Britbike forum

Classic British Spares Klempf British PartsBaxter Cycle BritBike Sponsor SteadfastCyclesSRM Engineering Lucas Classic Motorcycle Industrial tec supply Hepolite Pistons The Bonneville ShopLowbrow Customs

Upgrade your membership to: Premium Membership | Gold Membership | Life Membership | Vendor Membership | Site Sponsor Membership
Member Spotlight
MikeG
MikeG
New Hampshier USA
Posts: 3,272
Joined: August 2001
ShoutChat
Comment Guidelines: Do post respectful and insightful comments. Don't flame, hate, spam.
Top Posters(30 Days)
quinten 91
Rohan 65
Top Likes Received (30 Days)
quinten 13
Newest Members
makrph, vanGinneke, Gearhard, yornocT120R, robert wilby
11,840 Registered Users
Who's Online Now
4 members (Gordon Gray, Doug P, Tridentman, Gary Caines), 28 guests, and 85 robots.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Joined: Dec 2020
Posts: 13
A
Britbike forum member
OP Offline
Britbike forum member
A
Joined: Dec 2020
Posts: 13
Hi all,

I recently acquired what I thought was a 71 Lightning, and am trying (unsuccessfully) to strip the engine down. After being left outside with no spark plugs in, the pistons are well and truly seized in the barrels...

After trying to unseize for a while (a week now - lots of heat treatment, gentle but persuasive hammering, penetrating lubricant's, and even a dose of Phosphoric acid...) I am thinking maybe I cut my losses,,,

I should just strip down what I can, get another used set of barrels, and then re-sleeve or re-bore that one with new matching pistons...

According to my parts book the barrels are part # 71-1464. When I look at the actual seized barrels, they appear to be Part # 71-1033.

The engine VIN on the case is XE 02985 A65L, which I think would be a December 1971.

My question is - what do I look for? The Part # in the book, the Part # on the bike, or will any barrels from an A65 fit??? Thanks Adrian

BSA on eBay
Joined: May 2013
Posts: 8,194
Likes: 182
A
Britbike forum member
Offline
Britbike forum member
A
Joined: May 2013
Posts: 8,194
Likes: 182
With anything cast, look for the part number (casting number) from the bike.


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (now rebuilt)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

1 member likes this: Adrian C W
Joined: Dec 2002
Posts: 719
Likes: 14
M
Britbike forum member
Offline
Britbike forum member
M
Joined: Dec 2002
Posts: 719
Likes: 14
The part number and the number cast into the part are not often the same. The difference between the barrels off one year and the other may only be in machining, which would generate a new part number but keep the same casting.

Here is some good info: https://www.britbike.com/forums/ubbthreads.php?ubb=showflat&Number=719649

Last edited by MarcB; 07/27/21 7:00 pm.
1 member likes this: Adrian C W
Joined: Sep 2004
Posts: 1,677
Likes: 151
Britbike forum member
Offline
Britbike forum member
Joined: Sep 2004
Posts: 1,677
Likes: 151
Quote
a week now - lots of heat treatment, gentle but persuasive hammering, penetrating lubricant's, and even a dose of Phosphoric acid

In terms of freeing seized pistons, week is not that long to wait, I would keep cycling the heat penetrating oil etc. for a while longer, eventually something will give.

If it came to the worst, don't forget that pistons are easy and cheap to come by whilst barrels are not, so it may be easier to sacrifice the pistons by drilling some holes around the edge of the crown which should relieve the pressure and help free them.


1968 A65 Firebird
1967 B44 Shooting Star
1972 Norton Commando
1 member likes this: Adrian C W
Joined: Feb 2014
Posts: 906
Likes: 138
C
Britbike forum member
Offline
Britbike forum member
C
Joined: Feb 2014
Posts: 906
Likes: 138
Hi Adrian,
If the pistons are partway down the cylinder I would unbolt the cylinder from the cases, split the cases and undo the big end bearings
Now that the cylinder is off the engine it is a lot easier to work on and apply pressure to the pistons
This way it is also easier to get the cylinder mounted in a mill or large pillar drill to attack the pistons
Be very careful to support the cylinder properly if trying to push the pistons out !! If there is rust /crap in the bores below the rings when the piston is pushed down it can split the cylinder below the base flange

John

1 member likes this: Adrian C W
Joined: Aug 2001
Posts: 7,309
Likes: 98
Britbike forum member
Online Content
Britbike forum member
Joined: Aug 2001
Posts: 7,309
Likes: 98
Originally Posted by Adrian C W
I am thinking maybe I cut my losses
Adrian


No man,

Suck out whatever liquid is in the cylinders and refill with kerosene and expect to let it sit for at least a few weeks or maybe a little more. That doesn't mean you can't try and nudge it along periodically. My first ever BSA was freed that way as well as my 1974 Honda CB750.

