155 HP 920cc Norton on Nitros - crash at Bonneville

I thought the transmission loss was calculated in some way from allowing the engine to coast down unloaded on the dyno.

Only thing constant in the measures are the same dyno with same operator, duh. But dang it we should be able to come up with realistic drive train and tire drag to level the field on extrapolating to crank. I've turned my whole drive train by just thumb and index on clutch nut with most the effort just getting over inertia. I'll add this to Peel list to sort out. Texas Big D's not too far away, I think they've a shaft dyno. If not fun to track down one to adapt, then ruin some tires on rollers too.

I like teasing HD crowd as much as the sports bikers, recoiled a whole news crews once doing a noise report - no HDs handy and mine sounded deep enough with open megaphone, spiked them to the spine when given nod to liker RIP. At these huge rallies they have roller dyno contests, some supercharged. I know this whole hobby is plain flipping nutzo, so I plan to live it up pressing pecking orders.

Still nothing like a real time slip to settle bench racing banntering. Think about Peel's deal shoving your reclining hiney for fun : )

How did Fred's head seal to cylinder?

Perhaps it should also be pointed out that a Norton 16H uses exactly the same gearbox and transmission as an ES2 did - and the Norton 16h only puts out about 12 or 14 bhp, so its losses can't be anything of that order either.

Maybe this is why they call it ' bench racing'.
And the other phrase that goes with that is - '\when the flag drops, the bullshiiit stops'.

I had to face up to riding to crash again because I didn't know what went wrong the first few times. Can ya imagine this at 135.

Indeed.

It says there somewhere the rear tyre blew ?

I'd be having a close look at the ratings on those tyres - since the rims are off something quite small, and they (tyres) may well not have enough speed rating ???

Ugh, Rohan, ain' ya paid attention to me on BI list or watched old cycle movies? Hard tires are fine over their rating as long at not in rain road racing. Tire rating is way over rated and only concerns sustained speeds any way. Also flats at near the ton+ are almost undetectable if holding a straight line, though likely not if putting over 100 hp on it to accelerate over rough looseness. Tubes would come to my mind as 1000'x more likely to blow than tire. I've found Z rated in our sizes but can bump rating above their tubeless one by shaving or rubber and shoe polishing the cracks.

Aero dynamics vs CoG enters equation but prior 155 run had no fault mentioned with tire or handling. Ya don't know the limits of suspension on rough stuff til ya cross it too harshly.

I saw the junk posted about old tyres - and old tubes - remind me not to ride anywhere near folks with tyres like that.

And having had several car /truck tyres blow/disintegrate at beyond rated speeds (read the sidewalls, including load rating, CAREFULLY) and nails puncture tyres along the way, I'd say anyone who says a flat beyond 100 mph ya won't notice is talking garbage...

P.S. I've had an old tyre that blew out on a display bike - just sitting in the garage.

hehe, my point being - if I can get away with what I do for decades on old tires both bikes and cycles, then Fred's up to snuff tire would be a rare event if it failed. I have un-wraped new tires on cars, vans and trailers so no stranger to the tire itself failing, but these were later revealed as deflective production or me pressing beyond their ratting knowingly in weight and speed. Saw one fellas destroy some under rated old tires at Texas MIle, braking hard after the timing run the fronts blew to slide to a stop and delay next run a bit. Flexing and heat and puncture is what gets tires new or old. I've seen old tires on mowers, tractors and bikes split apart when a new tube put it, so of course there is some threshold but not nearly as dangerous as most percieve. I say "Always fit the best rubber you can afford", if you want to quote my best advice to others w/o skewing to absurdium.

Guess you'd have even lower opinion of old tire wisdom on this fella's tires.

Burt Monroes 1st Bonnyville attempt was on th' original tires his 1920 Scout came with , He had shaved all th' tread of down almost to th' cord and pumped them up to 65 psi !
His 212 mph pass is "unofficial" since he was unable to make th' 2nd run !

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Still mounted intact.

hobot said:

Guess you'd have even lower opinion of old tire wisdom on this fella's tires.

Burt Monroes 1st Bonnyville attempt was on th' original tires his 1920 Scout came with , He had shaved all th' tread of down almost to th' cord and pumped them up to 65 psi !

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A moments reflection reveals that that quote is absolute rubbish, on several fronts.

Firstly, a 1920 Scout would have had clincher rims. By the 1950s, if it was still on its "original tyres" his bike can't have been ridden much. ?? (The book says it was ridden, and raced, extensivley). And clincher rims used high pressures anyway - my old clunker uses 60 psi in the tyres just to hold the tyres on the rim, for display. For riding, the pressure should be more. Evil things, if the tyre blows - the tyre won't stay on the rim, can seize things and bring you down, big time.

If it had later rims, it wasn't uncommon practice to shave down NEW tyres for racing - even Vincents had problems with tyres on record runs in the 1950s. Someone reported the rubber actually partly melted - someone was doing 185 mph in NZ by that stage though.

Good high-speed tyres are actually a fairly recent invention...

Having said that, clincher tyres / rims were used on all speed records on bikes prior to the mid 1920s anyway - drop centre rims were only invented about then.

The Ace 4 cylinder did 129 mph in 1923, obviously on clincher rims. I think it was said they were pumped to 100 psi. You want to trust them though, they are diabolical if they go flat....

P.S. Ace offered $10,000 for anyone who could get a bike to go faster back then.
No-one took the money off them.

