Hi All
I'm posting this for information for anyone rebuilding or ordering parts for S&S 113 engines specifically but could apply to 100 and 107 engines also. I have been having some issues with a S&S 113 engine built about 18 months ago, and whilst waiting for a Rocker gasket set to arrive, I had the plugs out and noticed I could read the part number on the installed piston. As I was having issues and losing faith in the motor builder and thought ill check S&S web site to confirm Pistons/part #. My installed piston part # is 92-1402, S&S list this part for a 107.
S&S say all 3, four-inch engines have the same deck height pistons and the only thing I can assume is different skirt lengths to match the different strokes.
after emailing the builder and getting no response I'm getting worried I've got the wrong pistons installed and a potential piston to piston or piston to Flywheel clash is a possibility. I then remembered Max Headflow's 113 build and revied that for any insights. I found images of Max Headflow's new pistons, and they had the same Part number as mine. Hmmm something going on here. a few PMs to Max and an assumption was formed that possibly S&S re-machined some 107 pistons to 113 specs.
Thanks for your input Max.Max remembered on a previous set of pistons a revised part number scribed on the underside of the piston.
So, this around the 2020 to 2021 period when all the Covid impacts were affecting suppliers WoldWide, and our assumption is starting to make sense.
So I emailed S&S tech support and below is my query and their response.Hello from down under I have had a S&S 113 rebuilt by a builder here in Australia and I have noticed that he has fitted Pistons with part # 92-1402 your listings say they are for a 107. You have several different listings for 113 & 107 Pistons. my question is will they be ok in my 113? thanks in advance.

S&S Replied:

You will have to change out the piston to the correct ones. 92-1412
Not what I was hoping to hear so now I'm thinking the only way to confirm is pulldown the engine. so, I better get another set of pistons to swap out if my fears are confirmed. I found an Aussie S&S supplier doing clearance and they have one set of 92-1412 pistons left at a very good price.

Pistons arrived all the correct part numbers on the box/boxes, but when I opened the box and looked at the piston, the etched number was the same as mine and Max Headflow's (92-1402) but the underside has the revised number scribed on the pin boss.




So, the lesson or warning is, Have a good look at what you are replacing or installing to save yourself some stress.
PS: I can't 100% be confident mine are the same but now at least all roads lead to Rome.

 

We see many things are are not correct - it seems the money and quickly in getting it the most important thing - quality is thrown to the wind

my take when he did not respond he knew he was caught in not knowing what he did wrong - he still has no idea if you have not told him he would have no clue

 

So true, finally got back to me and he couldn't even remember weather it was 20 or 30thou over. He just he got the pistons from Tatro who bought direct from S&S and he asked he for +20 pistons for a 113. you think he would have a build sheet to reference. so fair to say never checked part # against the catalog or he would have remembered the revised part # scribed on the underside. That's not something you would forget, I know i never will.
PS I never told him

 

Who is he? I know that I was careful to check the dimensions on the piston before using them.. The guy that built Ozzie Johns may have done the same thing.. I unfortunately didn't check the number on the top.. I probably did do the bottoms but don't remember..

SnS does not make their own pistons.. IIRC it's wiseco.. Anyway with setup fee being significant on short runs, SnS probably buys 107 fronts and machines them in house to rears, and 113 fronts and rears. 3 less setup costs.. They may only be buying 100 pistons at a time..

BTW I've seen SnS screw up.. I ordered a set of cylinders for a 116ci TC, Front cylinder was only rough bored. Rear cylinder was finished and had a new rear piston sitting in the bottom of the cylinder.. Later that piston came in handy..

 

I wont share who he is yet, but i will share another one of his gems of machining excellence.
after getting the motor that i waited 2 years and 4 months for and installing in my bike, i had to replace the leaking oil pump before i even started the bike. After starting the bike i replaced the miss matched rocker covers (Pre 93 top and 93-99 bottom and middle) with a new set of 93-99 covers as found the covers wrong after pulling off to fix oil leak on 4th heat cycle. Installed new adjustable pushrods as pretty sure the ones fitted were Twin Cam as the front exhaust was nearly at the end of its adjustment and i just didn't trust it. i did all of that, then found air escaping from some where on the left only to discover the below.

The legend machined through the side of the head and exposed the decomp bottom thread to atmosphere and the tried to plug it up.

 

FFS! Who is this guy? We all need to avoid him.

 

He has finally responded so ill give him a chance to correct issues so i don't want to jeopardize that process. He's in Australia so low risk for a lot of you guys in the states. And NZ just looked at your profile Spanners39

 

Well the other work sucks.. You may be able to sink the compression release enough through the fin to get a good seat.

If you look at what I did, the compression release had to go all the way through the top fin.

https://www.hdforums.com/forum/evo/1418532-113-sns-rebuild-4.html#post20995806

WFOlarry gave me the specs on where the hole goes and mentioned that the seating surface went pretty deep..