1962 650SS – Drive Side Oil Leak

hello Alister - as far as I remember all the screw holes for securing the three alternator carrier bracket and the inner primary chain-case to the drive-side crankcase are through holes.  I usually secure them with a touch of stud lock into a degreased thread.  Good luck , Howard

Check that your crankcase pressure relief valve in the timing cover is working properly . They sometimes seem to seize up.  Howard

Gearbox oil leaking through clutch pushrod?

Hi Alistair - No the crankcase pressure relief valve on a 650SS is the big nut at the bottom of the timing cover.  It allows oil to pass into the timing cover when the pressure gets high after wet-sumping or knackered piston rings.  It consists of two large nuts with a spring-loaded piston and often shims to adjust the pressure.  They piston often seizes into the barrel with age and little use.  When the pressure builds oil is soon output past the crankcase oil seal.  Cheers, Howard

Did someone simply add unnecessary oil to the primary case?  They nearly all leak...which is why owners use belt drives.

Actually, the pressure relief valve is located in the oil pump delivery line to limit maximum delivery pressure to the big-ends and rockers. Not there to deal with excessive crankcase pressure caused by wet-sumping or ring blow-by; that is the crankcase breather's role.

...so no oil inside the chaincase?   Didn't you report oil coming from the chaincase?  If so, it's either from the engine (but the oil seal is good) or gearbox or someone has put it in there.  Oil can come along the actuator rod hole, but not a lot unless the gearbox is massively overfilled.

You're quite correct Andrew however the timed-breather for the crankcase barely copes with the early 500cc engines.  If something happens to cause a sudden onset of excess oil into the timing cover it can increase the volume of oil in the crankcase and so can become over-pressurised and oil can escape wherever it can on a downstroke of the pistons.  Having the breather piped back into the oil tank, like the 650SS and Atlas, did not cure the breathing problem.  It made another item susceptible to leaks.   If you have a good look around a race prepared pre-Commando twin power unit you will see the lengths to which people are driven with external tubes everywhere to get the engine breathing properly.  Good luck, howard   

Hi,

In some of your recent photos,  it looks like either the seal isn't fully home, or the crank has been shimmed towards the timing side a bit too much? 

is the seal lip actually running on the full circle of the mainshaft, or is it running across the keyway?

Also,check for any 'burrs' on the mainshaft opposite the key slot - if the sprocket has been tightened and the key is too high/slot in sprocket too small, it is possible to tighten the retainer nut and throw up a burr on the crank. 

Regards, 

George 

The inner cover and alternator housing fixings are well known for leaking crankcase oil into the primary area.

The crankshaft oil seal looks in the correct position but the sprocket key does look dangerously close to the seal itself.  How much crankshaft play is there? The oil pump worm will push the crankshaft sideways,  especially if there are two roller crankshaft bearings that have not been shimmed up correctly. More than 20 thou play is going to cause problems.

The oil seal looks like  the type with a poor reputation for wearing quickly and not doing its job properly. Also with a dry belt primary drive system, the inner seal lip does not get lubricated so well and may wear faster.  

The crankcase photo shows some damage in the lower section. Is that a crack across the flange in photo IMG_2421.JPG. and a line of pin holes lower down? This does not look so healthy and possibly worth investing in a tube of  JB Weld.

Wellseal is a low viscosity sealant that never sets hard. You can use it on metal to metal joints, gaskets and smear it on threads before fitting screws or studs. Has always worked perfectly for me.

Check the faces for flatness. The leftover blue sealant (Hylomar?) on the chaincase and engine in the region of the bolt holes tells me that there is some thing not flat. A close look at the photo showing the damage to the lower part of the gasket face shows what looks like a porous weld. Judicious use of RTV, smearing it over the damaged areas and on the gasket on assembly might stop the leak. Improve the crankcase breathing, the timed breather is pathetic.   Edit. A close look at photo 2419 shows what looks like a crack in the case, the edge of the case that locates the alternator basket has probably been built up with weld to help locate the basket. You need to dye penetrate test the case in that area    

Depends on how you view modifications. To fit a crankcase reed valve breather either buy the NYC reed breather kit, (expensive but no permanent mods) Or somehow fit an inexpensive reed valve unit from an XS650 or similar (search for 125 egr valve on ebay etc) The problem being is getting the vent pipe connection to the crankcase. 
Personally i would do away with the timed breather and tap into where the timed breather pipe exits the crankcase, increasing the ID of the drillway to approx 10mm. and directly connected it to the crankcase void (not going through the cam) Unfortunately this means an engine strip, but is the most un-intrusive way of getting a large bore vent connection to the crankcase. An engine strip anyway would be a good idea, if nothing else it will be a good check on what ever work has been done in the past. If you do strip the engine, be prepared for whatever horrors might, and probably do, exist inside.
Sorry if i sound like a pessimist but having dealt with bikes that have 'just been restored' etc I find that no end of bodges, sloppy work, fitting wrong bits and tall tales etc are just part and parcel of the old bike scene.
The latest 'bodge' i saw was on a little Ducati at Squires cafe last Thursday evening. Its front brake cable was fitted with a screw on nipple at the drum lever.....an accident waiting to happen

A close look at photo 2416 clearly shows a ring of weld all the way round the alternator basket spigot. Where the weld has been machined off also shows pinholes/porosity. This is indicative of some sort of catastrophic failure in the past, and somebodies effort to repair said damage.     A thorough degrease and smear RTV over all the affected area, might stop the oil seeping through the case. Buy a big tube of RTV, Wynns black gasket RTV is good 

Comparing photo 2419 against the Repair 2 & 3 photos looks to show the epoxy has fallen away from the area where the case looks to be cracked. Did you thoroughly degrease the case to the point of rubbing the area with a clean bit of kitchen roll shows NO dirt/oil? The oil held in the crack will seep out and it is almost impossible to clean out, It can be done but takes some effort.    

Hello again Alistair - cases look nice. I wonder why the intermediate spindle is missing - they are usually very tight fit.  I'd say they are from 66 or later.   Use new bushes and studs from a reputable supplier.  Cheers for now, Howard

Hi Peter,   your comment on a bodge on a Ducati single is incorrect !, they came like that from the factory. a similar detail also  on the clutch cable. I have never had one fail ,they  use a heavy duty cable and being so light a bike it just works. Looks a bit naff though !.