BSA A65 top end strip and findings discussed.

[@howlermonkey781]

I have just purchased 72 model A65 lightning im waiting for it to be delivered, my first British bike ever. Ive only ridden and worked on Japanese 2 strokes and that was nearly 40 years ago, these videos are valuable to me, i know ive got alot to learn, i love working on engines as much as love riding them, a big shout out to Paul thanks mate and to all blokes who give valuable comments. Cheers🍻

[@deanpinto6328]

This is why we need people like you who have the proper understanding of these machines

[@artiexr222]

Better than anything(rubbish)they put on the telly Paul just love your detective work and look forward to every instalment.

[@nigeljohnson505]

Good work Paul. Using your experience to discount each possible failure and not going at it like a bull at a gate. Slow and steady wins the day.

[@andrewgent5887]

Once again the shadow of doubt has been cast. I think we’re all sensing you won’t be happy until you’ve had a proper look round inside!

[@paulhewitt1488]

At least there is one saving grace , that being the owner is lucky enough to have entrusted you with his pride and joy. Congratulations on your persistence or should I say knowledge , craftsmanship and passion. It’s a crying shame that these lovely old bikes are seen as a cash cow rather than examples of an era that’s sadly disappeared. Well done Paul and cheers to all the positive comments made by all. 👍👍

[@guitarzanbikes1862]

Just to add Paul i have seen damage like that once before when i did an early motor on which the drive side ball bearing collapsed at hi revs, i revkon the crank hit the bridge piece, ripped the stud out as it cracked the barrel. That was 40 odd years ago and we repaired it. I reckon same thing has happened to this engine sometime in the past. My bet is what ever is in the drive side now (ball or roller) will be turning in the housing to. This is gonna be expensive for the owner.

[@steveosshenanigans]

Interesting series of videos on this A65 ….loving your work Paul

[@2Truth2you]

It needs a replacement left side crankcase or welded at least. I'd go stock on pistons, cams and compression ratio. Beautiful classic bikes like this deserve to be restored to as reliable as they were designed to be.

[@iandeumayne-jones1557]

Great bit of diagnosis Paul. Obviously built by someone's feet at the dead of night. I really feel for the owner who was obviously seen off. Glad he has you to rectify.

[@colintownsend5024]

Having owned an A65 back in the 70s. I am now hooked on the outcome of this investigation. Keep the videos coming.

[@cp4512]

Another really interesting bike. Amazing what you find after a few decades of ‘best intention’ or in some cases ‘cowboy’ mechanic tinkerings.

[@EdOfTheNorth]

To me, those engine covers look in very good condition. Like they have been replaced and polished. When one buys an old scrapper that has been in an accident, so often the engine covers need replacement. So considering the cracks in the main engine case, cracked cylinder and stripped cylinder stud as well as the tweaked valve adjuster hitting the valve cover, I'd suspect that engine took a very hard hit to the left front corner that nearly broke the entire engine in half. Personally, I think it would be cheaper to just buy a good bare bones replacement engine and use the good parts of this one to build it out to completion. Looking at the damage I would not trust that crank because if all that damage is so visibly apparent in a line originating in the left front corner, then the crank absorbed the hit as well and is bent a couple of thousands of an inch and that is the most probable origin of the vibration. I think that bike is a low mileage engine curb strike bike from a scrap yard just put together with parts from many bikes to look nice.

[@a65builder67]

hi Paul them pistons are 9,1 and the the piston in your hand is 7.1 there is 10,1 pistons which are for the spitfire, if you do pull the engine down the cam should be stamped with the number 68/437 and is standard for all a65 from 66 to the and of production hope that helps in anyway, and what a good job you took the top end off and to find that WOW. and like you said it some times pays to look that little bit deeper you just don't know what you might fine. you should start righting a book about what you've found in engine of other peoples handy work. best seller

[@davidhawkins120]

Very interesting case this A65 Paul, sums up why I bought a new Royal Enfield🙂

[@geraldscott4302]

That's a shame. If that were my bike, after seeing those cracks, I'd definitely just go ahead and tear it all down and start over again. Whoever worked on it last either didn't know what they were doing or didn't care. These old bikes have usually been apart many times and you never know what you might find. I'd still rather have one of these than a new computer bike.

[@williamnethercott4364]

Wow! I wasn't expecting those cracks. Now you've pointed it out, the one at the bottom of the barrel is quite obvious. Anyone can make mistakes but come on! Whoever put that engine together belongs in the Wild West.

