1981 Kawasaki GPz550: Restoration

[srsupertrap]

You are progressing well with this project, and will enjoy the results with no regrets, right?

Well the pivotal decision was made back in March. The options were to part out the GPz550 project or 2. Throw additional money at it to make it whole again. I made the decision to go with #2 and thankfully the KZ550 parts bike came along and largely offset the project cost. I have certainly have learned more and met more good motorcyclists along the way. So of course no regrets.

I need a damn 81 GPz exhaust cam with the tach drive. For the rest of the readers, I sold the Moriwaki mystery cams to fund the project because the stock GPz camshaft have approximately .325" lift while the Moriwaki camshafts I had measured .335"lift. Later realized 82 & on GPz550 used electronic tachometers so those GPz exhaust cams don't help. Corey wanted me to install Megacycle Cam 478-60 grind with .410 lift. Lots of interesting discussions with the guys on The GPz550 Forum about camshafts.

Lou D's website is great reading too with lots of valuable GPz information http://gpzweb.s3-website-us-east-1.a...com/index.html

[srsupertrap]

I have read the GPz550 starter clutches can cause problems so last weekend I rebuilt mine


Those allen head screws are torqued to 25 Ft-Lbs & loctitied


Used the secondary shaft that not's not going back in the motor to grab onto with a pipe wrench

Disassembled with new replacement dampers


New pins rollers and springs. Not sure what actually fails but seemed like the wise move to replace parts while its easily accessible.


Perhaps I will rebuild the original GPz550 starter clutch, someone on the The GPz550 forum was looking for one




Cannibalizing the KZ550 transmission shift forks too. Hard to see but the GPz550 shift forks have more visual wear across the width than the KZ550 shift forks.

Finally cannibalizing the KZ550 shift drum, overshifter lever, shift shaft because the original GPz 550 gear shift lever threads were damaged

[srsupertrap]

Ready to bolt the crankcase halves together after work. I ordered Kawabond #5 from Powersports Warehouse.com and it's back ordered. I still have a tube of ThreeBond Grey from 2014. Any reservations on using the older ThreeBond Grey?

[Big T]

As long as the Threebond is properly tacky, it should work

It's all the same stuff-Yamabond, Honda and Suzuki

[srsupertrap]

Buttoned up the crankcases this weekend, torqued the connecting rod bolts & new crankshaft seals




ThreeBond sealer




Went together real easy. Bagged all the bolts when disassembled. Torqued to spec with T-wrench


Next secondary shaft, oil pump & pan

[srsupertrap]

Tight fit for the starter clutch with tighter HyVo chain


Install the KZ550 secondary shaft



Loctite the two oil pump screw & bolt



New gasket & o-ring seals & primed the oil pump.


S/B ready to install in the frame

[srsupertrap]

New seals for the countershaft cover


Permatek Black RTV


Not going to stay that shiney



Should be ready to install

[srsupertrap]

I decided to make more progress and install the engine on Sunday. I called up Ray (Ghostgs1) to see if he could help out and less than an hour later he's at my garage helping me install the GPz engine. Less than 45 minutes later we got the engine installed. Big Thank You to Ray for dropping what he was doing on a Sunday.




Considering what type of break in oil I should use now that the weather is near freezing overnight. Perhaps Castrol 10W-40?

[psyguy]

Considering what type of break in oil I should use now that the weather is near freezing overnight. Perhaps Castrol 10W-40?

Don't know about what oil to use (it's a bit of a "religious topic" anyway ) but wanted to say great work on the engine!

[srsupertrap]

Don't know about what oil to use (it's a bit of a "religious topic" anyway ) but wanted to say great work on the engine!

Thank psyguy for the complement, not taking any short cuts. Oil is controversial topic maybe I will just review the threads elsewhere and review some old MCN engine oil evaluations. A little more progress during the week.

Barnett Extra Clutch Plate kit installed which came with the bike. Clutch Hub nut torqued to 98 Ft Lbs



Moving to the other side. Torqued the generator rotor to 50 Ft-Lbs and secondary shaft nut to 34 Ft-Lbs.



Starter is already installed. Starting to look like an engine again!

[bonanzadave]

Barnett Extra Clutch Plate kit installed

I installed one of those that ate up my basket. Coulda been the way I rode it. Have a tendency to brake down shift. Springs were waaay to stiff for me.

I dont even want to say it out loud but would hate to see something else go bad. This has been the most excruciating build ever on the GSRs. and now all the old pics are gone. If this ever has a happy ending you need to put it all down in a book. "The Murphy Bike Build"

[nvr2old]

Boy, no kidding. I have watched this build from the start and I have to compliment you on your tenacious and never-ending faith in getting this bike done, and done correctly. Most people would've called it off many months and dollars ago. Riding it will feel SO good.

[Nessism]

Using Chrome browser and the "photobucket" extension and most of the old photos show up. This has been a great thread that shows Steve's tenacity; Sh*t happens, what's important is how we deal with it!

[Zaddict]

I joined this forum just so I could say a few words of encouragement. I really admire your craftsmanship and tenacity. Plus I really, really want to see this bike running. It's going to be an absolute blast to ride when you're done. I have an old zr550 I'd like to give a similar treatment at some point. Keep it up!

[srsupertrap]

Thanks Dave, Larry, Ed for following along all these years and keeping me motivated too. Zaddict welcome to the GS Resource Forum as well and thanks for the encouragement. The GPz sure is lighter than the GS1000 and I am looking forward to riding instead of wrenching. I am feeling the end of the project is in sight. On Saturday I was hoping to get the pistons installed.

Installed the clutch cover, previously slotted the Dyna S ignition for additional range



Installed the C/S cover and generator cover too



Next I checked the ring end gap which I could have done months ago. First square off the rings using the piston


The top ring end gap measured .010" across a four which is tight ( suppose to be .012" min). The second ring measured by .017" across all four. I need a piston ring grinder for the top ring which I don't have. Last go around I borrowed Chris's [Cdnoel] grinder down in Colorado Springs.

PS: Any local options, rentals etc? I can order a Piston Ring Grinder on-line but delivery is likely a week out . . . Thoughts



I spoke with a Wiseco Tech this morning, he recommended a top ring gap of .013" because the calculations are minimums. He said the .017" for the second ring was fine and will reduce flutter.