Hi all and G'day from Aust , there are some Hepolite Pistons for sale on Ebay , does any one think these are ok to run on a MK3 850 they seem very cheap , are these domed top pistons better than the flat tops any thoughts Norton Dave .

I bought some new Hepolite pistons off eBay a few years ago to replace the JRC pistons I was using. Unbeknownst to me, there are Hepolites with a large oil ring groove cutout. They will fail in a Commando 750. One let go in my Combat. In fact, they are referred to as flip tops. As for an 850, I don't know if any flip top Hepolites exist. All I can say is, all Hepolites are not suitable for a Commandos.

The Hepolite brand name is now owned by Wassell.

http://www.totalbikebits.com/wassell_history.html

In 2011, the Company acquired the Hepolite brand, trademark and goodwill from the Federal Mogul Group. Originally Hepolite was a brand name of Hepworth & Grandage, who later merged with Wellworthy Pistons Ltd, to form A E Piston Products Ltd.

I believe these "new" Hepolite pistons are made by JCC.

Someone recently showed me that the new Hepolites are not made in England any more, but somewhere in the East....

That does not mean their quality has to be bad though. If you watch ebay long enough something always pops up, it seems there are quite a few sets of NOS 850 pistons lying around, more so than for 750 or other Nortons.

I have seen Hepolite boxes with the Federal Mogul tag on them that also carried a "Made in Italy" sticker. GPM? These were presumably made before the acquisition of the Hepolite name by Wassell.

beng wrote: Someone recently showed me that the new Hepolites are not made in England any more,

I doubt Hepolite pistons have been made in the UK for at least 20 years (not since they had "AE" on [Edit: black and yellow ] boxes!).

beng wrote:but somewhere in the East....

JCC = http://www.jcc-parts.com/jqen/web/about.asp

beng wrote:That does not mean their quality has to be bad though. If you watch ebay long enough something always pops up, it seems there are quite a few sets of NOS 850 pistons lying around, more so than for 750 or other Nortons.

However, buyers shouldn't be fooled by the new Wassel pistons which come in old-style Hepolite boxes that look as if they have been sitting on a dusty shelf for the past 40 years!

I've bought a pair of these hepolite pistons in the antique looking box off ebay. I had a good idea that they weren't original hepolite but at £106 inc p&p I thought they were worth a punt. They are for my planned rebore on my 70 fastback and to be honest they look good. The skirts have a very fine turned finish compared with a much smoother finish on an old slotted oil control ring AE item. That may just hold a film of oil where you need it.

The pistons are OK apparently, but I remember kommando making a comment that the rings are not so good?

post58572.html

L.A.B. wrote:The pistons are OK apparently, but I remember kommando making a comment that the rings are not so good?

post58572.html

yes +1 on this - your better off fitting hasting rings or real hepolites if you can find them (good luck, like the hepolite pistons they are recent manufactured rings packaged in hepolite boxes etc etc - believed licensed by wassel too)

The compression ring are just a plain cast iron ring so just basic but do work, the 17mm circlips for 11/16 pins pissed me off more.

"Real" Hepolites were quite all right in Commandos- we used them for decades, until AE phased them out and Andover Norton had them made by GPM due to Hepolite stopping production. Again, no problems with GPMs, neither race, nor road.
The "dangerous" Hepolites were for 750s, and the downward slots on these are joined by a horizontal slot each side that runs behind a piston ring (easy to see looking into the piston). these are fit only as ashtrays, but they haven't been made since the early 1970s. If you get them they are still there, new, because the experienced dealers and owners declined to buy and use them!

Real Hepolites have "AE" cast in their piston skirt.

The envelope that the rings came in supplied with my hepolite (wassel) pistons has "printed in USA" That doesn't mean that's where the rings came from. I might fork out for some genuine american Total Seal rings. Any opinions on these?

Some three or four years ago, on this forum, someone posted that a certain Hepolite, the one with the large oil ring cut out, would lose their tops in a Commando. Now I see posts saying that Hepolites are O.K. for Commandos. What's the deal? I did have a Hepolite piston fail in my Combat. The piston top split in half and separated from the remainder of the piston. Made for one hell of a rattle.

JimC wrote:Some three or four years ago, on this forum, someone posted that a certain Hepolite, the one with the large oil ring cut out, would lose their tops in a Commando. Now I see posts saying that Hepolites are O.K. for Commandos. What's the deal?

Hepolites are generally OK, except for those early Commando pistons with the cutouts which ZFD described:

ZFD wrote:The "dangerous" Hepolites were for 750s, and the downward slots on these are joined by a horizontal slot each side that runs behind a piston ring (easy to see looking into the piston). these are fit only as ashtrays, but they haven't been made since the early 1970s. If you get them they are still there, new, because the experienced dealers and owners declined to buy and use them!

http://www.norvilmotorcycle.co.uk/techtalk34.htm

JimC wrote:I did have a Hepolite piston fail in my Combat. The piston top split in half and separated from the remainder of the piston. Made for one hell of a rattle.

Early Combats did have those weak pistons.

NOC Service notes:

PISTONS: Don’t buy new pistons with a slot under the oil control ring. This slot was deleted to avoid the top coming
off the piston when the revs were kept up towards 7,000. Of course, the slotted pistons are OK for the man who never
goes over 5,000 rpm. The later type are identified as Combat Pistons in the parts list, but the only difference is this slot - the
compression height of combat (non slotted) and standard (slotted) pistons is identical.