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Thread: New life for a classic race bike

  1. #1
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    New life for a classic race bike

    This story starts back in 2020 but it's a tale worth telling for posterity.

    Colin Seeley was a highly successful British sidecar racer back in the 60's who subsequently gained international fame for building frames for race bikes which were light but produced better handling than virtually anything else available at the time. He was also associated with Brabham race cars in the 1980's because of his reputation.

    He built an ultra lightweight and physically tiny 500cc Matchless G50-engined race bike for well-known UK racer Dave Croxford to campaign for the 1971 season. As an aside, I was living in the UK at that time and regularly went to the various races so must have seen it, although I have no specific memory of the bike. Although the competitiveness of British singles was on strictly borrowed time against Japanese and Italian bikes, Dave Croxford and the Seeley had some epic battles and wins against them on the short circuits. A good example of power to weight ratio and sublime handling.

    Jumping forward to late 2020 to continue the story, UK auctioneers Bonhams; were auctioning a parcel of rare and classic bikes. My mate Paul successfully races a Norton 850 in NZ and he saw a Laverda Jota among the auction offerings as well as the Seeley. The auction was in the middle of the night NZ time but Paul sat up and joined the on-line bidding. The Jota went for far more than Paul was prepared to pay but for some unknown reason, he was the only bidder for the Seeley and got it at an excellent price.

    Unfortunately and no thanks to Covid and a UK dock strike, there was a substantial delay in getting it shipped to NZ. When it eventually arrived, Paul had it sent to the company which prepares his Norton racebike for a ground-up rebuild. The engine was pretty tired and needed TLC. By way of example, those big singles used to vibrate and the frequencies caused cooling fins among other things to fail. No mucking about, a new cylinder head was fitted and plastic wedges between the fins to dampen the vibrations.

    Referring to the attached photos, they show me sitting on the flawlessly restored bike. I'm only 5'7" and my knees are pretty bent whilst sitting on it. The side fairings have been temporarily removed for engine access. Small, light bikes don't need monster horses to go tolerably fast.

    The MGB GT belongs to my wife and me - a concession to advancing years!

    Here's the blurb which went with the Bonham's auction:

    THE EX-WORKS, DAVE CROXFORD

    1971 SEELEY 499CC G50 MARK 4 RACING MOTORCYCLE
    FRAME NO. MK4 CS EXP 152
    • Prototype Seeley Mark 4
    • Raced by Dave Croxford during the 1971 season
    • Present ownership since circa 2009
    • Fully restored 2009-2011
    • Offered from an important private collection


    Many-times British sidecar champion Colin Seeley bought Associated Motor Cycles' racing department when the company went into receivership in 1966. The previous year he had constructed the first Seeley racing frame to house a Matchless G50 engine, and the AMC purchase enabled him to produce complete Seeley G50 and 7R machines. With their improved frames, the ageing four-stroke singles enjoyed renewed competitiveness, Dave Croxford winning the British 500 Championship on a Seeley G50 in 1968 and '69.

    "Our association with him over two years had been just brilliant," recalled Colin in the first volume of his autobiography Colin Seeley Racer ...and the rest. "Dave was a real trouper and an entertainment on and off track. He had achieved so much in two seasons, winning races, circuit titles and two British 500cc championships on his Seeleys. Croxford's contribution to the Seeley Racing Company was considerable."

    The Seeley frame progressed from the duplex cradle original to the similar but lighter Mark 2 before the down-tubes were abandoned with the Mark 3, the headstock and swinging arm pivot of which were linked solely by tubes running diagonally above the engine. Introduced in May 1971, the Mark 4 featured a revised tubing layout and continued in production until 1973.

    Having enjoyed what by his standards was a rather disappointing season riding Yamahas, Croxford returned to the Seeley team in time for the 1970 August Bank Holiday meeting at Oulton Park to ride the prototype Seeley-QUB and was back in the Colin Seeley Racing Developments team full time for 1971. His first race was at the Transatlantic Trophy meeting at Brands Hatch riding the prototype Mark 4, the machine offered here. Colin recalled: "For the 500 race Dave Croxford came to the line with my new Mk4 Seeley G50, painted in a striking colour scheme of red, orange and black." Croxford scored a sensational debut win on the new Mark 4, pipping Gus Kuhn's Charlie Sanby on another Seeley. However, by this time over-bored Yamahas were beginning to assert themselves in the 500 class and wins would be ever harder to come by. When Seeley and MRD (parent company of the Brabham Formula 1 team) agreed to merge at the end of 1971, the Seeley motorcycle racing team was stood down and Croxford was left unemployed, though he swiftly found another job as Peter Williams' team-mate at John Player Norton.
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  2. #2
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    20th January 2010 - 14:41
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    They used to run a bead of Weld between the fins i think that was a Ron Lewis or Fred Walsmy mod?



    Kinky is using a feather. Perverted is using the whole chicken

  3. #3
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    Quote Originally Posted by husaberg View Post
    They used to run a bead of Weld between the fins i think that was a Ron Lewis or Fred Walsmy mod?
    Yep, anything to damp the vibration. A couple of photos here of the old head and one of the new barrel with the rubber vibration dampers.
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  4. #4
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    Great post! Thanks fopr sharing. Bike looks great!

  5. #5
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    20th January 2010 - 14:41
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    The one i remember was straight weld but this appears to be the solution on george beales replicas
    Your mates solution is far less intrusive.
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    Okay this is how i remember it.
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    Last edited by husaberg; 31st May 2025 at 13:36. Reason: edit found better pic



    Kinky is using a feather. Perverted is using the whole chicken

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