Engine RPM = what speed in top gear?

[78jotadave]

Last week I was fortunate enough to have a very enjoyable run-out and about thru the Hi-Desert area of California on the 78 Jota. Mostly well-maintained roads with excellent signage and markings, and we didn't come across any CHP. The roads have very little traffic and have some very long straights. One section was approx 14 miles straight slight downhill no breeze and air temp around 70 degrees F, perfect for giving the bike a full-throttle run so... Took it up through the gears 7600rpm in each gear before shifting then she pulled up into 7800rpm in top after the shift-up from 4th, the bike was rock solid stable like it was running on rails, backed off when an oncoming vehicle came into view. My speedo has about a 15 mph swing at those speeds the rev counter is very stable. My GPS recorded 133.7mph. What would the 7800rpm in top compute to (19 tooth front, 40 rear sprockets). Very enjoyable ride with triple-digits cruising, hi-speed sweepers perfect Laverda environment, and a stop at Roy's cafe.

 

[pf1]

Oh yes, I like the sound of that

 

[andre g]

In the fith gear it is about 28 Km/h/1000 revs, so without slip it is 218 Km/h. 133 mil/h meets it quiet good.

 

[Dellortoman]

One variable that you haven't mentioned is the rolling radius of the rear wheel. Tyre profiles can vary quite a bit. The difference between a new high profile tyre and a worn out low profile tyre could produce a difference in the calculated speed of around 5mph in top gear. To measure the rolling radius, set your usual tyre pressure, park on a level surface, sit on the bike with as little weight on your feet as you can manage without falling over (all of that is to produce a normal deflection of the tyre due to the weight of bike and rider), then get someone to measure from the ground to the centre of the rear axle.

Anyway, assuming a (typical) rolling radius of 315mm. 7800 rpm equates to 134mph with your gearing. Given that your GPS measured 133.7 it seems that your tacho is pretty bloody accurate. Not something I'd have expected for a ND instrument that's over 40 years old!

 

[chrisk]

Rev it to 8,800 next outing, needle should almost be off the dial

 

[Rusty Spokes]

Laverdamania has a speed in gear with sprockets chart:

LAVERDA 1000 3-cylinder:Theoretical speed in gears

 

[Vince]

Now you have done it, there is a place where we ride to with similar roads Mmmm, and I have a GPS

 

[Legs]

We have our road here in South Aus as well but it is a closely guarded secret, want to keep the riff-raff away.

 

[1200ts]

Dave,

From you description of the road and Roy's cafe. It sounds like you were on Amboy road?

Bruce

 

[chrisk]

Is that Dave in the distance ...... oh no, it’s Nash!

 

[sfcpiet]

Burt Munroe.

piet

 

[78jotadave]

Y

Dave,

From you description of the road and Roy's cafe. It sounds like you were on Amboy road?

Bruce
View attachment 54920

 

[78jotadave]

Yes Bruce, Amboy Rd, your photo shows the chloride flats after the long long straight coming down the mountain, (posted 55, why? no one out there) Was thinking of doing another different desert loop in a couple of weeks are you interested?

 

[piranha-bro2]

Burt Munroe.

piet

 

[motoddrob]

Fuck Dave you wouldn't attempt that on the Nullabore these days. The filth are everywhere!!

 

[78jotadave]

Fuck Dave you wouldn't attempt that on the Nullabore these days. The filth are everywhere!!

Rob, there are quite a few roads in the Hi-Desert areas of California where you can ride your bike or drive your car flat out for as long as you are brave enough, CHP pretty scarce in select areas. Now if you really want fast roads Nevada is the place it has the best-maintained roads in the USA (gambling is good for some things). Hwy 93 or 95 North, the cult movie 'Vanishing Point' was filmed on 95. East, west highways 6 or 50 are tops. Hwy 50 is billed as the loneliest road in America could well be true drove all day once and saw 5 vehicles. Definitely, a go-fast road with several absolute dead straight 50 mile stretches. No speed cameras anywhere in the west!!! One thing to keep in mind is many of these lonely dead straight flat land highways are at altitudes of 5000+ feet many stretches above 6500 feet, attached photo of back roading Nevada at 6600 feet, dually wheels work.

 

[Vince]

Hwy 50 is how we went from Cal to Salt Lake City on a Ski trip. It was winter, it reminded me of the road from Adelaide to The Alice. Long and lonely.

 

[motoddrob]

That looks like a great road for the GS BM.

 

[78jotadave]

You see that road behind my Toyota HiLux 'Sunrader', did not see another vehicle for 160 miles altitude 6400 to 6800 feet, camped out halfway. Fucking paradise mate big bonfire just me the wife, 4 dogs, (one is a blue heeler and one german shepherd the security team, and two foo foos) stars, guns, and coyotes only way it could be better is to get there with a few mates on bikes, just saying. Tequilla is an omnipresent 2 or 4 wheels, Cheers Dave. Sorry if you think this belongs on another forum but Laverda ties run deep, so screw you.
Bonneville flats this summer I hope, you in Paul?

 

[DaveB]

We have our road here in South Aus as well but it is a closely guarded secret, want to keep the riff-raff away.

I always favour the World’s End road between Burra and Robertstown, Terry, but I suspect that’s not your favourite. Maybe too many floodways.....coming out of those dips at illegal speeds can get pretty <now what’s the word???> aeronautic LOL