I was going to name this B(astard) S(topped) A(gain) but I was told that I must have sinned so named the post as such.
It's often the way that when you get a bike running quite sweetly that something goes tits up. And usually it's something that the DPO (or in this case DCO dumb current owner) has done. Cutting a long story short and how I might have inadvertently restricted oil flow to the motor by double jubilee clipping the feed hose in the desperate aim to stop it weeping (and I think that I have clamped where it wasn't over the pipe and crushed the pipe - hard to tell with braided stainless covered hose) but it only went bad after I did that. The big end or at least the big end shells have turned to toast and found themselves at the bottom of the sump.
I will find out later when I strip the motor completely exactly what has failed and if the big ends are fine then new shells and back it goes - however if it is the I will be surprised but very pleased. I will also examine the rods.
But my main testiment is the the rods from thunder engineering. The motor had eventually locked itself, and I can only assume that with a 50+ year old con rod then I would have seen the day light of it by now. But from what I can tell, it is still in one piece as it has not broken through. Thus saving me the expense of a barrel, piston and crank case weld, depending on how the rods look they may get refitted or if showing any signs of heat will get given to the gods of speed. It's also testiment that revving the bike into the upper rpm is not what causes the failure but pottering about at chug chug speed ( close ratio box and tall gearing is never a good thing for "all terrain" type roads) and limiting oil pressure is. (That I think is the more likely cause and that I haven't clamped the pipe at all).
As I say, and have always said. If stripping a motor, you should fit new rods if it doesn't already have them, as we have all seen old rods showing themselves through the crankcase and of course the lesson of the day is not to let you motor suffer low oil pressure. Even if it was whilst touring the beatiful Italian location of Lago Di Vico.
With machines of the age we on Britbike cherish, certain idiosyncrasies are par for course. It will be interesting what you discover. One thing I have been told about braided oil lines is, apart from their attributes at first glance, there is no resilience to deforming influences, such as indentations from blows by road debris, and such.I think distortion by an over tightend clamp, like suspected, would be readily evident soon after it was done !
One of the things I did try with the oil lines before I fitted them was to squash them between some mole grips to see if it would reform and it did. However if it is permenantly crushed then it won't last long
How did you determine that a problem was developing or had happened? Heat and noises from the motor? Was there (by chance) an oil pressure gauge involved?
After putting a new motor together I run a strapped-on pressure gauge for a while, but once I've benchmarked the hot and cold idle and operating speed values, I take it off; just one more place for a leak. Of course, if there's a major failure I wish I'd had a relay with a big flashing light for oil pressure at 0!
I'm like super lazy today. It's like normal lazy, but I'm wearing a cape.
Motor stripped and confirmed. It was just from a dumb moment to try and cure a weep and yup I squashed the pipe big time. So obvious with the motor out but not so from underneath - I guess that's being OCD against oil leaks. Well it won't leak now.
The DS journal ran dry, TS is still silky smooth to turn. But the white metal on the DS got hot and ran between the crank cheeks and the rod. Till it got that thick it held the rod in place, the journal is more peaks than troughs and may clean up. I have been tempted to clean it up, enjoy the rally with it then get it metal sprayed when I get home back to standard and then have the crank nitrided. I will want to change that rod anyway.
Nick (yeah I don't take any offence and will return the joke) each time I've had it apart I have been correcting oversights from when the motor had been at the engineers, TS needle bearing crush each time. I had just managed to get the motor exactly as I wanted it as well and with the head porting, the right cam and carburation it was a pleasure to ride and I had no intentions of pulling it apart again for the foreseeable future. All for the sake of a pipe which wasn't the size it should have been - and I noticed yesterday that I had lengths of spare pipe in my box of tools that I could have used
I really didn't want the leak to worsen and end up the back tyre - hence the trying to cure the problem.
As for vibes, the bike ran smooth for nearly 20 miles, it spent most of its time at pottering speed because of the road conditions and at low revs it had been a bit vibbey' but when I got the revs up to cruising speed it seemed OK. It was only when I stopped to fill up with fuel that the rocker box sounded a bit louder than normal ( and I had not fitted one of the Thackery washers properly and it had trapped, causing one rocker to have free play, however the bike got louder when I tried to start it again. So I just gently cruised till it cut out. Then wouldn't kick over.
And yes I have to have a positive mental attidude. Without that I'd be wanting to hang myself, but the mechanical build was fine, just the dumb move to do what I did caused the problem.
Stay chipper, "the man that never made a mistake , never made anything", an expensive lesson to learn though, Ive never seen the point of braided fuel and oil lines, that stuff will saw through anything it touches . Melted bearings , the journal should clean up, thats why the bearings are made of soft melty stuff. You will need a thorough purging to get all the bits of white metal out. PMA all the way! I find these clips are better than jubilee clips, less circular distortion, http://www.jhmbuttco.com/acatalog/miniclip.jpg Pod
Last edited by gavin eisler; 06/21/166:50 am.
