143MPH 850 MK1 Commando?

Rohan said:

JPN racers were on a fairly limited budget, so be interesting if anyone knows the answer to this.

George Hunt has what he says is as near to a works 500cc Domiracer as can get (what does that mean ?) and it has a set of titanium pushrods.

Titanium parts are of course a lot more common (and affordable) now than they were were back then - EXPENSIVE was then the word.

Seem to have wandered a long way from fast road bikes....

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Re; Titanium parts.
Unless I am very much mistaken and the metallurgy has improved over the last few decades, a Titanium con rod would be too elastic :?:

i want at least 160 mph street bike ya know, but not sure how or if I can and still remain in vintage Thunderbike style of Commando based cycle. Britton is like a God to me in many ways from him over coming his dyslexic handicaps to privately out classing the rest of the world back then. But I hope Peel can run circles around even Britton's extreme cycle up to some ridiculous speed so well * 200 mph won't be enough to catch up what they lost in corner speed and acceleration into opens. On Peel if the turn ain't a decrease'r radii it don't even feel like real turn on her. Ken Canaga says he'll lighten her Norton lifter slugs some but I don't think valve train will be the limiting factor as much as sustained hi power heat dump from engine and tires. Its occurred to me to fit a 17" rear wheel but what I'd really want to fit is a sports car tire. Don't want to move chain drive further out so the darkside may remain a Peel pipe dream. I love the high of embarrassing sports elites with eager pilots... who wouldn't. You can search up downsides to Ti pushrods and why steel is generally favored and why push rod and lifter mass is rather secondary to their alignment and stiffness.

Well, Hobot, just as a matter of relativity,
In July `94, Sport Rider mag tested a [production Rotax mill] customer Aprilia RSV 250R G.P. racebike, it weighed 211lb[dry] & went down the 1/4 mile in 10.91 @ 130.4 mph...

Bernhard said:

Re; Titanium parts.
Unless I am very much mistaken and the metallurgy has improved over the last few decades, a Titanium con rod would be too elastic :?:

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I believe aluminum is even way more elastic than titanium yet they use them for connecting rods. I know some will say aluminum rods are used for the springyness that protects crankshafts from hard hitting nitro but I am pretty sure it has to due with the fact that you need to use so much more cross section (bulk) to get the required strength that you end up with much more favourable slenderness ratio.

Peter Williams used steel pushrods in his Isle of Man winning F750 works racer.

The book, Norton, The Racing Story states that he felt they did not expand and compress as much as aluminum.

Tubular, or composite? [or filled, to damp out harmonic flexing/oscillations?]

I"m creeping up on the stuff to support Peels power unit but being as realistic conservative in online engine calculators with feed back of similar engines, Peel should break under 10 sec 1/4's if she can hook it up and not blow up. The fastest dual engine Triumph did rather under 9 sec 1/4's on 4 inch slick so its definitely possible. TC runs 16x5" on his street 850. i cut my teeth on a freaking 10.5 sec P!! champion with 4 in slick, not that I could pull that off of course but with its power/wt ratio low 11 sec was on tap any time I dared as all the H2 buzz bombs in capitol of Fla found out thinking they were getting the leap on a 50 cc size clunker 4 stroker. I ain't worried about the stock p-rods as tested them over 11 grand fine. Maney owes me a custom length steel set but first got to finalize the length to order, someday after Canaga makes up factory Al ones for valve train vs gasket thickeness I settle on with detonation feed back.

Norton 40 yr old rods likely beefy enough to even take Peels blown power but for how long is the question and ain't as light or effective as Jim's long Carrilo rods and pistons. The Al rod are used in the top fuelers to save crank and shells as cushions but only get a few 1000 cycles use before replaced after a run. No top fueler runs for a full minute just some warm up tire smoke, idle to stage lights then launch and shut off a hand full of seconds later.

Extra nose rubbing in, is Peel is legal street-able off road able long range comfy all weather heavy cargo hauler to earn her keep next couple decades. Her new form and mass lessening and centering hold subtle mysteries I'll have to creep up on but those likely will only show up in solo flights beyond what it takes to out zoom the elites in 1/4 mile lengths or for sure in turns, especially those over 45 degrees one after another. I"ve already discovered a fairly light Cdo with race like power can out leap the elites that climb the sky trying to beat Peel into one lane turns. Peel wasn't nearly as quick as my P!! whiplasher so Peel didn't need nose lowered to resist wheelies much but next Peel sure will.

