1981 Kawasaki GPz550: Restoration

[srsupertrap]

So what are you having them do to the engine?

Well I asked Tom Klemme to first measure & determine the serviceability of the head i.e. does it even have a second chance or is it a "boat anchor". If ok then

- mask & bead blast the head
- check valves guides, replace as required
- freshen/redo valve job
- skim the valve stems, retainers etc & adjust back into range
- R&R valve stem seals
- weld repair the fractured piece
- repair buggered threads

I told Tom to call me once he evaluates so this is the short list.

Pistons show some blowby. You figured out if rings are available yet?

Corey Clough the administrator on the GPz550 , knower of GPz550s said Wiseco BB kits & rings are available for the 615 BB but not the Moriwaki 593 BB pistons. My measurements may be low but the math says this has a 615 BB. Z-1 probably can order them, if not Wiseco.

Ed, could you look under your cylinder head and see if you have those marking embossed in your KZ750?

[Nessism]

Ed, could you look under your cylinder head and see if you have those marking embossed in your KZ750?

Steve, my head has the same marks. I think the round ball thing has to do with date code/lot control, although I didn't study it.

Regarding the rings, those don't look like Moriwaki pistons so I think you are on the right track. Moriwaki typically used one compression ring, L shaped, so that's further evidence.

[Wester Cooley]

For replacement rings for pistons that were NLA in the past. I used to have good luck with Total Seal Ring Company on having rings that would fit the pistons I had. Used to give them the measurements of the rings and the piston diameter, and the ring grooves, and they would see what they could come up with.

I have not talked to them in like 10 years now, but its worth a shot. Moriwaki didn't make the rings themselves, they bought them from somebody somewhere.

[srsupertrap]

For replacement rings for pistons that were NLA in the past. I used to have good luck with Total Seal Ring Company on having rings that would fit the pistons I had. Used to give them the measurements of the rings and the piston diameter, and the ring grooves, and they would see what they could come up with.

I have not talked to them in like 10 years now, but its worth a shot. Moriwaki didn't make the rings themselves, they bought them from somebody somewhere.

I have determined its a Wiseco BB 615 kit so it's definitely worth a shot . . . thank you. I have already sent them an email. http://www.totalseal.com/ContactUs.aspx

Because Corey Clough informed me, yes Wiseco still makes a GPz550/615 Big Bore kit but Wiseco discontinued their old style GPz550 piston & rings . . . so my 1980's BB kit piston rings are NLA too. Probably not too wise to reuse those rings . . .

[srsupertrap]

Well I received some welcome news today from Total Seal Piston Rings, see below

"Steve,
Just need to verify bore size of the cylinder and the ring groove sizes on the piston. Once we have that we should be able to fix you up.


Best Regards
Keith Jones"


Not being a Machinist does Keith need the minimum bore size of all four cylinders? Reading Ed's KZ750 thread I do not have a Bore Gage at my disposal so what would the experienced Machinist suggest I do?
BTW if you were boring a new 615 Big Bore kit cylinder what is the correct formula: 615/4 plus ?

[TeamDar]

They just need the standard bore size for the displacement. In your case 61mm or 2.402". Then measure the ring thickness or ring groove thickness and your good to go. Dar

[srsupertrap]

They just need the standard bore size for the displacement. In your case 61mm or 2.402". Then measure the ring thickness or ring groove thickness and your good to go. Dar

Thank you TeamDar for the information . . . Here is the update on the elusive Wiseco 615 rings I need. Keith at Total Seal Piston Rings was helpful but by Tuesday had bad news to share.

Steve,
I would assume if the piston is 60.85 at the bottom of the skirt the cylinder bore is most likely 61mm And if is cut for the XC set 1.0 1.2 2.8 you may be in trouble. Only thing I have of that nature in the 61mm bore is an XA pack .8 .8 1.5 ring combo. I've checked a few other sources and again unfortunatly don't see that pack available anymore it may be required to get new pistons made with the more common XA pack.

Sorry I couldn't help on this one.

Though I did find a listing on a 61mm bore Honda set # 13010-392-003 it is a 61mm 1.2 1.2 2.8 pack you can open your top groove to accept the 1.2mm top ring and be good to go if you can find these on the web. We can re-groove the piston if needed. "

Since Total Seal stated they could open the piston top groove on my pistons for $12.50/piece I spent yesterday evening searching through various Honda websites & Ebay looking for P/N 13010-392-003 (Keith did not have a Honda model) but no luck. Perhaps if someone with some free time on their hands knows of different sources than Carolina Cycle & Babbit or different piston ring supplier I would be grateful.

TIA
steve

[srsupertrap]

Pardon the pun but I am going to shift gears. While the head is away I decided to remove the oil pan & clean the sludge out from he bottom of the pan. As usual I found the oil filter bolt & drain plug so tight I needed a breaker bar to loosen both of them. The M6 pan bolts on the other hand were loose but I still needed my mallet and block of wood to break the seal.

A picture is worth a thousand words



At the front of the oil pan I spy this . . . . its cursed



I looked at the crank Hy-Vo gear, its Ok but the tooth is approximately the same width. What do you think transmission gear set? I never had a bike shear a tooth off a gear set what exactly is the symptom?

[tkent02]

Just one tooth I don't think you'd notice, as there are always two or three teeth engaged at a time. Maybe a funny noise, not sure. Had broken teeth in car trannies, couldn't tell at all.

[Nessism]

Missing gear teeth is never good.

[srsupertrap]

Ed I agree, I could not put it back together knowing the engine bottom end could explode underneath me at any time.

I have never had to split engine cases and don't know what special tools are required. Lets say I replace the entire gear set . . . how do I know the starter clutch isn't toast ( this happened to another GPz member).

Maybe the wise thing is to find a known good GPz 550 bottom end & graft my cylinder & Head (if okay & I can find 61mm XC piston rings) onto it.

Or throw in the towel & part it out.

[tkent02]

No don't even think about putting it together that way, but which gear is it? What makes you think the starter clutch is bad?

Splitting cases is easy. At least on Suzukis it takes no special tools, dunno about the Kaw.

[rustybronco]

Split the cases then decide whether or not to fix it, find another engine to replace yours with or to part it. That's the way I would attack it.

[tkent02]

I guess you have to split the cases to replace a starter clutch? If so throw a new one on just to make sure?

Do they ever wear out on the little 550 engines?

[Nessism]

Splitting the cases is easy enough. Only semi hard part is remembering where everything goes when you put it back together. Take lots of photos during disassembly if you have any questions.

Should be easy to find a transmission assembly on ebay if it comes to that. Regarding the starter clutch, on my 750 I'm going to replace the rollers and springs while the cases are apart just to hedge my bet. Can't see replacing the entire starter clutch straight away unless you know it's been acting up.