I've found the shop I'm willing to trust with my project. So I'm going to keep the stock stroke, see how bad the jugs are worn and then decide to go with .010, .020 etc. over bore. Now i need to decide on what compression i want. I'm more concerned about longevity than monster power. I'm thinking if i set my max compression at 9:1 i should still expect a good long lifespan for the engine. Would like to hear everyone's thoughts. At what compression ratio should i start to worry about too much stress on stock 40+ year old aluminum cases? FYI, planning on a mild low/mid range cam.

 

stock compression works the best with todays gas in a cast piston 8 1/2 to one with the moly coated top ring

for even better drivability the Andrews replacement cruising camshaft the - A2 is the deal

 

agree 31/2 8:1 is the best bore if you go higher you face detonation on low octane gas

 

My '79 FLH 1200 King of the Highway is a big ol' heavy bike all dressed out for touring.

Engine work done in 2002 mods include S&S Super Stock heads, Super E carb,
+0.020" forged pistons @ 10:1 compression and true dual exhaust.

Head Quarters Torquer cam @ 0.465" lift and Jim's hydraulic Powerglide Big Axle Tappets.

At EVERY fill up. I add a couple shots of Marvel Mystery Oil to the tanks and a shot in oil too.

I ALWAYS run 91-93 octane GOOD fuel !!!!

The previous owner had her for 27- years and did all the upgrades before he sold her to me.

He also had a newer Ultra that his ol' lady liked riding on better than this Shovelhead.

She starts easy, idles sweet and runs the country back roads and freeways ALL day & nite!

VERY dependable and easy rolling around town.

You did not mention year or model of bike or what type of riding your planning on...😎


Right now she's spending the winter at my indie's shop all warm and safe for fluid changes and
brake pads and WILL be getting a Dyno tune before I pick her up for this riding season.

 

so you just got this bike and you did not have the engine work done this is what you were told it has

or did you have the engine disassembled to confirm the parts you were told about and in fact they are in this engine

 

rockher man my ride is a '79 FXEF 80". Most of my riding is for pleasure, 2 hours one way, lot's of curvy roads in my neck of the woods. I'm not a very aggressive rider and I'm not too hard on her unless i'm trying to catch up to someone.

 

I have a 77 FX (lite bike) 1200 stock bore but 9:1 Pistons. Stock heads. I was running the Andrews #2 cam w/ 35*ivc. Hot days it would definitely ping heavily. It even created issues with the ignition at times where one cylinder would cut out and at idle it would stall sometimes. No matter what fuel I used. I also tried 3 different ignition systems and still nothing would cure my problems...The other issue created with the higher dynamic compression was my oil temps were consistently 245-250* On a suggestion from John I put the Andrews A2 back in.. all my problems disappeared and it still runs great..

 

I have always had to run 92 octane. Anything less and she runs crappy unless i put some boost in her. The previous owner told me the heads had been shaved, for what that's worth. So i plan on having the shop inspect my heads thoroughly. Hopefully the heads can be saved.

 

I have very detailed invoices from the shop work. S&S heads are easily identified as is carb.

I have the original "H" cam in the package the Head Quarters Torquer cam came in.

In fact I have every part ever replaced on this bike. Even the original tires from 1979.

The bike is definitely not "stock". Easy to tell just by starting and riding.

She's also running Dyna S Iggy and coils.