VIP Photo Contest - Racing Commandos

That's a cracking photo Steve, not seen that one before. I have one only photo! my son got for me taken at the hairpin. I haven't got the negative! I also went to chapel en le Frith to Ferodo to get my brakes done.

Has anybody got a picture of Tony Smith on the Thruxton Motorcycles Commando? He and the bike deserve to be mentioned here. I watched him and Pete Davies on the Slater Bros. Laverda Jota slugging it out during the Avon production series in the 70's, but don't have any photos unfortunately.

This is a poignant photo of my Commando Production Racer , First raced in 1976 as a converted 1974 850 Mk11a road bike , this picture was taken in 2013 having been de mothballed into service whilst waiting for my race bike to be completed , the poignant part is that this photo was taken 1min 14 secs ( next lap same place) before the crank let go completely destroying the engine : crank, cases, rods, cylinders, pistons, timing gears, timing cover &, primary cases. Sorry to say that the bike is still gatering dust in a dark corner of the garage along with a spare engine waiting for my upcoming retirement to give me the time to resurect it.

Love the caption when hovering over the picture

Did the crank break at the PTO shaft? or at the journal?

jseng1 said:

Did the crank break at the PTO shaft? or at the journal?

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Hi Jim, it broke right across the end of the left hand journal. mind you the crank was almost 40 years old it did 16000 miles as a road bike and 4 seasons as a race bike , it was no stranger to 8 - 8,500 rpm ( I dont do that anymore).

Moto55UK said:

This is a poignant photo of my Commando Production Racer , First raced in 1976 as a converted 1974 850 Mk11a road bike , this picture was taken in 2013 having been de mothballed into service whilst waiting for my race bike to be completed , the poignant part is that this photo was taken 1min 14 secs ( next lap same place) before the crank let go completely destroying the engine : crank, cases, rods, cylinders, pistons, timing gears, timing cover &, primary cases. Sorry to say that the bike is still gatering dust in a dark corner of the garage along with a spare engine waiting for my upcoming retirement to give me the time to resurect it.View attachment 16725

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I wish I had a photo of myself doing that. It looks excellent - a really lovely photo. If you are retiring, don't leave it too long before you get back on the bike, or you might lose the urge. These days my biggest problem is lack of motivation. I am too happy to relax and do nothing.

Moto55UK said:

Hi Jim, it broke right across the end of the left hand journal. mind you the crank was almost 40 years old it did 16000 miles as a road bike and 4 seasons as a race bike , it was no stranger to 8 - 8,500 rpm ( I dont do that anymore).

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had it been dynamically balanced or do you suspect simple stress fatigue?

Moto55UK said:

Hi Jim, it broke right across the end of the left hand journal. mind you the crank was almost 40 years old it did 16000 miles as a road bike and 4 seasons as a race bike , it was no stranger to 8 - 8,500 rpm ( I dont do that anymore).

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That is interesting. I always try to change up before 7000 RPM, and often see 7,500 RPM. I' have always been convinced that the Commando crank would not look at 8,500 RPM without flying apart. I have often wondered what I could rev it to, if I got desperate. My Triumph 650s would cop 8,000 RPM regularly, but I've never been game enough to do it with the Commando 850 engine.

acadian said:

had it been dynamically balanced or do you suspect simple stress fatigue?

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The crank in that engine had been balanced to 78-80% for use in a seeley commando, it was balanced and polished back in the 70's ,I would suppose it was stress fatigue. My race Bike last year had a fault with the clutch retaining circlip and on two occasions on one lap the clutch gave way and the Krober rev counter went off scale ( thats 10,000 rpm plus) the first time I didnt belive it, on the second time I pulled up. Had me worried but with circlip replaced it was still runing ok.

A radius on the PTO shaft reduces breakage in that area but it won't help the journal. Dynamic balancing is good but not enough in your case. You need to put your reciprocating weight on a diet. But nothing will survive at 10,000 and I also think that much RPM is hard to believe - your valves would be in the pistons.

jseng1 said:

A radius on the PTO shaft reduces breakage in that area but it won't help the journal. Dynamic balancing is good but not enough in your case. You need to put your reciprocating weight on a diet. But nothing will survive at 10,000 and I also think that much RPM is hard to believe - your valves would be in the pistons.

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My 500cc short stroke Triumph would rev reliably to 10,500 RPM. The valve gear was polished and lightened. The cams had very long duration, very slow lift rate and less max. lift than normal Triumph cams. It also had a very strong one-piece billet crank and the longer Triumph rods. But I would not have thought a Norton crank would cop that without leaving a piston behind. After I built the Seeley 850, it sat unraced for 25 years because I'd seen what was inside it. - YUK ! - For what they are, the Commando engine is unbelievably good.

Herewith my classic sidecar with/without firing (now smartened up and repainted Blue) with 850 Commando engine. This has been sleeved down to 750 to compete in a different class, mind you, still to get to this year!

lcrken said:

Well, the front brake photo contest was so much fun that I'm taking Jerry up on the challenge of posting another one. This time it's for pictures of racing Commandos. I'll try to make the rules clear enough that we don't get confused (right!). Winner is the one with the most votes at the end of 31 July. That should be enough time for everyone who wants to participate to sort out a picture and post it. Enter as many time as you want, but only one picture per bike and only one picture per post.

