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It was time to tear down the top end on my 1984 FXSB. Owned the bike 10 years with many happy miles. Never let me down.
A previous owner went thru the engine shortly before I bought it. S&S cylinders, dual plug OEM heads, S&S oil pump, unknown cam (waiting on cam cover puller), JCC cast pistons, stock crank.
The rear plug would oil foul. I found the rear intake valve has a pool of oil on it (wet). You can kinda see it in the pics and on top of the piston wet spot. The amount of oil/carbon buildup on both pistons and valves is crazy.... surprised it ran as well as it did and didn't bend a valve. Rear rocker box developed a pretty bad oil leak last year. Some vertical scoring on both cylinders.
I plan on bringing both cylinders/pistons/heads to a local shop.
Waiting on my friend's cam cover puller. As you can see in the pics, the cam lobe has pitting. Lifters have vertical scaring.
I'm thinking fresh hone, new cam (thinking Leineweber L3S or Andrews A2), get the heads inspected and gone through, new lifters and keeping it stock compression.... although, since it already has the dual plug heads maybe a slight bump in compression?
Advertised 9.5:1 pistons and an A2 Cam turned my 1200 FXS into a nice little ripper. VOES keeps it from pinging at low rpm on 93 octane.
looks good Joe. I may go with a bump in compression.
I plan on getting in contact with Hillside in NY and taking a trip up there with the top end in each of my FXDX saddlebags and spend some time riding and exploring up that way.
I enjoy oily hands. Especially when it some else doing it now.
i would definitely measure the cylinders. I see wear up in the top 3/4" of the cylinder that's probably past wear limit and trying to hone it is not going to be round and true to the bottom. .
Some one used a rought hone for sure in the last crosshatch. Did S&S do that?
It's Crane Fireball cam. Number on the face of the cam gear is 7-0004B. This comes up as a cam gear for Evos. It is a FB300H cam from 1995. The FB300H is listed as a Shovelhead cam. Evo gear on shovelhead cam?
Plastic breather gear. 3 of the teeth are chewed up. I am concerned about the breather gear bore. Lots of scoring.
I did not like the power of this cam. Very weak down low but came alive after about 3500 rpm.
Last edited by garystaven88; Apr 14, 2026 at 06:14 PM.
Question about the case studs. All but 2 studs came out when removing the cylinders. The threads are fine in the case.
I ordered a new set of studs. Problem is, they all thread in very easily and bottom out before ever really getting tight. I was reading these are interference fit.
I attached a photo. You can see one of the remaining 2 studs has about 2 threads exposed and is tight in the case. You can see the new stud to the right is bottomed all the way in.
Clean the stud threads and holes thoroughly, bore brush & brake clean, you can stuff a light rag or the blue shop paper towels in under to catch the crap. High heat red loctite 263. Set them to the right depth overnight and your good to go. Just went through this with a set of heads they had aped out on and several of the rocker box studs were pulling up, took all the threads when they did come out, got to play with the time sert kit. New studs were a sloppy.
Time Serts work well. I did this Time Sert repair on a wallowed out rear exhaust bolt hole 4 years and many miles ago. Still holding up strong.
My last adventure with them, 79 brutally abused shovel they had gone full troglodyte on tightening the rocker cover nuts trying to stop the leaks, had pulled 4 studs and crowned the mating surfaces on both heads , .017" rocking gap on one. Had to pull all the studs, no fun , fly cut them and time sert 5 holes.
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1984 FXSB Top End Overhaul
