speed vs rpm

[DeanR]

Had a brief moment of speed this morning but due to my 85mph speedo, speed was a ?.... Was wondering if someone could possibly post what typical revs should be at 80, 90, 100 et.
Thanks!!

[TopCatGr58]

Hey there Dean,

Tried to do a search, thought someone had posted the speeds for rpms, but couldn't find it, but found some comments and roughly for 5th gear of course:
4K = 60
5K=75
6K=90
7K=105
8K=120
8.5K=~130ish
Hope this helps!
T.C.

[DeanR]

Thanks TC

[DeanR]

By the way, my search basically came up empty too!

[xs650mike]

My tach and speedo say 3.5k at 55, 4k at 60, 6k at 85. Magazine road test says 8500rpm=128mph. We're talkin' Specials here.

[GNEPIG]

.. i would not trust yours or anyone elses gauges to determine your top speed.. it would only be an estimated guess
for not too much money you can get a good digital speedo from a bicycle shop.. they are easy to set up and are more accurate than the 25 year old analog meter the bike came with

[xs650mike]

I'm not trusting the instruments, especially the tach...gotta clean the contacts on that sucker anyway. I'm just putting out what the instruments say. My friend says to use GPS to get a speed clocking. My speedo is accurate at 55 mph according to the CHP's informational roadside radar if that can be trusted.

[84xj1100]

You may want to consider checking any mods in the bikes history to determine if gearing has been changed. As an owner of 2 xj1100's I can tell you that my original bike at 60 mph revs at approx 1K less that the one that I recently purchased. I have been told that there was some trans work done on it, to which I attribute the difference as no such mods have ever been done to my orig bike.

[turbopete]

My clocks show 80mph at 5000rpm in top. That makes 100mph at 6250rpm and 120mph at 7500rpm. That's as fast as I've had it

[xs650mike]

Ok, Turbopete's got a Maxim, What's the difference in gearing, if any, between a Maxim and a standard or Special? I know the Special is geared slightly lower than a standard since it has a smaller diameter tire. I believe the Maxim's got the same size tire as a Special, can I therefore assume that the gearing is the same as the Special? Who's got the answers?

[TopCatGr58]

Hey Mike,

Just checked the service data page on the parts list for XJ,
the Primary and Secondary drive ratios are the same as my 81H/SH handbook:

Primary Drive Ratio 25-25 x 58-35 . =1.657
Secondary Drive Shaft 44-47 x 19-18 x 33-10 =3.261

All gears in the tranny list start with 2H7, so as I was pretty sure, it's the SAME. Of course this is for USA models, can't speak with absolute certainty about Euro and other models/makes/years.

Hey 84XJ1100,
Would be interesting to find out WHAT kind of tranny work was done to lower the rpms 1000!? Are you sure your tach and speedo are reading accurately? Have you paced both bikes with another vehicle, or a set of road mileage markers ensuring you're taking 60 seconds to travel from 1 to the 2nd at 60mph!?
T.C.

[johnfrenchsr]

1979 XS

Go to Ebay and find you a speedometer for a 1979 XS. Mine goes up to 160 mph and I think the speedometer cable is the same.

[xs650mike]

For that matter a 140 mph speedo from an XS750 Special or a 120 mph speedo from a '78 or '79 XS650 will also work on an XS11 Special. It just depends on how fast you plan to go!

[GNEPIG]

.. i have the RPMs option on my fluke 88 meter, i hooked it up to my red bike today and if the fluke readings are good then my tachometer is right on the money, they seem to concur at every rpm range
.. but i know that my speedo is way wrong.. at red line in 5th gear it states that i'm only going 95 mph and the person riding next to me said we were going way over 100
i was wandering why when i'm trying to go the speed limit everyone else seems real poky

[xs650mike]

Hey you were doing 130. Congrats!