I have used what USED to be called "Cycle Craft" pistons in a lot of bikes and now called JCC or EMGO and are Asian made cast pistons and they tend to be excellent and *
* makes some of the purists angry but IMHO they are vastly superior to the original hepolites. Digital weight scales and calipers/Mics dont lie. The specs are very consistent to the point of on many Triumphs, Nortons and Unit A65s I would only order one set for each size and then have the machine shop bore and fit those pistons to multiple cyls back when I did a lot of engine rebuilds.
I did not worry about as they were spot on size wise. (And weights) But still good to check. After 25 years though I found one set mismatched.
Check ANY set of pistons and they are "graded", New out of the box they will typically have small paint dots typically on the pin bosses. Red, Yellow, green or sometimes 2 dots side by side.
Depending on QA or the inspectors they grade and sort the pistons to ensure consistent pairs. In my one exception they were mismatched and off by 1.5-2 grams IIRC. ( common and expected deviation with Original Hepolites & Wellworthy)
However the pins supplied tend to be weighted wildly different so best to check them. The circlips also reportedly have issues with some sets but I never experienced any issues but on some builds I use my own sourced specialty clips.
Rings tend to be cheap and so-so quality. Okay for a penny pincher and budget build but not up to mosts standards so I avoid the supplied rings and use a mix of US supplied as well as Hepolite and Hastings rings depending on availability and the builds specs.
One bit of a footnote, Maybe one day I will compile a ORG Chart or family tree of the companies but in the 40s thru 1960s most parts supplied were a select group of manufacturers, But some of these names live on but NOT the same company. IIRC Hepolite was bought out circa late 1990s but US Federal Mogul who promptly did a partial shut down, farmed out most production to a sub-par Spanish or Italian company,(GPM?) and then folded the Hepolite name entirely. The name has been revived but NOT the same company & think some sort of repops and merely branded with the Hepolite name.
So, flame suit on, *
* but model and brand specific enthusiasts tend to have limited fields of view and blinders on. At the end of the day its JUST a cast piston. British bike owners tend to reverently think a OEM Hepolite or WellWorthy are the be-all and end all of what the world revolves around. But in any other form of motorsports or performance a cast piston is the lowest echelon of quality. Something you might use in a air compressor or yard & Garden equipment but certainly not in a road going vehicle. Auto folks have some options for those on a budget and there is some quality mid point pistons out there but otherwise forged pistons are de rigueur and only a true Bodger would stoop to a cast piston.
So, I used to deal with people in my shop who would haughtily turn up their nose at a Cycle craft-JCC-EMGO piston ( on average $40-60 dollars a pair vs $180-200 USD for a Hepolite made in UK set) as if in the comparison of cast pistons was much more than a few minute degrees of separation in reality.
I still tell people if you want to reuse your rods, and run cast pistons then ride the bike accordingly. But if you want performance then step up and upgrade your crank, rods, pistons & valves to modern materials.
One final note: I have wondered about the BSA pistons with large slots in them, expansion joints certainly but in Nortons they are considered little more than a ornamental paper weights and most will warn you to NEVER run those slotted pistons. (Always a Alfred E Newman-What me worry types who relate years of service as an exception) But I have not heard the same tales of woe with BSA pistons of that type. Is it because better made or more agricultural usage? So, I do have some very ancient dealer stock Wellworthys with such slots and always wondered about them.
More relevant when asking about experiences of such is a summary of type of expected use, Parade, display and Sunday best rider? Or flogged in the Alps or Nurburgring?
