Q: Correct 1971 A65L Barrel Part #

[adriancw]

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

[ChrisG]

The part no. you see is correct. It is most likely the casting no. even though the numbers may appear stamped on rather than cast in. The 1970 onward barrels are different to earlier ones so if you do decide to replace them be sure to get a set with that part no.

I would try and persevere with freeing up the existing first.

Chris

[ChrisG]

Hi Adrian
I've also sent you a PM re the above
Chris

[Mike Farmer]

 

Hi
On your strip down. you don't say where you are in the "sequence" If, as I suspect your barrels are still on the casings you are unlikely to free the pistons.

I would try the following. Undo all the studs holding the barrel in place and then try to raise the barrel above the level of the studs. With the barrel raised you should be able to split the casings. Obviously you need to strip all the rest of the parts from both side, clutch and primary drive and all the timing side gears.

Now what you should have is the crank and pistons co-joined to the barrels Undo the B/E bearings and separate from crankshaft. Now the same applied persuations should move the pistons.

Accepting the fact that in its present state your engine aint a lot of use, if you can't raise the barrels above the level of the studs you can consider cutting them. But leave as much length as possible in the casings for obvious reasons.

I know this works. but its a time consuming and frustrating way to have to do it.

Mike

[Mike Farmer]

 

I should have added that its seriously difficult to get to the centre nut between the cases and as a last resort you may have to tap it round gently with a chisel. I guess that in some cases unless you can lift the barrel high enough it may not be possible.

Mike

[adriancw]

Hi
On your strip down. you don't say where you are in the "sequence" If, as I suspect your barrels are still on the casings you are unlikely to free the pistons.

I would try the following. Undo all the studs holding the barrel in place and then try to raise the barrel above the level of the studs. With the barrel raised you should be able to split the casings. Obviously you need to strip all the rest of the parts from both side, clutch and primary drive and all the timing side gears.

Now what you should have is the crank and pistons co-joined to the barrels Undo the B/E bearings and separate from crankshaft. Now the same applied persuations should move the pistons.

Accepting the fact that in its present state your engine aint a lot of use, if you can't raise the barrels above the level of the studs you can consider cutting them. But leave as much length as possible in the casings for obvious reasons.

I know this works. but its a time consuming and frustrating way to have to do it.

Mike

Hi Mike, and thanks for your suggestions above.  As an update - the barrels are free from the casings, and when I rotated the crank by hand they can be raised.  But as the pistons are seized in some sort of mid-stroke, I cannot do a full 360 degree rotation of the crank, and the cylinder block raises about 3/4".

I kept it in that position, and added some rust remover (Loctite, aka Jenolite in the UK, basically Phosphoric Acid, it's purple in colour) and  also penetrating fluid (not WD-40).  It's been about 2 weeks, I have used a block of wood and heavy mallet to try and free them up - and still no sign of movement, so...

I came to the same conclusion that you suggest.  Instead of the top-down disassembly I am trying a bottom-up...  After removing the Primary cover, I have removed the Stator and rotor. 

Next steps:  I'm waiting on a Clutch removal tool (arriving today) and will then look at the gearbox removal.  After that I hope to split the cases, take out the crankshaft with con rods, pistons and cylinder block... After that, undo the big end shells, and put the crank to one side.

This should allow me to get the pistons/con-rods and try to unseize them again...  One technique I saw was to put a petrol/gasoline mix with transmission fluid in the barrels, and ignite it.  Then use a very big hammer again on the piston crown...

I have also tried uploading some photo's that might make it clearer..

Thanks again!!   Adrian

[adriancw]

In case this is of interest to anybody - I'm adding a few photo's...  So far (2 weeks now) I have left the pistons soaking with a penetrating fluid, as well as heating up the cylinders, and applying some rust removal... (the purple liquid - basically an over the counter diluted Phosphoric Acid...)

Cheers,  Adrian

[chaz]

I have heard Coke works on unseizing pistons,never tried it, Diesel is another that I have tried along with a block f wood and a bolster.
one other option is to get an impact gun on the crank nut low torque first and the judderig might help break the seal/rust, make sure you do it up not undo.

[DAVE BRADY]

Hi,

Although the pistons will have corroded and be stuck to the cylinder they are probably not as stuck as the rings as they are ferrous like the bore.  As the pistons are scrap it may be possible to break up the rings with something thin that could be pushed down the side of the piston.  I would think that a spoon altered to the curve of the bore could be thin enough to get to the rings.  Then and option to either try and knock it down to break the rings or use it as a scraper to get some of the rust out.  The rust remover will then have fresh rust to attack. 

Dave.

[Bess]

Hi,
    Those barrels look beyond a rebore possibly beyond relining and the pistons unusable.

I would drill a series of holes in the piston, missing the con rods, as close to the bore as possible. Keep drilling and knocking until the piston circumference collapses.


Best wishes...

[Mike Farmer]

 

Thanks for the pics. She is surely poorly.

You could make a puller/pusher at least about 10mm thick and 40 wide Drill and tap/thread in two places. and bolt across the head, with the use of a couple of big bolts 20mm or so, You may be able to pull the barrels upward over the pistons.

The trouble with hammering is that you will always have the pressure of the "other"piston. Get an oxyacetylene/ torch and melt them.Or MAPS gas

Mike

[Mike Farmer]

 

Hiya

Where are you with this problem now.

Mike

[Pete A10]

You said you were using Phosphoric acid for rust removal. While good for converting surface rust I am not sure that it penetrates very well. I assume you have tried a good quality industrial penetrating oil?
Can you hang the barrels on something so that the whole weight of the engine and bike is bearing on the rusted areas. This will give a constant pull on the pistons while you hammer (large hammer, gentle hits) on the pistons

[adriancw]

I have heard Coke works on unseizing pistons,never tried it, Diesel is another that I have tried along with a block f wood and a bolster.
one other option is to get an impact gun on the crank nut low torque first and the judderig might help break the seal/rust, make sure you do it up not undo.

All great ideas, thanks Chaz!

I have read somewhere that the reason Coke works (at cleaning some rust) is because phosphoric acid is one of the ingredients...

The impact gun intrigues me, and I've been looking for a reason to get one!!

Cheers,  Adrian

[adriancw]

Hi,

Although the pistons will have corroded and be stuck to the cylinder they are probably not as stuck as the rings as they are ferrous like the bore.  As the pistons are scrap it may be possible to break up the rings with something thin that could be pushed down the side of the piston.  I would think that a spoon altered to the curve of the bore could be thin enough to get to the rings.  Then and option to either try and knock it down to break the rings or use it as a scraper to get some of the rust out.  The rust remover will then have fresh rust to attack. 

Dave.

Hi Dave,

I like the idea of making something that could get to the rings and attack the rust on them.  Might try something other than a spoon.  Either way - the piston, sleeve and whatever I use will all be un-usable afterwards.

I'll post any attempts here if I try this!!

Cheers,  Adrian