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Metal Fatigue & Other Mechanical Failures





Norman Williamson has been involved in the sport of Motorcycle Road Racing since 1974.  He has competed on many different circuits on the UK mainland, Northern Ireland and the Isle of Man and continues to do so.  As well as preparing many of the machines he rides, he also manages and organises his race team.  He has won many races and championships on short circuits over the years, and four Silver Replica's as well as many Finisher's Awards in the Manx GP between 1976 and 1991.  He remains a very competitive motorcycle racer.


Aermacchi 250 (1967 Grand Prix Class) Air cooled, Single Cylinder Four-Stroke, 5 speed gearbox.  The engine of this machine revs to approximately 10,500 rpm and it is capable of 115mph.  Norman has raced two of these machines since the early 80's.  One belonging to Terry Kermode and the other belonging to Roy & Sheila Clutton.  Norman continues to race Roy's bike in the 250 Classic races at Aintree and Oulton Park, and has won many races and championships on it.

Norman with friend and sponsor Roy Clutton in the assembly area before a Classic 250 race at Aintree.  Followed by various photo's taken at Aintree over the past few years.


Who needs to look where they are going!

Norman & Mark Livingstone starting the 1988 MGP 250 Classic Race.

Leaving Parliament Square Ramsey (MGP250 Classic Race)

Waiting in the warm up area at Aintree

Aermacchi 350 (1968 Grand Prix Class) Air cooled, Single Cylinder Four-Stroke. 5 speed gearbox.  The engine of this machine revs to approximately 8200 rpm and is capable of 130mph.  Norman started his racing career on a 344cc Aermacchi in 1974, he raced this machine up to 1982 and won many races on it.  He also raced a 344 Aermacchi belonging to Terry Kermode in the 2000 Pre-TT Classic race on the Billown circuit in the IOM.  Unfortunately, he crashed in that race and suffered a badly broken leg and ankle.

Quarter Bridge, 1976 Manx GP Junior Race

Ballaugh Bridge, 1976 Manx GP Junior Race.

Ballaugh Bridge, 1977 Manx GP Junior Race.

This is how not to take Ballaugh Bridge.  The rider that has just been passed on the approach to the bridge, re-passed while NW was trying to regain control of his bike.  Manx GP 1977 Junior Practice.

Signpost Corner, 1977 Manx GP Junior Race.

Ginger Hall, 1977 MGP Junior Race.

Greeba Bridge, 1977 MGP Junior Practice.

Quarter Bridge, 1978 Manx GP Junior Practice

Union Mills (1), 1978 MGP Junior Practice.

Yamaha TZ125 (1980 Grand Prix Class) Water cooled, single cylinder Two-Stroke, 6 speed gearbox - No pictures available as yet.  The engine on these machines revved to approximately 12000 rpm and they were capable of something in the region of 120 mph.

Yamaha TZR250 (1991 Production Class) Water cooled, Twin Cylinder Two-Stroke, 6 speed gearbox - No pictures available.  The engine of this machine revs to approximately 10,000 rpm and is capable of 125mph.  Norman raced one of these machines in the early 90's.

Yamaha TZ350A/E/G (1975/79/80 Grand Prix Class) Water cooled, Twin Cylinder Two-Stroke, 6 speed gearbox.  The engine of this machine revs to approximately 10500 rpm and is capable of 140/150mph.  Norman's first ride on a TZ350A Yam (B/W picture below) was an unofficial practice at Croft in 1975.  He purchased a TZ350E in 1979 and continues to race a TZ 350 Maxton Yam.  Some of the machines were his own (like the TZE & Maxton Yam shown below) and others were sponsored rides.

First ride on a TZ350(A) Yam.  Practice at Croft 1976 - just a little bit wet.  This bike was modified with a Tony Foal swing arm and Decarbon 'monoshock' suspension.

Village Corner, Aintree, mid 80's, TZ350E

Bradden Bridge, TZ350E, MGP Junior Race, mid 80's

Climbing up the mountain out of Ramsey, MGP Junior Race 1986.

Flat out (140mph+) and just landing at Ballacry, MGP Junior Race 1986.

Exiting Governors Bridge on a TZ 350G

Kepple Gate on the same TZ 350G as above

TZ350E into Lodge Corner Oulton Park

Maxton Yamaha TZ350G (1980 Grand Prix class) Water cooled, Twin Cylinder Two-Stroke, Gears 6.  The engine of this machine revs to approximately 10500 rpm and is capable of 140/150mph.

