rocker oil feed mercury

Rocker oiling has been an issue with the big twin. Early engines often not enough  things wear , ,later engines sometimes too much, plugs oil up,valves can burn and exhausts smoke, If the valve chambers look oily after a run and it runs clean I would be very happy. Trying to fix something that's not broke is frustrating and  pointless.  Do you have a problem?.

I have always thought that the pattern of usage  often brings different problems  for owners.Many years ago ,high speed and long distance riding meant that my valves got more than enough oil but my pistons were on the edge with the oil overheating ,wet sumping was unknown. With classic use the same motor got starved of oil to the head and the  oil stayed cold, condensation formed in the tank and plugs and engine got sooty, and the oil turned black sooner than it should .Wet sumping is normal.

Hi Terry.......your Mercury appears to have been part of a batch manufactured specifically for the Police or Military overseas. Of possible interest to you,  all of this batch have next to no individual detailed notes about them in the Factory Records.  Also despite being one of the last built, your bike and the others in this batch were some of the first dispatched from the factory. Most heading off overseas very early in 1969.  Bikes near yours 129 819, 820 & 821 all departing in the January of that year. Most of the 700 Mercury bikes were built in 1968 and then stored with last in the warehouse store often being first out of the Factory gate.

Possibly your bike would have been painted in all white of black and had an enlarged battery cover to cater for a bigger battery to power a radio set. Some of these bike might also have had a tank tub for a radio set or a single seat and rack for similar purposes. A few also had a bolt through the rear top bracing tube for the mounting of crash bars.

Terry,

I've been out to check my Mercury (No 129667) and can confirm that the bolt is drilled for securing.  When I purchased mine, back in 1998, it did not have any locking wire to secure the bolt, so I improvised and used an 'R' clip with a small zip tie to stop it being lost if it becomes loose.  Perhaps I should now wire it otherwise it'll mysteriously undo.

In the last 22 years I've never had a problem with the bolt loosening off, but I don't thrash it as it is often used for two up touring with luggage, and the pillion doesn't like going too fast!  This was my first Norton twin and has turned out to be a fabulous motorcycle.

Philip

Excuse me Philip but that is the  oil feed/return junction block.  The rocker feed banjo bolt is under the pressure relief valve at the back of the timing cover.. Cheers, Howard

As Howard pointed out, I took a photo showing the oil feed/return junction box so I've take a separate one, see below.  I replaced the feed pipe a couple of years ago and RGM made this for me use rubber hose rather than the metal pipework.

Regarding the number of Mercury's manufactured I checked the factory records when I visited the VMCC head office. This showed that there were 747 made between Sept 1968 and Feb 1970, numbers 129147 to 129894.  Mine was repatriated in 1990 from Canada and needed some TLC to make it safe to ride.

Terry....that is a great photograph. It has loads of extra detail not generally seen in pictures of Police or Military Nortons. Note the early headlamp. So possibly this 650 is an early 1960s machine. The speedo must have been hidden by that speaker box and the extra lights. It looks like the radio is in the right side pannier. Plus how did that dent get in the primary case??? Have you got any other photos like this???  

Can you post a photo of your mystery plumbing?  The only time I have seen added wiring has been a spiral guide to help keep the oil feed away from hot parts of the engine or sharp edges of the bodywork.

The frame and engine number 129822 is blank in the factory dispatch records, and there are many blank entries in the dispatch records for the Mercury's. There was dispatched to Malta a batch of black Mercury's for police use, as a friend of mine owns one of the last ones dispatched, and brought back to the UK.

That does look too restricted to me. try without. If it starts smoking put a thinner one in.Trial and error.

Thanks for the photos.....all is much clearer. A similar trick was used on the earlier Dominator low pressure return feed to help push oil more up to the cylinder head. Paul Dunstall used to fit Carburettor main jets into his rocker feed lines on his engines with 6 start oil pumps to help control the flow of oil. On a super clean engine this creative engineering would be OK but I would not like to try it otherwise. 

The rocker spindles on the Mercury should be plain with a single flat on each. If the flat on all of them is faced towards the rocker covers then the spindle shoulder should do a similar job in controlling the oil flow. Some AMC built engines had all plain (no flat) spindles fitted, possibly for this reason.

Terry......another great photo of the 650 in Police service. Keep them them coming please. This year will see the anniversary of the introduction of the first of the 650 bikes....the Manxman. I have put together an article for the Roadholder to celebrate this point in the history of Norton motorcycles but it could do with some fresh photographs of that particular model.

Actually it wasn't the first of the Norton  650 bikes. That honour went to the Unified Twin that was built in 1959 but never made it into production. Attachments show one of each model.

Hello Terry, with regard to your 5" speedo' , I feel it's  unlikely to have been an original fitment, although an ex traffic BMW that I have is fitted with an oversize calibrated Speedo' as well as the standard instrument,  apparently for speed checking. I think yours has possibly been fitted by a PO and it looks identical to the one on my Vincent Rapide. The Black Shadow came with a pair of these instruments as standard, a speedo' and r/counter.     If it is ex Vincent, they are very much sought after and in good order have a value around four figures or more.           There is a fellow at Kempton Park who repairs bike instruments. I am told by a fellow Vincent owner that his charge for restoring one of these is £800 + another chrono' speedo.                              The rarity and value is such,  that way back in the 70s while on the Island Vincent owners would be seen removing these instruments before retiring for the night.

Unless it is of great value, hasn't it become part of the machine by now, would it feel right without it?

Seeing rows of classic bikes all the same can be quite boring

John