Homemade float bowl gaskets ?

With the help of this forum, my 1980 KZ750LTD is running . Not running well, but running. It won't idle below around 2000 rpm and has little power off the line.
The float bowl gaskets were not in good shape after I got some carb cleaner on them when I was cleaning the siezed carbs. Could a bad float bowl gasket cause the problems, and could I make my own gaskets with some gasket stock and an exacto knife? I don't want to spend $100 on carb kits for a bike with 5000 miles on it.
I have new airbox to carb boots coming, they are hard and almost caused me to swear when I was putting the carbs back on the bike. I was going to check the carb to engine boots when I put the new airbox boots on.
Do I need to have a look at the ignition advance mechanism?

Requiescat wrote:

With the help of this forum, my 1980 KZ750LTD is running . Not running well, but running. It won't idle below around 2000 rpm and has little power off the line.
The float bowl gaskets were not in good shape after I got some carb cleaner on them when I was cleaning the siezed carbs. Could a bad float bowl gasket cause the problems, and could I make my own gaskets with some gasket stock and an exacto knife? I don't want to spend $100 on carb kits for a bike with 5000 miles on it.
I have new airbox to carb boots coming, they are hard and almost caused me to swear when I was putting the carbs back on the bike. I was going to check the carb to engine boots when I put the new airbox boots on.
Do I need to have a look at the ignition advance mechanism?

Z1e shows float bowl o-rings (not gaskets) for 1980 KZ750-H LTD, with a set of 4 for under $16.

The o-rings are reportedly fragile and often replaced during reassembly.

I don't suspect either failure to idle down or lack of power off the line is resulting from leaking floatbowls.

Would use strobe type timing light to assure correct ignition timing and correctly functioning advance mechanism. Would follow FSM instructions with regard to cleaning and lubing the advancer. .

Good Luck!

The float bowl is not sealed, it is open to the atmosphere by design. A bad gasket probably won't cause the symptoms you have.

I made bowl gaskets before and it is definitely not worth the trouble. It takes a specil material that is gas resistant. Regular cork disntegrates and paper is not usable.

I dont think the ignition advance will have any effect at idle.

It sounds like not enough gas at low speed and I would think carb related. When I got my 750/4 six years ago I had a lot of carb problems when under 3,000 rpm. I took them off and cleaned them ..........again and again until finally I decided to clean as thoroughly as possible. It's often not enough to soak them in cleaner. Only after I totally dissambled them, took out every jet and poked every oriface no matter how small with a stiff bristle or 50lb nylon fishing line or guitar string (carefully) until I was sure it was clear and then finally blew everything out with compressed air, only then did my problems go away.

Also, and assuming the carbs are Keihin CV34s, dont neglect the transition holes. To find them look into that end of the carb which faces the motor. Lift the throttle flaps and look up. The hole nearest the opening is from the air mix screw. Just behind that you will see 3 tiny holes. These need to be clear or motor will stutter or just generally bog under 3,000rpm.

Finally, make sure the fuel level in the float bowls is where it should be - about 1/4 - 1/8 of an inch below the bowl gasket.

Of course I could be totally out to lunch here and maybe the new carb boots will be the fix when you get them

Good luck

Thanks,
I thought I had cleaned all of the holes, I'll do it again and make sure I get all of the holes. These carbs were seized solid so I'm sure those holes are blocked if I didn't see them.
The bike seems to run well in a narrow range of engine speed, low end bogs and after 5000 or so RPM it doesn't feel right.
Thanks for your help.

sorry to hijack this thread, but I thought my question was along these same lines...
so I have float bowl gaskets that came in a whole KZ1000 gasket set. I tried fitting them in and they are just a little too large (we're talking fractions of millimeters). Is it bad to maybe cut them to fit? I'd rather not have to buy a whole new set of them.