Engine rebuild?

After completing a compression test cylinder 2 came back with a reading of about 40 psi.
I've done the tea spoon of oil in the barrel test and it came back with 130 psi so looks like I have blown rings.
Any suggestions where to go from here? As in what to expect to replace? Pistons, rings etc.
Is there anything to upgrade or replace while I have it apart?
Is it likely to need rebore
What make of parts do u recommend?
I'll start to take it apart tomorrow to see the extent of the problem

It depends on how bad of shape it is, but you might be a ble to get by with new rings and a good hone. While its apart id check all the idler gears for wear. Theres alot of stuff you could do while its apart like lap the valves. I buy most of my parts from z1 enterprises.

Have the engine sat for a long period, or has it been used regularly lately? It is not unusual for piston rings to get stuck when unused for long periods, but letting it soak for a few days in diesel often frees the rings. You can add the fluid from the spark plug hole at TDC. The small amount shouldn't ruin the engine oil even if all runs past the rings.

faffi wrote: Have the engine sat for a long period, or has it been used regularly lately? It is not unusual for piston rings to get stuck when unused for long periods, but letting it soak for a few days in diesel often frees the rings. You can add the fluid from the spark plug hole at TDC. The small amount shouldn't ruin the engine oil even if all runs past the rings.

ahhh that could be it. I have done a few miles on it since i got it but it was imported from US to Aus late last year and i bought it early this year. The speedo showed 12500 miles and the excellent condition of the bike made me believe it was, which i still do. but that did make me wonder why i was getting such a serious engine problem from a renowned tough engine so early.
The whole bike looked like it was a shed find and covered in a few years of storage dirt and protective oil stuff, and the engine oil and brake fluids had seen better days.
I'm half looking forward to taking it apart as i will know more about the bike i intend never to sell

It's your bike Personally, I'm a "if it ain't broken, don't fix it" person. Others live by the "if it ain't broken, rip it apart and find out why" token

I'm positive I'd find lots inside my engine that's not factory fresh. But it works just fine and doesn't use oil. Until it really asks for attention, my engine will stay together. And when attention is needed, I'll pop in the spare engine without opening it, either

faffi wrote: It's your bike Personally, I'm a "if it ain't broken, don't fix it" person. Others live by the "if it ain't broken, rip it apart and find out why" token

I'm positive I'd find lots inside my engine that's not factory fresh. But it works just fine and doesn't use oil. Until it really asks for attention, my engine will stay together. And when attention is needed, I'll pop in the spare engine without opening it, either

Oh i'm definitely with you on that one, but no2 cylinder was not firing and since ive had the bike it's never run properly..

KZ1000inaus wrote: After completing a compression test cylinder 2 came back with a reading of about 40 psi.
I've done the tea spoon of oil in the barrel test and it came back with 130 psi so looks like I have blown rings.
Any suggestions where to go from here? As in what to expect to replace? Pistons, rings etc.
Is there anything to upgrade or replace while I have it apart?
Is it likely to need rebore
What make of parts do u recommend?
I'll start to take it apart tomorrow to see the extent of the problem

I'd do a valve clearance check, and if tight, back of the camshaft bearing caps to get clearance. Then by hand, rotate the motor through both a dry and wet Leak Down Test. Rotate by the 17mm nut at the right engine ignition cover, not the 13mm one. In the direction of normal travel of course. You will have to hold down with a bit of tension on the cam chain, between the cams. When re-installing valve cover, be sure to take the Wedge out of the automatic cam chain tensioner. Thats under the cap, 17mm wrench/ spanner, under the carbs.

Motor Head wrote:

KZ1000inaus wrote: After completing a compression test cylinder 2 came back with a reading of about 40 psi.
I've done the tea spoon of oil in the barrel test and it came back with 130 psi so looks like I have blown rings.
Any suggestions where to go from here? As in what to expect to replace? Pistons, rings etc.
Is there anything to upgrade or replace while I have it apart?
Is it likely to need rebore
What make of parts do u recommend?
I'll start to take it apart tomorrow to see the extent of the problem

I'd do a valve clearance check, and if tight, back of the camshaft bearing caps to get clearance. Then by hand, rotate the motor through both a dry and wet Leak Down Test. Rotate by the 17mm nut at the right engine ignition cover, not the 13mm one. In the direction of normal travel of course. You will have to hold down with a bit of tension on the cam chain, between the cams. When re-installing valve cover, be sure to take the Wedge out of the automatic cam chain tensioner. Thats under the cap, 17mm wrench/ spanner, under the carbs.

I checked the valve clearances last night and if my memory serves me right No.2 was one of the better ones with a clearance of .08. where as No.4's exhaust was .23 ! which was the highest.
that begs another question. what is the correct clearance? as my manual says one thing (.15mm) and i think a thread in the forum says .05 to .10.
I think i'll get a guy around to do a leak down test as well

The .1mm sounds better.
Did you recheck compression, or restart the motor to see if there was any difference, after the adjustment?

What model engine?

Denvgasm wrote: What model engine?

it's a 1978 KZ 1000A2 - No. KZT00AE - 073210

Motor Head wrote: The .1mm sounds better.
Did you recheck compression, or restart the motor to see if there was any difference, after the adjustment?

Ive not adjusted the clearance as it's my first time on checking/adjusting them and i'm picking up the tool/shims today.
will it really make that much difference to a cylinder that runs at 40PSI normally and then 120-30 if oil is put in cylinder and a compression test run?
sorry but i'm a bit of a noobie (which i'm trying to rectify) when it comes to this much detail.