The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: coater87 on 29.07. 2015 16:04

Title: piston confusion, which kind?
Post by: coater87 on 29.07. 2015 16:04
 I am looking for a +20 set of 7.25 CR pistons.

 My confusion lies in everyones opinions. Some people say buy GPM, others say to try and find original Hepolites (almost impossible). Now I understand Wassel has bought the Hepolite name, and turned them into Wassel quality goods. Now every mention of Hepolite on the internet comes with "genuine Hepolite" branded with it- a Wassel gimmick. So finding real ones it out of the question.

 Are there other brands that are good? I have heard mention of JP pistons, but know nothing about them.

 And maybe someone can clear up my confusion with a site that I see all over called "fekked"- they seem to have many parts, too many. Is this just a clearing house or what is "Fekked" exactly?

Title: Re: piston confusion, which kind?
Post by: edboy on 29.07. 2015 20:55
i ve just bought some very old stock +30  flat top hepolites from dragonfly. try them first.
Title: Re: piston confusion, which kind?
Post by: Peter Gee on 29.07. 2015 22:08
JP are fine for your model, in fact they do not sell the later 8.5:1 A7SS and A10 SR ones at all.

I have seen Hepolite fail, any piston is fallible. If you don't intend to flog your bike open throttle and plan on easy riding, any number of pistons will do. If you are going for very serious competition or high speed riding, then  try Draganfly and pay the price.

Personally I have gone for a pair of Taiwanese psitons for My A7SS with the luck that I have some 1950's rings from Hepolite, so I will use those instead.

GPM used to be rubbish when they first came out but have been an established brand for years now. I have them in my Vincent and caned it quite gard with no bad results.

Cheers

Peter in Africa
Title: Re: piston confusion, which kind?
Post by: beezermacc on 29.07. 2015 22:14
I have used the Wassell / Hepolite  pistons and they have proved to be fine (std ones in my Golden flash), and Wassells have sold hundreds of them, maybe thousands of them. I have sold a number of sets and had no complaints. Most of the retailers have sold out of the popular sizes (+40 / +60) and there are none left at Wassells. The GPM's are made in Italy - I am told the rings aren't very good? This may or may not be true. JP pistons are also available - I am told these are too heavy? This may or may not be true. The problem is that these rumours start from heaven knows where (often people who like to present themselves as experts) and we fall victim to Chinese Whispers rather than any proper scientific evidence.
Title: Re: piston confusion, which kind?
Post by: KiwiGF on 30.07. 2015 06:15
There's some info piston weights in this post of mine link below (sorry for the shameless plug) JP pistons are certainly not the heaviest and so far I've done 4000 miles on them without issue, but I also know some people do not rate them.....

http://www.a7a10.net/forum/index.php?topic=6086.msg41598#msg41598

Odd thing is I bought them from dragonfly as that was cheaper than buying them from Aus where they are made, even though I live in New Zealand......I pointed this out to JP who were quite rude about their pricing policy  *problem* *problem*
Title: Re: piston confusion, which kind?
Post by: beezermacc on 30.07. 2015 07:37
Very useful information, KiwiGF. Thanks.
Title: Re: piston confusion, which kind?
Post by: coater87 on 30.07. 2015 10:14
 OK guys,

 It sounds like it does not matter what kind I get, JP, GMP, Wassel- they are all about the same I guess.

 I think I will just buy a set of OMEGAs' (Taiwan I believe), because I can get them over here.

 I thought there was a time when you could buy Wiseco for A10, but I see nothing on there site. Thats too bad, because that

 is quality stuff. *sad2*

 

Title: Re: piston confusion, which kind?
Post by: cyclobutch on 30.07. 2015 10:43
Roger at Cake St had a whole stock of Wiseco squirreled away. You could try him, but I don't suppose he will be cheap.

http://www.totalbikebits.com/product_locator/dealerdetails.php?id=9
Title: Re: piston confusion, which kind?
Post by: terryg on 30.07. 2015 21:21
Caught sight of this...  http://www.ebay.co.uk/itm/BSA-A10-NEW-HEPOLITE-7-25-1-STD-20-40-60-PISTONS-FOR-1950-TO-1962-MODELS-/271314158198?hash=item3f2b958276#ht_1240wt_817 (http://www.ebay.co.uk/itm/BSA-A10-NEW-HEPOLITE-7-25-1-STD-20-40-60-PISTONS-FOR-1950-TO-1962-MODELS-/271314158198?hash=item3f2b958276#ht_1240wt_817), which might be of interest.

