Honda305.com Forum

Hi I just bought a cb160, the bike was not running when I bought it but was
complete. I changed all the fluids checked the compression and it checked out
good 150psi at each cylinder. Than I tore apart the carbs to every nut and bolt,
and cleaned them. Put new spark plugs on and tryed to fire the sucker up. But it
did not want to fire; finaly after pulling out the spark plugs 3 times and
cheking for fuel and spark, the bike finaly fired up but it only ran on one
cylinder, the other cylinder did not fire. Now my question is, do I have a week
spark or is there something wrong with the carb, I can't figure out what my
problem could be, how can I test for a week spark? I do have a spark but it is
not so bright but the other side looks to be similar and fires up fine. Can
anyone point me in the right direction to figure out my problem. Any help would
be great. thanks.

You need 3 things to make it go: proper air/fuel mixture, compression and spark at the right time.

Sounds like you have compression, and if you've sniffed the exhaust or the plug hole on the faulty cylinder you should be able to confirm some measure of fuel. That leaves a correctly timed spark--and the key would be timing, which you haven't mentioned. Have you static timed it and checked the condition of the points? That's what I would be looking to confirm.

Wilf

Is the side thats not firing wet w/ fuel? Try trimming back the wires at the plug caps 1/2" . New plugs? Points and gap?

I had the same trouble on my cb160=bought non running, think it hadn't run in many years. As a matter of fact it looked like it had been stored underwater. I call it "the patina special".

Check your valves. Mine were too tight and it wouldn't run hardly at all. I didn't understand it at the time, but your valve adjustment effects the timing too.

Then, clean your carbs at least a couple more times. I had pieces of crap under the needle valve seat where the gas comes into the carb. Didn't see them but if I had turned the carb over they would have fallen out.

Check you timing, points condensor and coill. I ended up replacing my coil and it ran much better. Originals are hard to find, I used a harley sportster points coil, had to make a bracket to mount it to the horn mount.

It still doesn't run great, but I did complete one day of the Moto Giro East event on it a few weeks ago.

Oh, try the plug from the side that fires in the other side. I have had several plugs that were bad out of the box, sparking to the side of the plug instead of the electrode. Also be sure they are gapped correctly. They are not correct out of the box.

This can drive you crazy. I know from experience.......

Here's the Patina Special at the giro.

I got it fixed. One of my new spark plugs was faulty and would not spark, i was checking all the electrics and than swaped spark plugs and whoooallaaa no spark only on that perticular spark plug, so I changed it and it fired right up and ran like a dream, well not exactly. I found out that it is spitting oil out of the tail pipe so I suspect it has bad valve seals or piston rings so the head will have to come off. suck for me but if anyone knows what might be my problem now let me know. thanks.

try running it with your oil dipstick loosened all the way. You could have too much crankcase pressure.

I don't think your rings are bad with that much compression.