Help...KZ750 twin wont start

i have a 77 kz750 twin have had it for a few months now and have done quite a bit of work and still the bike wont start it like half cranks but will not turn over. some of the work i have done already just to weed out some issues rebuilt carbs re jetted replaced ignition coil,wires,spark plugs,wires rebuilt the starter replaced battery anything anyone could think of as to why this is still happening would be much appreciated i would love to get her on the road again and start the body work but cant till the mech problems are resolved

thanks in advance

malone wrote: i have a 77 kz750 twin have had it for a few months now and have done quite a bit of work and still the bike wont start it like half cranks but will not turn over. some of the work i have done already just to weed out some issues rebuilt carbs re jetted replaced ignition coil,wires,spark plugs,wires rebuilt the starter replaced battery anything anyone could think of as to why this is still happening would be much appreciated i would love to get her on the road again and start the body work but cant till the mech problems are resolved
thanks in advance

Hello, malone, and WELCOME to KZrider!

The three essentials are compression, fuel, and spark.

Beginning with spark --- is fat blue spark visible with plugs removed and held grounded against the engine while spinning over the engine?

Good Fortune!

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malone wrote: i have a 77 kz750 twin have had it for a few months now and have done quite a bit of work and still the bike wont start it like half cranks but will not turn over. some of the work i have done already just to weed out some issues rebuilt carbs re jetted replaced ignition coil,wires,spark plugs,wires rebuilt the starter replaced battery anything anyone could think of as to why this is still happening would be much appreciated i would love to get her on the road again and start the body work but cant till the mech problems are resolved

thanks in advance

Why rejetted? Changed pipes and air box?

Check for strong spark. Verify mechanical advancer is free and check static timing. Check compression and valve clearances. I would also check fuel levels in the carb bowls with clear tube.

Are the plugs wet after cranking it?

its got good spark just wont kick over

Have you tried kick starting it to see if it will run? If the engine is tuned properly it should kick start easily. Ed

malone wrote: its got good spark just wont kick over

1) Why rejetted? Changed pipes and air box?
2)Verify mechanical advancer is free and check static timing.
3)Check compression and valve clearances.
4)I would also check fuel levels in the carb bowls with clear tube.
5)Are the plugs wet after cranking it?

the original jets were to small or so i was told by a mech im new to the bike world so,kick start mechanism doesnt work tried jumping direct to starter which is when i had it rebuilt after that didnt work tried push start and it almost works but backfires and dies @bountyhunter being im new can you go into more detail as to how to check mechanical advancer etc

As far as your jets go if you've got the stock air box and stock exhaust, I'd start with the stock jetting, maybe one size up on pilot, but really I'd start with it stock, get it running and then fiddle with it if you want.

You should get a manual if you don't have one. It'll explain the clear tube method for checking float level. It assumes you have a special tool, but you can really do it with a little clear tubing and some plumbers tape wrapped around one end.

Mechanical advancer is on the right side of the bike behind the little round cover plate. Remove that and you'll see the contact breaker plate and your points. The mechanical advancer is behind the contact breaker plate, but I wouldn't start there.

I'd follow BountyHunter's advice but I'd add one more thing. Have you checked the point gap?

Seems to be you're going about things backwards. I'd get reliable cranking (electric and/or kick) and then work on the not starting problem. You can't even really check the spark since you can't turn the motor over, or the fuel, or the compression.

Fix the starter.