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TwiZted & Rains2Much: Thank you for weighing in on the dual plug option. Good deal--I'm leaving the S&S heads 'as is' in that regard.
Rains2Much: Thanks for the detailed info on the sealing surface. My neighbor/machinist (shop is literally across the canyon) can do that for me on the big CNC mill, no problem. I may hit you up for additional details when I get to that point.
No, I don't think I'm going any more radical than the J grind cam. I only want a skosh more oomph, but really 74" in a stripped down rigid frame is plenty for me. I think with the S&S heads, the Super E, the J grind and this exhaust, she oughta be a hoot to ride.
But also good to learn about the considerations re: benefits of early Sifton blocks. Maybe, just for fun, I'll see if I can hunt some down.
TwiZted & Rains2Much: Thank you for weighing in on the dual plug option. Good deal--I'm leaving the S&S heads 'as is' in that regard.
Rains2Much: Thanks for the detailed info on the sealing surface. My neighbor/machinist (shop is literally across the canyon) can do that for me on the big CNC mill, no problem. I may hit you up for additional details when I get to that point.
No, I don't think I'm going any more radical than the J grind cam. I only want a skosh more oomph, but really 74" in a stripped down rigid frame is plenty for me. I think with the S&S heads, the Super E, the J grind and this exhaust, she oughta be a hoot to ride.
But also good to learn about the considerations re: benefits of early Sifton blocks. Maybe, just for fun, I'll see if I can hunt some down.
One more secret …. Always turn the heads and jugs on a lathe. I can’t give you the science reason but the guy who needed every penny to count (me) learned long ago for whatever reason they sealed so much better when you turn them on a lathe vs milling them. Also copper gaskets with a copper coating are full proof, never a blown head gaskets even in big strokers with high compression.
One more secret . Always turn the heads and jugs on a lathe. I cant give you the science reason but the guy who needed every penny to count (me) learned long ago for whatever reason they sealed so much better when you turn them on a lathe vs milling them. Also copper gaskets with a copper coating are full proof, never a blown head gaskets even in big strokers with high compression.
Oh, okay, thank you. Ill talk to Zach about that. Hes got three lathes: a medium-sized one, a large one, and the (giant) CNC lathe he uses to make up some of my parts. My guess is the large standard lathe would be best for this task for the jugs.
I anticipate, though, that based on our past work for Creative Spridgets parts, hell tell me he doesnt want to make up a jig to hold the jugs (or heads) in the lathe. His big CNC mill (see below) is so accurate across its entire bed length that its mind-bogglingand its simpler to make up a fixture or in the case of the jugs, to just grab them in the vise by the squared-off base. There is actually zero measurable deviation across something the size of a cylinder head. Not rejecting your suggestion, here, just anticipating what Zach will say.
I remember once when he and his late father (who started the business) were consulting with me on some Creative Spridgets part I had designed, Zach rolled his eyes and said, Geez, Joel, were not freaking woodworkers! I am, and typically make up a prototype out of acrylic or hardwood, so theyre always poking fun at me...
But seriously, I appreciate your suggestion, and well see what he says!
Oh, BTW, the below pic is a Haas mill at the other local business I used to contract with for my Sprite/Midget disc brake adapters when I was still offering them. Zach's new mill is slightly smaller than the Hass and more accurate, he says.
Nice, no real advantage for the dual plugs unless you are going really hot on the build. I'm dropping one plug on mine to put compression releases in instead.
Hey, TwiZted, can you possibly post some close-ups of the paint job on your Shovel? My black-and-blue paint job (on the bike for ~30 years) is getting chipped and a bit faded, and I was thinking of doing her up silver with either blue or red pinstripes, since Im wanting to weld up some holes on the rear fender anyway when I have the engine out.
Trying to decide on a good silver, and there are lots out there
Update: I pulled the heads and the valves look fine (will check one of the rockers on one head tomorrow), and saw bad scoring on the cylinder walls (see pic); matching ugliness on pistonstheyre toast. Then, held my breath and pulled the jugs to check the bottom end and I was astounded to find that the crank turns smoothly and silentlywith not a whisper from the cam chest or oil pump.
There was zero up-and-down play at the rods, so measured the rod shake side-to-side per the OEM manual, which is supposed to be 3/32 or less and the thing is still in spec! Amazing!
So, the felonious b______s at Home Depot cost me a set of cylinders and pistons, but at least I do not have to split the cases and rebuild the bottom end, as I had feared. Man, are these things bullet proof.
Question: Im looking at a V-Twin cylinder and piston kit from J&P Cycle (plus a set of James wrist pin bushes, which I figure I might as well replace while im in there), and wonder if anyone has had a good or bad experience with them?
Very excited to get her running within a couple of weeks and in time for summer riding, no less.
Well, my goodness… if they could be, I could get these TRW forged pistons available in .030 to .060” as a complete set for $40! I’d only be saving, like, $400 or so… and I’d be upgrading to forged pistons…
Let me carry these jugs down to the local shop tomorrow and see what’s what!
Last edited by NM Pan-shovel; Apr 10, 2025 at 09:53 AM.
Since this engine was oil-starved, that means the scavenger pump was pulling oil out of the bottom end while nothing was coming in from the other (main) pump chamber.
So: should I pour a little oil over the crank before installing the cylinders, so there’s something to sling up onto the cylinder walls in the few seconds it takes for the oil pump to achieve pressure and recharge the oil passages and galleries?
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