1961 Oil pressure Relief Valve??

Hi Bryan

The Dome nut you have been looking at does indeed, underneath contain all the parts of the oil pressure release valve. If you can undo the bigger nut you will find all the working bits of this unit. Check out the attachment. This is quite an important part of the engine which does benefit from a clean every so often. But try not to lose the metal disc shims which sometimes fall out of the inside of the piston. These are used to tension the spring so that the piston operateswhen theoil pressure exceeds45 psi. Generally on a cold engine start-up.

As a rule, these components are quite robust and only cause a problem in engines that have been sitting around and not run for years. So a very corroded piston or bent/rusty spring might need changing. The good news here is that this item was common to almost all the Dominator and Commando range of engines for nearly 30 years, so are easy to find at auto-jumbles and also new replacement parts can still be obtained from norton sparesdealers.

Previously wrote:

Hi,

I have a 1961 Dominator and the engine is stamped 14R which I think is 1961. However can someone tell me what the large dome nut(which in turn fits onto alarger flat nut) is next to the mainoil inlet/return connection on the crankcase? There is a spring under the dome nut so I believe it might be the oil pressure relief valve. However the model history here says that the valve is inside the cover from '58. Please see pic.I can't see this in my Haynes manual. Again thanks in advance. I'm on a steep learning curve.

hello bryan 14R Is 1960 Model 99C Its Not A 1961 Model 99 yours anna j dixon

Bryan,

Just to add to that handy image of the pressure release valve diagram from Phil.I thought you might like to see what the timing cover for coil ignition Dommies looks like. They are 10-a-penny, with stacks still lying in peoples' sheds & lofts (but why dopeople always bruise the price up to £30+ on 'Satan's Swapshop'?) they're worth £5.I usually cut the coil ignition ones up for the cutaway tool, to use when removing/replacing the cam sprocket, or adjusting timing chains.Makes a great Christmas gift and stops your mates tearing their intermediate shafts out of their crankcases. Leave yours as it is.

I used to love the smell of 5-Star, when starting my first 650ss back in the early 70's. The trouble is, this Unleaded stuff is carcinogenic.........

Paul

Here's a shot of the inside, with pressure release valve under that hex-head.

Paul

Previously wrote:

Phil, Anna,

Thank yoiu for the info. Very helpful. It's all very new to me and the fact that it's a cafe racer doesn't help matters with somany mods having been done. I found a 4" nail in the oil tank the other day for example. Surely not a standard mod~!?and the oil smelt more like petrol although that is probably from my initial "starting routine" which used to take meabout 20 minuteswith petrol all over the place. Now it's down to about 3-5 kicks so progress is being made. I don't thinkthe bike hasbeen used for many years as all the receipts are from the early 90's so it's a work in progress. Thanks again.

Bryan

Hello bryan after reading your answer It sounds like you have a Norton bitser and a night mare ?? and you say this bike as not been run since the 1990,?? If I where you I would not start this bike again ,I would dismantal the hole bike and start again with it and As for that petrol smell in the oil tank Tell me your barrels are worn out as that petrol get past the piston rings and in to the oil in the bottom of the engine , I will say time too stip your engine and see whots worn out ? and then I would strip the gearbox too if you are not shure of what you are doing there all way Paul And Phill and me ?and a dvds of engine and gearbox strip and rebuild by the late John Hudson Norton engineer price too Norton members 6 pounds &50pense Contact Me on 01430430831 or annajeannette@btinternet.com

Previously wrote:

Phil, Anna,

Thank yoiu for the info. Very helpful. It's all very new to me and the fact that it's a cafe racer doesn't help matters with somany mods having been done. I found a 4" nail in the oil tank the other day for example. Surely not a standard mod~!?and the oil smelt more like petrol although that is probably from my initial "starting routine" which used to take meabout 20 minuteswith petrol all over the place. Now it's down to about 3-5 kicks so progress is being made. I don't thinkthe bike hasbeen used for many years as all the receipts are from the early 90's so it's a work in progress. Thanks again.

Bryan

The 4" nail waspossibly magnetized, dropped into the oil tank to pick up any metal fragments traveling aroundthe lubrication system. I ve never heard tell of that but it's a clever idea and certainly couldnt hurt anything. Is it then fished out with any piece of steel tocheck and clean offor does it remain stuck to the side of the oil tank...?

There were/are quite a few varieties of timing cover, from the range of Norton Twins,that will fit on a model 99. Plus, there were almost just as many versions that could mount a Rev Counter Drive. The factory produced several types withacastboss and a choice ofeither verticalor inclined mounting holes. Several 'Go Faster Goodies' shops also produced and sold their own versions of the cover. Some with a cast boss, others with a built-up welded boss and the cheapo with just a ground away mounting area.

The proper factory produced covers, with the boss for mounting the Rev Counter drive, will all have had a pressure release valve fitted as standard unless someone has done a bodge job. They are opposite ends of the cover so there is no reason to mess around with the release valve.

Previously wrote:

Hi all and thanks again. To be fair to the bike it seems to have all been done properly much of it by Mick Hemmings including a rebore etc. I'm going to get some fresh oil back into it and run it again to see if the oil pump is actually "spasmodically" returning the oil. The tank filter was very dirty and the sump filter too with what looked like orange silicone trapped in the gauze. There was a decent coating of oil in the case though. By the way I'm trying 20-50 for the oil. I don't want to do a flush in case it makes things worse. I'll need to go through more receipts to see when it was last worked on.

One more question though. I have a non return valve in the oil feed line not mentioned in the manuals. Why is that there (apart from the obvious .. Is the suction and oil head enough to push past the ball? It's an RGM device and I've bought a new one to try.

The DVD sounds good. I'll give you a call this week.

Cheers,

Bryan hello bryan I hope mick as not fitted thoes horried GPM Or JP Piston Ask Martin Maynard what they are like He sezed his bike upno end of times ?with them ? in the end he broke it up and sold it for spares ? So bang goes aother domie ?