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Can I use my 79 cylinder block and head on my 81? 8 years 1 week ago #11885

  • Kawboy
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A leakdown tester will always tell the story. you apply air through the spark plug hole at 100 psi and measure the pressure held within the cylinder as a percentage of the 100 psi. You then have a quantity number. While the air pressure is on, you listen for air pissing out of the exhaust, the intake, the coolant system and also the crankcase oil filler cap. Air pissing out the exhaust would be a faulty exhaust valve. air leaking back through the carbs would be a bad intake valve. Air coming from the oil fill cap is faulty rings and air in the coolant system is a bad head gasket.
Leakdown testers can cost anywhere between $50-$80 bucks. It's worth its weight in gold. I've bought several boats in the past and a condition of purchase is a leak down test. I've had several mechanics ask what in the hell is a leak down test. I've had other mechanics who were asked to do the test smile because they know I know the mechanicals of an engine and know I'm not going to buy a piece of shit with good money.

Compression testing is ok in a pinch, but definitely not a reliable measurement of the quality of the mechanicals in an engine. I could take a perfectly good engine and drop a camshaft in it with a 300 deg duration, you do a compression test and tell me it only has 75 psi and needs rebuilding. Or I could delay the valve timing by 10 degrees and it would show 80% of normal compression.
Bottom line, the only test that will determine the status of an engine is a leak down test, end of story.

You're in Canada so NAPA has them even Canadian tire has them. I don't know how old you are but if you plan on tinkering with engines for the next 20 years, spend the 50-80 bucks. You won't regret it. Last but not least, if you test an engine before you tear it down, you know exactly where to go looking for the problem and won't be spending silly money on parts you don't need. Chances are your oil consumption problem on the 79 was valve seals but you ended up pulling the cylinders and boring, new pistons and rings and if your goal was just to fix the oil consumption, then you threw money into a bottom end job for nothing. Not saying that it was a mistake since you should end up with virtually a new engine assuming all of the bottom end chains are in good state of repair.
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Can I use my 79 cylinder block and head on my 81? 8 years 1 week ago #11887

  • Ledkz1300
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Kawboy wrote: A leakdown tester will always tell the story. you apply air through the spark plug hole at 100 psi and measure the pressure held within the cylinder as a percentage of the 100 psi. You then have a quantity number. While the air pressure is on, you listen for air pissing out of the exhaust, the intake, the coolant system and also the crankcase oil filler cap. Air pissing out the exhaust would be a faulty exhaust valve. air leaking back through the carbs would be a bad intake valve. Air coming from the oil fill cap is faulty rings and air in the coolant system is a bad head gasket.
Leakdown testers can cost anywhere between $50-$80 bucks. It's worth its weight in gold. I've bought several boats in the past and a condition of purchase is a leak down test. I've had several mechanics ask what in the hell is a leak down test. I've had other mechanics who were asked to do the test smile because they know I know the mechanicals of an engine and know I'm not going to buy a piece of shit with good money.

Compression testing is ok in a pinch, but definitely not a reliable measurement of the quality of the mechanicals in an engine. I could take a perfectly good engine and drop a camshaft in it with a 300 deg duration, you do a compression test and tell me it only has 75 psi and needs rebuilding. Or I could delay the valve timing by 10 degrees and it would show 80% of normal compression.
Bottom line, the only test that will determine the status of an engine is a leak down test, end of story.

You're in Canada so NAPA has them even Canadian tire has them. I don't know how old you are but if you plan on tinkering with engines for the next 20 years, spend the 50-80 bucks. You won't regret it. Last but not least, if you test an engine before you tear it down, you know exactly where to go looking for the problem and won't be spending silly money on parts you don't need. Chances are your oil consumption problem on the 79 was valve seals but you ended up pulling the cylinders and boring, new pistons and rings and if your goal was just to fix the oil consumption, then you threw money into a bottom end job for nothing. Not saying that it was a mistake since you should end up with virtually a new engine assuming all of the bottom end chains are in good state of repair.


When I got the 79 it came with the piston/ring set and two gasket sets so my plan was to do the top end. The mechanic suggested I pull the bottom end covers to have a look inside, and I wanted to strip and polish the covers anyhow so why not? After months of trying to get this mope to do anything suddenly the crank was out and the cases split. His inspection turned into a complete disassembly. It was at this point where he tells me I need a primary and secondary chain, as well as bearings.

I've been bugging him for the last few weeks to tell me what bearings I need but he tells me he hasn't gauged them yet. It all came to a head last Friday when he answered the phone for once and told me to come by and pick up the engine case since I might as well have that soda blasted along with the covers. After loading it in the car I ask what bearings I need and he tells me he hasn't measured them yet but he'll do it when I bring the case back.

