Red Lining

[Nightsbane]

If you don't have a tach, how do you know if you are?

I am currently commuting this fall to class about 25 min away. I am not wanting to damage the bike. I know height, weight, hills, wind affect speed, but how do I know if I am running it too hard? Just trying to be careful. There is one stretch for five miles where it's low traffic and still only two lane, but 65mph. I'm 6ft, 200 pounds.

[blaine]

In 5th gear,at 50 MPH you are reving about 5000 RPM,at 60 MPH about 6000 RPM, and 70 MPH about 7000 RPM.
:cool:

[5th_bike]

...And in 4th gear, you can get up to 65 (stock 15 tooth front sprocket) at 8000 rpm, but I wouldn't do it for long.

The official redline is 9,000 rpm as far as I know.

[Nightsbane]

The odd thing is that since I went out driving tonight the sound of the ngine has changed (in town) in went from its normal throaty sound, to a much lighter, quieter, and tinny sound and I can't figure out why. I was pretty low on gas and I have just put some B-12 Carb Cleaner into the last tank run through, other than that I am hoping I haven't done something.

On RPM terms, there have been a couple times I have been in 5th gear and full throttle, only at a top of 70 mph, but in the wind sometimes it take giving it all she's got to maintain speed and get over some light hills.

Thanks for info so far, any other info would be appreciated, just trying to protect the bike.

[Nightsbane]

I wanted to add that outside the wind as a resistant, the roads are 99% totally flat. Right now my main concern is the sudden change in engine sound. It is much cooler outside tonight as well for the first time in two months. Just trying to figure out if I have a problem or if I broke something with highway driving...

[alantf]

I've just bought a new helmet. Same as my old one, but a much snugger fit, because the lining hasn't had time to squash up. The engine sounds MUCH different. Like a different bike, in fact.

[Nightsbane]

I'm talking about my engine sound without a a helmet on, has changed dramatically to a lighter, tinny, and less powerful sound though I notice no power loss.

[blaine]

Originally Posted by Nightsbane

The odd thing is that since I went out driving tonight the sound of the ngine has changed (in town) in went from its normal throaty sound, to a much lighter, quieter, and tinny sound and I can't figure out why. I was pretty low on gas and I have just put some B-12 Carb Cleaner into the last tank run through, other than that I am hoping I haven't done something.

On RPM terms, there have been a couple times I have been in 5th gear and full throttle, only at a top of 70 mph, but in the wind sometimes it take giving it all she's got to maintain speed and get over some light hills.

You will not damage the engine going 70 in 5th gear for short bursts.The B-12 probably loosened up some carbon in the combustion chamber,causing the bike to sound different.
:cool:

[jonathan180iq]

Bikes do change sound overtime.
I'll agree with Blaine, here. A good hot run on the interstate, coupled with a tank of carb cleaner and some age on the bike probably broke off some specs of carbon. The engine is probably running like it should now. These things were never known to be throaty speed demons

And for what it's worth, the 70mph into a headwind part is just about as fast as you're going to be going. If you spend much time on the interstate, I would recommend a 16T sprocket change, simply to keep engine revs down a bit. The change is easy enough. If you see a time when you won't be commuting as much, drop back to the 15 if you want. I just kept it in there.

[jonathan180iq]

Some handy reading for you:

Speed for Gears - viewtopic.php?f=4&t=4675&hilit=speed+chart

16T sprocket "How-to" - viewtopic.php?f=8&t=317