[@marcpinion]

So sad for the owner. What a nice looking bike that they got in good faith. As you say who puts a bike together like that.

[@richardsouthey430]

Great work, i just bought a xs650 flatracker from a company. he rebuilds the engines with reconditioned parts , i have only done 300 miles and it smokes like anything, asked for his help but insisted that the engine was built to top spec, i striped it down myself to find that it has not even been rebored and a rusty crank ,its all been vapoured blasted and looks pretty on the outside, another monster, making money .he has built around 30 of these bikes. Richard

[@paulhenshaw4514]

That is terrible!

[@peter7624]

Good idea, about the beer. Always helps following a stripdown.

[@davefrench3608]

Oh dear, when you start digging it’s amazing what you find.

[@andrewslattery403]

Don't fret, Paul. You'll wake up soon and the nightmare will be over. Another great video - keep them coming.

[@anthonydexter262]

What a shame, sometimes all that glitters is not gold......

[@garyroth2764]

What I can see of those cam lobes doesn't thrill me either. After building several of these engines for customers back in the day, this one looks like it's time for a complete rebuild. At their best they were a clanky sort even after blueprinting the entire reassembly. I often saw the cylinder studs pulled out mostly from over torquing to stop oil leaks especially when fitted with high compression pistons. I would trade 2 of these engines for one complete unit from a Super Rocket, probably the best of the vertical twins in my opinion. At any rate, nostalgia really kicks in when I see one of these old Beezers, simple, durable, pretty as a Spring morning, and the chrome didn't rust away overnight.

[@noeldoran8884]

Right choice Paul to pull down at least the owner will have a clear picture of the problems, he would have a good bike at the end mate. Cheers Noel

[@charleskyler1928]

I would love to grab a flight across the pond sit down and have a pint with you. I bought a 76-ish royal Enfield bullet. I’m a gentleman in New York. From the pictures he included, I could tell the bike and the hack were made up from badged together pieces, and knowing that, I made the appropriate offer. He had imported the bike from India, and it was sold to him as a “completely restored“ unit. As you pointed out, completely restored means fresh coat of paint. Many of the major phones haven’t even been replaced. I believe it has a new top in the piston rings, new brakes, new electronic components, but the frame and other body components were all coded with a fresh coat of lipstick sent on their way. The front fender had peeling paint because they had painted over a chrome. Many parts of the frame had pink flaking off of the rust that had simply been painted over. The side car fender tips at a very strange angle because when they were welding it back together, they reversed the supports from front to back, so I need to cut those off switch them back around and reattach them. Like I said, I knew what I was getting and paid accordingly. You just have to scratch your head and ask why anyone would bother doing such a bad job.

[@windmilljohn]

I recently bought a rebuilt CD175. Spent tons in the past on rebuilding bikes, this time I thought someone else can do all that, I’ll just continue with maintenance, repairs etc. Anyhoo, there is a noise from the top end. I was made aware of it, but, the slight oil mist on the left side of engine…. I snugged up the 6mm bolts on the left side to discover three of them just spin. I’m going to enjoy for the mo and then sort those out later in the year. But the PO must have known about these….

[@donparker1823]

I desperately wanted one of these as a teen. Now that I could afford one, I know I'm no where nearly a good enough wrench turner to keep one running like it was designed to do. My KTM 790 800cc parallel twin will have to do. The 275 degree crank has a nice sound but I sure like the sound of those old 360 degree cranks.

[@norsehall309]

G'day from Australia, Paul l wouldn't be surprised if it's not one of the conrod bearing top or bottom are on the way out or bad fit, the amount of vibration your talking about would be a bad problem on any Motorbike, cheers mate, Neil 🤠.

[@Blahshog]

Hell of a lot of piston slap there! Loose head stud, cracks in the crankcase bridge, and a cracked barrel, gotta wonder who's been doing the spannering!

[@mrp410]

Nice work Paul. Been great eeing you do the Sherlock Holmes work on this old girl. Good luck with the next phase, repair and so on. That crack on that cross beam looks very dodgy so will be ingersting how you tackle that one. Cheers.