I hope for 1 hp per 4 lb bike+pilot and similar 1 lb ft per 4 lb total mass. Look up them elite figures on this to see Peel might not be out classed except for land speed only bikes or pure drag race only bikes, neither of which can turn worth a dam. There are a few isolated roads near me, one called Race Track Road I rode twice this weekend that 150+ mph would be safe as pie leading into the chicanes that really test bike and pilot. There are fastest mile events all over so won't have to guess about Peel bee line pecking order. You and I will know Peel ain't really a Norton but strangers won't know when passed.

Above is on pump gas and water, so still leaves methanol and nitromethane fuels for special events if I get bored. Excuse my devil may care attitude but to run like I'm talking one can't be timid or unsure about ones self much or better not press on. Peel can be detuned to meet vintage race rules so may find out how well her handling does unboosted even if low on power compered to 1007 cc road racers. It ain't about me i want world to notice its what lurks in the genius of isolastic chassis and Roadholders brought up to full potential cheap and easy anyone can enjoy, then add what ever power and subtracts as much mass as ya can afford. Crash cage is for real life events I fear not safe race events.

Hobot, you`re not concerned that a cage might infact be a cause of extra injury?, maybe as more tubing to be impaled upon?
FYI the last 250 G.P. bikes made ~115hp, went ~ 190mph, weighed ~220lb [by rule book].

Ugh Jaw absolutely I've considered the crash bars crushing parts of me after a crash but if it don't kill me out right or cut off a major part then I'm a cheap fix but Peel is expensive as hell. Crash bars won't focus any more intensely than whats already been impressed by barrel fins or landing on head with bike on top. Yo'all just don't/can't comprehend how secure Peel is beyond two tire traction speeds so I don't fear crashes in same sense as anyone else in the world ie: lossing control unexpected, I've tried to near death states to find Peels limits but its beyond what power she had or the wagon trail bluff face roads switch backs I've tested on. Only things that scares me is un-avoidable big animals and tree falls or other craft hogging the road while I'm going sanely routinely along to lose another bike no fault of my own but putting butt in a saddle. I've horse experiences too ok, like on Gravel and tarmac and into dead tree falls with bare branches sticking out like spears. One of my greatest fears going into brush or grass too high to see everything is having a branch lance me through. Same as going off the edge about any where not paved here, speared or barbed wire sliced or bashed on stump or rock face. I'm kinda scared of speed, but it don't scare me while accelerating up to it strangely.

Peel power needs like 30 lb of blower and water and air station stuff so should come in 320-ish lb road legal and better make more than 115 hp so with fairing and lowers what you report implies 200 mph potential but I've been to that scale event and can't even dream that fast. My dream is to run cable-fabric biplane like craft in circles around the elite missiles before they can hit full after burner to break sound barrier. Acceleration is Peel's middle name not record top end. Peel invites me to stunts and recovering or avoiding road race crashes is exactly the same thing so there's plenty of other fun thrills with power to weight and insane handling than just going fast all the time. Its the animals I expect to get hurt on the crash bars.

Monroe said 5 min on a bike like his was worth a life on others. Chasing deer on wet grass for half a min toward tree fall or fence is worth a few years racer hair raising.

I believe aluminum is even way more elastic than titanium yet they use them for connecting rods. I know some will say aluminum rods are used for the springyness that protects crankshafts from hard hitting nitro but I am pretty sure it has to due with the fact that you need to use so much more cross section (bulk) to get the required strength that you end up with much more favourable slenderness ratio.[/quote]

The difference is that aluminium con rods can be heat treated to get the right specification, whereas with titanium you might be able to do it, but titanium metal is still too expensive, and has a limited life span.
Anything made from titanium would have to be replaced after about five years or it will fail.

Yes Al needs more size for the strength and reason Norton rods have steel caps. M.A.P. sells all Al rods but the Al end caps are so big the crank cases have to be relieved to clear them I've read. TC engines were factory parts inside and did like 165 run through some years w/o having to open engines. Amazing evidence Norton rods are plenty good enough for 150 hp level and 8000-ish rpm TC told me he tried to shift at. I'll be pretty happy to see 120 rwhp on Peel but hope for a 10-20 more. Ken told me the un-blown 920 should be good for 150 on level pavement.

