Backfire through carb

[The Plunger]

I revisited my running issue (see R67/2 progress thread). I replaced the carbs and it is still backfiring through the RHC carb. The left runs great but the right putt-putts back through so it isn't a carb issue. At start-up, smoke puffs out at carb flange so I took off the head to see if I had a sticking lifter...nope. It starts easily enough but gas (exhaust?) feels like it is puffing out the bottom of the carb but that is impossible so it's coming through the gasket between the head and the carb. I took off the carb and sanded a very slight warp out but that did not change anything. I suddenly now have a rotational noise when increasing throttle. CRAP!!!
I'm at a loss here. Here are the facts:

Plenty of fuel is getting to carbs
static timing has been verified at least four times
valves have been checked the same
Runs great on LHC only
Will not run on RHC only
The RHC is hotter and noisier

What, mechanically can cause this? If the cam timing is perfect on the LHC, when rotated 180 degrees, it should be so on the RHC, correct?

Brian

[The Plunger]

Ack! After asking my friend Tony about the problem he suggested a head gasket leak. Sure as shootin', the new gasket has the paper burned off down to the metal 'wafflle' layer about the size of a dime and the head shows signs of exhaust leakage, PLUS IT'S RIGHT AT THE INTAKE! So, sanded the head face to true it up as well as the cylinder face. Now I have to get some new gaskets. BTW, is there a correct side of the gasket to face outward? And what's the rotation sound?

[schrader7032]

I'm not sure about bikes this old, but on my /7, the head gasket can only go one way. The way I can tell is that the wrong way covers up some of the opening in the cylinder for the pushrod tubes to fit through. Maybe something similar works for the plungers??

[The Plunger]

Kurt, nope, either face can be out. I'll ask Vech when I order.

[Daves79x]

Your sound is likely the 'woosh, woosh' of the compression blowing past the leaking gasket. Fix that and you'll be good.

Dave

[The Plunger]

OK, the never ending nightmare continues. Got my new gasket on, head and valves on and adjusted, mounted the carb and tried to fire her up. Nothing. Pulled the plugs and checked for spark - NONE! WTF?! The only thing I did electrically in the interim was tighten up a loose kill switch wire (blk/red) because I hadn't been able to shut down via the spike and I charged the battery whilst in the bike. Now, no spark. Did I fry the coil or capacitor by trickle charging? It seems improbable. All the other electrical stuff associated with the battery are working perfectly, but... any thoughts?

[wa1nca]

No
The charging system is independent of the mag for the spark
Maybe undo the last thing you did for the spark
Disconnect the blk/red wire and try it again

Tommy

[The Plunger]

This is getting silly. I tried just that after posting and it magically came back! Decided to run her around the block on her maiden voyage to see if she'd even move. A few issues remain. The charge light stays on and the intermittent whine is still present. I Guess the next step is to take off the magneto and generator and work through those. Hopefully it's not deeper, as this is a Gunther Wurst built motor and gearbox. I swear, this chasing ghosts crap is not what I wanted in this hobby!

[808Airhead]

There are always bugs to sort out. Enjoy the challenge

[The Plunger]

Well, here is the awful noise coming from my brand new rebuilt motor...anybody heard this sound before who can offer me a clue as to what and where it's coming from? Does it sounds louder on the right side, or am I nuts.

https://youtu.be/B5AseA8M-yA