[@johnmarsh2078]

I wouldn't personally have the crankcase brace welded up. I would go for a matched pair of second hand cases. Blame our American cousins for domed pistons and high compressions. Most British parralel twins in the 1960s had compression ratios of 7:1 or thereabouts, raising in the 1960s to 8:1 ish but the 70s saw ratios of 9:1 and 10.5:1 to keep the power race going. The Norton Commando Interstate with the "Combat" engine always blew oil seals especially the camshaft end seal for the points because of the blow-past and crankcase pressure. The bottom end was short life as well due to the high loads on the con-rods and big ends. Low comp pistons may not be sexy but they smooth out your engine and lengthen its life. The A65 , particularly in T-Bolt tune is plenty fast and smooth with a single carb. The plain timing side mains bush is long lasting, as long as it is original spec and the oil is kept religiously clean and changed often.

[@leegraves101]

And with the gas that they sell today low comp makes more sense

[@johnmarsh2078]

@@leegraves101 In the UK in the 1950s we had to put up with "Pool" petrol which was 80 odd octane and would go bang without a spark while the Yanks had 101 super plus which would not induce pre-ignition with massive comp ratios so up went comp ratios and down went engine life as the crankcase and big end bearings got super-stressed.

[@shingerz]

Good video I know how this owner feels buying this bike 👍

[@4418CARLOU]

Shocking news for the owner.

[@deltabluesdavidraye]

Thanks Paul.I learned something

[@learningturningmetal]

Oh dear. It looks like that engine has a lot of history. Bodge job springs to mind 😢

[@hermangibbs8163]

Thanks Paul.

[@bobss3704]

At first I thought a thrown rod broke the case but I reckon the drive side main bearing collapsed causing the rod to hit the case, had a mates Royal Star do that many years ago!

[@progvinyl9021]

Interresting to se what you will find👍

[@stuartburton1167]

I feel sorry for the owners wallet😢

[@jackwilliams3343]

Money can be printed .its the work that has value lad

[@neilmcintosh1200]

More material for trading standards, if the trail to the culprits is not too well covered up. The usual common theme as you said. Pretty paint and chrome, covering all kinds of grim misdeeds. Criminal.

[@jjrider6758]

That bridge piece inside the crankcases looks fit to snap at any time, and man it would make a REAL mess if it did !..

[@leewarry8641]

The early A65 had the flat top pistons & a small valve head with a smooth rocker cover & the later ones with a finned cover had high top pistons & larger valves .that’s why the smooth rocker cover won’t fit the latter heads . Those cracks would be caused by a snapped con rod .

[@ChasDean-d8y]

Hi Paul. I've gone down the piston road with my A50, which is supposed to run 9:1 units. Their profile more or less matches the fitted pistons in your customer's bike. I found it tough to find 9:1 pistons for my bike, and for one reason or another was forced to fit pistons whose crowns match your low compression ones. I very carefully measured the new compression ratio, which turned out to be 7.9:1. Considering that my A50 head has suffered at the hands of enthusiastic head planers over the years, I figure that those pistons are actually 7.5:1 as fitted to the very early models. I think the same might apply to yours. The part number on the box was genuine BSA Covmo. As an aside, my bike doesn't seem to have suffered unduly from the low comp pistons. I ride the bike often - at least once a week when I can, and it's still very usable, if a trifle breathless (like most A50s, I guess!).

[@markotuomas672]

This is why I buy my bikes as projects - running and in pieces. I will go it through, put it back together and if something is wrong, the one to blame is looking from the mirror.

[@alexdieudonne1924]

Agree with all the above complete strip down to the measure big ends be a shame to put it back and still knocks.

[@notwocdivad]

Don't know if you noticed Paul (bet you did) but noticed scrape marks on the rear of the left hand con rod as though it was touching the cross brace at some point? After seen these bits of amazing(ly bad) restoration if she was mine I think I would bite the proverbial bullet and go for a full strip and a proper RE BUILD for my own peace of mind!!

[@hermangibbs8163]

I hope the owner will get it fixed,then give it loving care.

[@derekgee8504]

Great work Paul thanks for posting

[@mikego18753]

Enjoyable vid mate. Thumbs up,nuff said lol.

[@stevewilliams5428]

I was right about the HC pistons!! Bet the head has been skimmed as well.

[@florabee9283]

Those cracks made me a little bit queasy to be honest. Brings all else about the monster-built engine into question!

