Sunday, 29 December 2013

Am always tempted by some of the more exotic racing fuels but am happy for the moment to stick with normal pump fuel. Inspite of all the worries about using unleaded all seems well with the valve seats in that regard.

Winter work is something I feel you have to stick at as if you leave off too long you forget what bits you were working on !

Tuesday, 3 December 2013

managed after very many years to get hold of a copy of that wonderful book by Philip H Smith " The High Speed two-stroke petrol engine" . As a young man I was enthralled by it when borrowed from my local library and since many of my generation started out on two strokes I am certain others retain a soft spot for them. This page above illustrates a range of piston crowns and for good measure Smith included a Manx Norton one on the bottom right corner. 

I was significantly lighter in my younger days and so the scale of those lightweight machines was an added attraction. The popularity of the disc intake valve provided the answer to a lot of the issues of timing racers using the two stroke principle. What a pity that emission laws have all but made them disappear. There is certainly a need to redevelop the two-stroke in harmony with current emission thinking and technology.

Friday, 22 November 2013

This is a good drift for helping remove a big end . I made it from a piece of old steel scaffolding tube off-cut which happened to be on the edge of a pavement I was walking along near abuilding site ! 

Inevitably a new big end is expensive as it is made of very high quality steel and rollers. This one cost me £130; but for single cylinder Norton's I have seen the same bearing priced at £200 and I don't mean for a Manx model which is very different type of big end bearing.

Wednesday, 6 November 2013

crank at work !

Managed to get hold of a very good condition standard conrod.
It is getting more difficult to source stuff like this as some things people sell are very poor having been left outside for years. 

Testing the trueness of the drive side flywheel. For some reason the timing side wheel seems perfectly straight but I can detect a slight high spot on the drive side wheel. The main concern is if it is caused by a bend in the main shaft.

Saturday, 26 October 2013

Still having trouble with blue smoke. Checking ring gap which is 8 thou so that seems within tolerances...

The Australian JP pistons seem to have an oil scraper ring visibly thicker than a conventional British made ring such as Hepolite etc. Which represents a difficulty as I hoped to fit different rings to effect a cure or at least help in the diagnoses of my oil problem.

Sunday, 22 September 2013

A local chap gave me a Bosch r6 spark plug which has the smaller hex body and thinner insulation. The fact that the central electrode protrudes so much however, gives me reservations about the combustion process.

Still having problems with oil burning. I have had the head off about six times trying to solve the problem. A standard size piston in a standard sized bored liner must be right. However oil is finding it's way passed the rings. I conclude that the Australian JP pistons need some fettling in the ring grooves.

Just as well I took the head and barrel off this time as the small end bush has moved in the conrod.
Good photo of Derek Minter standing beside Steve Lancefield the famous Manx Norton tuner.

Friday, 9 August 2013

The spark plug on the right is the NGK racing version of the normal plug on the left. the smaller size of the central electrode is quite noticeable.

The reverse is true of the plug body as the racing plug has a significantly thicker body.

Friday, 26 July 2013

Very sad to learn that the chap, William Robertson who runs the sprint strip at Crail, Fife, has died suddenly at home aged only 47 as the result of an accident. I hope that it keeps going as it is the only strip in Scotland . These are me last time I was there.

Thursday, 18 July 2013

There were few artists and illustrators in the 1920's through to the 1950's which had the very remarkable skills of Leslie Carr. This highly evocative picture -in print form- graces my workshop wall and seems to capture the very spirit of motorcycle racing at one period in time. The Norton and the AJS seem like wild monsters battling for the lead.
Leslie Carr also did ships and steam trains and I have memories of his work in books as a child. Some towns had tourist posters as well by him. Anyone interested in cars as well as bikes may know that he did a similar style of work of the Le Mans D-Type Jaguar competing about - I think- 1957 and it is with the Glasgow Art Galleries and Museums - but I believe in their reserve stores.
As a "homage" to my late father I still use his old brass petrol tap, not only because of sentiment but because it is the only one I know never leaks !

Wednesday, 17 July 2013

pins and rings

The gudgeon pin ( or wrist pin in the USA) on the right is the type favoured by JP pistons of Australian who supply my pistons with pins and rings. Presumably on a cost basis the hole through the middle is parallel . The original pin has double tapered hole being narrowest in the middle section and therefore lighter.
Since I have taken the bore back to the standard 71mm new rings are fitted. It is still a misconception among new boys to this game that the rings are made springy to form the gas seal. The fact is that at or approaching Top Dead Centre there has to be just enough ring gap to allow high pressure gas to get behind it and force it out onto the cylinder wall. Old books on engines tend to show illustrations of lapping the horizontal walls of the piston rings to ensure the gap is big enough.

Wednesday, 10 July 2013

The significant engineering task of installing a new cylinder liner is one not to be taken lightly. I entrusted this to Blane Precision Engineering of Killearn not far from me and near where Bob Macintyre planned to have a garage with Alastair King...
....note however that not only have the conrod clearance indents been re-machined but that the tiny...perhaps 1.5 mm hole into the cylinder has been re-machined through the new liner fitted...
...machining off the old spigot and retaining the same height is a job not many would say they could do well.
All of this incredible expertise is due to one man. Mike Cowie who runs the show.
He is ex Rolls Royce in Hillington - 25 years -and knows everything about Merlin and Griffon engines.
I think for certain there must be only a handful of people like Mike in the UK today.

Friday, 22 March 2013


Amal monobloc 389 - quite 'clean' internally - no choke fitted in this case.
...attempting to make the frontal area as small as possible...

..however the 'works' Nortons in the 1930's managed to keep area to a minimum.


Normally I, like many others, would rather take acold bath than open up the gearbox.
Needs must this time however as the kickstart was not catching.

the fault is obvious..a badly worn pawl. the end of the day every barrel and/or piston wears to the point something has to be done. A new liner is called for with a standard piston .

Monday, 28 January 2013

Winter work on my Norton Model 50

The later alternator type crank on the Model 50 like mine or on an ES2 model is longer to hold the rotor. The retaining nut is also smaller than on the earlier type.

The standard Norton conrod for my machine is the lower one. I am experimenting with an alloy racing one which is also 6 1/2 " between centres. The problem of it fouling the cylinder wall is one which one has always to be carefully considered and the wall relieved.

Always worried the bike will come off the trailer when towing !! Hence the many tie-downs...I must find a more efficient way as it takes an age to up load and down load at a track.
last season ! a bent valve smashed piston on the left...what they should look like on the right !

Getting back to has been a long winter...timing side....

...the only bit of the original paintwork from the norton works in Bracebridge Street in Birmingham is on the
 inner primary chaincase and I am keeping it that way !
Using my old 'periscope' type dial gauge mainly as an aid to checking taper in the bore.

Lumpy racing cams- compare with below- make a transformational difference to performance.

Standard cams were designed for a compromise of smooth running; economy and noise.

I always taper the valve head end of valve guides as they seem to come parallel nowadays.
At last getting things back to normal