What RPM for Midnight

[FJ111200]

Well I've got my '81 LH Midnight up and running, carbs have got all standard jetting though i'm running with 120 mains across all four.
Headed off on the motorway, you lads might call it the freeway, and got up to 75mph and the rev counter is at 5500 rpm.
It seemed a bit high considering my previous XS's were at about 4000 rpm for the same mph.
Does it seem right for a Midnight?

[motoman]

All XS1100 series had same tranny gearing and same stock final drive gearing. With that said, at approx. 4,000rpm in fifth gear is 60-62mph. Those rpm's are a tad lower at same speed with the Standard, as it uses the 17inch rear wheel as opposed to the 16inch rear wheel of the Specials and Midnite Specials.

[Ranger_xs1100]

An rpm test I did before and after the XS850 final drive swap on my 1980 XS1100LG (MNS)

with XS1100 stock final drive:

3000 rpm = 45mph

3500 rpm = 52mph

4000 rpm = 59mph

After XS850 final drive swap:

3000 rpm = 52mph

3500 rpm = 59mph

4000 rpm = 66mph

All readings were in 5th gear of course.

[motoman]

BTW, interesting pattern done on the re-covered seat. Even more interesting, considering your location, as to how that Midnight Special came into your possession?

[IanDMacDonald]

Yes, it seems too high. Average for any of my XS bikes is 4900-5k rpm's @ 75mph.

[FJ111200]

OK, so 5500 rpm at 75 mph could be about right, unless anyone else knows better.

Regarding the seat pattern, that was how it came with the bike and the bike came to the UK in 1997 according to the V5C, which is the UK registration documentation every UK owner has, and seems like quite a late import. But that doesn't mean anything really as bikes are imported here all the time.
But thanks for the replies from everyone, as I was thinking the timing was a tooth out since I replaced the camchain and tensioner for new and a VMX ACCT.

It's great to ride though with those MX 'bars, it's easy to throw around and considering the 37mm forks quite stable.

[FJ111200]

Originally Posted by IanDMacDonald

Yes, it seems too high. Average for any of my XS bikes is 4900-5k rpm's @ 75mph.

Maybe my speedo is off as well

[Eveready1100]

If these pics are any help to your question, mate.
Bike is a 79SF with the 16 incher running an Avon Roadrider 130/90-16

[IanDMacDonald]

Originally Posted by Eveready1100

If these pics are any help to your question, mate.
Bike is a 79SF with the 16 incher running an Avon Roadrider 130/90-16

Holy cow!!! 3500k @ 75mph??? You must get awesome fuel mileage on that bike!!!!

[IanDMacDonald]

If that's the case, I need to swap to a 16" rear wheel!

[IanDMacDonald]

I'll just come-out and say that the tach or speedo is off. No way are those readings right!

[BA80]

Either your tach or the speedo is wrong. I'm guessing the speedo.

[3Phase]

It looks like the tip of the needle is missing in the speedometer.

If the needle's too light it would read faster than it should when the mouse ran 'up' the clock, then slow a little after the clock struck 12 and the mouse ran 'down' past 120 KPH.

[motoman]

Originally Posted by 3Phase

It looks like the tip of the needle is missing in the speedometer.

If the needle's too light it would read faster than it should when the mouse ran 'up' the clock, then slow a little after the clock struck 12 and the mouse ran 'down' past 120 KPH.

Conclusion of speedo incorrect or no longer working.......replace the mouse.

[3Phase]

Originally Posted by motoman

Conclusion of speedo incorrect or no longer working.......replace the mouse.

Perzactly!

You can also try to open up the clock to repair, replace and recalibrate or just get another clock.