1982 Z550GP H1

A workmate watched me ride up the road and said it was blowing smoke when i change gears. I hadnt noticed this but now when the bikes sitting there idling and i give it a hand full of revs the bike will blow quite a bit of smoke when the throttles closed.
So i removed the head for a look :ohmy: The pistons looked like the had a couple of teaspoons of engine oil sitting on them . I could see oil down the inlet ports so i removed the valves,
A picture is worth one thousand expletives

1. Have the head rebuilt. They will check for cracked/damaged valves and seats, and install new seals,. They will also ream, or replace the valve guides with bronze.
2, Ball-hone the cylinders, and check for grooves. of OK, then replace the rings.
/www.brushresearch.com/flex-hone.php

-Looking at the spark plugs, are they treaded in completely? Looks like the reach is too short.
-If you haven't yet, drop the oil pan and see what is inside. Look for flakes of bearing shell material. If nothing is there, you could be good with a top end rebuild.

do you have any need for 2 front OEM brake rotors? I have 2 Ill part with cheap. Tom

tomsbadkz wrote: do you have any need for 2 front OEM brake rotors? I have 2 Ill part with cheap. Tom

Where were you a year ago before i forked out for three new disks. Thanks any way

Plugs are correct just not screwed all the way in i comp tested before removing the head.
It looks like i the PO had a dodgy top end assembly done. The valve seals are all damaged to some degree and not from me removing them. I could see they where torn before removal and they are nice and soft like new ones and came out easily
. Three of the inlets are torn half way around , 6 have canted over tops and one even had a o ring inside.
The valves miked out fine and well within service limits and the seats actually look pretty good after i removed the oil and carbon,.
I was thinking of lapping them to see what they look like before comitting to finding a machine shop over here.

The cylinder block should be interesting, the PO mentioned it had been re ringed but didnt read to much into it at the time as there wasn't any receipts for the work,,
At a glance it looks like its been honed with sand paper.:whistle:

ignore the grit i dropped them on the ground

The bores are std.at 58mm but No.1 has some water damage , Thankfully whoever did the work has sanded it kind of smooth once they dialed in their skills on the other cylinders,
Well that's my conclusion due to the different styles and depth of scratches each bore has. I dont think a hone is going to fix this.
Im going to drop the sump next. :blink:
Feels like im going backwards

That #2 pic looks really bad! I see new oversize pistons and cylinder rebores in your future...

azman857 wrote: That #2 pic looks really bad! I see new oversize pistons and cylinder rebores in your future...

thats what my wallet is thinking

and thats not the end of it
After removing the Sump this morning i found quite a bit of foreign material in the bottom and some of it looks like sand, i can only guess it got in there when the top end was open.



I filtered the oil that was left in the sump through a clean white rag



a small patch on oil pump pickup

The oil pump has some scratches

So ive split the cases now , its not something i had plans on doing but with the trail of damage i had to look. This is the first time working on a motor cycle engine so i hope it goes back together right



to my surprise the bearings are in good condition , looks like the filter has done its job



Flexigauged the mains and conrods

Those black things in your pan are probably clutch dampers . There's rubber dampers in the basket behind those rivets . If you check the basket it probably has play in it .

Its a well known problem on the turbo amd 650 site . Hes a link you can read about it . Its a long read but you will get the gist and the fix is in there .

www.750turbo.com/forum/viewtopic.php?f=4&t=12071

riturbo wrote: Those black things in your pan are probably clutch dampers . There's rubber dampers in the basket behind those rivets . If you check the basket it probably has play in it .

Its a well known problem on the turbo amd 650 site . Hes a link you can read about it . Its a long read but you will get the gist and the fix is in there .

www.750turbo.com/forum/viewtopic.php?f=4&t=12071

Thanks riturbo, Good read. After your words of doom i checked and the basket definitly has play .
Think i will drill the rivets out tomorrow

Does anyone know of someone who makes replacement dampers for the 550 clutches?
The problem is the 650/750 and the 550 clutch dampers are not the same. They are a totally different size and shape, so they are not interchangeable.

550 clutch



750 clutch