Left Cylinder is a No-Go (CB350)

[Jonas]

Hi all-

Well, I've checked in here very so often whenever a particularly troublesome issue has confronted me, and I've got another (which will, it seems, be my last.)

My bike is one left cylinder away from being legal. I've done everything (or so it seems): times it three times, once with a gun (which confirmed that it was accurate; checked spark (big juicy blue ones); checked and adjusted valve clearances (0.05mm for the intake, 0.1mm for the exhaust); gutted and thoroughly cleaned the carbs at least four times but probably more, and finally replaced the left carb completely. I've also synced the carbs, both at idle and 4k.

Does anyone have any ideas? One of the guys in the shop I'm working in (a BMW and MMI trained technician) seems to think its trouble with the carbs, but having used two different carb bodies and having extensively cleaned both, that seems impossible. I'm wondering if it could be some trouble with spark that goes away when I take the plugs out to test them - is that too far fetched?

Any help is deeply appreciated!

Thanks guys

 

[xb33bsa]

fully charged battery ? if you swap coils/wires does the problem move ?

 

[Deadfrednc]

Have you done a compression test?

 

[cxman]

when it is running squirt a bit of starting fluid or carb cleaner in the carb on the dead side and see if it picks up if it does its still a fuel problem

 

[jpmobius]

Do NOT use starting fluid. EVER. Not for any reason whatsoever unless you are starting your grill or live in Alaska. It is pretty hard to learn anything correctly by squirting anything but gasoline into a running engine, and then you are likely to mostly learn how dangerous gasoline can be. If the engine is running, hold your hand over the carb of the cylinder is not running. The increased air resistance usually will work like a choke and add a lot of fuel, and probably not start a fire or destroy the motor. If you get fuel on your hand, it is either fine or too rich if it does not fire that cylinder up. Look for an ignition or compression problem. If it does fire it up, take the carb apart and figure out why no fuel is being presented.

 

[xb33bsa]

i wouldnt use charcoal bbq starting fluid either
for finding air leaks,ether starting fluid works very well though and it is not overtly hazardous unless you are
it is a proven true method for finding air leaks
but gasoline engines dont tolerate it very well in large quan-titties like directly through the carb throat,it could actually damage
brake cleaner is not flammable so it really is worthless
if you do use ether starting fluid use it only for finding air lreaks and yeah keep your face away,do the test outside and always have a fire extinguisher on hand at your shop area