Hepolite piston

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charles.bulloch
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Hepolite piston

Postby charles.bulloch » Thu Aug 11, 2011 1:03 pm

Hello all!
I have a NOS piston, Hepolite 5045, +20. What will the compression ratio be with this in my alloy head VH?
I am seriously considering relining my barrel to take this piston, to replace the +60 GPM 13246 which I am using, as at over 70mph I really have to hang on!
Can I expect more speed with the 5045?

Charlie

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dave.owen
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Postby dave.owen » Thu Aug 11, 2011 3:28 pm

Charlie,

Is the piston Flat , dished or domed

these are usually 6.8:1,6.2 or lower ;1,7.5;1

Dave
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charles.bulloch
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Re: Hepolite piston

Postby charles.bulloch » Thu Aug 11, 2011 5:06 pm

Hi, Dave, its flat.

Charlie

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adrie.degraaff
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Re: Hepolite piston

Postby adrie.degraaff » Fri Aug 12, 2011 9:22 am

A flat piston is not good for speed if with an alu head.

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Postby robin.parker » Fri Aug 12, 2011 9:16 pm

But, the Hepolite piston is probably the correct weight for the engine's balance factor, so you'd expect a smoother motor at high revs and would likely be able to go quicker.

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Postby Simon.Gardiner » Fri Aug 12, 2011 11:08 pm

It's a 7.5:1.
If the GPM really is 7:1 (according to google) then I wouldn't think it would be any quicker, but it might be smoother if it's lighter.
Having said that getting the bottom end set up really well seemed to have a big effect on mine.
(How odd, there was a 5045 just like that on ebay not very long ago!!)
'55 Huntmaster, '56 VH, ' 51 VH, '80 R100RT, '00 Sprint ST (but all those Ariel parts can only make one running bike...)


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