crank balance

hybridracer said:

On a normally used road going Commando there is absolutely no need to dynamically balance the crankshaft. Spend your money on something useful.

Click to expand...

Amen, brother.

seattle##gs said:

Correct, but it sure can't hurt.

Click to expand...

Well, that's a true statement. Brings to mine the old saying: "chrome won't get you home…"

milfordite said:

I would be more apt to have the pistons and the rods balanced if you don't want to mess with the crank. I've seen new pistons way out of balance.

Click to expand...

When my crank was balanced back in the 80s I had to take my crank, rods, pistons, gudgeon pins, slipper bearings, everything connected to the crank for balancing, so not just the crank.

Just to slightly diverge to pistons as milfordite suggested to weight them.

Over the years I have rebuilt 3 water cooled engines .
When the air-cooled rebores were done, the pistons would always come back marking which cylinder each piston should go into.

This was my first air cooled rebuild. I learned a lot and the rebuild has not seized up after 1000 miles. Thanks to all of you.

I rebuilt my 850 engine to 0.20 oversize and when the pistons and cylinders came back, the pistons were not marked for which bore.
I asked the machine shop, and they said the pistons measured identical. I put them in the bores and there was no difference measuring wall clearance in either bore.
The rings gaps were on spec. I had to file a thou off one top ring.

When I saw that the bores had a very, very light hone, I said to the shop that my water cooled experience was a coarser hone and they said the top ring is chrome and thus a light hone. They said to use break in oil, change it at 50 miles to get the assembly lube etc out and the rings should be broken in at 300 or 400 miles.

They also resized my con rod big ends. I think they can measure to a tenth of a thou.

Dennis

thanks for everybodies input.

If you are just doing a top end use the lightweight pistons and you will have good results.

seattle##gs said:

If you are just doing a top end use the lightweight pistons and you will have good results.

Click to expand...

He said he already had the crank out and had cleaned the sludge trap.

yes sludge trap cleaned not too bad. I like what JS has to offer. I purchased front fork upgrade items. top notch.

I like the Idea of lightweight pistons.