Bernhard said:

The difference is that aluminium con rods can be heat treated to get the right specification, whereas with titanium you might be able to do it, but titanium metal is still too expensive, and has a limited life span.
Anything made from titanium would have to be replaced after about five years or it will fail.

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You can get the right specifications with Titanium. As for too expensive; well when pushing the technological limits, an ounce of prevention is woth ten pounds of cure, or, in other words, a proper application (be it Ti or whatever) of say $700 is worth a blown engine, missed race or death $$$$$$$$$$$$$.

As for replacement, you can say that with more certainty with Aluminum and maybe/maye not with respect to steel, depneding upon the magnitude of stress reversals and number of stress reversals.

hobot said:

Yes Al needs more size for the strength and reason Norton rods have steel caps. M.A.P. sells all Al rods but the Al end caps are so big the crank cases have to be relieved to clear them I've read. TC engines were factory parts inside and did like 165 run through some years w/o having to open engines. Amazing evidence Norton rods are plenty good enough for 150 hp level and 8000-ish rpm TC told me he tried to shift at. I'll be pretty happy to see 120 rwhp on Peel but hope for a 10-20 more. Ken told me the un-blown 920 should be good for 150 on level pavement.

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Not that simple. Measures of durabilty are the magnitude of load (actually stress) reversals and number of stress reversals. Time is really not a factor unless you want to predict when a component will fail.

I smile when you bring up TC's application. Let's say he averaged 13 second runs and 6,500 rpm; that's roughly 1,400 load reversals. On a typical Vintage road race weekend (AHRMA) signed up for two classes, Friday practice and Saturday and Sunday racing you would expect to see upwards of 780,000 load reversals in and around 6,500 rpm. Road applications will far exceed this but at much lower average loads. I don't believe there's a linear relationship between stress cycles and durability but I may be mistaken.


The point is you cannot look at one thing in isolation as it is more than an oversimplification, it is flat out missing the point.

Well . . . this thread has certainly rained on my parade and contributed to the demise of my ego. In the early 80's I was taking a long weekend camping trip with about a dozen buddies, traveling from San Francisco to Bakersfield (for a Brit bike swap meet) then on to the Sequoia National Forest for camping. My group left the city very early--before sunrise--and my girlfriend and I, heavily laden with tents strapped to the handlebars and duffle bags/sleeping bags strapped to the rear grab bar, were wide awake and excited to begin the trip. As was our group's habit, the Nortons led because we always ran out of gas first and, after a lengthy time on Highway 101 and a fill up or two, my girlfriend locked her fingers together with her hands around my waist and fell back to sleep, somewhere between Salinas and San Miguel . I'll never forget the feel of her helmet bumping my left shoulder and my helmet. Anyway, I was in the lead of the pack when all of a sudden, two BMW K100RSs screamed past me. I had no idea how fast they were going, or I, because my guages were covered with camping gear. As they got smaller and smaller on the horizon, and knowing my girlfriend was asleep, I decided I would try to catch them. I gave my 850 Commando full throttle and about twenty or thirty minutes later I was beginning to get closer to them. A little longer and I was a hundred yards behind them but staying up with them, finally. It was at that point I decided I had accomplished what I didn't know if I could do and backed off the throttle. They took the next exit and I followed, thinking I should refill after my lengthy use of a full throttle. They, too, pulled into a gas station and filled up. When my girlfriend left to use the bathroom and get us some coffee, one of the bikers came over and admired my Norton. After letting me know how beautiful he thought it was he asked, "Do you have any idea how fast you were going?" I answered I couldn't tell (as he could see) because my guages were covered. He told me that, according to their speedos, I had caught and stayed with them doing around 130 mph. All I could say was, "wow." I've never questioned their info nor done enough research to question whether what they said was accurate or not. All I know is that I had a pretty nice glow going for about 30 years that could very well be gone, now. C'est la vie . . .

defixione said:

