HEPOLITE 8.5:1 +40 PISTONS

Started by mo goldie, 29 Jun, 2021, 22:06

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mo goldie

29 Jun, 2021, 22:06
Hi

has anyone got a set or know where you can Buy a set of HEPOLITE 8.5:1 +40 PISTONS as cant seem to find any ?

as the pistons that are in it I have been told are no good ....so i have been told  :-\

cheers

Mo

idie

#1
29 Jun, 2021, 22:08
Pistons for what!

mo goldie

#2
29 Jun, 2021, 22:16
Oh sorry lol

Bsa rocket 650  ;D

DAVE BRADY

#3
29 Jun, 2021, 22:39
Hi,

Why are the ones in it no good?

Dave.

mo goldie

#4
29 Jun, 2021, 23:37
Hi dave

well as you know they hit the flywheel even tho I have took some off them.......but a bloke told me that that make are rubbish they are GPM

Mike Farmer

#5
30 Jun, 2021, 07:08
 :) :) :)

I got mine from 'British Only Austria'. Not 8.5's but 7.5's. They are GPM. This is the third set of GPM pistons that I have used and have not had any real problem. Except the price.

Did the bloke tell you why they are rubbish and in what way.

Mike 8) 8) 8)

DAVE BRADY

#6
30 Jun, 2021, 08:47
Hi,

I would agree.  GPM have a reasonable reputation.  Did you take any before and after photos of the pistons?  If the contact with the flywheel was not enough to cause distortion and or cracking of the skirt or any other damage then they are probably OK to use.
Perhaps it would be worth giving them another examination and check for any slight distortion.  A magnifying glass or a good 'macro' photo may help.  You could also check them in the bores for uniformity but bear in mind that they may have been made with a very slight ovality.  However, the puzzle still remains as to why they made contact with the flywheel in the first place?

Dave.

Mike Farmer

#7
30 Jun, 2021, 11:33
 :) :) :) :)

Hi

I think we would all be interested to know why they made contact. Must confess I think unless something is extremely out of sync it shouldn't be possible. The only thing that comes to mind is severely worn B/E or S/E bearings but I imagine you would hear that long before it got to that state.

Anything else would be pure guessing games ???????????? wrong conrods--unlikely

Mike 8) 8) 8) 8)

Mike Farmer

#8
30 Jun, 2021, 11:42
 :) :) :) :)

Was the A65 ever produced with 8.5:1 pistons. No idea but don't recall it.

Burton are advertising Hepolite 8.5:1 +040"(71mm) for Triumph T140.

It just could be that someone has fitted Trumpet pistons. As I say just guessing.
, no idea really.

Mike 8) 8) 8)

mo goldie

#9
30 Jun, 2021, 13:35
Hi all

Well I await to take out the engine and strip to understand why the pistons have hit the flywheel I think very strange as I have done 2,300 miles with no problems so can`t guess so will wait till it comes apart,

As for the bloke who said they are rubbish I don`t know why he said that......but they will be going back in as they look fine to me and as I say they have done 2,300 miles...... just old school thinking that there are No better then Hepolite so just said they are rubbish...... :'(

cheers Mo 

DAVE BRADY

#10
30 Jun, 2021, 19:15
Hi Mike,

Re T140 (std bore is 76mm) pistons in A65 (75mm bore).   They have a slightly different compression height so sit a bit down the bore so giving less compression.  I am running T140 pistons in one of my A65s.
I think that a std 76mm piston would equate to 75mm + 0.040 so a 76mm + 0.040  piston would be 77mm so like a plus 0.080 on the A65.  Someone confirm or reject my findings please.

Dave.

Mike Farmer

#11
30 Jun, 2021, 19:45
 :) :) :)
Hi9

Yes sorry about giving wrong size Stupid but I'm good at that.

What do you reckon running T140 pistons CR equates to in the A65.

Wish I d known that before I paid over £300 for a set of 7.5's, Tuff but well worth consideration if there's a next time.

Mike 8) 8) 8)

Mike Farmer

#12
30 Jun, 2021, 19:56
 :) :) :) :)

Hi Dave

What CR T140 pistons are you using. 8.5's or 7.4's.

I assume your general impression is favourable.

My "on the bench" engine could still do with lower compression. Actually me---not the engine.

Mike 8) 8) 8) 8)

DAVE BRADY

#13
30 Jun, 2021, 22:22 Last Edit: 30 Jun, 2021, 22:34 by DAVE BRADY
Hi Mike,

I am not too sure what I end up with but I am pretty sure they would be 8.5s or even a bit more in a Triumph but I would guess 7.5:1 as they sit about 2mm down the bore.  I should add that I am running an A70 crank so that will complicate things.
The engine runs very well but it is interesting how the longer stroke and a few more CCs make the engine a bit harder to start.  More like an A10 than an A65 in kicking technique but still very easy with Pazon EI.

Dave.

Mike Farmer

#14
01 Jul, 2021, 11:32
 :) :) :)

Hi Dave thanks for that.

Worth some thought but I guess that I'll stick with what I have.

Mike 8) 8) 8)
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