TOPIC:

I still have my spring loaded tensioner. I'm tempted to put it back on. If my chain had broken, it would have made for one FK'ED UP DAY. It's ironic I was warning about them and here is the perfect example.
You can see the number 45 stamped on the crank. Before I button it up I'll measure the rods. 2.5mm is a lot. No wonder I had low compression. If I lose cc's, so FKing what. That would mean it IS a 750 crank and should spin faster as planned. I'll take more pics tomorrow.
Steve

i was right you had a low compresion POS

I expected that.
Steve

looks like you need a valve job i would send it out and have new viton seals put in .one of the cylinders looks pretty scored up time for a rebore.take some more pics so we can see how bad the cylinder is do you have a dial bore gauge to measure the tapper ? and take a valve out so we can see how bad the seats are.

I have no interest in YOUR opinion or anything you can dig out of a book. Valves done last year. For everyone else.
Kibblewhite valve springs, new valve guide seals, new Dorimi valves. More pics to come.
kzrider.com/forum/2-engine/596420-valves#653678
Steve

Bruce, you're right. I'll need to drop the pan and clean out all the junk on the strainer. When I did my oil change a small piece of plastic came out. It was from the cam chain sprocket. 40 years old so I wasn't alarmed, now I am'. Everything is cleaned up and I will put it back together today. Still have to take pics of the rings and if they migrated or not , more of the crank, the hone job, etc. There always has to be a snag and I was prepared for it.
Steve

I took some pics of the rings. They migrated quite a bit. Not close to where they were set.






Head cleaned up, painted and ready to go.


Some pics of the crank and rods. The only place you can see where it was welded is the center pin. I'll also jot down the markings on the rods. You can barely see them.










Steve

Interesting looking below the rings where the oil has been burning, and how it differs slightly between pistons. Looks to me like they were past their best.

I'm thinking now the most critical thing for good ring seating is the cross hatch hone, I have a honing tool taht I've used in the past but In future I'll leave it to a pro..

It was a used set I got on eBay. Great shape, wasn't planning on using the pistons, that's when I found I lunched one of my good ones. I put them in used rings and all with a light hone. The bores have light scratches in them now. I honed them and they will work. I see a 1075 or 1105 in my future.
Steve

These are used pistons and rings going into a different block? Done that myself too. Just hope your rings bed in.

I cant find nos old design wiseco rings for my GPz615 so I'm going to have to risk it and use 'quick seat' lube from total seal and some running-in oil.

Maybe check your installed ring gap to match the pistons to the bores as best you can, there is often a measureable difference - 4 thou on my last used set.

swest wrote: It was a used set I got on eBay. Great shape, wasn't planning on using the pistons, that's when I found I lunched one of my good ones. I put it one used rings and all with a light hone. The bores have light scratches in them now. I honed them and they will work. I see a 1075 or 1105 in my future.
Steve

Go big!
My curiosity : what kind of oil do you use?

thank you

Those were the stock pistons for a KZ 1000. I just fitted the new rings to the bores. Didn't have to shave any of them. New piston clearance is .002 so I can hone more to get the marks out or at least most of them. Got some room to play with. These are Wiseco 10.25/1 pistons. Taking my time and they should be fine.
I'm using Rotilla oil.
I didn't want to use the old rings that came with the stock pistons but had no choice. The oil on the pistons is after two years of running. The bike ran like a scalded cat even tho it did have low compression. I figure with the 2.5mm drop, I was running at 7/7.5/1 compression. With these new pistons, I should be at around 9/9.5. Good enough for now.
Steve