TOPIC:

Hi all
Just got my new toy home. 81 550 ltd 6k miles, complete and clear title, $300. Guy owned it since 06. Sat for last two years. Got it running 2 yrs ago but it wouldn't idle. Notice the super cool harley pipes and really good weld job...wonder if that has anything to do with it running poorly... The bike is complete, is dirty, but looks in good shape. The tank looks new inside!

Not sure what my plan is. Initially I wanted just a new top end because mine is so-so on #2. But with so few miles on this bike, I'm tempted to do rings, lap valves, hone jugs and new valve seals and just swap the motors...

I'll be swapping parts between the two bikes too, so in the end I'll still have two complete, titled bikes that run (hopefully). Not sure if I should flip this one with my current motor in it or just keep the whole thing for parts.

Now, I know my lower end is ok, but would it make sense to use the lower end on this new one? I have about 20k miles on mine. This one has 6. I need to find a way to check to make sure it will run through the gears though before I do the top end and engine swap.

Anyway, I'm excited. Even if the motor is junk, just the gas tank, seat, speedo/tach and carbs should at least net me back the $300 I bought it for.

With 6 K miles that motor ain't even broke in, unless of course it was abused and not maintained
I'd wash the damn thing, so when working on it dirt doesn't fall into places it doesn't belong, usually small orifices
The carb look like they need removed ,tore down, and soaked,then spray pressure clean out certain passage ways, Info is abundant on this site on how to do this
Change the oil
Check the plugs (for color).

What EZ said. Check for signs of abuse and neglect, redo the carbs (pilots most likely plugged leading to not idling), and swap the whole thing. With 6k, unless it was run low on oil or trashed, it should be tight and ready to go with maintenance like fluids, filters, and plugs.

Cory

So, look for abuse - aside from physical or cosmetic abuse I see none. I was thinking of putting my good carbs on it and seeing if it will run well before I dive in. (After oil and new plugs). How else can I look for abuse besides opening the top end up?

Would expect the valve clearances to still be okay after only 6K miles, but it's relatively quick and easy to check them and wouldn't hurt to do so.

Could also perform compression tests on cold engine (both dry test and wet test), and repeat same compression testing on warm engine, and then again after riding a hundred or so miles to possibly help loosen any sticking rings.

Same for leak-down testing, which gives a better idea as to overall condition of the engine's top end.

If needed --

A leak down test injects air pressure through the spark plug hole to pressurize the combustion chamber.

Can perform a poor man's leak down test by introducing compressed air into a spark plug hole and listening to where it escapes from the combustion clamber. This may be done at TDC or any other cam positions where both valves are fully closed. Top dead center (TDC) is when the piston is at its highest position. An easy way to tell TDC is by alignment of the T mark with the case mark when viewed through the timing window.

May introduce a spurt of compressed air by using a rubber cone-tip blow gun (rubber air nozzle) held into the spark plug hole. And of course keep holding it in position to keep air from coming back out the spark plug hole while listening for escaping air at other places. The air compressor should not be running while listening because the noise will likely drown out any sound of escaping air. Or just use a portable compressed air tank.

Air heard escaping from exhaust port indicates exhaust valve not fully closing (perhaps too tight clearance or damaged valve or valve seat).

Air heard escaping from carb intake indicates intake valve not fully closing (perhaps too tight clearance or damaged valve or valve seat).

Air heard escaping from crankcase breather indicates loss of compression past rings into crankcase (perhaps worn piston rings or cylinders).

Air heard escaping from head gasket area indicates indicates loss of compression past head gasket (perhaps due to a blown head gasket).

A leaking valve may sometimes be resolved by adjusting the clearance to within specs.

A leaking head gasket may sometimes be resolved by torquing the head fasteners when the engine is stone cold (such as after sitting overnight).

Good Fortune!

Thanks Patton. I will do your recommendations. I'm leaning towards pulling the head anyway... Looks like the gasket is starting to leak a little on the ends. Base gasket looks ok, but I know these bikes are known to leak a bit at them.

I guess I could just throw the motor in my bikes if it's ok and ride it without the rebuild... Would save me a bunch of work and I could save my gasket set and piston rings for when I actually need them.

Don't open it until after you have it running and can do a compression test. If you can't get it to run nicely, then look into it. But if you can get your good carbs to make it run and idle nicely, a simple highway run will tell you if the valves are out of tolerance. No need to invite trouble unnecessarily. If the oil is just a tiny seep, just clean it, forget it, and move on.

If you look at the regulator rectifier, and it has 3 yellow wires, it should be a 1981 C2. If it has 2 yellow wires it should be a 1980 C1. (The stator with 3 wires is 3-phase and has 18 pole pieces. The stator with 2 wires is 1-phase and has 12 pole pieces.) Other differences might be in how the disks mount, and how the caliper looks. I think the 1980 C1 had its disk riveted to a carrier and that bolted to the wheel. I think the 1981 C2 disk bolts directly to the wheel.

Normally I would have verified this on the Kaw site, but I haven't located a good fiche site yet.

But, of course, it's hard to say whether the factory might have just slipped out some C1 frames as 1981 models, in which case the title and vin sticker would have to have the C1 designation since that's what's stamped into the frame. In that case, the wheels, disks, calipers, and stator wiring will be the same as your 1982 C3.

The first year KZ550's did have different part numbers for internal motor parts as well, so it's kind of good to know whether the engine is made with 1980 parts or 1981 parts, but it may not matter if the parts are interchangeable.

Here's one way to help positively identify the exact point of oil leakage ---

Thoroughly clean engine and allow to fully dry.
Spray foot powder deodorant over edges of head gasket, valve gasket, half moons, tach drive, exhaust ports, and any oil cooler line fittings.

Basically, cover top end of the clean dry engine with white foot powder.
It will appear almost as "painted" white.

Using a flash light or shop light, start the engine and inspect closely for the first sign of emerging oil, which will darken at the point of leakage.

Good Fortune!

Hey Loudhvx, didn't you tell me once that the cams were a little hotter in the 80 or 81 550? Or was that only in the standard and GPZ models?

I also noticed Kaw truncated the years they now cover on their part fiches

It's on my Kz550 valve train warning site.

The KZ550A and KZ550C cams are the same.
The Gpz cams are "hotter".

Just went out to the garage for a bit... I threw my trickle charger on the new 550. All the electricals work. I pulled the plugs and shot a little kroil in the cylinders. Didn't see any issues from up on. I put it in gear on the center stand and I cannot get the motor to move without what I thought was too much force. I then just bumped the starter and all it did was tick. Not sure if it's due to the ancient battery or the starter is shot or the motor is seized. Like I said I could get it to move by rotating the rear wheel in 1st gear, but it seemed really hard for having the plugs out... Guess I'll have to wait til I have time to get a wrench on the crank and see if it's free.

False alarm. Must have been the battery. Left it charge for a while and she turns over just fine.