Getting a 200A going again.

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RobertM
Posts:27
Joined:Sun Nov 14, 2021 9:00 am
Re: Getting a 200A going again.

Post by RobertM » Tue Feb 01, 2022 11:31 pm

My friend Craig checked the balance of the crank to a new piston and it was quite a bit off. He had to take some weight off the top of the flywheels and then weld two 3/8 plugs made out of Tungsten in the bottom of the flywheels to get it into balance.

The new piston was lighter than the old one so the crank was pretty far off from the factory.

It should run real smooth now.
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RobertM
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Re: Getting a 200A going again.

Post by RobertM » Tue Feb 01, 2022 11:59 pm

I couldn't find any thrust washers to replace the originals, so I had to find a substitute that would work. The washers are really hard, and the only thing I could find with the same hardness was valve spring shims. I ordered some as close the size as I could find then shaped them to match the originals.
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RobertM
Posts:27
Joined:Sun Nov 14, 2021 9:00 am

Re: Getting a 200A going again.

Post by RobertM » Wed Feb 02, 2022 12:04 am

To solve the crank slippage problem I bored tapered holes at a 5 degree angle in both sides of the Gudgeon pin. After installing it back into the flywheels and getting the crank true again I pressed aluminum wedgedes into the holes. After that I milled off the extra aluminum that stuck out.

This should keep the flywheels from ever slipping, and now the crank is balanced and I got it to just over a thousandths of being true.
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Schoobytwo (Bruce)
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Re: Getting a 200A going again.

Post by Schoobytwo (Bruce) » Wed Feb 02, 2022 2:46 pm

All I can say is "WOW"!

I've never seen anyone go this far into fixing up one of these little JLOs.
Too many Diablos and parts to count.
Yamaha 600 SX

RobertM
Posts:27
Joined:Sun Nov 14, 2021 9:00 am

Re: Getting a 200A going again.

Post by RobertM » Wed Feb 02, 2022 10:58 pm

Trying to get the most out this little engine while learning lots of new things is fun and a challenge. I have a few more ideas to throw at it, so we will see what I can pull off.

The squish band is offset in this head which has its benefits, but I think a modern style squish will gain a few percent in power so I welded up the head and reshaped it.

After that I welded up the 14mm spark plug hole and went back with a 12mm threaded hole because that size has way more spark plug options to choose from.

Welding cast aluminum is a tough weld because of whats in the aluminum. They put Zink in it to help the molten aluminum flow into casting moulds, but this does not help when your trying to weld on it. You end up with porosity.
Its quite strong enough for what I'm trying to do none the less.
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RobertM
Posts:27
Joined:Sun Nov 14, 2021 9:00 am

Re: Getting a 200A going again.

Post by RobertM » Wed Feb 02, 2022 11:01 pm

.
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RobertM
Posts:27
Joined:Sun Nov 14, 2021 9:00 am

Re: Getting a 200A going again.

Post by RobertM » Wed Feb 02, 2022 11:11 pm

Lathed the cylinder and head bolts like this to make them stronger.

If the bolt were to brake it will most likely happen right where the threads start on the shank. By taking some metal off right where the threads start it smoothens out the area making it harder for a crack to happen. It also helps with the bolt stretch which keeps the nuts tight.
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RobertM
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Re: Getting a 200A going again.

Post by RobertM » Sat Feb 12, 2022 8:13 pm

My dad has mentioned several times we should get a vapor blaster. I didn't really know what it was. After a look I quickly realized how cool they are, so we went halves on a unit. These are the first parts finished.
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Schoobytwo (Bruce)
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Re: Getting a 200A going again.

Post by Schoobytwo (Bruce) » Sat Feb 12, 2022 9:11 pm

That looks awesome Robert? You say "vapor" blasting? Not familiar with that. Care to explain?

Something I did to my last bead blasting of aluminum was to put clear coat on. Pictures don't do the clear coat justice but so far, I like the way it holds up.
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Too many Diablos and parts to count.
Yamaha 600 SX

RobertM
Posts:27
Joined:Sun Nov 14, 2021 9:00 am

Re: Getting a 200A going again.

Post by RobertM » Sat Feb 12, 2022 11:06 pm

Its really just a wet sandblaster with fine abrasives. I used the glass bead it came with on this run. It feels real fine and smooth compared to regular blasting sand. I'm not sure what grit it was because it wasn't labeled.

No dust, and it runs a lot cooler than a dry sand blast cabinet.

The finish in person looks like it just came out of the casting mould. Seems to work as good as advertised.

I watched a lot of this guys videos for info.

https://www.youtube.com/watch?v=O-rSJHjaWoE

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