Heavy pistons

Hi Lucky,

The new Hepolite (AE) pistons are almost as heavy as the Australian JP pistons you have.
You can find wrist pins (gudgeon pins) made from "thin wall" tool steel that are almost 30g lighter than standard pins. MAP Cycle in Florida can supply these.

Seeley920 said:

swooshdave said:

Lucky said:

Yes, these really look great, but as you said, when the bottom is disassembled you want new main etc. etc.

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What would be really cool is lightweight pistons that fit on the standard rods.

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Steve Maney!!!!!

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Are they actually lighter?

It would have been nice if some visionary at Norton had come up with short light pistons and simply stretched their alum rods. But that ground had not been broken at the time. Its not a bad idea to raise the balance factor in a Commando into the 65% range. But its not so good lowering it. The higher balance factor helps offset the piston trying to throw itself through the head - the worst of the shaking forces.

If your bike is jumping of the ground just off idle, but its ridable - maybe you can live with it and it may not seem so bad when you're rolling, (unless something breaks).

Yes the quality Longer proprietary lightweight Carrillo rods are expensive - but they are cheaper than new original forged aluminum Norton rods. There are cheaper alum billet rods but they are heavy and some have a reputation of failing when stressed. Old parts (35 year old alum rods) do need replacing. It gets ugly and dangerous when those old aluminum rods let go.

Are they actually lighter?

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yes

jseng1 said:

It would have been nice if some visionary at Norton had come up with short light pistons and simply stretched their alum rods.

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Probably wouldn't have mattered. At the time the metallurgy probably wasn't up to snuff.

Not sure if this will help you but MAP Cycle in St. Petersburg, FL sells a Taiwan made cast piston fairly inexpensive and they weigh 299 grams w/o wrist pin and 372 grams with the wrist pin. They work with the stock rods and if your not into racing should give good service. Cast pistons do require a bit more clearance but like i said if your not building a racer should work fine.

Scooter

Hi John

Now you got me worried again!

How much does the new hepolite weigh, do you have the correct numbers, it seems as I can find nothing at all on the net on Hepolite pistons, does the company not have a homepage?.

BTW. just got back from the local "cylinder service" there is a "older" guy (hope he dosent read this) he has a lot of expirence renovating and tuning engines. He had a look a by barrel and measured it, it is still 77,00mm he said it would be stupid to rebore it as he probably could not make it better as it is, a hone is all what is needed. I wonder how many miles this engine has on it? Probably not a lot I would guess.

Regards
Henrik

Lucky said:

it seems as I can find nothing at all on the net on Hepolite pistons, does the company not have a homepage?.

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The "Hepolite" (AE) name is now owned by Federal Mogul, so I wouldn't expect to find much useful piston information on their website.


http://www.federalmogul.com/en

Hi L.A.B.

Seems you are right, no information to find there.

Anyone know the weight of the "new" hepolites?

Regards
Henrik

For what its worth - the early hepolites weighed about 315 bare in standard size.

Just going to a light piston helps but the other problem is the stroke to rod ratio in a stock Nort (1.67 to 1). The stock rod is too short and causes a lot of vibration, stress on bearings, and some extra friction heat from sideways pressure on the cylinder. The triumph guys will tell you that the long rod triumph runs better than the short rod.

Talked to RGM today and had them weigh a complete AE Heoplite piston for me,
405g pretty close to my "old" original ones, so new ones is in the post for me

Hope this will reduce my vibes to a more comfortable level.

Regards
Henrik