  Ballacry, MGP 1987 Junior Race - again flat out but on the Maxton framed bike this time, which handled quite differently to the standard Yamaha frame.

Creg-ny-ba, 1987 Senior MGP Race

Forgotten Era race at Aintree 06/2005

Exiting Druids Corner Oulton Park

Going into Lodge Corner Oulton Park

Exiting Lodge Corner Oulton Park 10/2008

Church Bends Pre-TT Post Classic Race

Yamaha SR500 (SR/XT 500 Road based conversion) Air cooled, Single Cylinder Four-Stroke, Gears 5.  The engine of this machine revs to approximately 9000rpm and is capable of 120mph.

  Beechers Bend, Aintree early 80's.

Honda 492 (1975 CB400F Road based conversion) Air cooled, Four Cylinder Four-Stroke, Gears 6.  The engine of this machine revs to approximately 12000 rpm and is capable of 130mph.

Entering the first corner (23) after the start of the unlimited cc Forgotten Era race, Aintree 2001.  Followed by various photo's at Aintree.

Castletown Corner Pre-TT Post Classic Race

Suzuki 250 Gamma (1990 Production class) Water cooled, Twin Cylinder Two-Stroke, Gears 6 - No pictures available.  The engine of this machine revs to approximately 10500 rpm and is capable of 125mph.

Suzuki TR320 (1967 T20 250cc Road based conversion)  Air cooled, Twin Cylinder 320cc Two-Stroke, Gears 6.  The engine of this machine revs to approximately 10000 rpm and is capable of 130mph.

Club Corner, Aintree 1999.

Castletown Corner, Pre-TT 350 Classic Race, Billown Circuit 1999.

Suzuki T500 (1967 T500 Road based conversion) Air cooled, Twin Cylinder Two-Stroke, Gears 5.  The engine of this machine revs to approximately 10,000 rpm and is capable of 145/155mph.

NW and sponsor Eric Hulme, Aintree paddock 2001.

Ballakeighan corner, Pre-TT Post Classic Super-bike Race, 2002

Aintree, 2001/02


Norman and Dave Whitehouse (Manx Norton) battle it out at Aintree 09/05

In the warm up area for the Unlimited Classic Race at Aintree

Going into Village Corner at Aintree 09/2008


Greeves Silverstone 250 1966 Air cooled, Single Cylinder Two-Stroke, Gears 6.  The engine of this machine revs to approximately 10500 rpm and is capable of 125mph.

Sponsors Terry Kermode and Ron Leighton discuss which bit goes where on the 250 Greeves.

Ballakeighan Corner, Pre-TT 250 Single Cylinder Classic Race, 2002

  3rd place on the rostrum, Pre-TT 250 Single Cylinder Classic Race, 2002

Honda RS125 GP 1996 Water Cooled, Single Cylinder, Two-Stroke 125cc, Gears 6.  The engine of this machine revs to approximately 13,000 rpm and is capable of 130 mph.

Aintree Road Races 14/07/07 going into Club Corner

Aintree Road Races exiting Club Corner


Suzuki GSXR750 1985 Liquid cooled, 4 cylinder, four-stroke 750cc, Gears 6.  The engine of this machine revs to 11,000 rpm and is capable of 170 mph.




Norman has raced on the following Road Race Circuits;

Isle of Man, TT (Mountain Circuit)

Isle of Man, Billown (Southern 100 Circuit)

Dundrod (Ulster GP Circuit)


Oulton Park (three configurations, full circuit, Fosters & Brittens)

Brands Hatch (GP Circuit)

Cadwell Park (Mountain & Club Circuits)

Mallory Park

Donington Park

Croft (Old Circuit)

Three Sisters (Wigan) (New & old)

Longridge (Preston)

Ty-Cros Anglesey (New & old)

New Brighton Road Race (Wirral)


The 2002 season was like most racing events, full of action, unpredictable events, some success and some disappointments.

The Aermacchi 250 owned and prepared by Roy Clutton had been tuned over the closed season but still could not live with the single cylinder Greeves two-stroke machines with good riders on them.  After starting well in the Aintree championship, an engine failure caused a DNF in one round while lying third.  The loss of points was a disaster as far as the championship was concerned.  After lying third up until the last round, Norman eventually finished fifth in the championship.

Norman rode Ron Leighton's 250 Greeves in the Pre-TT 250 Singles Classic race and finished third.  This was the first time he had ridden this machine.  He usually has to contend with Phil Carpenter riding against him on this particular Greeves, while Norman rides Roy Clutton's 250 Aermacchi.