I've made no further enquiries and have no affiliation etc.
Title: Re: piston confusion, which kind?
Post by: chaterlea25 on 31.07. 2015 00:42
Hi All,
Hmmm!!! UK made  *????* I dont think so  *ex* *ex* *ex* *ex* *ex* *ex*

http://www.ebay.com/itm/Golden-Flash-pre-unit-Piston-Set-BSA-A10-020-over-pistons-UK-Made-20-over-/201328906920?hash=item2ee02352a8&vxp=mtr

John
Title: Re: piston confusion, which kind?
Post by: Rocket Racer on 31.07. 2015 01:52
Pistons another area (like oil) that has many opinions coming to the fore.
My own is I avoid JP's like the plague (I've had horrible issues with several sets) only resolved by fitting taiwanese pistons which were far better.
In terms of new pistons I'd have no issue with the Hepolites.
I cannot comment on GPM (never tried them).
The Wiseco's are also an excellent piston.
I always keep my eyes open for NOS and where possible use those.

Rings are another topic on their own! one piece oil rings typically need a lot of breaking in and of variable quality. 3 or 4 piece oil rings the go.
Title: Re: piston confusion, which kind?
Post by: Rocket Racer on 31.07. 2015 01:58
I am looking for a +20 set of 7.25 CR pistons.

 

I have over time collected several bare sets of genuine nos 8.25 & 9 :1 in +20 on the shelf. I could spare one of those sets
The 8.25 are genuine BSA and would be happy in a cooking thin flange small journal motor.
PM me if interested

If you want Wiseco's you'll need to contact Cake Street Classics directly
Title: Re: piston confusion, which kind?
Post by: RichardL on 31.07. 2015 13:29
Hi All,
Hmmm!!! UK made  *????* I dont think so  *ex* *ex* *ex* *ex* *ex* *ex*


Not sure what it is about the Wassell pistons John doesn't like, but they are definatley different from those he pointed to, which seem to have an additional groove below the oil scraper. The seller of the former was forthcoming about the Wassell name and the source as JCC in Taiwan. I can't actually say anything about the quality of the JCC pistons, but I sure was impressed by what I saw on their website in terms of products, facilities and apparent business mentality. i really liked the giant piston on the roof of their building.

Richard L.
Title: Re: piston confusion, which kind?
Post by: chaterlea25 on 31.07. 2015 19:04
Hi Richard,
The point I was trying to make was,
The vendor states, UK Made
Where as you state they are from Taiwan,  = False advertising

I used a set of these a couple of years ago when they came in plain unmarked boxes,
The pistons were fine but the rings had huge end gaps, the supplier replaced the rings without question

I got sent a set of "Hepolite" rings for a Triumph I was rebuilding, they were crap *angry* (same issue)
again replaced without question,

I am told that the Wassel Hepolites now have Hastings rings fitted? but have not needed a set since

I have Wiseco's for my RGS project 9:1
My SR has done a lot of miles on GPM's on tighter than standard BSA clearance and has not given a problem *smile*
The A10 on the bench for far too long has original AE Hepolites fitted

Regards
John

Title: Re: piston confusion, which kind?
Post by: coater87 on 02.08. 2015 01:43
 I settled on a set of the "genuine  *conf*" hepolites at 7.25, no idea if they have the hastings rings or not, will just have to measure the gaps.

 On to the other question for this post, does anyone know who or what "fekked" is? Like I say, I see their ads for BSA parts all over the internet.

 Are they like a J.C. Whitney (theres a blast from the past) or are they an actual brick and mortar store?
Title: Re: piston confusion, which kind?
Post by: coater87 on 02.08. 2015 03:11
 Oops, sorry. Its "feked" and they have some kind of little bug or somesuch in their ads...
Title: Re: piston confusion, which kind?
Post by: East_Coast_BSA on 02.08. 2015 04:27
I purchased some bits and pieces from them, maybe even a carburetor (I don't remember now).  I dealt with them over the phone and they were great.  Communication was excellent and they were very helpful.  I don't know if they are an "Internet" store, since I live on the other side of the pond.
Title: Re: piston confusion, which kind?
Post by: Rocket Racer on 02.08. 2015 05:35
I purchased some bits and pieces from them, maybe even a carburetor (I don't remember now).  I dealt with them over the phone and they were great.  Communication was excellent and they were very helpful.  I don't know if they are an "Internet" store, since I live on the other side of the pond.