1. Must be Commando engine and frame, modifications allowed. No Seeleys, Rickmans, etc.
2. Must have been or about to be raced. Road racers, landspeed racers, hillclimbers, ice racers, flat track, motocross, trials, etc., as long as it's racing.
3. Poster must be personally involved in some way with the bike, owner, rider, bulder, mechanic, sponsor, pit tootsie, etc. Edited to also include photos taken personally by the poster, even if no other involvement in the bike. Still no fair just posting a picture of something you saw online.
4. Vote for it on whatever basis you like, photo quality, originality of design, racing history, blingness, or just plain coolness.

Ken

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lcrken said:

Well, the front brake photo contest was so much fun that I'm taking Jerry up on the challenge of posting another one. This time it's for pictures of racing Commandos. I'll try to make the rules clear enough that we don't get confused (right!). Winner is the one with the most votes at the end of 31 July. That should be enough time for everyone who wants to participate to sort out a picture and post it. Enter as many time as you want, but only one picture per bike and only one picture per post.

1. Must be Commando engine and frame, modifications allowed. No Seeleys, Rickmans, etc.
2. Must have been or about to be raced. Road racers, landspeed racers, hillclimbers, ice racers, flat track, motocross, trials, etc., as long as it's racing.
3. Poster must be personally involved in some way with the bike, owner, rider, bulder, mechanic, sponsor, pit tootsie, etc. Edited to also include photos taken personally by the poster, even if no other involvement in the bike. Still no fair just posting a picture of something you saw online.
4. Vote for it on whatever basis you like, photo quality, originality of design, racing history, blingness, or just plain coolness.

Ken

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Hi
I guess this is only open to VIP members? Pity. I have a classic racing sidecar with a Commando engine installed!

Champy72 said:

Hi
I guess this is only open to VIP members? Pity. I have a classic racing sidecar with a Commando engine installed!

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Ian should be in the other frames competition? Your not running a Commando frame lol are you?

Champy72 said:

Hi
I guess this is only open to VIP members? Pity. I have a classic racing sidecar with a Commando engine installed!

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I don't think that's the case. As I understand it, putting up a new photo contest is restricted to VIP members, but any forum member can enter the contest. Just post to the thread and include at least one picture of your bike. Jerry's software automatically picks up the first photo in your post and adds it to the contest list. If I'm wrong about this, I'm sure someone will cheerfully correct me.

But as Chris already pointed out, this is the contest for Commando racers, i.e. Commandos that are raced, not just something with a Commando engine. The other contest I started is for Commando engines in other frames.

Ken

Usually there is a prize if you win a contest. I've just bought a tube of metal polish.

cliffa said:

Has anybody got a picture of Tony Smith on the Thruxton Motorcycles Commando? He and the bike deserve to be mentioned here. I watched him and Pete Davies on the Slater Bros. Laverda Jota slugging it out during the Avon production series in the 70's, but don't have any photos unfortunately.

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Pics of Tony Smith in this thread https://www.accessnorton.com/NortonCommando/thruxton-motorcycles-commando.22906/

lcrken said:

I don't think that's the case. As I understand it, putting up a new photo contest is restricted to VIP members, but any forum member can enter the contest. Just post to the thread and include at least one picture of your bike. Jerry's software automatically picks up the first photo in your post and adds it to the contest list. If I'm wrong about this, I'm sure someone will cheerfully correct me.

But as Chris already pointed out, this is the contest for Commando racers, i.e. Commandos that are raced, not just something with a Commando engine. The other contest I started is for Commando engines in other frames.

Ken

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Thanks Ken (and Chris). I missed the bit about the engine being mounted in a Norton frame! Mine obviously isn't, although it is a race engine and is raced at circuits (when the madness ceases!!!)
Ian

Here is a photo from my California days. I am almost certain that it's the exit of the banked turn at the old Riverside Raceway (a photographer walked up to me at the next AFM race and handed me a slide saying "I took this at the last race and wanted to share it with you"). The race before this one, a fairing mount had failed from a fatigue-crack at Ontario and when I looked at the one on the other side, it was also cracked, so I took it off (I have an "AMA" fairing) and put a front number plate. That "single race" expedient became preserved for history (although I like the look of the clean bike in the photo).
This motorcycle has what I think is the first "John Baker" hopped-up 850 engine (if not the first, it's almost certainly the oldest surviving one). I had a 72 750 Combat roadster and after almost 10,000 miles on the road and some pretty intense club racing, the engine appeared to be absolutely solid and the Service Department offered me a swap -- my "unbroken" Combat 750 for teardown and analysis for an 850 assembled from Experimental shop parts. John and I built up this engine from December 72 until about February 73. It was his experiment in head work and bottom end preparation for a go-faster 850. It also happened that Service Dept. had a complete PR chassis kit that was donated (I love the Isolastic head steady). The glassfibre bits were special ordered for me from RGM in red gel coat.


Oh, hell. How ITF do I get the photo to show up without having to click on the link ????