Thanks for indulging the bike lovers, Ryan. I lost my manual and I need help knowing how the pistons are installed on a '78 shovelhead. If anyone can scan pictures from a manual and pm them to me, I'd really appreciate it. Thanks a bunch.
Turn your piston up-side down and look at the pin boss. One side will have a small web on it. That side goes to timing gear side of motor. The Wizzard
pist'n'broke, there's no web on the piston. There's a thing in the middle that looks like it's made of sheet metal, it's molded into the piston itself. The bottom end and cases are stock 80" S&S, the heads are 1978s, the jugs and pistons might be post '78 design, possibly, I don't know. I also don't know what the piston ring gaps ought to be, it's also possible I bought the wrong piston rings. My heads just came back from the machine shop, the machinist rebuilt the heads and checked the pistons and jugs for wear. He said they were within specs and all he did was hone the jugs. I just want to get my bike back together again, but I'm too cheap to spend $32 on a manual if I can help it. Thanks.
Nads, don't got nothing for ya - (I could prolly help with WL stuff ) - you might try asking on the Horse website...you ought to get a quick response there...
Are they after market or stock H-D parts. Some H-d pistons have the web ,or a dot,or an arrow. Most good ( not Tiwan made ) parts have the arrow. Dot and arrows toward the front or facing the timing cover ( depends on location ) Web always faces the timing cover. I've been out of the bike biz for about 10 years now so things could have changed but thats what I remember. Chuck Fish
my manual shows a nub under the piston on the surface the wrist pin runs through,it says nub must face left (sprocket shaft) side of the motor.It says to mark them when you remove them but not what to do if your using new pistons.Sorry probably not much help.
Most guys don't remove both keeper rings when removing pistons. Can you remember what direction you pushed the wrist pin when removing? The other option is to take a piston to your machinest and see if he can help you out. I havn't seen any piston yet that didn't have some kind of mark for direction. Wrist pin oiling can be compromized if put in backwards. The Wizzard
Ring end gap is ten to twenty (use .020) pistons have a arrow that points forward clean the carbon off the top to see it or cast onto the bosses that hold the wrist pin is a small identification (like everyone has said) that goes toward the carb side. you should have .0015 to .003 clearance on the skirt 90 degrees from the pin with cast pistons (factory) for side clearance. Sorry this is so late hope you got the motor together.
Call "Jireh" 1-877-681-0448. Ask for catalog. Their catalog has lots of diagrams and its free. you will need a hand truck to get it into the house. Been a Midwest delar for years. LATER
Dudes, I've tried to get back on The Horse message board so many times but it won't let me. I registered ages ago. Thanks for all your tips, I'm gonna check my pistons out right now, I hope to God they're not Taiwanese junk, but I have a bad feeling they might be.
One other thing you could look at. Most stroker pistons have a champfer on the piston skirt that goes to center. Factory H.d.'s only have them on one side so there is a front and rear piston. Jap pistons will be champfered on both skirts. Even if yu have H.D. pistons you need to know what one was front and rear. The Wizzard
Nads, "singledownloop" has it right out of the HD manual.My manual says the same or to quote from the manual "mark the piston by scribing an "F" or "R", for front or rear cylinder, on the piston pin boss opposite the the boss having the raised "nub". Marking the piston is important since the piston pin is offset and the pistons must not be installed backwards"."Install the pistons making sure they are properly oriented front to back.The raised nub on the pin boss must go to the left or SPROCKET SHAFT SIDE." This hint is NOT OUT of the HD manual, SOMETIMES it is possible to tell which is the front or rear piston by the wear pattern on the piston skirt. One side of the skirt MAY show more wear (the thrust side) than the other side. The front piston will show wear on the front side of the piston skirt, rear piston will show wear on the rear side of the piston skirt, AS LONG AS THE SPROCKET SIDE OF THE PISTONS ARE KNOWN.
Okay I used my head and figured it out. Seeing as how it was the front intake valve seat that fell out, it was easy to tell by looking at the the nicked piston to see which way it gots. I flipped the piston over and both sides of the pin boss are the same but there is a small dot which faces the cam cover side. I borrowed a Haynes manual from thee library last night and it's about as useless as good quality strings on a Mexican guitar. I reckon I've got it all figured out, the gal oughta be back on the road bythe weekend, unless I drink myself to death on new year's eve. Thanks for all your help, have a terrific 2005.
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