1981 Kawasaki GPz550: Restoration

[Corey]

Awesome Steve! Looks like it is not only a runner, but a show winner too.

On the exhast, just remember, loud pipes saves lives.

[Nessism]

Congratulations Steve! Hope it rides as good as it looks!

[srsupertrap]

Thanks Roger, Larry, Ray, Steve, Corey & Ed for the support and help over the years! I took the day off and unfortunately a ran/snow mix today here in Colorado. The weekend will be nicer weather.

This might be a Corey or Ed-K750 question. What size spark plug wrench do you use for the NGK D8EA spark plug? The only tool which fits is the spark plug wrench from the OEM tool kit. I would like to torque the spark plugs correctly.

[GSXR7ED]

What a beautiful bike! Thanks for posting the video...nice clean garage too!


Ed

[Big T]

Steve - at last! Can't wait to see some pics from the road.

And, thanks again for that nut. You wouldn't have believed the look on The Collectors face when I returned the other one to him. i don't think anyone's ever borrowed any hardware from him and returned it.

[2BRacing]

..... What size spark plug wrench do you use for the NGK D8EA spark plug? The only tool which fits is the spark plug wrench from the OEM tool kit. I would like to torque the spark plugs correctly.

The GS650G I am working on at the moment also uses NGK D8EA sparkplugs. I had to buy a deep ("long") 18 mm socket (11/16) for the sparkplugs.

Well done! Fantastic job on your GPz!

[Nessism]

This might be a Corey or Ed-K750 question. What size spark plug wrench do you use for the NGK D8EA spark plug? The only tool which fits is the spark plug wrench from the OEM tool kit. I would like to torque the spark plugs correctly.

Sorry Steve, can't help you with that question. My bike takes regular B8ES plugs and a normal plug wrench fits.

[srsupertrap]

I purchased a Craftsman 18mm spark plug socket to remove the NGK D8EA spark plug which works nicely. I have ridden the GPz about 10 miles around town. Everything seems to be working well enough transmission shifts through the gears, no engine noise, charging system charges and handles nimbly. Like so many 4 cylinder bikes the carbs need adjustment because it does not idle. When I initially disassembled the GPz in 2013 the plug were fouled, not much changed in 2018 when I started it up. Perhaps worse @ 5100 Ft. I initially thought carb synchronization but checking with my TwinMax Electronic Carb synchronizer the drill bit settings was pretty close. The Mikuni Flatslides had 32.5 pilots which might have been the factory jets but those jets are too rich even with fuel screws 2 full turns out as evident below



Pulled the Mikunis and swapped out the 32.5 pilot jets and installed a set of size 30 pilot jets.



I will start with fuel air screws 1.5 turns which hopefully will make the GPz idle which sounds about right?

[Big T]

Looking good!

Now, how about a video of it running?

[Zaddict]

As happy as I am to see the bike finally assembled and running I'm even more excited to get your report once you dial things in and get a chance to thrash it about a bit. I guess the good news with jetting is the pods should make pulling and reinstalling the carbs much easier.

[dweller]

Wow, great job. Really cool bike! How did the 30 pilots work?

[Nessism]

Bump for a ride report!

[srsupertrap]

Wow, great job. Really cool bike! How did the 30 pilots work?

Took a test ride around the neighborhood today with the 30 pilots installed and air screws 1.5 turns out from seated. Better, but still not right.

Issues:

• Still won't idle or start when hot without giving some choke.
• Will stall when approaching stops.
• While on the pilot circuit and the throttle closed the GPz surges as engine rpm drops.
• Above 3500 rpm when timing is fully advanced the engine hangs up @ 3500 -4000 rpm ??? Note: Short shifting is much better but its not rideable in traffic.
• Right fork seal leaks

Verified the timing and spark plug gap was correct afterwards. After 12 miles the plugs look like. I ran these same plugs with the 32.5 pilots and they were pretty fouled. The Flatslides have Push / Pull thottle cables like VM equipped GS750/1000s. Both cables have slack and the throttle spring snap the slides shut. Thoughts?

[GS1150Pilot]

Fantastic sound!
Be rightfully proud of a job well done.

That makes me miss my '82 badly. I had a Kerker on it, and it sounded wonderful, too. What a stunning bike!

[Corey]

Still hanging in there Steve? Keep at it you are getting closer. Might need to invest in a Wideband System for tuning. Check out this:

https://www.innovatemotorsports.com/products/db.phpi