[@GordonGoblin-f3r]

I have done quite a few A65s over the years. The most common fault is a worn timing side bush, which after a while knocks the big end bearings out. The quickest and easiest way to detect crank related problems, is to remove the sump plate, and check for metallic particles from the timing side bush, and big end bearings. I would guess this motor has at some stage snapped a rod, which has damaged the cases, and destroyed the cylinder base flange? It's likely the timing side bush is badly worn, and there may well be other damage on the crankcase half which is not visible? Needs to be completely stripped to see if weld repairs are possible, and everything very carefully checked, and anything iffy replaced. I would guess it might be pretty costly to do, if the rest of it is a bad as the top end and the damaged case?

[@edwardellery3032]

Had some shiny bikes and had many problems,now I go for the real barn finds,cheaper can put your mark on it and restore to your own satisfaction,at least your money is not going skyward after your expensive buy.

[@aliasdeputydog]

Paul Henshaw Those con-rods look reasonably new, do you think that one of the original rods broke and cracked that `bridge` between the two halves of the casing?. Back in the early 60`s I had an A10 Road Rocket that did exactly that and a bit more damage to boot, I ended up putting in a re-con engine as the cost of repairs was too high..

[@441rider]

Sad state if that bridge lets loose from vibes could be bad. New barrel search maybe in order.

[@sicks6six]

right from the start i thought top end problem, piston related, seems the barrel wasn't able to cope with the piston slap and it destroyed itself, specialised welding, helicoils etc etc, big job now, and the big end journals are possibly warped and misshaped as well,

[@whalesong999]

Ouch. Time for the bore gauges and calipers along with whatever else pops up. So disappointing. No telling what's beneath those crankcase bridge cracks. Whew.

[@tmackinator]

To do other than a complete strip down is false economy. The crack in the inner web support looks on video to go into the threads where the barrel stud pulled out possibly causing the stripping?

[@Anotherflyonmyvisor]

Great Work - Thank you for posting regular updates

[@ClaudeInsecte]

God I wouldn't want to buy a bike off whoever 'restored' this one. Hope it's sortable for the owner.

[@dinomalta712]

Sounds just like the Maltese car and bike owners, all polish and chrome, no oil in the motor, more fuel in the exhaust, brake pads on the metal, and when it stops "It's a good one, can't understand what happened". Cheers DINO.

[@Cobra427Veight]

Pistons have gudeon offset to make it quieter.

[@guitarzanbikes1862]

Pretty typical that Paul, having found what you have so far what chance do reckon the "monster builder" cleaned the sludge trap??? This one's gotta go all the way, total strip to what else has been "monster munched"!!!! You know it won't be just what you've found so far mate...

[@lesmontgomery6498]

All sizzle no steak. Aluminum paint is a great sealant fpr head gaskets

[@colinmartin2921]

What a mess, and there may be more to come yet.

[@jjrider6758]

My '65 Norton 650SS has always had a quite alarming, b*ll-rattling throb under acceleration for around 250 revs around 2000 revs (ish..) - Either side of this and the engine runs as smooth a silk, all the fasteners are tight, the engine is quiet, no knocks, rumbles or rattles, it doesn't smoke or use oil and it's never got any worse, the crank has been balanced, mains and big ends were all replaced recently, as well as a rebore with new pistons and rings, none of this made a blind bit of difference difference !!.. As it runs perfectly either side of 'the throb' I've now decided to grit my teeth and put up with it, clearly something is resonating but I've checked literally everything and I just can't find any problem - I'm sure that if there IS one it will rear it's ugly head sooner or later !..

[@grateberk6435]

Well done Paul. can the barrel be repaired?

[@paulhenshaw4514]

Thanks, I am not sure at present.

[@allenmckenzie2831]

Looks like the usual drive side rod has let go in the past due to a blocked sludge trap.

[@daveco1270]

Its amazing how just the smallest bit of play will cause a lot of noise when the engine is running. I had some play in my front TLS brake hub stay, where that nub on inside of the bottom fork goes into the notch on the brake hub. There was about .1 mm of play in it... and when the bike was idling, the brake hub would rattle like mad. Took me a minute to figure out what was happening but once I did, I cut two small pieces of paper and used them as shims...and that cured the problem. How can you tell they're high compression pistons? The shape of the top?

[@derekcollins1972]

Yes,the higher domed faces reach further up into the combustion chamber creating more squeeze effect hence the "high compression."

[@Cobra427Veight]

Look for shinny top lands , may need a rebore or .010" machined off the lands . Hasn't got std pistons in a .020 over bore!, you'll figure it out .

[@amelierenoncule]

Near the end of this fine offering, you mention your intentions re. 'The pub'. As a thought,a personal-interest diversion, why not allow us a walk-around with you to that magical place. A wee 'look-see' of same ?