71 Devimead A65 750 56 Norbsa 68 Longstroke A65 Cagiva Raptor 650 MZ TS 250 The poster formerly known as Pod
This view of the hose is from the top, because of the worm and the over hang of the (long) jubilee clip you could not tell from underneath. But as plain as day with the engine out.
I had done 80 miles with no leaks then it started leaking past whilst being stood hence the desire to try and sort it before the pipe came off or something. The motor had done about 20 miles before any knocking was apparent, and after this I am thinking of adding a take off point for an oil pressure gauge. This problem would have been apparent on start up and would have shown instantly on a gauge. Maybe the semi synthetic helped it to last as long as it did.
Typically [censored] happens and as I'm at the international there is little chance or point of bodgeing it back together before our return. I'll take the crank into the engineering shop when I return home. I have been told that the rod should be fine but I am still tempted to replace it. I will do a full bearing change also.
Sorry to hear of your troubles. On the last photo of the crank, while it maybe a photograph error. The actual counter sinking of the breaking feed looks a little bit shallow! As I say could be the photo, but make sure there is a proper relief from the oil hole to the bearing face.
Get some hydrochloric / muriatic acid and swab the journal to remove the white metal. Once it has gone you can then assess the journal. They oft look a lot worse then they are and A65's are a lot more robust than folk lore would have you believe, Some heavy oil and a gentle hand will mod likely get you there & back and some good insurance just in case it dosn't.
I was removing shards of bearing from the bottom of the lightning sump for several years before I finally retired it . From memory I stopped using it when it would not hold oil pressure below 3000rpm running strait 50 oil.
Thanks guys. Yeah nick. This was a rookie mistake, but like you I am also a confirmed idiot (least I am now), especially when it clicked that I had enough normal pipe with me to have swapped it.
Apart from the cheek damage to the rods there is no damage and neither is there damage to the piston. It was at low revs when it just died.
The local engineering shop have said they will look at the crank. If it means another grind (.040") then I will send it for nitriding too.
John. Yes the oil holes have not been finished off, I noticed it on a drawing in the manual after I put the motor back together but it has never caused an issue. There is also no written information regarding it in the manual either (in the regrind and engine section anyway) they will be added at the rebuild.
Trevors fix is a natty idea , you may be surprised at the results. Our large hydro units wiped brgs. from time to time, after cleaning out the mess, the journals would be cleaned up where necessary, often times they were fine .Some , the turbine brgs in particular looked like ploughed fields due to dirt contamination, it used to appall me. Eventually after seeing them run for years like this I began to think of the grooves as extra brg area, these were large bearing journals though 29 " diameter. In theory the babbit metal is too soft to damage the steel journal , especially when molten, any serious marks will be from other contamination.
71 Devimead A65 750 56 Norbsa 68 Longstroke A65 Cagiva Raptor 650 MZ TS 250 The poster formerly known as Pod
That was my thoughts Gavin. Although I worry that the heat may have effected the case hardening on the crank. I will micrometer the journals when I get home, that will give me the best idea. But mean while I will enjoy the rest of the rally
We all sin. Its about who admits. My first BB rebuild in 1993 (Turnip 120) I got the oil pipes the wrong way round. Got about 5 miles out of it. Instant grank grind needed. Good thing I had only replaced the shells.
I now nitride all my cranks I put back in engines. I have a local heat treater that is not too badly priced. Flywheel off and make sure it is CLEAN. Oily film will stop gas penetration and give an uneven treatment.
I've seen arguments on the web about whether these cranks are made of the correct steel to take the case hardening effect, but it seems to work despite the nay-sayers. WM20 Trev could give us a run down on the relevant metallurgy. In fact I'm sure he has at some point in the past.
Ditch the bling!! Ray
BSA 1969 A65F BSA 1966 A65H Triumph 1968 T120 Kawasaki A1R & too many projects!
No I won't but you are welcome to do a search I did do it a few years back.
But I will do some correcting. Nitriding does increase the surface hardness but only marginally. It is not a surface treatment it is deep metal treatment which is why it takes so long. Nitriding prevents cracks from traveling through the steel making it tougher and more resistant to fracture. Carbo Nitriding adds both Carbon & Nitrogen and will increase th surface hardness of the steel. Very similar processes very different results. A nitrided surface will take machining a carbo nitrided surface wont so you have to finish grind the crank before heat treatment. And for our old iron it is a no brainer. If the crank has to come out then send it out t the heat treaters. Down here it costs about $ 45 for a twin crank, money well spent, less than a gasket set.