So I was browsing local motorcycle classifieds when I came across a very interesting post. Someone in my city was giving away their C10 project for free. This project is a 1986 C10 which was running perfectly two summers ago, but popping out of 4th gear. I'm not one to shun a free project, especially a C10 as I am a diehard Kawi fan.

Amidst the flurry of people contacting this gentleman I was the first to say I intended to finish the build and put the Connie back on the road...thus I was given a truck load of parts to disperse around my garage whilst my befuddled wife looked on.

The previous owner is an auto mechanic, and sourced doubles of everything except the frame and gas tank.

The PO fixed an issue with the dash, rebuilt the fuel petcock, cleaned the carbs pulled the engine from the bike to diagnose a chipped 4th gear (through oil pan) and cracked the donor engine to pull a thankfully not broken 4th gear.

My plan of attack with the bike is to sort out the parts I will need (more on that later),  crack the good engine and replace 4th gear, then start putting the bike back together.

I have a couple questions I'm hoping the forum can answer (and of course I will have many more as this project moves along).

First, while putting the bike back together what trouble spots should I address/upgrade? The PO said the spark plugs wires should be replaced, and I was planning to install overflow tubes into the carbs to prevent hydrolocking. Is there anything else I should be doing while the bike is apart.

Second, does anyone have any tips or tricks to cracking the C10 engine case?   

Regarding the spare parts, once I have the project completed I plan to "pay it forward" by dispersing all left over parts to anyone who will pay shipping or come pick them up locally in Calgary, Alberta.

Welcome! You have taken on a big project. And you have a nice wife who lets you bring so many greasy pieces in to your garage like that!

I have never cracked an engine open. But one thing jumps to mind since you said you had gear issues, replace the star spring in the clutch. That is a weak point on these 1gen bikes and is known to break.

Welcome! You have taken on a big project. And you have a nice wife who lets you bring so many greasy pieces in to your garage like that!

I have never cracked an engine open. But one thing jumps to mind since you said you had gear issues, replace the star spring in the clutch. That is a weak point on these 1gen bikes and is known to break.

Thanks, I will do that. Looks like a cheap part and some good insurance while I am in there.

I actually misunderstood the PO when we spoke and thought he had already replaced 4th gear, but he had only pulled the donor. Getting that deep into the engine will be new for me. Adventure!

Forgot to mention I will also adjust the valves, replace all the fluids and there is a nice new air filter ready for me to install.

Welcome 

1 - Fit late model 2-part clutch star-springs and nut (from 94 and later models).

2 - Beef up the alternator chain tensioner
https://www.kwick.biz/product/tensioner-tamer-alternator-starter-chain-tensioner-fix/

3 - Fit '95 or later model (or manual) cam chain tensioner.
Manual - https://www.ebay.com/itm/KT1100-C-1986-2006-Kawasaki-ZG1000-Concours-APE-Manual-Cam-Chain-Tensioner-/380012550912

4 - Replace the alternator connector with a better quality higher current connector (2 pole)
I used Anderson SB50 connectors on mine and 10 years on all good.

5 - Re-flow the solder on the relay joints in the J-box.

Finally, the 86's have a tendency to tulip their intake valves at around 120k miles.
If yer nowhere near that mileage, don't worry about it, but bear it in mind.

I also seriously recommend adding a flushing additive to the oil and getting the engine good and hot before you first change it.
These engines sometimes suffer from blockages in the crankshaft oil ways and that leads to oil starved big-end bearing and the piston exiting the engine.
I use a flushing additive every other oil change. Using a flushing additive often shows up worn out seals so you can replace those.

To crack the crankcase there are a LOT of bolts, both from the top, and from underneath.
Hopefully none of yours will be chocolate, but some of mine were.
They are all detailed in the Service Manual. If you don't have one, let me know via PM and I can fix that.
http://gtr1000.com/graphics/gearbox/GEARBOX.HTM

Thanks for the great info on what to look for, and for the link to your writeup. I will definitely look to replace the set ring you mention on the output shaft while I am in there. The other items also seem like no brainer's while I am this deep into the bike.

Another question. Do people seem to prefer getting kits to replace worn spark plugs wires, or go the do it yourself route?

Thanks again the for help and warm welcome.

Another question. Do people seem to prefer getting kits to replace worn spark plugs wires, or go the do it yourself route?

I ordered 5 metres of stranded copper core plug wire (7mm I believe) and still have 3 metres left.
The wire unscrews from the plug cap, and if you unscrew the cap from the coil end, you can pull the wire off that end.

Murphs does a kit for US$36 with new plug caps. https://murphskits.com/spark-plug-wire-and-boot-replacement-kit-1/
By the way, if you look around Murphs site, you'll need another credit card 

Great write-up Boomer. How do the valves get tulipped?

My 2001 at 10k miles already had numerous camshaft lobe chips/pits. Kawiguy, check yours for it too. This is a common problem in many of these bikes.

Boomer, thanks for the link...I have a feeling I will be frequenting that site quite a bit.

DC, thanks for the heads up. The Previous owner said he checked the cams for pitting when he pulled the engine and they were clean (80,000 km on bike). I will double check when I do the valve adjustment.

Great write-up Boomer. How do the valves get tulipped?
My 2001 at 10k miles already had numerous camshaft lobe chips/pits. Kawiguy, check yours for it too. This is a common problem in many of these bikes.

For some reason some of the intake valves on the 86 model ONLY were not correctly hardened by Kawasaki's supplier, so over time they "tulip".
They are already Tulip type valves as they have a dish in the face of the valve, but over time the rim of the "soft" valve lifts, deepening the dish and leading to the mating face not sealing properly, which leads to compression issues. You can see it happening if one of your valves goes out of adjustment much faster/worse than the others. My 86 engine had tuliping on both #1 intake valves so I replaced those with new ones, but the rest were fine at 135k miles. I just finished rebuilding the top end of my 89 motor (180k miles) and apart from needing new piston rings and lapping in the valves to give a like new seal, she was good to go.

The Cam pits are a similar cause but in this case it seems that over-hardening may be the cause, or possibly too much carbon in the steel used for them.
86-93 engines didn't really suffer from this. I've only ever seen pitting on cams from 1994 and later C10s.

So I've been thinking about this, and instead of taking the chipped gears off the shafts on my keeper engine (and replacing broken ones) I am thinking it's easier to simply swap out the entire input and output shafts from the donor engine into my keeper. The donor gears all look great.

Is there a reason to not do the entire transmission swap over like this?  Am I missing something?

nope. prob the best way to do it if the donor is = or better everywhere

I dug out the donor transmission to take a look. Here are the pics.

I skipped the overflow tubes because like you I rebuilt the petcock and also if it failed would rather have a hydrolocked engine over a tank of gas on the garage floor and a fire.