The Post Classic Super-Bike race at the Pre-TT was a bit of a disaster.  Norman had only gone twenty yards out of the warm up area in the first practice session, when he was knocked off the Suzuki by another rider.  Fortunately there was little damage and he was able to continue.  The Suzuki TR500 then ate yet another piston during the final practice.  Frantic efforts and the kindness of Les Trotter (who provided a piston), got the bike to the start line.  Unfortunately the gremlins were hungry again during the Post Classic Super-Bike race and yet another piston went two laps before the finish.  Two engine seizures flat out at 140/150mph on the Billown circuit cannot be a pleasant experience!!!

Eric Hulme's (Earache Racing) Suzuki TR500, although a rocket ship when going right, continued to eat pistons at an alarming rate.  These piston failures eventually caused the crankshaft seals to fail, which in turn resulted in a failure to get to the start line at Ty-Cros for one meeting.  The problem now seems to have been cured (fingers crossed!!!) as Norman once again finished first 500 and fifth overall in the unlimited Classic race in the final round at Aintree.  He finished seventh overall in the unlimited classic championship in spite of two DNF's in the championship.


The 2003 season will start with a similar setup to last year.  As well as the machines he rode last year, Norman will race a Maxton Yamaha TZ350G in the Forgotten Era Races at Aintree and some other circuits.  He will continue to race the Aermacchi 250 belonging to Roy & Sheila Clutton in selective 250cc Single Cylinder Classic Races.  He will also race the Suzuki TR500 belonging to Eric Hulme in selective 500/Unlimited cc Classic Races.

The Maxton Yam is one of Norman's old bikes that he raced in the 80's.  He has bought it back from Cliff Mylchreest who last raced it in 1990.  The bike has not been used since then, so there is quite at bit of work required to bring it back to race trim.

His first race of the season was at Aintree, the weather was pretty bad with heavy rain and high winds.  Some unfortunate rider also dropped a substantial amount of oil around the circuit when his engine blew and some of the racing had to be abandoned on safety grounds.  However, not before Norman won his class on the 250 Aermacchi.

Meeting number two was the Pre-TT Classic event on the Billown road circuit in the IOM.  Norman raced the Suzuki TR500 and Maxton 349cc TZ Yamaha at this meeting finishing fourth (2nd 350) in his class (unlimited superbikes) on the Maxton Yam.

The rest of the season brought mixed fortunes, the Aermacchi 250 broke twice, once while lying second (push rod failure in the engine) and the 2nd time on the first lap of a qualifying race (big end bearing) which put him out of the final.

However, he still managed to finish 3rd in the Aintree 250cc Singles Classic Race Championship on the Aermacchi and the Aintree 500cc Forgotten Era Class on the 350cc Maxton Yam.  He also finished 1st 500 in the Aintree Unlimited cc Classic Race Championship.

Norman continued to race between 2003 and 2008 and we will get around to updating the intervening period one day!

2008 Racing Season

This year was a bit up and down on the results with little success on the Honda RS125 (35 years too old and 3 stone too heavy for a 125!).  There was also the matter of binning the RS125 going into the corkscrew at Anglesey in July on the first lap of his first race there on the new circuit, resulting in one badly broken bike and more importantly a badly broken collar bone.

However, Norman did manage to finish 3rd in the Ace of Aintree 500 Classic Championship riding his T500 Suzuki.

2009 Racing Season

The first race of the season was at Oulton Park on the Suzuki T500.  However, this was a none event as the T500 was excluded from the meeting because it did not pass the noise tests.  We tried to rectify the excessive noise in the time available but to no avail - no racing so one p****d off rider!  When we eventually got the bike back to the workshop and dismantled the silencers it was found that the silencer fibre packing had completely disappeared.  The silencers were repacked and noise levels are now at the normal ear aching and not ear bleeding levels.

The second meeting was at Aintree and Norman managed to finish 5th in the 500 Classic race on the Suzuki T500.

The third meeting was at Aintree and Norman finished 3rd in the 500 Classic race on the T500 and 5th in the 125 race on the Honda RS125.  The T500 seemed a bit down on power so and a quick check of the spark plugs revealed some difference in colour.  Shining a torch down the left cylinder plughole at the piston crown showed what appeared to be a slight crack.  On removal of the cylinder head it was found that the piston had cracked and the combustion gases had burnt into the crack right through the crown at the edge.  The gases had also been directed at the small end bearing and con-rod eye, which was also damaged.  Close inspection of the right side piston revealed that this had also started to crack across the crown but not as badly at this stage.  This is a common fault with the Suzuki cast pistons and not the first time they have failed in this engine.