At this point I get mad. He's had my bike since NOVEMBER and only started work on it in Feb, despite my repeated requests to start earlier. I told him when I hired him I wanted this done by spring. Well here it is. I told him I needed the bearing measurements before I take the cases because I still have to find the damn things. I can get them from MCG but I still need to know which size, plus... at $50 euro each I really don't want to arbitrarily replace them all. He also tells me I need the cam chain and some other chain. I asked him if he has measured them and he tells me there is no reliable way to measure them so I might as well get new ones. This makes me very afraid. I've seen discussions here and these chains CAN be measured.

Well that is easy for him to say because they will cost me a fortune. Which I didn't mind spending as long as this was going to get done right and in a timely fashion. We are past the timely fashion part. At this point I am thinking he did not measure the primary or secondary and this was an arbitrary decision. His ability to drag his ass on the most basic of things has ruined my confidence in his build and ability to even finish it this year. Plus the fact he somehow managed to break the timing advancer gear and timing advancer taking them out. I don't want to spend a fortune on parts and have him mess it up or leave it till Christmas to put back together.

So here I sit.

I do have a friend coming out Sunday and he is going to go over the 81 as I mentioned earlier. If he isn't bringing a leak down tester with him I will buy one. I'll buy one just to have anyways. I didn't know they were so inexpensive.

Thanks again to you and the others.

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Can I use my 79 cylinder block and head on my 81? 8 years 1 week ago #11888

  • Mark
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Hi contrary to others advise, you are not a mechanic and the mess you have got yourself into demonstrates that, in my opinion you are heading into a long road of heartache and costings and at this rate another disaster, apologies for being blunt but I say it as I see it. My advise was to source a complete motor and drop it in preferably to the A1, this is probably a days work with some help and assistance, which would get your bike back on the road rapidly. Then start to un-muddle the mess that you are in at your own leisure. At present you are talking cost wise, Gasket sets Primary chains, secondary Chains, cam chains probably a water pump chain, tensioners, crank shaft bearings ATU the list will get bigger and bigger. Along with the Labour costs of someone sorting this mess out. You need to recognize that you are out of your depth. Listed on E-Bay in I think Michigan is a complete A1/A2 motor for $1200 do your self a big big favour. E-Bay number 121952731025. Ignore my advise if you choose and hopefully in a years time you won't be saying wish I had listened, at this minute in time you have 2 bikes that you have de-valued massively.
17 years a Z13 owner at present 3 x A1's and an A4

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Can I use my 79 cylinder block and head on my 81? 8 years 1 week ago #11890

  • kwak1261
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Im wondering , you say they replaced the starter clutch.
perhaps they didnt know that the main bolt that holds it all onto the end of the crank is a left hand thread and possibly over tightened it before realising, then trying to undo it they put excessive force on the CCT which gave in and let a load of slack chain go over the cam sprockets.
i know its a long shot but it might explain the loss in compression
just a thought

Ian
Z1300 A4 ZG1300 DFI X2
Z1261J GS1000S
Vmax1200 XT500

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Can I use my 79 cylinder block and head on my 81? 8 years 1 week ago #11892

  • Elroythekid
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Hi Folks, I am the above mentioned friend who is going to try to sort this mess out. I was a mechanic and service Mgr in a full line Yamaha, Kawasaki shop in the 80's. I got tired of being laid off in the winter (joys of northern living) and moved on. I have tho always had my own shop and buy/sell/restore many bikes. My current inventory is 2013 GSXR 1000, 2011 VICTORY VISION, 2008 VROD, 2007 VTX1300, 2005 VICTORY KINGPIN (SOLD PENDING SAFTY INSP) 1977 KZ1000, 1971 A1SS, 1978 KE100, AND.. 1971 MT1-75. All in various stages of smashed blown up or restoration. I'm way behind schedule due to my wife having a major health issue this fall/winter so I can't help right now but I have another friend who worked at the same dealership who has agreed to have a look at the 81 and really figure out what it's issues are and try to make it his rider for this year. Once I catch up on my stuff, the 79 can hit the bench and we will figure that one out. Other than assembly PDI and regular maintenance I have never seen the inside of a 1300, but both of us have built many engines so with a few.questions posted here I'm sure we can make this work. Thanks for having me!
C.

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Last edit: by Elroythekid. Reason: big sausage fingers.. little tiny keys...

Can I use my 79 cylinder block and head on my 81? 8 years 1 week ago #11893

  • Mark
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I would imagine there is a big sigh of relief going on in Canada at the moment lol. Keep us all posted on the problems you come up with along with photo's and the way you resolve.
17 years a Z13 owner at present 3 x A1's and an A4
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