Do I need to replace Crank Seals? Pistons?
Posted: Fri Mar 31, 2017 9:38 pm
First of all, sorry if this subject has been answered on this Forum. However, I haven't been able to find enough information to satisfy this question and my searches haven't yielded good results.
My bike is a 1972 GT750J. When I bought it from the original owner a couple of years ago, he started it and his nephew rode it up and down the lane to demostrate it. I haven't run it since but when I spray layup oil in it, and crank the engine, it tries to run. The bike has 10,000 miles on the clock and is completely unmodified other than a set of ugly 1970s style ape hanger bars that were dealer installed (the guy still had reciepts from the 1970s to prove it) The engine has never been apart or out of the frame. I'm working on a full restoration.
I changed the crankcase oil after I got the bike. The oil came out milky white meaning it had water contamination in it.
My understanding is that a radiator leak-stop (like Bars Leaks) might seal up the cooling galleries. But apparently the 'J' leaks easily at the barrel to crankcase joint. This problem was later fixed with an o-ring in the cooling gallery joint.
My question: should I plan to pull the barrel off to fix this leak. I have no idea how long the bike sat like this with the contaminated oil so it's possible that there's rust in the engine. While I have thinks apart should I plan to replace the crank seals? Crank Bearings? Pistons? If I replace the pistons, should I rebuild with the old style pistons that have the connecting rod 'fixed' at the big ends or should I rebuild with the newer style pistons that have the connecting rods fixed at the wrist pins?
These questions are important because if I'm going to order parts I want to try to get as many in one shot as possible. This saves in shipping cost.
Thoughts?
Olaf
My bike is a 1972 GT750J. When I bought it from the original owner a couple of years ago, he started it and his nephew rode it up and down the lane to demostrate it. I haven't run it since but when I spray layup oil in it, and crank the engine, it tries to run. The bike has 10,000 miles on the clock and is completely unmodified other than a set of ugly 1970s style ape hanger bars that were dealer installed (the guy still had reciepts from the 1970s to prove it) The engine has never been apart or out of the frame. I'm working on a full restoration.
I changed the crankcase oil after I got the bike. The oil came out milky white meaning it had water contamination in it.
My understanding is that a radiator leak-stop (like Bars Leaks) might seal up the cooling galleries. But apparently the 'J' leaks easily at the barrel to crankcase joint. This problem was later fixed with an o-ring in the cooling gallery joint.
My question: should I plan to pull the barrel off to fix this leak. I have no idea how long the bike sat like this with the contaminated oil so it's possible that there's rust in the engine. While I have thinks apart should I plan to replace the crank seals? Crank Bearings? Pistons? If I replace the pistons, should I rebuild with the old style pistons that have the connecting rod 'fixed' at the big ends or should I rebuild with the newer style pistons that have the connecting rods fixed at the wrist pins?
These questions are important because if I'm going to order parts I want to try to get as many in one shot as possible. This saves in shipping cost.
Thoughts?
Olaf