Back fire and runnin rough

I finally got my 82 750 twin running but it is back fireing through the carbs and the exhaust. Also when I twis the throtle it bogs down and wants to die. I had the carbs gone over and cleaned. It has pods on it and the clean air injection has been removed and pluged. I have spark but it really doesn't look that strong. I tried to do the hot wire set up that Wiredgeorge wrote about in the tech section but I couldn't get it to work. Also how do you check the timing and the valve clearance? I have an electronic ignition. There is good compression too.

The ignition timing is not adjustable.

You have to take off the tank, coils, top motor mount bracket (bolts to the cam cover), and cam cover to check the valve clearance. If you need the specs PM me later, but hopefully someone else will post them first (my manual is in the garage).

I suggest using a multimeter to check the coils though.

Post edited by: steell, at: 2006/05/21 01:01

Thank you Steell
What kind of readings should I get when I check the coil?

2-3 ohms on the primary side (the small wires), 16k-22k on the secondary side (the spark plug wires, measured with out the plug caps on). Then measure the plug caps and make sure they are no more than 5k ohms.
If the readings are reasonably near those, then they should be ok.

1. did you use high octane gas ?
2. did you put a fuel addative in your tank?
3. are your plugs black and sooty
4. are you running ngk b8es
5. do your carb mounting boots(manifold side) have cracks or the vacuum caps leaking?

Sorry for all of the questions but all of the above are things that I changed and my carb poping sounds and small backfires are all but gone.

1. I put lower octane after I completley draind the tank
2. Well I put a carb cleaner in the tank I'm used to a car tank.....overkill
3 I cleaned them many times, I think it was the combonation in the tank fouling them.
4 I put hotter NGK in I dont have the number on me but I believe they were b6es
5 I pulled the carbs off ooooooh I was scared and I discovered I has one boot had a small tear in it. I kick myself know I shoul have replaced them when I had the carbs off. Anyhow hope this helps:)

Post edited by: 2bskor, at: 2006/05/21 07:57

Steell:
Thanks for the figures I will check them out and see what I get.

2bskor:
I didn't use high octane gas I belive it was 87 octane.
No fuel additive.
The plugs aren't black and sooty. They are actually pretty clean.
I have ngk plugs but not too sure what number.
I didn't check the boots due to the fact that the bike only has 8000 miles on it but it is something I will check into.

Thanks guys for the info it is greatly appreciated.

Ya' might wanna' check battery voltage AND charging system as the symptoms you describe here can sometimes be traced to electrical insufficiency
RTG
Rancho Mirage, Ca.
"83 KZ 1100 A-3

Have a look for air leaks at carb manifolds. Carbs not in all the way or damaged, cracked manifolds. Just got my GPZ back from shop had same synptoms , #2 manifold had big piece missing got sucked into engine.

I had the same problem many years ago (on a KZ 650)and it was the 'smog' reduction 'features' on the California model. Once I plugged up the so called feature I did not have anymore problems. If you search this forum for 'smog', you will be enlightened on how to defeat said feature. Good luck!