[@paulhenshaw4514]

That would take 30 minutes at best, going up the Roman Road, my camera does 29 minutes in one go, so perhaps if I can get myself a bit fitter!

[@amelierenoncule]

@@paulhenshaw4514 Well, you see, you would NOT need to continuously tape the stroll, since it is the pub we are primarily interested in...and your demeanor after a 1/2 dozen pints. It is but a matter of prudent caution for me to know these things about one who I would be drinking with. Something I learned in No. Africa, with the French marines. i.imgur.com/Gxuzts9.png

[@mikeburton7077]

I never trust any "just rebuilt " without checking it out myself

[@francovance1]

Enjoy your pints-you deserve them!

[@markmathews6876]

check out British bikes by Brian , the A65 is probably the prettiest bike ever built imho, I gave up on them decades ago just to much grief ,but you can up grade them , 270deg end feed cranks with rollers & longer stroke, get them doing 60mph @ 3000rpm & you can end up with a trusty BSA twin,{ I had many singles & they were almost indestructible}

[@paulhenshaw4514]

360 or 180 degrees are my personal preference for cranks in parallel twins, 270 is just a v twin, with side by side cylinders to me.

[@markmathews6876]

@@paulhenshaw4514, fair enough but short of a counter balance shafts these things {especially the over square BSA ) are lets face it , not reliable, I used to do many miles here in OZ on my A65 ,moons ago , it used to go like a scolded cat but was always shaking it self to bits , one time I was two up through the Blue Mountains (300 hundred mile from home & the barrels broke in half ! never mind the mud guard / head light failures }, a big mile bike it was not , I ended up with Yamaha , a500 single , 650 twin or four doesn't matter ,it will get there & home again. but even after this I still think the A65 is the prettiest bike ever , just make the bastard work I reckon , cheers Paul .great blog

[@p--n]

Base gasket was leaking oil, so barrels would have had to come off to cure.

[@iandawson7723]

It leaves me thinking unless you know and trust someone selling an old bike like this , what is the chance of being sold a lemon , and paying thousands to find out it needs hundreds or more putting into a bodged up machine that is prettified to sell but not to last. 😢

[@gyanendrasingh4471]

@Paul what is the compression height of BSA A65 piston? Asking because i am thinking of fitting these on a Royal Enfield 350 bored to 400 cc (which means I need 75 mm dia piston)

[@paulhenshaw4514]

I don't know, sorry.

[@gyanendrasingh4471]

@paulhenshaw4514 Ok no problem Paul

[@grahamwalker5693]

if it were my bike I would do a complete engine rebuild

[@BLUESBOYBENFIELD]

Gosh

[@a65builder67]

sorry cam number 68/374

[@MrSideoiler]

Wow. Nice bit of investigative surgery. It's crazy what gets slapped together these days. No pride at all.

[@onecookieboy]

Sorry to mention this, but rocking the pistons around in the bore proves absolutely nothing and is no indicator of wear, the correct way is to measure the piston skirt (about 1/3 of the way up from the bottom) and measure the bore and then compare the clearance to factory specs. Bear in mind that an alloy piston on an air cooled engine is going to expand quite a lot and the piston should never come into contact with the cylinder wall. TBH, the pistons looked fine, but that blown head gasket would be causing some major running issues which would very likely cause bad vibration.

[@paulhenshaw4514]

I have been doing this for long enough to know those pistons rock too much in the bores.

[@onecookieboy]

@@paulhenshaw4514 And yet, somehow, the skirts looked undamaged and it seems the rings were sealing quite well, who would have thought it aye.

[@boathippy1963]

It’s an A65 cam bushes are toast as is totally normal and makes them clatter

[@paulhenshaw4514]

I have yet to see worn cam bushes in any of many A65 engines I have rebuilt.

[@eskimojulie]

Poor owner !

[@milesrogers8314]

Some these machines are real heart breakers especially when the owner has handed over thousands of pounds for them only to find they have to spend more money to get them right.

[@wdhewson]

I think she grenaded at some prior point in her life!

[@williamdouglas2393]

I was wrong it's not but ends but what a mess. Looks are only skin deep.I

[@DrRobert7898]

Show pony that shouldn’t be run

[@progvinyl9021]

Weak engines those bsa a10's

[@paulhenshaw4514]

Do you mean A65's?

[@JeremyFairbairn-mv3sz]

looks like it might have lost a rod at some point