Topic: sandcast cylinder and head ID Q?s Fin welding?

[Don R]

 One of the K5 750's I bought this week has a sandcast engine in it. The head is a later one, probably came on the bike. Is there a way to ID the cylinder to tell if it's early or late?  I wonder how correct an early diecast head would be.
 The sandy is 1002695 my diecast head is 104something. Way closer than the K5 anyway.

[754]

No bolt in front middle till  # 26,***.

[Don R]

 Well I better go look or I'll lay awake wondering. lol. If it's the sandy cylinder block there would be no center head bolt because the block wouldn't be drilled.  Thanks Frank.
 I'm assuming someone broke the K5 bottom end and used what was laying around to fix it. It has clean oil in the tank and kicks over easily with plugs out and oil in the cylinders.

[Don R]

  The bike with the sandcast crankcase had the center bolt so they must have used the K5 cylinder and head. My 104xxxx would appear correct from the sides but would have the offending center bolt.  It also has a 10 bolt clutch cover with the 10th hole hanging in the breeze. I'm thinking of welding one up and re shaping the 10 spot using Honda metal for tig rod.
 For now I'm going to pull it out,  buy a sheet metal engine stand from ebay and correctly assemble it as I'm able to find parts.

[754]

One of my KO motors has the bolt hole with no bolt meaning they changed head, but it still has original cylinder.

[Don R]

 That's what I was hoping to find, no bolt would have indicated they used the early cylinder block.
 There are jugs and heads on ebay but all have broken fins.

  I can't find a thread where anyone had ever claimed to have successfully built up a chipped off fin. I've heated and straightened a few bent ones with a vice grip sheet metal folder tool and tried the aluminum brazing rod over a steel plate with no luck at all.

[Davez134]

I built up a chipped off fin, but it was only a small area/corner. It was a PITA, and lots of shaping afterward but it worked. How big are the chips you've seen?

Here, I forgot i had pics in my thread, top fin on the jugs:
http://forums.sohc4.net/index.php/topic,139768.msg1628386.html#msg1628386

It could be done with bigger chips I'm sure. Just more time/patience.

[754]

I think Jim the microwelder could do them ?
Lots of folks out there doing fin repair.
Sometimes tyey weld donor pieces on, or they straight build it up with filler.

[Davez134]

That was my thought on a bigger section, find a donor piece. Would be much easier. Either way, very doable.

[Don R]

 I found my fin guy, he said try to not get one with a middle fin broken. He has had to remove fins and later weld them back in to get to broken ones in the middle. He has material to make the fins from.