1981 KZ1000LTD misfiring?

hey guys. As some of you may remember, i posted a video of my bike running and i was all happy. I can't get a straight answer out of the mechanic that i bought if from so im coming to you guys. I want to know if this sounds like misfiring or not. its the same video i posted. Theres just a rattling noise on the left side of the engine. Do you guys think it needs a rebuild? No im not asking that lightly either, im scared shitless of that...
Heres a link...


Thats what it still sounds like. I installed an airbox and new boots and a filter today but i didn't get a chance to start it yet because i had to go in and watch the kids. Will it run better with an airbox?

Well young man, have to say I'm impressed....

"There's just a rattling noise on the left side of the engine."... Not sure I heard it in the avi clip. Possibly due to not warmed up but here goes anyways...

Probably best to give us a little update on the following...

Valve Clearances to specifications?
Ignition Timing to spec (idle and at 3500 rpm)?
Charging and electrical system to spec?
Carbs synced to spec?
Timing chain tensioner adjusted to spec?

When running on the road, lags, hesitations, stuttering, flat spots in different gears at different rpms?

Backfires out the exhaust during deceleration?

I'm sure the others will chime in...

Keep at it kid, you're soooooo close to victory! :woohoo:


OMR

Open up a CD sized cover on the right side of the engine, inside you should see the mechanical ignition advancer.

With the engine off, you should be able to give it a twist with your hand and see if it returns to where it was.

If it sticks, remove the 13mm bolt holding it to the crankshaft and clean and lube the advancer.

Make note to how it's mounted to the crankshaft as it can be installed 180 out(you'll find out quickly if the bike won't start).

Light oil like 3-in-one or sewing machine oil will work good for the lubrication.

Put a few drops on the weight pivot and spring attachment places.

Kitten Tooth, I have an 81 CSR 1000- almost the same bike, and it is the same engine.
It seems to be idling roughly. I KNOW the sound well, because I had the same problem you do when I bought my bike= the carbs full of water, rust, and corrosion.
You will need more than the air compressor to blow out the carbs. Get some spray carb cleaner, and most importantly, get some small piano or music wire from the local ace hardware store to clear your idle pilot jets. Pull carbs, remove float bowls, remove floats, now there will be a plugged orifice next to the main jet. Take some pliers, and remove the plugs. Look down that orifice, and you will see the idle pilot jet. Its hole it TINY, and that is why you must use the smallest music wire. Remove the main jet, and blow and spray everything. The idle pilot jet is fed fuel from that main jet tube via an angle passageway. It would be best if you removed the top of the carbs, remove the vacuum piston, and tapered needle jet to allow maximum blowing thru the passages.
Now, the rattle on the left side of your engine is three loose bolts holding the flywheel on. It must be removed with a special puller to get it off, and then you will see the loose bolts. The more you run it like it is, the more it will waller, and hammer on the loose bolts, and their holes.

ok, the mechanical ignition advancer is on the right side of the motor under that circular cover. Is this part also called the signal generator? It has a rotor that spins in between two pillars with metal contacts on them right? Are you saying to remove that rotor that spins around and oil it up in there if it sticks? I'll give it a shot, its like 3 little bolts to remove that cover.

I assure you that there is no water in the carbs. I know the jets are free, i checked them with the wire just like you just said. I already did all of that stuff. As far as the carbs, i believe that they need synced. but that flywheel that you were talking about with the loose bolts... Is that like... in the crank case? Do i have to remove the big engine cover on the left side of the motor?
Thanks guys. somebody told me that that rattling noise was misfiring, like pre-ignition and sometimes, firing wrong can make the motor sound like its come apart if its bad enough...

I have an 1982 GPz1100 B2 model, in my shop manual the mechanical timing advancer is not listed as a signal generator, but later years of these bike's they may have changed descriptions.

The left side of the engine(as you sit on the seat) has the cover for the alternator, it's made up of the stator or stationary part with the wire windings.

The rotor or rotating part has several magnets that when spun around the stator produce the Alternating Current(A.C.) that is converted to Direct Current(D.C.) by the rectifier/regulator.

The regulator controls the current going to the battery and the bike's electrical system and will shed excess current/voltage through the cooling fins on it's package.

so... that how that works.. i really didn't know how that worked, i thought that the rectifier just regulated votage, i didn't know it convert AC to DC. He said the mechanical ignition advancer was on the right side of the motor under a CD sized cover. i'll check it out. As for that flywheel thing that Jmotor said, where is that flywheel located? IS it like, easy to get at? I don't know if im ready to split open my crank case like that. If its just under one of the engine covers though, I can do that.

Timothy, get a 5 mm allen driver bit, and remove the allen bolts on the left side of the engine. There are 2 covers- one for the drive sprocket, and one for the alternator/flywheel. Just remove the front on for the alternator. Also get a 10 mm wrench and remove the chrome starter cover if it is in the way. You will likely have to remove the foot peg, and shifter. You will not need a drain pan for it is a dry area under that cover.
Be careful for there are wires attached to the cover, so do not tug on those wire. If I remember correctly, I just let the cover hang on the wires, and did not disconnect them.
Now, you will see a big nut holding the flywheel on. Remove that nut, and then borrow a special puller, or do like I did, and haul the bike to someone who has a puller. You will not need the puller to reinstall the flywheel. Once they remove the flywheel for you, you will see the bolts I am talking about. Good luck, David

Some more info Timothy, the 3 loose bolts hold a "one-way clutch assembly for the starter" onto the flywheel.
The bolts point towards the outside of the bike. In other words, the bolt point towards you as you are removing the cover. My bike had this exact same problem when I got it, I just degreased them and their holes with brake cleaner, put loc tite on them, and carefully tightened them snugly. I have put many miles on my bike since this repair.
Personally, I would repair this first before anything else for 2 reasons- it is hard to enjoy running the bike knowing it is damaging those bolts, and you will be better able to hear and sense how it is running with it nice and quiet.
David

Not sure about the J motor but my 900 had a noise that was just awful and sounded like the motor was going to grenade at any moment. Turns out it was the rotor on the left side. It came loose from the crank and was smacking the stator. Destroyed two stators before I got it worked out. On the early 900/1000 motors the big nut on the top triple tree is the puller for the rotor. Not sure about the J motor though. If that is the problem your charging system will fail very soon. My .02 cents

I am having to remember back about 2.5 yrs on this, but I think the following is a description of the flywheel puller.

The flywheel has some threads in its central hole. The puller is like 2 tubes, one threaded inside the other. The outer tube has threads on the end that thread into the flywheel. The inner tube is turned, pressing against the end of the crankshaft, and drawing the outer tube, and flywheel with it.

my 2 cents. I am no guru, but I do not see how the top triple tree nut could work as a substitute for this puller. Maybe they changed the design from the earlier bikes.
No offense or argument intended.:woohoo: