Adding up the parts so far - head, cylinders, pistons, rings, rods, pins and bearings - we're at about $300 and we haven't went into the bottom end yet or paid a machine shop. A donor motor was located on eBay for 399+160 shipping. Could we just pop the donor in to get the bike running and call it a day? Yes, but that's not what the owner wants. He wants to keep the bike as original as possible and I don't blame him. If I was tearing a bike apart and bringing back to showroom fresh condition I'd want matching numbers on the frame and engine too. By going this route the engine will have all genuine Honda parts also.
The donor is a 79 CB400 T1. Compression was reported as 150 psi left, 160 psi right. You won't get much better readings with a new set of rings.
Monday, July 28, 2014
Wednesday, July 23, 2014
A melted piston.
The engine didn't throw a rod, it melted a piston.
I suspect it was running rich before it died but I have to confirm this with the owner.
I've found used cylinders, used heads and possibly new pistons if the interchange numbers work but I haven't been able to locate connecting rods and pins. I'm going to try the local junkyard tomorrow and see if I can come up with something.
Tuesday, July 22, 2014
Teardown starts.
This is the motor out of a '79 Honda CB400T (II). It threw a rod so there is sure to be some damage.
As you can see the left side isn't very happy.
At 12 and 3 o'clock you can see some deep gouges in the cylinder. Unfortunately these are too deep to be machined out.
Above the intake valves there are some deep gouges, and a part of the exhaust valve has broken off. It's hard to see but from 4-6 o'clock the outside edge of the valve is missing. The Cylinder head will also have to be replaced.
I've managed to locate both the head and the cylinders on ebay but they are from two different sellers. I'm going to dig a little deeper on the web and try to find a matched set. Also I need to try the bike junkyard in town and see what they have.
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