shooting flames outta carbs

[desmodromic]

Long story short, I completely rebuilt my 81', new seals bearings, rings cam chain, ect. I did new VM 34 carbs from MMM and Boyer ignition. It ran for 10 min before it blew up, I didn't tighten the valve tappets good enough. So I had to replace 90 % the top end. I re timed it, advanced the ignition, did valve clearances and set everything like I had it before. I couldn't get it started, I just had fire shooting outta my carbs. I feel like my ignition timing is of, but Ive tried advancing it and retarding it with no luck. Plugs/coils are fine and battery has more than enough juice. I'm guessing its the carbs but what gets me is that it was running great with the same set up. Any imput would be great.

p.s cam timing is correct I am 300% sure and so are valve clearances.

 

[Chris300s]

You mounted the carbs on the back of the motor, not the front right?
I think the ignition timing must be off somehow like it's firing out of phase. Sorry I be more helpful than that and a smartass comment but my $.02 anyway.

 

[jd750ace]

Both carbs? If so, your timing is advanced way too far I would guess. It has to be sparking with the intake valve open in order to light the charge in the intake runner.