The images below show the damaged piston. (Click on the image to get a more detailed view)


New Taiwanese pattern pistons and rings were fitted, the co-rod can wait for another time, hopefully it will last until the end of the season.

In spite of riding the wheels off the 125 he just cannot make up for the extra weight and age he is carrying - need more speed!

The fourth meeting (11/07/09) was again at Aintree and Norman managed to win the 500 Classic race and was 3rd overall in the unlimited Classic Class.  So the cheap Taiwanese pistons seem to work OK - for now!  Norman now leads the 500cc Classic Championship at Aintree by one point over Steve Ferguson riding the very quick Honda 500.

For the fifth meeting, Norman relinquished his lead in the Aintree Championship by not attending the August meeting at Aintree in favour of attending the BSB round at Brands Hatch, in an official capacity (MCRCB Safety Delegate) and as a rider in the International Classic Grand Prix on his MAXTON TZ350 Yamaha.  The competition was tough with riders such as Eric Saul (GP winner), Lea Gourlay, Ian Simpson and many other talented riders.  In spite of riding as hard as he dare, Norman only managed to finish 29th out of 45 entrants because of his relatively slow machine.  The speed difference (sector 1 & 2 timing) between his Yam and the leaders was substantial, finish line, Norman's TZ = 115.1 mph, fastest TZ = 128.1 mph, Cooper Straight, Norman's TZ = 81.8 mph, leader = 103.4 mph!  Some serious tuning is required to the Maxton TZ350.

However, Norman was privileged to be the only rider on the grid to have two 'brolly dollies'  no one else was allowed any!

 Karen & Jane do the honours 

Norman and Marc Auboiron (France) battle it out into Paddock Hill bend.

  Chris Rose (UK) leads Norman and Steve Boam (UK) into Paddock Hill bend.

Norman at Paddock Hill bend.

Paddock again

Norman into Stirlings bend.


Round five (sixth race meeting) at Aintree saw Norman finish third in both the heat and final races in the 500 Classic on the T500.  This was in spite of a blown head gasket which seriously affected the performance of the big Suzy and ultimately caused it not to start for the final FE 500 race.

Click on the image below to see the offending gaskets in detail.  The right hand gasket has blown completely and the left hand has been damaged by detonation.

However, the third place in the Classic 500 race was enough for Norman to be placed 2nd in the Ace of Aintree 500 Classic Championship.

The seventh and last race meeting of the season was at Oulton Park on 24th of October.  Norman rode in the up to 500cc Classic race on Roy Clutton's 250 Aermacchi and rode his own Maxton 350 Yam in the up to 500cc Forgotten Era race.  The weather was predictably grim, with light to heavy rain, strong winds and (on occasion) a low sun on a wet road, not the easiest of racing conditions as many found out to their cost!  However, Norman managed to finish 7th on the Yam in the 500 FE race and 6th in the 250 Classic race on the Aermacchi while running in a rebuilt engine.  However, post race examination of the Aermacchi discovered a broken piston ring.  More work and expense for Roy in preparation for next season.

British Super Bikes

Norman has been appointed the Motorcycle Circuit Racing Control Board (MCRCB) Safety Delegate/Track Inspector by Jonathan Palmer (MRPC), Dennis Carter (AMRCO) and Stuart Higgs (MSVR) on 01/05/09.  His responsibilities in this role include race circuit inspections and licensing of all the circuits used in the British Super Bike and supporting championship races within the UK, investigation and recording of serious racing accidents, judicial and other delegated duties as required.


Norman has been sponsored to ride the Aermacchi belonging to Roy Clutton for many years.  Eric Hulme also sponsored him for many years on the TR500 Suzuki.  Eric has now retired from racing and Norman has purchased the Suzuki T500 from him.  In the past he has been sponsored by other generous people, such as; Terry & Barbara Kermode with the 250/350 Aermacchi's and a 320 Suzuki, Ron Leighton with the 250 Greeves, Mike Ridgeway with a Yamaha TZR250 and Tony Newby with the 500SR  Yamaha.

Sponsorship of any kind is always greatly appreciated, without it Norman's racing career would have been drastically curtailed.  Any offers of help with machines, supplies, entry fees, tyres, fuel or transport would be of great help.


The following web address takes you to the MYLAPS.COM site where the results of most of the racing in the UK are available for you to see.

Send mail to with questions or comments about this web site.
Last modified: 12/22/12