'81 gs450 trouble

[pat_in_the_hat]

ok. so need a little help.
Ive been trying to get a gs450 running. Bought the bike in pieces. So far i have rewired the bike with a very simple schematic and I have cleaned the carbs.

BUT. when I turn it over, it doesnt fire. It has compression of 100 and 105 (cold), enough to get it running, right? Ive grounded the plugs to the motor and seen a healthy spark, Ive given the carbs a good clean. Ive just been pouring fuel into the fuel line where it would connect to the tank (no tank for now). That should still work right, it doesnt need a higher back pressure from fluid in the tank? And the battery turns the motor over, so the battery shouldnt be the problem.

Ive sprayed a squirt of starting fluid into the back of one of the carbs. But it backfired once, sent a decent flame out of the exhaust and a flame back out of the carb.

To me, it seems to be missing fuel, is there something im missing about these bs34 carbs? Some little trick? i dont have the vacuum conection plugged since im not using the petcock/tank right now, but that shouldnt matter, right?

If the timing is off, it would still fire, right? Just wouldnt run right?

[Big Rich]

Throw the starting fluid away.

Have you checked the valve clearances yet? That's probably why your compression numbers are so low. You'll need to cap off the vacuum line going to the carbs - without it you're basically just allowing a huge air leak into the intake.

And timing is a very important aspect. A degree or 2 off won't hurt anything for testing, but try flipping it 180? and you'll get nothing.

Pat, it really sounds like you're "jumping the gun" so to speak..... An internal combustion engine is a pretty marvelous thing, which requires many different parts to run flawlessly. Just concentrate on what part at a time, and in the end it will all work as designed.

[Nessism]

Check the Newbie Mistakes thread linked in my signature.