• tel: +44 (0) 1946 841517
  • fax: +44 (0) 1946 841261
  • Contact Us

RGM Motors Ltd - The UK's Premier Norton Specialist

My Account

My basket



  • You are here

  • Home
  • faq Engine Bottom End

Change in office hours. (Please note callers by appointment)

As our last mail collection has been brought forward to 4.00 P.M. Our office hours are now.. 8.00 to 4.30 Monday to Friday.

Closed Weekends and Bank Holidays.


I am trying to find available Pushrods/Pushrod-Ends which will enable me to construct a pair of Pushrods for a 1926 348cc ohv TT Blackburne engine. The end-pieces require to have Cup and Male-Ball ends to suit existing rocker and tappet features which are 5/16" nominal spherical diameter . Does Norton use this diameter on cup/ball ends of say Commando Push Rods ? Hope you can help, even if it eliminates another maker! Velocettes are too small, Ariels are too big...
Well the ball that fits into the socket on the top measures a tat over .300" I guess the socket is nominal 5/16 and the undersize ball allows for the articulation. the ball on the other end of the pushrod sits into a socket in the top of the cam follower so there would be less articulation it measures, (the ball) approx .350 we have both ends and hollow steel tube if you think they may work, we could linnish them down a bit but I would take no responsibility for them being the correct size, if I had the mating part I would have a better chance. Our steel tube is cut to lengths so we may not have any long enough for your engine, its probably got a 1/2" mile stroke.

I'm most grateful for your immediate response to my "non-Norton" enquiry. It encourages me to look for a Norton, if this is an example of your customer service. I think, from your measurements, that I will have to continue my search for 'rod-ends, as the Norton male end will not seat in my "cup" socket of the tappet. I presume the Rocker Ball Ends you show on your site-shop have the same (larger than 0.312") ball, otherwise that part might help me to achieve on end. However, many thanks again for your attention.
Hello again, yes we focus very much on Norton and by doing so manage to be busy all the time if not exactly rich. The ball on the rocker is actually coming in at about .302" so if that would fit it may be a go, as I mentioned we can linnish and polish down to any size with reasonable results should you get stuck.

I have brought solid washers to replace the spring washer on my rocker spindles I wondered how much clearance to give them. In your special products brochure number 2 it is mentioned "the fitting of oversized high tensile center less ground bolts into sized and reamed crankcase boss and rear engine mounting bolt holes is advised to insure maintenance of rigidity of assembly" can I buy the bolts from yourselves or would you have a supplier you could recommend please thanks so much.
Thanks for enquiry, Re the rocker spindles, it will not require much clearance, free to turn upto .005" should be fine. re the ground centerless bolts and rigidity, crankcase shuffling can become a problem on really high output engines. This particular job would be done in house as you built the bike, light interference being achieved by checking against the size of the reamed hole, its not something we have ever attempted to do as an Item to sell. What we have just recently done is drawn and ordered some very high tensile bolts with the correct head size etc and we have lifted the tolerance up .005" from top tolerance on the original factory drawing. These are stronger than originals, will be a closer fit and are UK made. They should help without requiring much work too fit, so they are a step in the right direction. This is a very recent item and I have not even had chance to put them on the website yet, Part numbers are 063211 for the rear bottom 5/16 063212 for the 3/8 rear and 063213 for the 3/8 front.

I have received my Conrod Bolts. I see on the Andover Website they warn not to use this type of Bolt. Can you give me input. As I am now hesitant to fit these in my Bike.
Its a bit sad really, Andover Norton were a good company, still are to some extent but there is no relevant connection to the original factory, its just a bought name, they have no production facilities no inspection facilities to speak of and judging from the piffle (read criticism of other peoples parts) little technical knowledge. The bolts are indeed mine, I had ten thousand made and therefore achieved access to quite major production facilities, I have tested my own bolts and many others, I only found one faulty one and it was not mine. I do not like what I see as unprofessional "marketing" so do not respond to anything I read on the internet or in the press unless I have something constructive to add. I also had the bolts independently tested as did a third party that purchases a few of them, they are truly bullet prove. I just checked on the PC for you and in the last three years we have sold 1808 without a single failure or problem which is as I would expect. I think from what I have been told most of the criticism was concerning the price, i.e. nothing that cheap can be any good. But as I say 10,000 gets you places a few hundred will not. If you like I can try to dig out one of the independent reports if you are still worried. In case you are really interested the only genuinely faulty one that would eventually fail was an isolated one from Andover Norton that had not been finish machined properly, It was missing the rads. That's a one off problem but its what can happen if you have outside suppliers producing lots of small batches and you are not very careful with inspection. I do look at things carefully and the samples I checked/had checked spanned many batches and sources stretching back 40 years.

Roger, thanks for the prompt answer, the reason why I inquired was after reading the last page in the Norton workshop manual piece about all of the updates that were done at Engine No 116372, around February 1966, mine is a January! One of the updates was pressure feed to the rockers, I thought it might be a help to prevent the valve guide wear I found when I stripped the motor. I found the overall condition of the engine to be poor, it even needs a crank regrind, neglect I suspect being the reason. I have not owned this bike for long, has spent 30 odd years in a basement apparently. Would 065561D oil feed hose assy do the job, maybe with the plain rocker spindles?
Morning, well I see where you are coming from, part of the problem though is balancing the requirements, for example if you pressure feed the rockers you will need to check you have the six start pump and the spindles would probably want to be plain or you would over oil, of course you could pressure feed the rockers with a three start pump and scrolled spindles but then the big ends may be starved. Six start pump, plain spindles and pressure fed rocker is probably the best. A lot of the wear is probably down to a poor (non existent) maintenance regime. Changing the oil regularly would probably of done the trick. The filtration system is poor and perhaps an inline cartridge filter kit would be a good addition, we make these and they are not expensive. We also supply inline magnetic filters but have not come up with a good clamp yet. and we can supply 3/8 drain plugs in BSC, BSW, UNF, and BSF fitted with a magnet, and a stainless steel large sump plug with a 3/8BSW thread in the bottom that would allow you to fit one of these. All ideas, all helps I hope.

Please can you advise me on what I need to change to update the lube system on my 1966 650SS, engine no. 166188. Is there an advantage in enlarging the oil feed pipes and fitting positive rocker feed?
Hello, thank you for your enquiry, there are no specific problems with the lube system on your SS I cannot foresee any problems and is it not the case that your bike already has the pressurized rocker feed? I guess the question must have been prompted by something, have you had any problems with it up to now?