Well . . . this thread has certainly rained on my parade and contributed to the demise of my ego. In the early 80's I was taking a long weekend camping trip with about a dozen buddies, traveling from San Francisco to Bakersfield (for a Brit bike swap meet) then on to the Sequoia National Forest for camping. My group left the city very early--before sunrise--and my girlfriend and I, heavily laden with tents strapped to the handlebars and duffle bags/sleeping bags strapped to the rear grab bar, were wide awake and excited to begin the trip. As was our group's habit, the Nortons led because we always ran out of gas first and, after a lengthy time on Highway 101 and a fill up or two, my girlfriend locked her fingers together with her hands around my waist and fell back to sleep, somewhere between Salinas and San Miguel . I'll never forget the feel of her helmet bumping my left shoulder and my helmet. Anyway, I was in the lead of the pack when all of a sudden, two BMW K100RSs screamed past me. I had no idea how fast they were going, or I, because my guages were covered with camping gear. As they got smaller and smaller on the horizon, and knowing my girlfriend was asleep, I decided I would try to catch them. I gave my 850 Commando full throttle and about twenty or thirty minutes later I was beginning to get closer to them. A little longer and I was a hundred yards behind them but staying up with them, finally. It was at that point I decided I had accomplished what I didn't know if I could do and backed off the throttle. They took the next exit and I followed, thinking I should refill after my lengthy use of a full throttle. They, too, pulled into a gas station and filled up. When my girlfriend left to use the bathroom and get us some coffee, one of the bikers came over and admired my Norton. After letting me know how beautiful he thought it was he asked, "Do you have any idea how fast you were going?" I answered I couldn't tell (as he could see) because my guages were covered. He told me that, according to their speedos, I had caught and stayed with them doing around 130 mph. All I could say was, "wow." I've never questioned their info nor done enough research to question whether what they said was accurate or not. All I know is that I had a pretty nice glow going for about 30 years that could very well be gone, now. C'est la vie . . .

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130... two up... camping gear... no need to research anything. :roll:

defixione » Tue Sep 11, 2012 10:42 am
Well . . . this thread has certainly rained on my parade and contributed to the demise of my ego. In the early 80's I was taking a long weekend camping trip with about a dozen buddies, traveling from San Francisco to Bakersfield (for a Brit bike swap meet) then on to the Sequoia National Forest for camping. My group left the city very early--before sunrise--and my girlfriend and I, heavily laden with tents strapped to the handlebars and duffle bags/sleeping bags strapped to the rear grab bar, were wide awake and excited to begin the trip. As was our group's habit, the Nortons led because we always ran out of gas first and, after a lengthy time on Highway 101 and a fill up or two, my girlfriend locked her fingers together with her hands around my waist and fell back to sleep, somewhere between Salinas and San Miguel . I'll never forget the feel of her helmet bumping my left shoulder and my helmet. Anyway, I was in the lead of the pack when all of a sudden, two BMW K100RSs screamed past me. I had no idea how fast they were going, or I, because my guages were covered with camping gear. As they got smaller and smaller on the horizon, and knowing my girlfriend was asleep, I decided I would try to catch them. I gave my 850 Commando full throttle and about twenty or thirty minutes later I was beginning to get closer to them. A little longer and I was a hundred yards behind them but staying up with them, finally. It was at that point I decided I had accomplished what I didn't know if I could do and backed off the throttle. They took the next exit and I followed, thinking I should refill after my lengthy use of a full throttle. They, too, pulled into a gas station and filled up. When my girlfriend left to use the bathroom and get us some coffee, one of the bikers came over and admired my Norton. After letting me know how beautiful he thought it was he asked, "Do you have any idea how fast you were going?" I answered I couldn't tell (as he could see) because my guages were covered. He told me that, according to their speedos, I had caught and stayed with them doing around 130 mph. All I could say was, "wow." I've never questioned their info nor done enough research to question whether what they said was accurate or not. All I know is that I had a pretty nice glow going for about 30 years that could very well be gone, now. C'est la vie . .

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Oh my what a tale I'll savor now and then a long time. Over 120 is high speed to me and to hold there so smoother and sure your gal didn't notice is magic flying carpet as it gets. I missed out on that - so far. Not many will do 130 even if bike capable of it. We have seen a test that showed Smith speedos are within 1 mph to hi speeds so congraates on pulling even over that to catch up to em!!

