Engine Not Firing

Zacka

New Member
Oct 20, 2013
2
0
0
Sydney, Australia
Hello fellow community,


I own a 2 stroke engine, still in the run in period. I think i may have ran my engine too rich because the spark plug is definitely not sparking but the engine is not seized. i was riding it pretty far and i was going down a hill and it suddenly just bogged out and would'nt fire again. im running with an NGK B5HS spark plug and a speed carby and the bike runs so good with these attachments. Here is my bike as shown:



man i had the worst night i had to disconnect the engine chain and pedal 20km home with a full tank of fuel and a heavy engine on the back and bear in mind that it is a bmx ahahh

Cheers,

Zack
 

rustycase

Gutter Rider
May 26, 2011
2,746
0
0
Left coast
Z, you have done a great job on that bmx!
Wow!

Have you tried completely disconnecting the kill wire?
Is the spark plug wire from the coil good? Many are defective.
B6HS is a fine plug to begin with...

Seems to me the carb might be tilted just enough to cause trouble... but that should not affect spark, unless it's fouling the plug.

Good luck
rc
 

maniac57

Old, Fat, and still faster than you
Oct 8, 2011
4,484
16
0
memphis Tn
What oil mixture are you using?
The 16:1 suggested by the manual is far too rich and will foul plugs.
I use 40:1 but most people seem to like 32:1.
 

Zacka

New Member
Oct 20, 2013
2
0
0
Sydney, Australia
Okay !

I went through a few things, and yes i was wrong. i thought i had ran the engine rich and fouled the the sparkplug, but no. i tested it by disconnecting the sparkplug from the cylinder and held it as i went down a hill in gear to feel for a zap zpt and if there were equal sparks to the engine revs. I didnt even get one spark. So i checked the magneto coil, and man that magneto was burnt to sh*t. I must have rode the bike pretty hard to make that magneto red hot and just buckle under pressure. I swapped the magneto from my old bike and now the BMX fires fine. does anyone know where you can get some good quality after market magneto coils?

Thanks for the suggestions guys.

~Zack
 
Last edited:

Kioshk

Active Member
Oct 21, 2012
1,152
7
38
Connecticut
Great build...looks like you can relax your feets on those pegs too. I highly recommend carrying a spare magneto-coil in your toolkit (you HAVE a toolkit, right?) if you ride hard/long-distance. I have had enough experience with blown coils to know better. It's easily over 80% of the time that the coil's blown when it comes to inopportune engine troubles. You can get 'em on eBay for under $15.