RD400 running on one cylinder

[Joe6v6]

So I got my 400 running, half way, I only ran it for a few minutes. Ran very ruff & would not idle. It was apparent that it was only running on the left side as the left got warm & was smoking & the right stayed cool & only smoked very little. I am sure the spark, timing & points gap are all correct. I have not verified compression  but I am very confident it will be in spec. I would like any info that would help verifiy the carbs are working correctly & maybe an order in which I should check things. Seems to me that maybe the right carb is wonky, I suppose a leak down test is in order. Would an air leak around the intakes cause something like this?   

[Brad-Man]

An air leak would have the engine revving high.  What is your battery voltage while idling and at ~3500 rpms?

[Joe6v6]

An air leak would have the engine revving high.  What is your battery voltage while idling and at ~3500 rpms?

13 - 13.5 volts, admittedly I have a small battery 3AH , but in only running the motor right now. Seems the charging system is operating sufficiently. 

[Brad-Man]

Swap coils around. If nothing changes swap condensers around.

[m in sc]

agreed. if that doesnt do it, plug the choke crossover and swap carbs.

[Joe6v6]

Swap coils around. If nothing changes swap condensers around.

agreed. if that doesnt do it, plug the choke crossover and swap carbs.

Thanks for the replies. As soon as I read this I thought It could not be this simple. I spent enough time on the points & timing to know the correct cylinders were sparking with the correct coil, but of course it is worth a shot. So with high expectations I swapped the coil leads & it would not fire at all, so I put them back & started it. Within 30 seconds the issue became all too apparent. Engine / transmission oil began spurting out of the right header flange. I shut it down & thought well thats what happens to a 50 year old rd engine that has never had the cases split. To be fair I was very far along with this engine before I even learned of the potential Crank seal problems with these engines, so I hoped for the best .  .   So we know what im doing or at least starting this week end.  .   Has any one seen one this bad that oil is preventing ignition? & spewing forth from the header connection? Or probably you guys know - Do not assemble the motor with out doing the seals.  .  I have a good out look here, chalk it up to experience & move on.   . 

[Joe6v6]

So I started the disassembly of my motor today & wanted to report a rather unusual finding. If you read my previous post the condition I described was rather extreme, today I found out why. See the pictures. When I pulled the gear that keys onto the crankshaft there was a piece of metal between the seal and the surface of the gear that the seal rides on. It seems like it may have been a thrust washer at one time, its definitely a hardened steel maybe .020 thick. What is this? how did it get there?

[m in sc]

well THATS a new one. wavy washer under the idler gear or a bearing cage ? either way, thats super messed up. have never seen that before. 

[RDnuTZ]

will be interesting to see what that seal looks like after you get it out of there