I had a similar experience, no issues
Title: Re: piston confusion, which kind?
Post by: terryg on 02.08. 2015 05:46
On the Feked web site I noticed that they welcome customers to collect from their location in Dorset (near Wimborne I think).  Difficult for non-UK customers I know but I find the existence of some sort of 'real shop' and a face-to-face opportunity reassuring.
Title: Re: piston confusion, which kind?
Post by: bsa-bill on 02.08. 2015 08:41
Actual brick and mortor, I've had bits n bobs off them, stuffs been ok but price does not include the dreaded VAT or p&p and then VAT on the p&p.
used to trade under another name (which I can't recall) and then sons I think, Something along the Arthur Clegg and sons (thats a stab in the dark could be way off), near Portsmouth I believe

Feked - slightly politer version of similar, -  can be heard often on "Mrs Browns boys" on tv
Title: Re: piston confusion, which kind?
Post by: Greybeard on 02.08. 2015 13:00
I bought bits from Feked online, including my exhaust system. No problems.
Title: Re: piston confusion, which kind?
Post by: KeithJ on 04.08. 2015 20:12
OK guys,

 It sounds like it does not matter what kind I get, JP, GMP, Wassel- they are all about the same I guess.

 I think I will just buy a set of OMEGAs' (Taiwan I believe), because I can get them over here.

 I thought there was a time when you could buy Wiseco for A10, but I see nothing on there site. Thats too bad, because that

 is quality stuff. *sad2*

I about to fit some Wiseco pistons.  On the box it says
7949MO7000
Vic Eastwood A10 2vp domed,
Clear: 0.0040 (0.102mm)
2756xc  cw19  S746
092210/0/aa/6839

They are only slightly domed, I'd guess about 7.25 ish

ATB
Title: Re: piston confusion, which kind?
Post by: bsa-bill on 04.08. 2015 20:34
Think my Flash has 7.25 and they are I believe flat, so possible yours are a bit more.

Quote
Vic Eastwood A10 2vp domed

now there's a name from the scrambling era - same fella???? or sons maybe
Title: Re: piston confusion, which kind?
Post by: KeithJ on 04.08. 2015 20:55
Only one problem.  As they are symetrical with equal cutouts for the valves, not sure which way to fit them!  Any suggestions how I can find out?  Does it matter?
Title: Re: piston confusion, which kind?
Post by: bsa-bill on 04.08. 2015 21:46
Quote
As they are symmetrical

means they are the same so does not matter, asymmetrical = different one side to the other
Title: Re: piston confusion, which kind?
Post by: KeithJ on 04.08. 2015 21:53
Whilst they look symetrical to me, it may be I have missed an orientation feature, oilway or marking.  I guess then they would not be symetrical?
Title: Re: piston confusion, which kind?
Post by: Rocket Racer on 04.08. 2015 21:54
My recollection is that the wiseco's are 9:1.
If they have a dome that would be the case. The 7.25's are flat tops.
The 8.25's have a cone type shape to a slightly raised raised flat top.(sometimes also described as 8.5:1)
The old school 9:1's have a soft curved dome.
The 10.5 and 14:1 are clearly high comp with clearly high tops. But all the more normal ratio pistons are not that dissimilar in dome, being none to bugger all.
Title: Re: piston confusion, which kind?
Post by: bsa-bill on 04.08. 2015 22:02
would think if the were asymmetrical they would have a very clear marking to indicate which way, don't know that you could get any other for an A10 but me having only bought three sets in my life means I'm no expert *smiley4*
Title: Re: piston confusion, which kind?
Post by: Rocket Racer on 04.08. 2015 22:19
If they are not slotted (early golden flash), do not have differing valve cutaways, or an arrow indicating fitting direction on the dome I would say they can be fitted either way around.
Title: Re: piston confusion, which kind?
Post by: KeithJ on 04.08. 2015 22:24
Slotted?
Title: Re: piston confusion, which kind?
Post by: Rocket Racer on 04.08. 2015 22:59
early genuine pistons had a diagonal slot on one side of the skirt to allow for piston expansion without seizure. It allowed for tighter piston clearances. You wont find a modern repro piston with those. I cannot remember off the cuff if that slot fitted forwards or backwards, none of mine are slotted, but they are referred to in the books.
Title: Re: piston confusion, which kind?
Post by: muskrat on 05.08. 2015 12:13
Those split skirt pistons were the first set I put in the plunger 30 odd years ago. They lasted well. Only a thou and a half clearance.
Cheers
http://www.ebay.com/itm/BSA-A7-STD-ORIGINAL-PISTON-67-465-SPLIT-SKIRT-TYPE-27-/390840880602
Title: Re: piston confusion, which kind?
Post by: RichardL on 05.08. 2015 13:00
Oh boy! One piston.
Title: Re: piston confusion, which kind?
Post by: cyclobutch on 06.08. 2015 12:33
Found mine had one split type and one not when I first pulled it down.