When trying to break it loose, you can try to nudge it using the kick start, you can put it in gear and try and rock it loose by turning the rear wheel (chain must be installed) or you can remove the primary cover and put a breaker bar on the crankshaft nut (most preferred method for maximum torque).


Jon W.


1957 6T Thunderbird 650
1968 T100R Daytona 500
1971 TR6R Tiger 650
1970 BSA A65F 650
1955 Tiger 100 - Project
1971 BSA A65 650 - Project
1972 Norton Commando 750 "Combat"


"Every time I listen to AC/DC, so do my neighbors"

1 member likes this: Adrian C W
Joined: Dec 2020
Posts: 13
A
Britbike forum member
OP Offline
Britbike forum member
A
Joined: Dec 2020
Posts: 13
Thank Jon,

I am letting it soak again... I did apply a rust remover (containing phosphoric acid) and it cleaned up the crown and some of the sleeve on the barrel.

I am slowly learning to just be patient with it.. And hope for the best :-)

Cheers, Adrian

Joined: Dec 2020
Posts: 13
A
Britbike forum member
OP Offline
Britbike forum member
A
Joined: Dec 2020
Posts: 13
Originally Posted by gunner
Quote
a week now - lots of heat treatment, gentle but persuasive hammering, penetrating lubricant's, and even a dose of Phosphoric acid

In terms of freeing seized pistons, week is not that long to wait, I would keep cycling the heat penetrating oil etc. for a while longer, eventually something will give.

If it came to the worst, don't forget that pistons are easy and cheap to come by whilst barrels are not, so it may be easier to sacrifice the pistons by drilling some holes around the edge of the crown which should relieve the pressure and help free them.


Hi Gunner, and thanks! I am continuing with soaking with penetrating fluid (not WD-40), as well as applying heat, and applying some downward force (a big mallet, via a piece of wood)...

As to the pistons - they were always going to be sacrificed, and I had not thought of drilling into them. That might be the penultimate thing I try...

Cheers, Adrian

Joined: Dec 2020
Posts: 13
A
Britbike forum member
OP Offline
Britbike forum member
A
Joined: Dec 2020
Posts: 13
Originally Posted by Jon W. Whitley
Originally Posted by Adrian C W
I am thinking maybe I cut my losses
Adrian


When trying to break it loose, you can try to nudge it using the kick start, you can put it in gear and try and rock it loose by turning the rear wheel (chain must be installed) or you can remove the primary cover and put a breaker bar on the crankshaft nut (most preferred method for maximum torque).



Jon, FWIW - The engine is out of the frame and on a workbench. I forgot to mention that I have taken the Primary Cover off, and have applied some force with a breaker bar to the Crankshaft nut. Not helping yet - but it's soaking again - I might leave it for a a week or 2...


I really appreciate your suggestions though - obviously great minds think alike... :-)

Cheers, Adrian

Joined: Dec 2020
Posts: 13
A
Britbike forum member
OP Offline
Britbike forum member
A
Joined: Dec 2020
Posts: 13
Originally Posted by chaterlea25
Hi Adrian,
If the pistons are partway down the cylinder I would unbolt the cylinder from the cases, split the cases and undo the big end bearings
Now that the cylinder is off the engine it is a lot easier to work on and apply pressure to the pistons
This way it is also easier to get the cylinder mounted in a mill or large pillar drill to attack the pistons
Be very careful to support the cylinder properly if trying to push the pistons out !! If there is rust /crap in the bores below the rings when the piston is pushed down it can split the cylinder below the base flange

John

Hi John, and thank for the suggestions. The pistons are indeed partway down the cases, and while I am leaving the pistons to soak for a while - I also plan to do what you suggest.

Instead of a "top-down" approach I will start from the "bottom-up", and remove the stator and clutch so I can split the cases...The kick start mechanism also if needed, so I can get the to the crank and undo the big ends.

After that - I think I will be very careful of the Cylinders, the fins and maybe the sleeves...

Cheers, Adrian

Joined: Feb 2019
Posts: 649
Likes: 236
S
Britbike forum member
Offline
Britbike forum member
S
Joined: Feb 2019
Posts: 649
Likes: 236
Originally Posted by Adrian C W
.... I will start from the "bottom-up".....
One little word of warning.
There is a nut inside the crankcases that has to be undone to split the cases. It may be hard to get to with an end wrench if the cylinder is in the way and the head sometimes hasn't enough side clearance to use a socket on it.

1 member likes this: NickL
Joined: Sep 2004
Posts: 1,677
Likes: 151
Britbike forum member
Offline
Britbike forum member
Joined: Sep 2004
Posts: 1,677
Likes: 151
Might be worth trying some of the homemade penetrating fluids, a mix of 50/50 acetone & ATF apparently works well as does brake fluid.


