speed vs rpm

[xs650mike]

I just realized that Mikes XS has a mini speedo that's calibrated for Yamahas with 19" front wheels, should be accurate on an 1100. The tach won't work since it's mechanical.

[Lamric]

Dean,

On my LG I get

Revs to mph
5000 = 70
6000 = 85
7000 = 100

Speed measured by GPS so should be pretty accurate, revs measured by unfaired eyeball on shaking rev counter

[xs650mike]

That's right in line with what my instruments are telling me.

[84xj1100]

TC,

The rpm is up not down - My 84 1100 sits at approx 3500 rpm at 100kph/60mph - this is my original bike with no work done to it at all. My 82 1100 (that has had work - from 2 owners previous) sits at approx 4500 rpm at 100kph/60mph.

I haven't had them paced at all but after riding the same bike for 20 yrs+, the 82 "feels/sounds" different. Given the amount of time on my orig bike, when I ride the moded bike I find myself more often than not shifting from 5th gear into 5th gear because of the feel/sound.

Do ya know what I mean?? Does that make sense??

[MAXIMAN]

Just found this thread. I got Zilla put together today and ran it down hwy 51 about 30 miles.

What you are saying is correlative with my '82 XJ1100.

I'm seeing about 4400 to 4500 rpm for 60 mph and at 6200 rpm it's registering 80 mph on the nose.

For some reason that's not what I thought it did on the trips I took last year I thought it was spinning 4000 @ 60 mph.

I'll verify tommorrow with a GPS. I'll also post pics of the "New and Improved Zilla"

L8R

[xs650mike]

Was just riding my SF and it shows 4,000 @ an indicated 60. I'm not sure about that tach but the speedo seems pretty accurate at highway speeds. I plan to clean up the wires and terminals going into the tach and see what I get then because my tach is somewhat erratic when changing engine speed.

[MartyA]

On our return from So. Indiana last summer on the 4-lane we sat mostly at right at 80MPH indicated on the speedo and that was 5,000 RPM on my 78. I recall somewhere seeing 3,990 was 60MPH? and that is about what I got, within the width of the needle error.

If you believe those construction zone speedo indicators then my speedo was always 1 mph optimistic when the tires were new and about 2-3 when they were about to be replaced - 75 MPH indicated was 74 on the PennDOT indicator. Er I mean 50 MPH indicated was 49 on the PennDOT indicator. 75 MPH is of course not allowed in a construciton zone.

[Pat Kelly]

Add 500RPM for a Special. 80 MPH would be 5500RPM

Originally posted by MartyA
On our return from So. Indiana last summer on the 4-lane we sat mostly at right at 80MPH indicated on the speedo and that was 5,000 RPM on my 78. I recall somewhere seeing 3,990 was 60MPH? and that is about what I got, within the width of the needle error.

If you believe those construction zone speedo indicators then my speedo was always 1 mph optimistic when the tires were new and about 2-3 when they were about to be replaced - 75 MPH indicated was 74 on the PennDOT indicator. Er I mean 50 MPH indicated was 49 on the PennDOT indicator. 75 MPH is of course not allowed in a construciton zone.

[xs650mike]

I remember noticing on our ride down I-5 to Los Baños last summer that cruising at 85 on my Special the tach was right around 6100 rpm which neatly coincides with the engine's torque peak. A twist of the wrist brought a positively vicious roar from the air box and a quick yank to over the ton.

[trbig]

Maximan,

I checked my XJ today, and it was right at 4k at 60mph, like you remembered... and just a sliver over 4500... maybe 4600-4700 at 70... but again... going by my old gauges.

Tod