Spark plug CSI

I pulled one of the plugs from my '83 GPz550 last night (had been sitting outside about a year before I got it, steady use before that ... apparently) and was wondering if anyone would like to offer some professional opinions on what to expect when I open the block.

I've attached a bunch of close-ups of the spark plug to help with the investigation/theorising.

My deductions would be: old plug (rust and eroded terminals) but running rich (black deposits around base of the plug). Maybe the plug is too hot for the engine? Not sure about the crud in the threads. There looks to be a small piece missing from the top electrode ... which is worrying.

What do you think?

Thanks all

Full view, it's a "Champion" brand, didn't check the part number. Heavy rust.


Close up showing the dirty thread. The light spot on the top terminal is where a piece appears to be missing?!


Nice shot of the top of the plug. Can clearly see the missing piece. Eek! Did it end up inside the engine?!


Another top shot. Electrodes don't look melted, just old and worn would be my guess. But then this is my first spark plug analysis

Why "open the block?"

I'm a little hesitant to try firing the bike up without having a look at the internals first. It's been fairly badly abused cosmetically, so not sure what condition the inside is in and would rather find out about problems with the engine off than revving up

But by that comment you think those are decent looking, but old, plugs?

Looking at those plugs I'd guess the previous owner thought maintenance was a 4-letter word. I would be tempted to pull the plugs (they need to be replaced in any event) squirt a little shot of lube in each cylinder, and with the plugs still out turn the engine over slowly by hand to see if I could feel any roughness as the pistons move up & down. If they move freely, I would do a compression test, and if the compression was good I wouldn't bother dismantling the engine. Ed

If the compression is way down(80 PSI or more) the engine might run but won't have a lot of power.
New/rebuilt engines can have 180 PSI or more, put a few years on it and 160 PSI is about all you'll see.

If you pull it down for overhaul, don't forget new valve stem seals as they get brittle and don't seal well, causing oil burning/plug fouling.

While you didn't post the mileage on the Odometer, it may not be accurate anyway.
That first picture looks like a plug that is oil fouled, that may be why it was parked, years ago. Those others have quite a bit of deposits, from oil that has burned. IMO it would need the top end refurbished. Looks like that first plugs cylinder has a problem that will foul the plug with oil. Of course it could "Run" and just keep spare plugs handy.

I'd try turning it over by hand (plugs out) to see if it turns smoothly. You can look down the holes with a light and see what's in there. Check compression. If it turns smooth and has decent compression, I would change the oil and filter, flush the fuel system and carbs and see if it runs.

+1

and dont use Champion plugs like in the first photo. Get NGK or whatever is recommended in the manual. Champions dont seem to work well in motorcycles

The knowledge and advice given on this forum never ceases to amaze me. Thank-you all for the invaluable input

So a few days back I pulled out the plugs again and sprayed a generous amount of PB Blaster into each cylinder, then replaced the plugs.

This morning I removed the plugs again, pulled off the right-side engine cover to expose the end of the crankshaft and gave the 17mm nut (the manual was very specific about which one to try turn) a few clockwise turns to get the pistons moving.

The cover removed ... interesting gasket :huh:


Clearly I'm not the first one in here, someone had some fun with this screw!


So, how'd it turn ... well it turned. A little stiff at irst but loosened up as I kept cranking it over. It's smoother at some parts of the cycle than others, but not what I would describe as smooth. Looking in through the spark plug holes, I could see the tops of the pistons covered in a nasty black deposit. Out of curiosity, I pulled off the two smog valve covers ...

The following images may be disturbing to sensitive viewers


The entire inside of the valve assembling is coated in a layer of soft, oily deposit about 1/16 - 1/8" thick. I'm surprised this bike could even run with such a rich mix!

Right side


Close up of the top


Close up of the bottom


Small scraping through the muck



So given the level of deposits, what do you all think I should do? Even bother with a compression test? I'm going to need to open her up to clean the cylinders and pistons anyway, right?

Thanks

It looks like an abused horse ("Rode hard and put away wet")I'd be doing a compression check to see the condition of each cylinder, then check the valve clearances(I'd be surprised if a few arn't open with zero clearance.

What you've got in your hand at the bottom of the picture is the reed valves for the "Smog Gear" Kawasaki designed for a cleaner burning engine. They called it the "Kawasaki Clean Air Suction System"(KCASS). Most riders here in the states have removed this sytem and installed block off plates, capping off the vacuum lines and hose openings.

Smog Block Off Plates
www.tpoparts.com (Comes as a kit, with the plates,vinyl plugs & rubber caps for vacuum lines)
www.kzzone.com/billet.html

Check with these websites as they may not have the plates for your bike. If you know a friend with a CNC mill. he might be able to make you plates using your old ones as a template for new ones. I'd think some Aluminum 1/8" 6061 T6 will work for this.

Measurements of valve spacings taken ... continued in engine section: kzrider.com/forum/2-engine/461342-engine-csi