1968 A65 Firebird
1967 B44 Shooting Star
1972 Norton Commando
Joined: Dec 2020
Posts: 13
A
Britbike forum member
OP Offline
Britbike forum member
A
Joined: Dec 2020
Posts: 13
Thanks Stuart - Can you elaborate on the specific nut on the crankcase?

I've been looking at the Parts List and see 3 crankcase bolts, and a couple of studs...

I am at the point where I am just about to split the cases, after removing the Stator, Clutch and Gearbox...

Many thanks!! Adrian

Joined: Dec 2020
Posts: 13
A
Britbike forum member
OP Offline
Britbike forum member
A
Joined: Dec 2020
Posts: 13
Thanks Gunnar, I will try that too

Cheers, Adrian

Joined: Dec 2020
Posts: 13
A
Britbike forum member
OP Offline
Britbike forum member
A
Joined: Dec 2020
Posts: 13
Originally Posted by Stuart Kirk
Originally Posted by Adrian C W
.... I will start from the "bottom-up".....
One little word of warning.
There is a nut inside the crankcases that has to be undone to split the cases. It may be hard to get to with an end wrench if the cylinder is in the way and the head sometimes hasn't enough side clearance to use a socket on it.


Hi Stuart - I'm hoping this diagram in the link below (courtesy of Draganfly) might make it easier to share the nut I should look for... I see bolts at # 6 (Quantity 2), 16 (Quantity 2) and 17. Studs at #11 and #26 (qty 3 of those...).

Is it the Locknut & washer at #7 and #8? That looks almost impossible to get to, unless I can drill out the stud (#11) from the gearbox side...

Crankcase Illustration


Many thanks, Adrian

Joined: Dec 2002
Posts: 719
Likes: 14
M
Britbike forum member
Offline
Britbike forum member
M
Joined: Dec 2002
Posts: 719
Likes: 14
Originally Posted by Adrian C W
Thanks Stuart - Can you elaborate on the specific nut on the crankcase?
Stuart is referring to the single nut inside the crankcase, underneath the cylinder barrels. Normally, you'd have the barrels removed and this nut would be easily accessible but, in your case, it may be hard to get to.

In the 1971 parts book, this is illustrated as #7 on Plate 4

Joined: Sep 2013
Posts: 3,338
Likes: 142
Q
Britbike forum member
Offline
Britbike forum member
Q
Joined: Sep 2013
Posts: 3,338
Likes: 142
nut ... 7
threads onto ... stud 11
[Linked Image from draganfly.co.uk]
the stud , without the nut , can be seen here
Just above the end of engine numbers
[Linked Image from moto-amore.com]

Joined: Dec 2020
Posts: 13
A
Britbike forum member
OP Offline
Britbike forum member
A
Joined: Dec 2020
Posts: 13
Many more thanks to MarcB and quinten for their responses and ideas...

I doubt now that I will be able to split the cases as this locknut is in place... There is insufficient room to get under the cylinder barrel to undo the locknut...

I may have to revert to Plan A - continue trying to free up the pistons in the barrel/sleeves...

I would hope it's just rusty rings that are seized and keeping the piston from moving, so lots more penetrating fluid, heat, hammering, throw in some patience, and as a last resort - small drill bits in strategic places... The pistons were never going to be re-used, and a new sleeve was always an option (assuming it is possible to remove the old ones...)

Thanks all - I'll keep you posted. Adrian

Joined: Aug 2001
Posts: 5,827
Likes: 169
G
Britbike forum member
Offline
Britbike forum member
G
Joined: Aug 2001
Posts: 5,827
Likes: 169
heres a cuppla ideas, Mix ATF and Acetone 50/50, this is a very good penetrating fluid, it works in an interesting chemical way.

heres a link to a beardie chemist explaining how it works and why, ignore his secret ingredient, save that for self medication.

Repeated heat and cool cycles.
before getting medieval on the pistons, make a " strong back" which fixes to the barrel studs, this will have jacking bolts centred over the pistons,protect the piston tops with Al discs , soak in penetrating oil, heat . cool .apply pressure, eventually it will move, think weeks not days.

Last edited by gavin eisler; 08/02/21 8:44 pm.

71 Devimead, John Hill, John Holmes A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
Joined: Dec 2020
Posts: 13
A
Britbike forum member
OP Offline
Britbike forum member
A
Joined: Dec 2020
Posts: 13
Originally Posted by gavin eisler
heres a cuppla ideas, Mix ATF and Acetone 50/50, this is a very good penetrating fluid, it works in an interesting chemical way.

heres a link to a beardie chemist explaining how it works and why, ignore his secret ingredient, save that for self medication.

