Question about RPM

[thewright1]

Hi All,

Just curious, when you're on the freeway, say doing about 65 to 70mph, where are your RPMs? Mine are around 4 to 5 and then if I go a little faster, it may get to about 6. Is that normal? I've had the bike since October, but due to all the work i've been doing on it, I've never once really rode it until this week.

Also, how fast do these bikes go? Speedometer stops at 80 but it seems like it would go faster. I'm too scurred to go anywhere past 70 (i don't even like going 70 to be honest).

[natemoen]

Dont know about the RPMs cause I havent really ridden mine either. Top speed I have heard somewhere around 130 - 135 ish. Speedo stops at 85 cause the US government made that law back in I think 80 that said speedometers could only go up to 85 so that is why all vehicles for a long time after that only had speedos that went up to 85. But that law is gone now!

[DGXSER]

Yep, with the stock Final Drive you will see about 5k rpm at about 70 mph. Seems like it is running high rpm to most folks. Which is why the popularity of the XS750/850 final drive swap.

I've never had one up to top speed, I took my older bike up to what I calc as 115 mph once. Tach was about 7500.

[thewright1]

Oh ok, so it's normal to feel like the RPMs are running high then, that's cool. Just wanted to be sure. These XS1100's are pretty sweet rides.

[Incubus]

Japanese 4-cylinder engines are designed to thrive at higher rpms. My bike does 4,000 rpm at 60, and 5000 rpm at 75, which is pretty standard for rice burners from the 70s, at least in my experience. My SOHC Honda 750s also do 4000 at 60 and 5000 at 75.

Patrick

[silvertwist]

Mine does at about 4000 rpm 120 km/h

[b.walker5]

That seems low, someone may have already done a drive swap on yours or did the later models have taller gearing?

I ride by my rev counter and at 5k im doing a little over 120kmh, and the engine, while appearing to be revving high, ticks over nicely at that. Everything seems in sync and harmony, and the exhaust note is smooth and throaty Problem for me is our speed limit is 100kmh and at 4 to 4.5k things arent as smooth.

I've been toying with the drive swap idea, and I've got one here from my old 750 2D, but after having got used to not grabbing for 6th gear, I'm not sure that I'd enjoy the rev reduction given the way mine runs up higher.

[freak_leg]

Does any one have the gear ratios, final drive ratio and tire hight? I can tell you exactly what rpms you SHOULD have at what speed...

[DGXSER]

I know the final drive is 3.3:1 stock. Not sure on the rest, but then there is the Primary chain ratio to deal with as well besides the gears.

[petejw]

hi tony,

there was a post a little while back regarding
rpm's in relation to speed,

you'll also need the middle drive
ratio's to work it out correctly.

[Deathdeelr]

Yesterday I was turning 3K at 50mph, 4-4200 @ 65, and 4800-5000 at 75mph. I made a 100mph blast but the giant Vetter windshield started making me nervous so I backed off. I didn't look down at the tach. I think natemoen's 130-135mph top speed might bring you up into the 7K range and is a good idea of a concrete limit.

[DGXSER]

Some time ago I did a ratio comparison similar to yours with the stock FD in place. I found that 7k was about 110-115 MPH. I would think you need to go redline or so to get to 130 or more.

If you want to see which FD you have installed, pull one side of the rubber boot off at the drive shaft to middle drive connection. Then watch how many times the drive shaft turns for one rev of the wheel.