only firering on one

[Lucky_Lou]

Well the rebuild is almost finished only got cosmetic stuff to do cranked her up for the fist time today got new points plugs ect but will only fire on the right cylinder definte spark on the left stripped the carb again again and all looks good anyone got any bright ideas!!!! any easy way to check compression?
Ta Lou

[MrRiden]

any easy way to check compression?
Ta Lou

Lou,
You should be able to feel the pressure at the tail pipe by hand but with a crossover tube on the exhaust that might be unreliable. With the spark plug removed a thumb over the plug hole should easily be pushed off by the compression. Did a quick search of automotive stores by you but only came up with the A1 automotive chain, looked useless for a compression gauge. Have the intake tube off the carb to facilitate a look see if your getting fuel while running. Perhaps before all this have a second look under your valve cover while cranking.
rich

[Justin B.]

After doing that you can swap plugs between sides then dribble a bit of gas into the non-firing cylinder and see if it at least coughs.  All of my "running on one cylinder" issues always seem to have been carb related...

[not-so-fast-ed]

Right.  You can even swap the spark plug wires from side to side.  With the wasted spark design, the engine doesn't know or care which plug lead (or coil) is which.

 :-/

[montmil]

Right.  You can even swap the spark plug wires from side to side.  With the wasted spark design, the engine doesn't know or care which plug lead (or coil) is which.

 :-/

Could it be the dreaded "Crack-O-Matic" coil? Evil among us  

Monte

[balibeemer]

I had exactly the same problem a week ago. Then I touched the coil and nearly burnt my hand off, hotter than hell. The right HT lead is charred where it went into the coil - Still waiting on a new coil, plug caps and HT leads from Motobins.

[Lucky_Lou]

Think ive sussed it when i partialy block the carb intake with my hand it runs fine going to rejet the carbs even though the old ones look ok thanks for the help anyway. Had a ride on her with one pot couldnt resist it after 4 months of tlc first time running for 6 1/2 years put a smile on my face in these days of doom and gloom i hope the old boy who had her before was looking down with a smile bless him{died in 2003 RIP}Will post some piccis soon and sort out an avatar
Lou.

[Lucky_Lou]

Still no joy rejetted the carb no better only firering intermittantly......has anyone fitted electronic ignition motobins have one for a reasonable looking 66 pounds mignt be my next step
Lou

[not-so-fast-ed]

Any chance there is some sort of fuel blockage or float hangup, keeping the fuel from filling the bowl?

Just my  [smiley=2cents.gif]

 :-/

Ed

[balibeemer]

And................... have you checked your carb diaphragm?

[drewboid]

If swapping the sparkplugs, caps, and leads from side to side does not move the problem then the ignition is OK. Have you checked the valves? It has happened that the valve lash was set at TDC of the intake stroke rather than the compression stroke.  
Mext step is to try a shot of starting fluid while the engine is running into the side that is not firing. If it fires than you have confirmation of the valves and ifnition being OK. - Time to look into the carb then.

[not-so-fast-ed]

"Think ive sussed it when i partialy block the carb intake with my hand it runs fine"

Sounds like he's traced it to a fuel problem already, Drew.  Cut off a bit of air to make it run rich and it "runs fine" would indicate the carb's not passing enough fuel... No?    :-/

Ed

[Justin B.]

Yeah, running too lean on that side...

[Lucky_Lou]

thanks for all the help ill strip the carb again must be a blockage didnt pull the air screw out last time may be blocked it does run if you blank the inlet with your hand so must be too lean, the diaphragm looks ok replaced floats ,inlet valve, needle & jet ect will have a look at the weekend or tomorrow if im snowed in
Lou

[Justin B.]

The idle jet is also prone to clog up as it has little bitty holes in it that don't take kindly to crud.  I usually use a single strand from a copper wire to clean them with.  Diaphragms don't affect idle.