Dances I've have my ears up for like 13 yr now plus years to read threw every Norton archive site and years of quizing old gizzers on 3 other long enduring list and really have not read of a report of Norton rods being the weak point other than maybe some of the big blocks rev'd like crazy. My reasoning is also based on the numbers of long range ridders not reporting rod source blow ups. Al has a cycle life time * if built light enough so there is some threshold of compression/ tension/ flexion stress waves - then its life time is litterally numbered - but if built stout enough then there is not enough stress cycles waves to matter awhitworth for indeterminate life time with some pretty powerful engines. My humble impression is that crank flex tips the journals which then binds the shells to let go if ever a rod were the first item to break its still not exactly its fault if crank didn't flex rod would hang on too. I'm correctable on my impressions and certainly there are faulty rods made so await my slapping to be set straighter.

Check out Phantom Oiler for some desert racer Al rod time cycle tales of pressing 8500 to get past them new fangled inline 4's.
http://vintagenet.us/phantom/contents.html

Check out Capt. Norton Notes archives on crank shaft rpm issues with a number of drag racers reports that involved crank, bearings and cases but not rod as rpm limiters.
http://www.captain.norton.clara.net/

Still stewing on 5 hp tire drag vs rpm vs PSI. Not all power use is just for high speed runs, its also thrilling to spin tire to high speed while not going nearly as fast as the speedo shows.

130... two up... camping gear... no need to research anything

properly secured , the steamling could be worth a few wotsits . If they were japanese speedos :lol: but they were efficient tuetonic ones .

Nevertheless , im now wondering if mine wouldve run to 7200 or 7500 in top , on the 23 teeth . Old trick was ly flat and place left hand on
left fork staunchion. Indeed , some of the bizzare quatermile times in magazines utilised this tecnique .

a strong post 72 engine may well have been capeable of it in favourable conditions , undulateing roads dont necesarilly slow things .
Onto motorway once , set the progressive Weber at the stop for the second choke and left there , it would pick up speed on each downhill and
hold that up the next , add infiniteum . just as well we ran out of undulations , it couldve well taken off . :lol: 8) Thats on HALF throttle.
Primary Choke Only , with a good exhaust system . Two actually . :wink:

Hobot, high speed wheelspin-wise, unless you are heeled over, or topping a rise in the road, so get some dynamic input - just feels like clutchslip to me.
& Matt, I`d reckon you`d need at least 2, [possibly 3] good exhaust systems to expell all the smoke you blow...

J.A.W. said:

"As for lap times..." Indeed, Frank Perris J.P.N. team boss, disputes P.William's claim that the Mono was quicker than the space frame, he wrote that they were dimensonally [cycle-wise] identical, but the S-F weighed considerably less, & the clincher is in the lap charts which shows the S-F lapped quicker...
Incidentally, John Cooper couldn`t cope with the +15 hp drop from his trick BSA R3 - when he raced the J.P.N. bikes[he was faster on his 350 Yamsel], & prefered the `72 Commando based chassis of the lot.

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I think it highly likely that John Cooper would naturally prefer the Commando based bike. After all John was never a small man, bigger than most racers at the time I should think, and Peter was both pretty wiry then and somewhat obsessed with getting tucked in and he worked in the wind tunnel with his own physique for guidance....the fact that Croxford was also able to get sufficiently tucked in is a tribute to his physique and determination....

I doubt I would have been comfortable on the JPNs either....I find myself sufficiently challenged by a MkIV Seeley....

As for John being faster on his 350 Yamsel, many riders of the later '70s regularly did faster laps on 350 Yamaha twins, even when the other bike they may have been riding was a TZ750 or RG500...

Hobot, high speed wheelspin-wise, unless you are heeled over, or topping a rise in the road, so get some dynamic input - just feels like clutchslip to me.

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Yes sir JAW tire spin sucks for straight line get go but not for thrilling tight cornering w/o loosing momentum and one of the reasons I've mentioned Peel getting into reversed control states, throttle is used to slow into apex, as it trips out to lean and steer, so relieves the need of much if any front tire traction. I'm not that fascinated by pure speed, my addiction is the acceleration w/o much tire spin. Maybe next year Peel can collect a Texas Mile speeding ticket both naked and with fairing. One more welding job to hook up controls then tedium of hoses and wires and tubes and tuning to get an old Norton noticed. One of the best ways to tell how well tucked in ya are is ride in cold air and tuck in to feel it the least. Btw exhaust blast aim definitely is a factor in hi speed drag reduction. I've gotten to see the whole air flow of un-faired Commando high lighted by fog in full moon light so Peel may have extra mud flaps to help deflect the turbulence.