides a new motor. Cheers on a great site
 

Mac

New Member
Dec 3, 2009
486
1
0
Maine
Hmmmm... Harzeeent, good to see your working with the kids!! welcome to the forum. A few things that may help you. Look at the magnito, is the rotor centered in the magnito? any mag particles sticking to the rotor? the three wires that should be in the mag is a Black ground to one of the mount bolts, this goes to black on the CDI, a Blue wire from one side of the Mag coil and a white on the other, blue to mag, white terminated. check connections. As far as the muffler goes, the motor will run better without the muffler, don't run it long like that, clean airfilter?? PM me and I can give you the specs on the magnito/CDI if you have a multimeter, check the connections from the coil to mag are not taped to the frame(shorting), disconnect kill switch for Troubleshooting, oh, check to see if the spark plug wire isn't bad (multimeter) a few ohms is OK, 1000 ohms =Not good, check the screw in to the CDI side of the spark plug wire etc...
Sounds like your on the right track, one system at a time so you can get a conclusive solution. Let me know if you need any more guidance.

R/Mac
 

Venice Motor Bikes

Custom Builder / Dealer/Los Angeles
Mar 20, 2008
7,266
1,797
113
Los Angeles, CA.
This is a pretty basic question... Could there be too much oil in the gas??
Who mixed the gas; you or the kid?? (& did he shake it well before filling the tank?)
 

corgi1

New Member
Aug 13, 2009
2,272
3
0
KCMO
and if the mix is right did it get left setting w the fuel valve on and fill the crankcase w/fuel mix ,the gas would evaporate leaving a concentrated oil rich mix to splash up and foul the plug
 

harzeeent

New Member
Nov 15, 2010
2
0
0
Australia
Hi guys
Sorry about the delay in getting back to you. Just been flat out lately with Xmas and all. One good thing that came out of it all is a mate of mine that works on small motors (lawnmowers chainsaws etc.) agreed to have a look at it. He has reported back to me that the bore is scored and the rings destroyed. Obviously they didn't mix the fuel properly.
Thanks to everyone for their ideas. On a good note my bike is still running sweet and life is good
 

Viktor Reznov

New Member
Jan 19, 2011
2
0
0
Queensland, Australia
Hi harzeeent,
had the same problem as you. I stopped riding my bike for 2 weeks sitting with half a tank of fuel. i'm using E10 unleaded and penrite high performance synthetic thoroughly mixed at 16:1. Then decided to take it out again this morning, same problem, refused to wake up, refused to idle, but lots of misfiring and would barely stay alive unless revved at WOT. Peddled like a madman for ~300m trying to get it to start.

Shouldv'e consulted this forum earlier and hopefully havent destroyed the rings or worse, cylinder bore
 

deathmonkeypoo

New Member
Jan 29, 2011
7
0
0
ithaca ny
and if the mix is right did it get left setting w the fuel valve on and fill the crankcase w/fuel mix ,the gas would evaporate leaving a concentrated oil rich mix to splash up and foul the plug
How long can you leave the valve open? I have left mine open before a few hours but it has ran fine for a few miles and died. Could it be that the spark plug is getting oily or maybe its a vacuum in the tank? How do I clean the oil out? If its not a vacuum in tank?
 

Venice Motor Bikes

Custom Builder / Dealer/Los Angeles
Mar 20, 2008
7,266
1,797
113
Los Angeles, CA.
A problem with mixing gas & oil is that if it's left sitting for too long, the oil can settle to the bottom of the tank, & when you open the petcock, it's mostly oil flowing down into the carb! This will cause poor performance, sputtering & back firing. :(

If the bike has been sitting for awhile, just shake the whole bike real hard to try to remix the gas & oil BEFORE opening the petcock! ;)

Also... 16:1 is too much oil. General wisdom around here is to use 24:1 for the break in & 32:1 after that using standard 2-cycle oil.
 
Last edited: