1979 Oil Consumption Fix from Kawboy at KZ1300.com

Pistons off now and rings removed. the 79 and 80 pistons only have 5 oil drain back holes and the later pistons have a second set of holes below the oil scrapper ring, so I will modify these pistons with the additional holes since there's a reported problem with oil consumption in the 79 and 80 model years, and I'm thinking that one of the permanent fixes was the additional drain back holes.

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After rearranging the garage, I found a way to have the car in the garage and the bike in an area so I can work on it. Yippee !!

Cylinder block came off today. Note -  When removing the water pump drive shaft so that the camshaft chain is free, I found that doubling up the 12mm wrench to hold the shaft was a must to do in order to remove the bolt on the end of the shaft. One open end wrench on the shaft was not enough and the shaft spun in the wrench.
The cylinder block slipped off really nice and there's no rust in the bores, in fact the pistons were still wet with engine oil. Love it.

Pistons off now and rings removed. the 79 and 80 pistons only have 5 oil drain back holes and the later pistons have a second set of holes below the oil scrapper ring, so I will modify these pistons with the additional holes since there's a reported problem with oil consumption in the 79 and 80 model years, and I'm thinking that one of the permanent fixes was the additional drain back holes. 

I took the opportunity to measure the primary chain slack. I found that a vernier caliper worked great here. Measured down from the upper crankcase to the top of the primary chain and recorded. Then lifted the chain up with a 90 degree scribe while holding the vernier and recorded the number. The difference in the number is the slack in the chain. In this case I came up with .810" ( 20.6mm) I did this several times just to confirm and the numbers were all within .010" - .015" so I'm confident that the measurement is worthy of consideration. The service limit according to the Service Manual is  22mm, so here we are, engine top end removed and the chain is almost maxed out. Fortunately, about 8 years ago I spent countless hours searching for a supplier for replacement primary and secondary chains and ended up working with Ramsay Chains in the USA. I sent them a sample of the primary and secondary chains and they manufactured new chains for me. If I remember correctly, the new chains came in at around $500 CDN. So I have 2 new chains sitting in the shelf, so I guess it's time to bite the bullet and pull the engine and do the chains.

 

Stock 1979 pistons which have 5 drain back oil holes in the oil scrapper ring groove