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View Full Version : 3 5/8" Shovel back to 3 7/16"???



BurnoutNova
02-16-2016, 9:40 AM
Hey guys,

I know just enough about shovels to get myself into trouble. There is a guy that has a set of shovel cases for sale and they have been bored for 3 5/8" bore cylinders. I know that the cylinder skirt sits in the bore of the case... and I think there is enough play in the studs that you shouldn't rely on them to locate the cylinder properly. The reason I ask is I want to scab a motor together with some 74" jugs I have and use this bottom end that has already been bored.

That is a bad idea... right? Or is that something that guys do with success?

The motor is a good deal so worst case I will probably buy it and end up getting a set of 3 5/8" cylinders if that is all I can do.

And then how about using a stock 80" set of wheels... and the 3 5/8" bore? I would love stroker wheels but that isn't in the cards for me right now. That is a fine combo, correct?

THANKS for the help!

Sky
02-25-2016, 11:55 PM
Can of worms there. Not unsurmountable though.
Those cylinder sleeves need the support of the cases to stay intact. And you right about centering them up too. Might be able to come up with some adaptor sleeve/spacers to fill the void.
Make sure you get the right cylinder height and pistons for your intended bore/stroke combination if you decide to go with big bore cylinders. And yes, big bore/stock stroke is mighty fine.
One more caveat, Buy American! Those import cylinders are junk!

nmaineron
03-02-2016, 1:48 PM
Have the cases welded..

farmall
03-02-2016, 10:12 PM
Welding and machining the case bore and decks costs money on what appears to be a tight budget build and if improperly done could ruin them.

What makes those cases such an awesome deal (post the price, shit ain't classified information) vs other used or aftermarket cases? I'm kinda seeing the old "I really want a motor but I haven't thought out what to do with it" problem. Trying to piece mismatched shit together can get expensive. The NET COST of your complete engine is how to judge a course of action.

What is OPs end goal and engine budget range? Got cylinder heads and rocker boxes?

If all you have is jugs and ambition, I suggest saving for an engine because you don't have anything and buying odd parts is a trap. If you don't have a titled motorcycle as recipient for this engine, I suggest saving to buy a complete project bike because buying one piece at a time is gonna be painfully expensive. It's the worst route to a motorcycle unless you have a shitload of cheap/free parts on hand or friends with same.

Make a spreadsheet (yes, really) and crunch the numbers. A motorcycle is the number of dollars it took to make it real.

Dragstews
03-03-2016, 9:00 AM
Not so long ago member Lilbill asked this same question...

Think I told him to just run it as a Big Bore or find a case that hasn't been bored for the 3-5/8" bore...
Not sure which he did do...???

Note: If you do decide to go Big Bore, the heads will need to be machined for the larger jugs....

http://i279.photobucket.com/albums/kk140/dragstews/Camel/IMG_0028-10.jpg

BurnoutNova
03-22-2016, 8:05 AM
Welding and machining the case bore and decks costs money on what appears to be a tight budget build and if improperly done could ruin them.

What makes those cases such an awesome deal (post the price, shit ain't classified information) vs other used or aftermarket cases? I'm kinda seeing the old "I really want a motor but I haven't thought out what to do with it" problem. Trying to piece mismatched shit together can get expensive. The NET COST of your complete engine is how to judge a course of action.

What is OPs end goal and engine budget range? Got cylinder heads and rocker boxes?

If all you have is jugs and ambition, I suggest saving for an engine because you don't have anything and buying odd parts is a trap. If you don't have a titled motorcycle as recipient for this engine, I suggest saving to buy a complete project bike because buying one piece at a time is gonna be painfully expensive. It's the worst route to a motorcycle unless you have a shitload of cheap/free parts on hand or friends with same.

Make a spreadsheet (yes, really) and crunch the numbers. A motorcycle is the number of dollars it took to make it real.

The appealing part is they are a titled set of 66 cases and I have a pre-69 frame that they will be going in. I did buy them ($1400 not a steal but they had a title, so that made it worth it to me), and they are already bored like I had said. I will plan on new cylinders and stroker wheels it will just take me longer to build it. I knew that was the answer just hoping there was some way to rig it up. I have a complete 80" top end I could have used but I'll save it for something else.

farmall
03-22-2016, 7:56 PM
1400 isn't unreasonable nowadays to accomplish the end result with your other parts. A titled big twin frame or cases is worth at least a grand. A few hundred more is background noise in the overall cost of a complete bike.

If you wait to do it right you will be happier.