Trouble shooting the bicycle engine that won't start

deacon · #1 (**permalink**) 02-21-2008, 09:53 AM

So here is a chance for all of us new guys to trouble shoot an engine that just doesn't start. So it has sat for a couple of weeks and been moved from one bike to another but it should still be the same things.

The engine rotates but doesn't start. It appears to be dead. It has compression since it won't roll freely.

So what is the next thing to check and how do i go about it.

I have checked the simple things... There is gas in the line. I have wired the black and green wire twice since it had to be rewired. I have disconnected the kill switch

deacon · #2 (**permalink**) 02-21-2008, 10:33 AM

Okay I found mine in the wiring but, we still need this thread I think. What do you do first if one day your engine won't start.

**CRUISER** · #3 (**permalink**) 02-21-2008, 10:42 AM

first think i do is cuss

then i check for good spark
then getting gas
these 2 things are usually gonna be the reason for not starting
then i go to wireing etc

deacon · #4 (**permalink**) 02-21-2008, 11:47 AM

Okay but in detail how do you verify each of them

deacon · #5 (**permalink**) 02-21-2008, 04:10 PM

I can see I'm gonna have to pull teeth... Okay suppose I couldn't get the engine to fire.

I check the fuel line and the fuel turn off switch and its okay.

So do I pull the spark plug to see if it's wet and smells of gasoline. Is that the easiest way to determine if there is gasoline getting to the cylinder.

So if the plug is wet go on if not check the carburator. (I tapped on the bottom of mine just in case the float was stuck by the way)

**Bikeguy Joe** · #6 (**permalink**) 02-21-2008, 05:59 PM

I have only ever had a problem with the crappy kill switches that come with the kits....buy a momentary switch at you favorite electronics store to replace it asap.

deacon · #7 (**permalink**) 02-21-2008, 08:05 PM

I use a toggle switch for an ignition type switch and kill. I expect you could use a key lock as well but the toggle works I hope for some kid trying to start it when I'm inside a store. I do sometimes not chain it down if I'm gonna be gone just a minute.

**Norman** · #8 (**permalink**) 02-21-2008, 09:48 PM

Not chaining it invites someone to take your bike a good chain and lock will slow down an honest thief.

deacon · #9 (**permalink**) 02-21-2008, 10:08 PM

I know i'm a bad daddy for my bike... Good to see you back how was the vacation...

deacon · #10 (**permalink**) 02-22-2008, 06:09 AM

Okay you got a wet stinky plug and its out of the head so now is the time to check the spark. Now I'm telling this from memory so don't be surprised if I get this wrong. Norman needs to tell it but he hasn't joined in yet so here goes.
take off the chain cover and get the rear wheel off the ground. with the plug wire near the head turn the engine over and look for a spark.

Now I think that is how he said to do it. I have never had to go that far yet.

I think that tells you that your electrical system is okay.

If you don't have spark, I would check out all the wiring. The kill switch, as well as the connections on the blue/green and the black ground from the engine magneto to the coil. There does not seem to be a lot to go wrong with the wiring, but I still managed to screw mine up.

I think if my plug was wet and stinky, and my spark was present I would think the spark plug itself was bad.

I have had cracked plugs in cars a few times so I wouldn't rule that out as many times as I have had to pull mine in this engine. I hope I don't have to pull it any more.

When I switched frames I installed the new plug and wire. It did seem to make the engine smoother but that is probably all in my head.

I'm sure if Norman weighs in he will improve this a lot.