Sorry, you will have to take up the tire statement with the museum curator. Only shaved tires I've ever heard of were only for bee line speeding not road racing. Grooving and changing profile are related but done for traction/handling not for extending speed rating. Don't know if clincher rims used on salt lake or if clincher tires can fit other rims. Anywho Burt was an extremist and didn't leave much alone for long. If you find more facts on his old tires or what Nortons can get away with over 160 pass it on. Here's a quote for you and a site Fred could use right now. A large part of it are the many brief descriptions of injuries.

http://www.racingcampbells.com/content/ ... etter.html

many wheels built as tyres and rims changed. The last one was for the front wheel last July when I changed from 19” to 18” as I cannot get high speed from 19 x 2.75 tires anymore. This I cut the tread off with a knife then smoothed down to the bottom of the non-skid groove.

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The wheels and tires are from a 125 GP bike, TZ 125, I think. They are rated for the speed, but I'm not so sure about the weight and horsepower. Fred's Norton makes a lot more horsepower, and is a lot heavier.

Ken

lcrken said:

The wheels and tires are from a 125 GP bike, TZ 125, I think. They are rated for the speed, but I'm not so sure about the weight and horsepower. Fred's Norton makes a lot more horsepower, and is a lot heavier.
Ken

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If a tyre blowout was the cause of the crash, sounds like either there was a fitting problem, or they are not sufficient for the job. Hard to determine now, of course.
Best wishes for him.

Burts talk of 18 or 19 inch wheels means they are no longer Indian scout items, but later model rims of the drop centre type.

Somewhere there it mentions oversize 29 inch front wheel in 1927, which means it was still a drop centre type rim. But a bit taller than original scout item too.

Clincher rims and tyres (beaded edge) are totally different to drop centre tyres and rims.
Clincher tyres have a 'bead' which hooks into a lip on the inside of the rim - and relies on high pressure in the tube to keep the bead in the edge of the rim. No pressure, and the whole tyre and tube will just roll off the rim.

Museum curator was wrong to say what he did then...

Hopethishelps.

I had to look up the clincher history to get what you were pointing out. I will try to find site and see if owner can clarify the tire fitted claim. But Burt raced on tires we'd toss in trash it seems. I'd run em to use up on/off road but not brave as Burt to risk record attempts on em - wheweepeepee. Peel's power if holds together should shove us, rather over 150 on pavement below 2000 ft elevation, so tire endurance is on my mind for heat handling smoking sprints, grinding turns as well as bee line runs. Just fitted all her tuck down muscles to find they will fit fine - after I do it again : (

Every Texas Mile bike capable of 200 mph region had forks strapped way down and steering damper set upward. Listened to them comparing notes with bikes side by side, the faster seasoned ones were lower. In MX bikes they call it a Hole Shot Device but releases on first fork compression brake use. At some speed nearing 200 mph I think only 17" sizes available. Tires are one reason I've not really considered in actual details, special fuels and NOS-fuel injection.

To stay on point and repeat my personal uninformed opinion going by prior runs to 155, I'd suspect pure rough surface with wind conditions got Fred, not a tire failure. He and crew have got to figure out what happened before trying it again.

Update on the horsepower numbers. The 107 hp is actual measured value at the rear wheel on Jim Mosher's dyno, which is at 7,000' elevation. The 155 crankshaft horsepower is calculated at sea level, with corrections for altitude and transmission loss included. Jim says he's had very good correlation between his measurements and the local Dyno-jet facility. Impressive numbers for a Norton by any standard.

Ken

Thanks for the clarification Ken. That is some serious pony power.

How much would the NOS account for ?

(Have I got this right, it is using NOS ?,
Forgotten where this bike/engine spec was discussed initially, apart from salt record.)

Generalizing, a chain drive motorcycle will have about 20% less power at the rear wheel than at the crankshaft, while a shaft drive model will lose a little bit more than that due to greater friction.

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http://en.wikipedia.org/wiki/Motorcycle ... and_torque

But in the end its a moot point to calculate shaft hp vs whp as essentially the whole motor sport world only measures whp as that's what matters most putting the power to the ground or inertial dyno. Here's a rather interesting forum discussion this subject. This one don't cover it but there are like 3-4 standards to convert whp to crank that can vary half dozen hp in Norton scale power plants.

http://forums.tdiclub.com/showthread.php?t=75062

Rohan said:

Thanks for the clarification Ken. That is some serious pony power.

How much would the NOS account for ?

(Have I got this right, it is using NOS ?,
Forgotten where this bike/engine spec was discussed initially, apart from salt record.)

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Yes, it is on nitrous. They ran it with the 873 engine on gas at Bonneville in 2008 and weren't happy with the speed (low 130s). In 2009 they fitted the nitrous system, but with a really low hit to check it out, and ran in the 140s. In 2010 they ran a larger dose of nitrous, and ran 155. This year, the took the engine out to 920 and ran a bit more nitrous.

FWIW, Fred said the lightweight 920 rod/piston set from Jim Schmidt was so much smoother than the previous 873 (Crower titanium rod, Omega pistons) that he couldn't believe it. He's now sold on the concept.

Ken

Intense issues here. Just guessitmating going mostly by Maney reports, assuming the 920 was good for about 100 hp w/o NOS, then about a 3rd of the total is sprayed in hp near top rpm range. NOS kits are sold by hp amounts in their ads, so ~50 hp kit applied this last go round to get off on. Damn what a rush that must of been.