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Hi HB,

It does seem increasingly likely that the 133 mph was really at something like 7350 rpm.

From what you learned on the dyno, perhaps there is a possibility of squeezing a few more mph out of the lump by losing 1 more tooth on the rear sprocket (which would bring the rpm at 133 down to ~7185) or even 2 teeth (bringing the rpm at 133 to ~7020).
Just thoughts.

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Hi Koan; man; can you upload a photo of your Triton?

Thanks

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Originally Posted by koan58
Hi HB,

It does seem increasingly likely that the 133 mph was really at something like 7350 rpm.

From what you learned on the dyno, perhaps there is a possibility of squeezing a few more mph out of the lump by losing 1 more tooth on the rear sprocket (which would bring the rpm at 133 down to ~7185) or even 2 teeth (bringing the rpm at 133 to ~7020).
Just thoughts.
yes, on the dyno the engine makes 46 ft lbs of rear wheel torque at a low 5100 rpm and at 7000 rpm it still has 39 ft pounds....the engine is not radical and has been street driven..At 330 pounds with an estimated 65 or so crankshaft HP it moves out adequately...


79 T140D, 89 Honda 650NT ,61 A10 .On a bike you can out run the demons
"I don't know what the world may need
But a V8 engine is a good start for me
Think I'll drive to find a place, to be surly"
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Hi Reverb,
I can't be bothered with the photo posting process.
If you send me your email I will send you some pics of the different setups over 40 years.

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It's easier, for me at least, to measure the circumference of the tire on the wheel. A dress-maker's tape works just fine.


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72 T120V cafe project "Mr. Jim"
72 T150V "Wotan"
92 BMW K100rs "Gustav"
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Back to BAinLA and his original question about freeway riding.

Geared 20/46 equals about 17 mph/1000 rpm; that is about 68 mph at 4000. 4500 rpm gets you about to 77mph. The bike in good fettle will certainly handle 4500 rpm for a long, long ways. Sure it will wear out faster, but then, you get to rebuild it and do it all again--these are made to use, wear out, rebuild.

Remember, at those sustained speeds, rebuilding with quality mechanical parts, like name brand valves and valve springs--Kibblewhite Black Diamond, say, and quality pistons and rings, for instance, will serve you well and extend the wear cycle. And of course, that rpm and freeway use puts a premium on keeping the thing in tune and fettled. You don't want to be rolling down the Ventura Freeway in heavy traffic and have an old worn out throttle cable break, or a duff 50 year old wire somewhere short out, or something similar--keep it up to snuff for reliability.

But hey, turn up the throttle and let it roll, these things were hot rods when they were made and not much has changed with them ever since.

As to the 21/43 gearing--I ran my race bike at Daytona and Willow at 20/43 and it would barely, like just, pull it to 7300 rpm, say, 126. That gearing was on the ragged edge of too much to get to red line for a 63-65 hp road racer with no fairing, with a belly pan, air cleaners, big brakes, bike high up so it would have cornering clearance, all that stuff and not all lowered down and narrowed like a land speed bike.

Last edited by linker48x; 10/09/21 12:50 am.
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20-47 is what my '69 t120 is and has been for 20 odd years.
It knocks along at 70 all day if i want it to. You'll have more problems with
bits falling off on a triumph, than engines wearing out.

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Originally Posted by NickL
You'll have more problems with
bits falling off on a triumph, than engines wearing out.

Yes, as originally built, a Triumph twin loses parts, cracks the exhausts and blows light bulbs, if you go fast. Someone is bound to chime in with stories about their new 68 Bonnie that didn’t do any of that!

A 1960s little Suzuki had rubber mounted lamps when Triumphs didn’t!


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knuckle head
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Originally Posted by triton thrasher
Originally Posted by NickL
You'll have more problems with
bits falling off on a triumph, than engines wearing out.

Yes, as originally built, a Triumph twin loses parts, cracks the exhausts and blows light bulbs, if you go fast. Someone is bound to chime in with stories about their new 68 Bonnie that didn’t do any of that!

A 1960s little Suzuki had rubber mounted lamps when Triumphs didn’t!
America was Triumph's biggest market and the higher steady road speeds gave Triumph and other Brit twins a reputation for falling apart..
I have been riding Triumphs since 1974 and never felt comfortable running them at steady high speeds. The engine can handle it but the type of vibration is very annoying to me..My T140 is smooth for a Triumph at 4500 rpm but it ain't long before the vibes felt through the seat set my butt on fire...


79 T140D, 89 Honda 650NT ,61 A10 .On a bike you can out run the demons
"I don't know what the world may need
But a V8 engine is a good start for me
Think I'll drive to find a place, to be surly"
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I happily ride my pre-unit Triton at a steady 80 mph, but it took some time to fix all the bits that were vulnerable to vibration.

For instance, the stainless pipes are welded to the stainless silencers and each side is attached to the frame only by the port stubs at the front and rubber bobbins at the rear.


Amateur Loctite enthusiast.
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