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Discussion Starter · #1 ·
I'm redoing my shovelhead baby stroker ( 80 in. flywheels with a 74 top end .020 over, STD cases, S&S wheels, rods, pistons), and was wondering if i should remove the ridge at the top of the jugs. It will eventually be given big bore jugs and heads, probably next year. could there be a clearance issue with the new rings at the top of the stroke? I'm probably just being a tight wad but i've been rideless for over two years and if i don't ride somethin' soon, the old lady excluded, someone's gonna get hurt.
 

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if your trying to reuse a set of stock 74 pistons dont just break down and buy the correct piston from S&S in a .030 over and have the cylinders done other wise you will be ridge reaming and have to modify the top and bottoms of the 74 pistons bottom to clear wheels and the top because it will hit the head and valve pockets need to be clearanced the piston will get thin between pocket & ring and will break i have done this but about 15 years ago but it did not last long
 

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midwestbiker said:
I'm redoing my shovelhead baby stroker ( 80 in. flywheels with a 74 top end .020 over, STD cases, S&S wheels, rods, pistons), and was wondering if i should remove the ridge at the top of the jugs. It will eventually be given big bore jugs and heads, probably next year. could there be a clearance issue with the new rings at the top of the stroke? I'm probably just being a tight wad but i've been rideless for over two years and if i don't ride somethin' soon, the old lady excluded, someone's gonna get hurt.
If you don't remove the ridge, you may crack your rings. Always remove this ridge during a top end job. I believe it's mentioned in the service manual. No sense in hurrying the replacement of parts if you are going to do it next year. A new set of rings, and a light hone job to score the cylinder walls will work fine. Make sure you go through the break-in period after changing the rings or they won't seat well and you will lose compression. I've done this to my Sportster for a few years in a row with no lose of compression or any other problems. If the ridge is more than about .040 thick, then you might want to go with oversized pistons. Other than that, you just might hear a little more noise until you go with the oversize pistons. It still won't hurt anything.
 

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The 74" cylinders can be bored .060 so you could bore if you wish. If you remove the ridge, you need to get it all. If the pistons are more than .003 loose, you will have a noisy engine, thouugh.
 

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Discussion Starter · #5 ·
Thanks guys, that's pretty much the answer i expected. I'll probably chuck 'em up in the lathe and be done with it. as far as piston fit goes, this will be her last run at +.020. She's getting alittle loose.
 

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midwestbiker said:
Thanks guys, that's pretty much the answer i expected. I'll probably chuck 'em up in the lathe and be done with it. as far as piston fit goes, this will be her last run at +.020. She's getting alittle loose.
If you don't want to take the time to get them set up in the lathe, you may be able to borrow or rent a ridge reamer from a machine shop. It might take less time that way. Either way will work, though.
 
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