Ok, so I'm still trying to fight with this thing to get it running. I've got all the valves adjusted correctly, new plugs, carbs have been taken apart and cleaned many times to get everything working correctly. Float levels are 14.6mm for one carb, and 13.9mm for the other (a little high, but still within spec). New boots between the carbs and cylinder. 147.5 mains, 35 pilot, 3 turns out, 2 washers @ 2300 feet altitude. (no filter right now until it starts, and a race style open exhaust) I kinda screwed up the valve chain tensioner because I can't read right, but rigged it to be working. I have a new one on order. My problem is it won't start. You can crank it for about 5-10 seconds and little puffs of smoke will come out of the exhaust and then BANG, a flame and backfire as loud as a 12 gauge. Choke or no choke doesn't matter, it does the same thing. Where should I go from here?
Sounds like the valve timing is off.What was the problem with the chain tensioner?The chain or one of the cams could have slipped out of time.
You're probably right about the cam timing. I turned the screw the wrong way on the chain tensioner enough to where it broke the spring inside. I took it apart and rewound the spring, minus the 8 inches or so that broke off. It excerts enough tension on the chain for now, but I ordered a new one so it will be right. I probably got one of the cams a tooth off while adjusting them. I spun the motor over by hand and nothing bound or hit, so I figured I got it right, but I guess not. Whats the process for installing the cams and getting the timing right?
Our engines are noninterference engines so the valves will not contact the pistons.
Good to know I can't screw up the internals by getting the valve timing off. Guess I'll fool around with it and see what happens tonight.