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1978 R80–7 cruising speed

Awurman78R807
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1978 R80–7 cruising speed

Post by Awurman78R807 »

Hey there! Just bought myself a nice clean R80–7. 42,000 km on the OD. Wondering what the maximum cruising speed should be. Feels like 4500 RPMs is the best. That’ll get me 68 miles an hour. Going to ride from Los Angeles to Montana in June. Don’t wanna push the bike too hard, but also wanna get there before July! Any thoughts? Thanks!

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schrader7032
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Re: 1978 R80–7 cruising speed

Post by schrader7032 »

Welcome to the forum! Wondering what your final drive ratio is...probably 32/10. My R100/7 with a 33/11 final drive feels best at about 4K RPM which is nearing 70 mph. So you numbers are probably about right.
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.

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srankin
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Re: 1978 R80–7 cruising speed

Post by srankin »

LOL, the best cursing speed in my case is just 1MPH under the point where I would get a ticket for speeding. St.
Owner of a 84, R80RT and 78, R100RS

cwf
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Re: 1978 R80–7 cruising speed

Post by cwf »

I think the motors are probably a lot tougher than you think and the highest cruising speed is probably faster than you can cope with, unless you have a windscreen or fairing. However, probably in the US and certainly in Europe, outside a few motorways in Germany, legal limits are what you have to work to.

I had a 75/7 and three 80RTs for work in the UK. In those days I could cruise at 80mph = c5000 rpm, no faster as I didn't want to draw attention to myself. All did 250,000+, with a ring change about 150,000.

I ride a 50/2 these days, partly because it's lower, lighter, simpler and partly to reduce the temptation, so many cameras etc nowadays but in France it's even worse. Just like with my Dad, the best times were always when we were young.

Charlie.
75/7+ offroad sidecar; 50/2; R 35; XR125V; XR200A; Solex; 1939 Hillman Minx DHC.

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srankin
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Re: 1978 R80–7 cruising speed

Post by srankin »

In all honesty, I ride the heck out of my two bikes, and have never had problems for the first 100k miles. I have eased off a bit on the wear and tear as I have wear and tear on my body that has slowed my reflexes down.

My R80RT went 125 K miles before the pistons started slapping the inside of the bore. I am now at 220K miles and things are still good since that rebuild.

My R0RT seems happiest at 70Mph, but, I am usually only doing 60 due to speed limits here. It is also happy to 75 or 80 all day long when I get the chance. No oil consumption and smooth.

I would expect my major engine wear is due more to the amount of start and stop, up and down shifting and such which I AM aggressive with rather than straight cruising. If I were a bit gentler on the bikes, they might last longer between engine rebuilds, LOL. St.
Owner of a 84, R80RT and 78, R100RS

cwf
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Re: 1978 R80–7 cruising speed

Post by cwf »

Yes, I think the fact that the bikes were ridden all day, every day meant that they were always warmed up. Also, doing that amount of miles meant that you learned to hear things beginning to go wrong and could fix them before a disaster. I was also conscious that riding smoothly meant less wear, meant less work at the weekend.

So strangely, despite the heavy mileage, the bikes probably wore out less quickly than bikes with lower mileage but ridden harder or with lots of short runs.

Charlie.
75/7+ offroad sidecar; 50/2; R 35; XR125V; XR200A; Solex; 1939 Hillman Minx DHC.

weh8127
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Re: 1978 R80–7 cruising speed

Post by weh8127 »

Those highways in the west are posted at 75mph and the traffic cruises at 80. If your bike is well sorted out it will be just fine with that and still have plenty left on tap. You may not be fine with that, however. You'll need wind protection or euro bars with a tank bag.
Bill Husted
Barre, MA USA
1963 R60/2 w/ 1955 Steib S500
1973 R75/5

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srankin
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Re: 1978 R80–7 cruising speed

Post by srankin »

Charlie, yes, the short runs do wear things out faster than long runs for many reasons. Not just short runs but any run where there is a lot of up and down shifting, braking and such, all is harder on bikes than causing at 80mph for hours at a time.

While I have a lot of miles on my R80RT, I have a friend with similar milage on his bike and he has far less trouble and repairs due to the riding conditions he has versus mine. He is in open country with lots of long stretches little up and down shifting and braking.

I have seen a few posts where fellows write in and pooh poo downshifting as an evil. I personally have never bought into that and since I haven't, I take them at their word but, am not interested in changing my ways. St.
Owner of a 84, R80RT and 78, R100RS

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schrader7032
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Re: 1978 R80–7 cruising speed

Post by schrader7032 »

Replacing brakes is a lot cheaper than doing a top end. Just sayin'!
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.

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srankin
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Re: 1978 R80–7 cruising speed

Post by srankin »

LOL, depends on how many times brakes have to be replaced. St.
Owner of a 84, R80RT and 78, R100RS

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