Repeated heat and cool cycles.
before getting medieval on the pistons, make a " strong back" which fixes to the barrel studs, this will have jacking bolts centred over the pistons,protect the piston tops with Al discs , soak in penetrating oil, heat . cool .apply pressure, eventually it will move, think weeks not days.


Thanks Gavin, I will give it a try!! Cheers, Adrian

Joined: Sep 2004
Posts: 1,677
Likes: 151
Britbike forum member
Offline
Britbike forum member
Joined: Sep 2004
Posts: 1,677
Likes: 151
Don't know of this would work, but in addition to adding the penetrating oil to the top of the pistons, you could try turning the engine upside down and filling the engine with penetrating oil via the sump.

Hopefully the penetrating oil will find its way into the barrels and pistons, thereby attacking rust etc. from the bottom. Leave for a day or so then turn the engine over and start from the top again.

When you do the heat cycling aim to get the heat on the barrels and not the pistons. If you heat the pistons they will expand into the barrels but if you heat the barrels they should expand away from the pistons. You need quite a bit of heat to get the barrels hot enough, so use a couple of blow torches with the flame played all over the fins for a good 5 mins or so. Whilst nice and hot give the pistons a good whack with a big hammer using a block of wood on top of the pistons.

Another thing to try is a freezing spray aerosol as used by plumbers to freeze pipes. You could try spraying some on the piston crowns whilst the barrels are hot, hopefully they will shrink and free up.

It;s really a question of keeping at it with a combination of penetrating oil, heat, cold & force etc. something will give eventually.


1968 A65 Firebird
1967 B44 Shooting Star
1972 Norton Commando
Joined: Dec 2020
Posts: 13
A
Britbike forum member
OP Offline
Britbike forum member
A
Joined: Dec 2020
Posts: 13
Originally Posted by gunner
Don't know of this would work, but in addition to adding the penetrating oil to the top of the pistons, you could try turning the engine upside down and filling the engine with penetrating oil via the sump.

Hopefully the penetrating oil will find its way into the barrels and pistons, thereby attacking rust etc. from the bottom. Leave for a day or so then turn the engine over and start from the top again.

When you do the heat cycling aim to get the heat on the barrels and not the pistons. If you heat the pistons they will expand into the barrels but if you heat the barrels they should expand away from the pistons. You need quite a bit of heat to get the barrels hot enough, so use a couple of blow torches with the flame played all over the fins for a good 5 mins or so. Whilst nice and hot give the pistons a good whack with a big hammer using a block of wood on top of the pistons.

Another thing to try is a freezing spray aerosol as used by plumbers to freeze pipes. You could try spraying some on the piston crowns whilst the barrels are hot, hopefully they will shrink and free up.

It's really a question of keeping at it with a combination of penetrating oil, heat, cold & force etc. something will give eventually.



Thanks Gunner!!

I had not thought of turning it over/upside down. I might give it a try by squirting penetrating fluid in (It has a small pipe/tube on the nozzle). I will have to support it somehow.... (I'll share a photo if I can do this).

I have been applying heat to the outside of the cylinder, as you mention. Also cooling down the pistons as well. The "soak" has been on for around 2 weeks now. Despite a lock of "whacking" (technical term) and with a block of wood - no movement yet.

I'm in no hurry, so I'll just keep at it. Soaking, heating, cooling, and whacking it.

Cheers, Adrian

Joined: Dec 2020
Posts: 13
A
Britbike forum member
OP Offline
Britbike forum member
A
Joined: Dec 2020
Posts: 13
Made some progress...

I managed to remove the clutch and primary drive (not fun), and after using igneous (ingenious?) method (aka burning some petrol mixed with transmission fluid soaked in a rag and set on fire...) - I managed to get the pistons to move down about 1/2 an inch...

I also removed the clutch assembly and primary chain. Although - the "Clutch Sleeve" is still attached and won't come off..

So, after all this, I can now lift the cylinders/barrels and have enough clearance to get to the nut and remove it (as shown in quenten's post above) along with the other studs and bolts holding the crank cases together...

The next step will be to remove the crankshaft, with con-rods and pistons attached along with the cylinder/barrels. Then remove the big ends, separate the crank from the rods - and have a clear line of attack to continue with each of the pistons.

Many thanks all !!


Moderated by  Allan G, Jon W. Whitley 

Link Copied to Clipboard
Job CycleBritish Cycle SupplyMorries PlaceKlempf British PartsPodtronicVintage MagazineBSA Unit SinglesBritBike SponsorBritish Tools & FastenersBritBike SponsorBritBike Sponsor






© 1996-2021 britbike.com
Powered by UBB.threads™ PHP Forum Software 7.7.5