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GZ 250 Forums (http://www.gz250bike.com/forum/index.php)
-   Beginners (http://www.gz250bike.com/forum/forumdisplay.php?f=16)
-   -   Gear Shifting (http://www.gz250bike.com/forum/showthread.php?t=3397)

diffluere 07-04-2010 08:14 PM
Re: Gear Shifting
 
On my travels Friday I checked, and yeah, I shift into second going 20mph. The noise is similar to the noise of going about 32 in 2nd gear. I don't have a tach so I have no idea what rpm that is.

The fastest I've been on the bike is about 75 but I've never TRIED to go faster than that. I'm usually with other people when I'm on highways that have a 65mph speed limit, and I don't really want to get a ticket! I haven't tried (nor desire to) go on I-75 on the GZ. I've been on a nice fast highway on a Ninja 250 though, and that was a piece of cake! It will do 80 before you even realize it.

Easy Rider 07-04-2010 09:45 PM
Re: Gear Shifting
 
Quote:
Originally Posted by diffluere
On my travels Friday I checked, and yeah, I shift into second going 20mph. The noise is similar to the noise of going about 32 in 2nd gear.
Both of those are probably too fast for prolonged engine life, serioiusly.
Your GZ can cruise comfortably in 3rd gear at 30 mph....or less.
Unless you are REALLY in a hurry, there is no good reason to push your engine that hard.

zenbutcher 07-06-2010 12:23 PM
Re: Gear Shifting
 
Quote:
Originally Posted by Easy Rider
Quote:
Originally Posted by zenbutcher
Instead of shifting at 4-5000 rpms, I'll take it up to what I feel like is 6500 or more. Now, the little bike is screaming, but I'm coming around to the idea that motorcycle engines are meant to scream.
You're pushing the envelope. You might get away with it for a long time and you might NOT too.
Single and twin cylinder "long stroke" engines are NOT meant to "scream". Their most efficient power generation is with low to medium end torque.....not screaming horsepower.

If you want to see a small engine that IS designed for screaming high end horsepower, ride a Ninja 250 sometime. I think someone said that the red line was something like 14,000 rpm......and it will scream along at 12,000 all day long.

Like I mentioned before, we've only had two riders come here and report engine failures (not counting things like "no oil"). One liked to make it "scream" before every shift and the other ran his for long periods at 80 or slightly above. Since you seem to be doing both, I wouldn't want to give odds on the longevity of your engine. It was NOT designed to be riden that way.
Well, you're right on both accounts, Easy... I do rev the bike quite high and also cruise around 70 for extended periods (maybe only 20 minutes around town, but 2 hours if I'm on a trip). This is my first bike, so I may be making some mistakes. Thanks for the input.

3-D Video 07-06-2010 01:09 PM
Re: Gear Shifting
 
[quote="diffluere"]On my travels Friday I checked, and yeah, I shift into second going 20mph. The noise is similar to the noise of going about 32 in 2nd gear. I don't have a tach so I have no idea what rpm that is.

I found the "Gearing Commander" site that pbro posted recently (http://www.gearingcommander.com/) to be useful to me as I learn more about my bike. It says that 20mph in first is about 6500 rpm, 31.4mph in second is about 6500 rpm, and that 65mph in fifth is, again, about 6500 rpm. 75mph is around 7500 rpm.

Easy Rider 07-06-2010 01:27 PM
Re: Gear Shifting
 
Quote:
Originally Posted by zenbutcher
and also cruise around 70 for extended periods (maybe only 20 minutes around town, but 2 hours if I'm on a trip).
I don't really think THAT is going to be a problem.
It's hard to push the GZ beyond it's limit (or even TO it) in top gear; even harder if you put on a 16T front sprocket.

fg1234567892000 07-06-2010 03:43 PM
Re: Gear Shifting
 
Quote:
Originally Posted by Easy Rider
You can, if the need arrises, run it for short distances in 4th about 55 (STEEP hills, which you don't have in Iowa except maybe Dubuque).
I tried this out when I rode home on the weekend. On the trip, there was a strong wind against me, so using 4th at this speed really helped me maintain my speed on hills, since even minor grades seemed to really sap my power.

On my return trip, I instead had a tail wind and did not need to shift out of 5th at all. Thank you for your tips; they were quite helpful. I guess I just never knew that power was available to me in 4th!

diffluere 07-06-2010 09:00 PM
Re: Gear Shifting
 
Quote:
Originally Posted by 3-D Video

I found the "Gearing Commander" site that pbro posted recently (http://www.gearingcommander.com/) to be useful to me as I learn more about my bike. It says that 20mph in first is about 6500 rpm, 31.4mph in second is about 6500 rpm, and that 65mph in fifth is, again, about 6500 rpm. 75mph is around 7500 rpm.
I noticed that too, and if redline is 9000 rpm is 6500 really that bad?

Also, today I rode with a friend all day. We both gassed up at the same time, but at the end of the ride her trip meter was at 140 miles and I was at 137. Maybe the slight error in my speedometer is affecting what speed I "think" I'm shifting at? Probably not a significant amount but who knows...Either way my bike doesn't sound like I'm killing it when I shift. It might help that I only weigh 125 and I'm in Florida, land of the flat straight roads.

alantf 07-07-2010 04:39 AM
Re: Gear Shifting
 
Quote:
Originally Posted by diffluere
her trip meter was at 140 miles and I was at 137. .
If my maths is correct, that's just over 2% difference, so at 50 mph that's 1 mph difference, at 25 mph thats ½ mph difference. I don't think that those figures will make any significant difference.

BTW don't think that this 2% difference can only be a difference in speedo accuracy. If she takes the curves wider than you, or weaves while you're riding straight, then this could account for the 3 mile difference in 140 miles. :2tup:

I've noticed a difference in the "going to" & "coming back from" mileage, due to right hand curves (going) versus left hand curves (coming back) or vice versa.

Easy Rider 07-07-2010 10:17 AM
Re: Gear Shifting
 
Quote:
Originally Posted by diffluere
I noticed that too, and if redline is 9000 rpm is 6500 really that bad?
How did we get up to 9000? I thought the most quoted figure was 8500 ?? .......which is the rev. limiter point and not a conventional "red line".

Anyhow, the thing IS that in the lower gears where the revs increase rapidly, IF you are in the habit of reving it high (6500) and something distracts you.....or your habit slowly increases as you get more comfortable with the sound......then you can rapidly hit 7000....or 7500....and the higher it goes, the more likely of a stress related failure. In 5th gear, it's hard to over-rev even if you try.

ncff07 07-07-2010 10:23 AM
Re: Gear Shifting
 
Ive been shifting like I would in a car, tried letting it wind up more before shifting yesterday when I was out on it and it actually does better with more RPM's between shifting.


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