72 CB450 - Running on one cylinder - Please help

[jammer415]

1972 Honda CB450

Running on one cylinder only (left header pipe stays cold, bike is sluggish). There is a little bit of oil seeping out from underneath where the header meets the block. There is also oil inside the spark plug hole after I pulled the plugs.

I haven't done a compression test yet, I wanted to exclude all other (easier) possibilities first. I wanted to replace the plugs, swap the coils around, re-sync carbs and re-time the points.... But are the oil leaks symptoms clear indications of something particular? Like a head gasket or valve gasket?

Anything else I can do prior to compression test?

 

[jammer415]

Also, this seems to have started after I forgot to turn off the fuel, like an idiot, and left it on overnight. There was a few drops of fuel under the bike the next morning. I of course turned off and let the bike sit for two days. Is this a coincidence?

Could the flow of fuel overnight have cause to flood the engine and fowl up one of the plugs?

Any other ideas?

 

[jammer415]

So I also noticed that the left carb is leaking some fuel (photo attached).

Upon checking for spark on both sides after installing brand new plugs, I'm not getting spark on the left side, and that plug is dry (even after starting and running/idling on one cylinder for a few minutes). Does this also mean this plug is not getting fuel? Shouldn't the plug be wet?

If the cuplrit is a bad wire, cap or coil... Could this result in the oil build up around where the spark plug opening and oil seeping out from where the header meets the block when I'm running hot the one other cylinder?

Otherwise maybe a clogged jet, in addition to the bad wire/coil?

I'm going to replace the wires and coils... If anyone has any additional insight... Please feel free to chime

 

[frogman]

Check your oil level, SMELL the dipstick if it smells like fuel DON'T run the engine. Drain the oil and replace. 450s are bad for filling the crankcase full of fuel if you leave the petcock on and running fuel thinned oil in them will ruin them.

Plugs die, get a new set, you can also unscrew the plug cap on that side and cut off about 1/4"-1/2" and screw that cap back on and test.

Head gaskets leak sometimes, compression test will tell you if it is blown, looking for at least 165 psi or more on these engines.

Think simple, does it have spark> fix if not, does it have fuel> if not figure out why.

 

[jammer415]

Thank you so much for all of that insight, much much appreciated.

So before I start testing compression, I need to make sure both sides are getting spark and fuel. I ordered new coils and wires, as well as an oil filter to drain the oil and change it out.

I'm really concerned about ruining the motor from running fuel thinned oil the few times that I did that when trying to troubleshoot.

How would I know something is already fouled up from fuel in the oil?

 

[frogman]

The cams and rockers wear out quickly with little to no lubrication. May see lots of Metal in the oil and in the centrifugal oil filter. And you can inspect the cams directly.

 

[jammer415]

Ok thanks, I will definitely change the oil and check for metal shavings.

Parts finally arrived...

I had ordered the Pamco kit for the cb450, which includes two "high output Magna" ignition coils and NGK wires/caps, and also comes with their electronic ignition and advancer. I wanted to install the coils and wires first to get the bike running, then update the ignition.

The Magna coils that came with the Pamco kit are bigger and don't fit in place of the original coils... Are they meant to be re-wired and placed somewhere else on the bike?

Also, do I need these coils for the electronic ignition to work properly or can I update the ignition using oem coils?

 

[jammer415]

Bike is now running on both cylinders!

So those Magna coils didn't fit at all... I contacted the place I ordered the CB450 ignition kit from (Magna coils were included), and they told me that the small print states that I would have to fabricate my own bracket to accommodate the big ass coils, wtf. I wanted to get the bike running well stock before upgrading anything, so I ordered OEM ignition coils, replaced them, checked for spark on both sides, buttoned everything up and she fired up.

Even though both headers are getting equally hot and I can clearly see that it is now running on both cylinders, it seems to be running a bit off...

Do I have to reset the timing after upgrading the coils?

I already have the electronic ignition and advancer... Should I just install that instead of resetting the points?

Is setting the electronic ignition the same process as setting the points?

Thank you for all of your help.

 

[frogman]

I would say that you are correct in thinking you need to reset the timing or at least check it. I would also bet you need to balance the carbs as best you can too. Could be running more so on one cylinder because of lack of fuel on the other.