Bouncing tachometer

[Modern_Monkey]

I was cruising home from school one sunny afternoon, just chugging along at the speed limit, when this Harley rider passes me at about 90 in my lane!
I let him go, but then decided to give him a taste of what I've got. Maybe it wasn't the smartest thing to do, but that's outside the scope of this post. I rocketed my '50R to top speed. I was approaching redline in 6th, indicated 132 on speedo. I watched the tach to make sure I didn't blow my machine up, and to my surprise, it was bouncing around. Quite unsettling. It has never done this before in the 3 months I have owned it, and hasn't done it since. I guess it was just at the ragged edge of the envelope? Everything is stock. 8,000 miles. 2005 model.

I have also noticed a decrease in fuel economy about a month ago, and it feels like it has lost a bit of power. Not anything dramatic, just barely noticeable. I suspect stick coils?

Thanks for any insight.

[iowabeakster]

That was a really stupid thing to do. I mean really, really stupid. You make all of us look bad when you ride like that.



























Keep aware so that you are never again passed by a Harley rider!

The stick coils on the 2-spark bikes are not of great quality. They have a tendency to fail regularly. That certainly could explain what is happening.

[boxermania]

No offense, but maybe you meant approaching red line in 5th gear as there is no way you are going to hit redline in 6th gear, it is way too low (long geared) for that. You might hit a bit over 6000 rpm in 6th gear wide open and on along run.....

Now there are three possible things that will bring about your symptoms

1) You are hitting the rev limiter which is set somewhere between 7800 rpm and 8200 rpm, however, you would notice because the engine will turn off and on. Don't think so.....
2) The dreaded heat deterioration of the stick coils. Possibly, but you should have noticed rough idle and subttle engine skiping along midrange - Possibly....
3) Nylon ties under the light nacelle, has been documented many times - Possibly.....

Good luck and keep us posted

[R1150Rclean]

The Max speed for the R1150R is listed as 135 mph, so if you were doing 132 maybe you were near redline in 6th. As for chasing down a lower echelon bike, been there just make sure your on a empty stretch of road when you do it. An accident at that speed in traffic could turn out to be rather deadly.

[AirForceDirt]

The Max speed for the R1150R is listed as 135 mph, so if you were doing 132 maybe you were near redline in 6th. As for chasing down a lower echelon bike, been there just make sure your on a empty stretch of road when you do it. An accident at that speed in traffic could turn out to be rather deadly.

To echo boxermania, and from personal experience: You are not going to hit redline in 6th gear on an 1150R. Second, indicated 132 means around 120; again, from personal experience (ie GPS and a second bike to compare speedo reading to). Third, short of throwing it out of an airplane, a stock or even lightly modified 1150R is not going to hit 135mph.


Redline in 5th Gear would get you damn close to 120mph, but 6th is just way too tall to ever hit redline..there's too much wind resistance and the bike doesn't make enough power to push itself that hard..I've tried...a lot. I can see this story taking place in 5th gear, but not 6th.



To the OP: did you see the look on the Harley rider's face? And don't get pulled over going that fast, trust me, it's expensive.

[Modern_Monkey]

AirForceDirt: Yes I am aware of speedo inaccuracies, and top speed limitations of this machine. The point of my post is that my tach was bouncing, and I'd like to know what the cause of that is. And my words were that I was "approaching redline in 6th", I have no idea how close I was because the instrument that tells me that information was not functioning properly.
On another note, my 6th gear feels rather short. I get 70mph at 4k rpm. Does this line up with others' experience?

[NoRRmad]

Yeah, that's the "short" top gear. Overdrive top gear gives 80 MPH at 4K RPM. Some bikes have it, others don't. I've seen posts here about the "bouncing tach," a search might find it...

OK, I did a search. Here's an example: viewtopic.php?f=2&t=20120&p=177250&hili ... er#p177250

[AirForceDirt]

I've had the bouncing speedo needle, but never a bouncing tach. And that only happens after I crack triple digits and goes away when it sits for awhile. Very annoying.

How much is it oscillating? (the range that it covers from one extreme to the other..)

[Modern_Monkey]

It bounced from about redline to ~5k. The bike ran strong while it was happening.

I never got a chance to see the Harley rider's face. He wasn't wearing a helmet, but I never looked back either. Mirrors were pretty buzzy, and I then moved into full tuck. He must have thought he was the fastest thing on the road until then. And he was pretty fast... for a Harley. Never seen one doing 110-115 like that.
I think our Roadsters don't really look that fast to a lot of people. People I meet ask me "Is that thing like a cruiser, or a crotch rocket"? I tell them that it's sort of a hybrid, or a sport touring bike, but that just leaves them scratching their head. "So it's a crotch rocket then"? Yes. It is.

[CycleRob]

A Harley going that fast likely put $,$$$ into the motor and was trying it out.

[Sunbeemer]

I've had the bouncing speedo needle, but never a bouncing tach. And that only happens after I crack triple digits and goes away when it sits for awhile. Very annoying.

Could that be a cable lubrication issue? Mine doesn't do that.

A Harley going that fast likely put $,$$$ into the motor and was trying it out.

And will probably need more $,$$$ after the trial!

[AirForceDirt]

I've had the bouncing speedo needle, but never a bouncing tach. And that only happens after I crack triple digits and goes away when it sits for awhile. Very annoying.

Could that be a cable lubrication issue? Mine doesn't do that.

Its likely, as I've never touched the cable, and i do live in the desert..but it only starts after 100mph. I'd think that a lubrication issue would be present all the time.

[chibbert]

I'm betting that with the short 6th gear (as opposed to the touring 6th as some have) you could hit very near redline.

I've yet to take mine (touring 6th) anywhere near it. About 123 indicated is the closest I have been and I think the GPS was reading 114.

It could be that the end of the flex cable is worn more on some (2) of the lobes and that the variation indicated should show more extreme at higher revs.