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-   -   5th gear - overdrive? (http://www.gz250bike.com/forum/showthread.php?t=2143)

03-22-2009 08:57 PM

5th gear - overdrive?
 
I've heard a few guys on here refer to 5th gear as "overdrive". Though I think I can guess what they mean, I'd like to be sure - so what, exactly, do you mean by that? To me, when the bike is near 50 mph or more, it "wants" to be shifted into 5th gear. Some have said they drive in 4th gear at even faster speeds and do it for long periods of time; this is okay for the engine?

PS - I think you guys who ride these little bikes at 75 mph or faster are nuts - not dissing you, even admire your balls, but Jesus, the bike does not feel stable to me at that speed, especially if there is wind or other mitigating factors (heavy traffic, wet roads, etc.).

Thanks,

Keith

Sarris 03-22-2009 09:04 PM

Re: 5th gear - overdrive?
 
You are probably referring to the bantor surrounding the 16 tooth front sprocket change. With that
mod done, you will reach your max speed in 4th utilizing 5th gear as a cruising or "overdrive". It's only because
the 16 tooth changes the powerband a bit.

Also, 75 mph??? You shittin me?? At 6'-1 280lbs. I'm lucky to keep 65 to 68 mph w/ no headwind. But some
physically smaller folks have reported over 80 mph. I'll take the Harley if I need to go that fast.

:2tup:

03-22-2009 09:11 PM

Re: 5th gear - overdrive?
 
Thanks, Sarris, I did forget that those mentions of "overdrive" were related to the 16T mod. BTW, I only weigh 160 and I still think anything over 60-65 feels unstable to me, especially now with a bigger windshield. But, hey, I'll live vicariously through the speed demons (but be safe, boys)!

Keith

alanmcorcoran 03-23-2009 01:16 AM

Re: 5th gear - overdrive?
 
km, I think Easy(?) and others have referred to it as an overdrive, not in the strict technical sense (that output of the tranny is greater than input) but in that:

1) It's the last gear.
2) It's where you can get some top end speed, but it's got no torque.

Basically, you want to be already moving pretty good, on a flat, smooth road, and then, put it in fifth and go for it. If you are climbing hills or fighting wind, you might as well leave it in fourth, cause otherwise you'll probably be slowing down.

Re riding 75. Mine will do it, but only under near perfect conditions. (Flat, smooth road, maybe a small tailwind or behind a semi.) Actually, if the road is smooth asphalt, my bike is very stable at 75. There just aren't many roads around here where the smoothness, the flatness and the straightness all combine. Ironically, most of our high speed roads have pretty shitty surfaces. I weigh about 178. Generally I am happy if I can keep at or just above the speed limit (65.)

When I first got the bike it was not as fast as it is now. I often had to leave it in fourth to maintain 60 or better on the freeways. There are other threads on here that talk about redlines, limiters, and riding WTFO (Wide The F*ck Open) all the time. Some anecdotal evidence seemed to suggest it wasn't the best thing for the bike, but I don't think there's been any science presented. To be honest, that "any minute now I think I'm gonna pop" sound the GZ makes when it is hammering along at 65-70 is one of the reasons I got a bigger bike for that kind of riding.

Water Warrior 2 03-23-2009 02:56 AM

Re: 5th gear - overdrive?
 
:popcorn: :popcorn: :popcorn: I am just going to sit back and let Easy explain overdrives.

JWR 03-23-2009 09:14 AM

Re: 5th gear - overdrive?
 
I could do the :

1 to 1
or
.81 to 1

but this is too much fun....


Easy would just correct me anyway. :roll:

Easy Rider 03-23-2009 09:23 AM

Re: 5th gear - overdrive?
 
Quote:

Originally Posted by kmkindred
Some have said they drive in 4th gear at even faster speeds and do it for long periods of time; this is okay for the engine?

No, not for long periods of time.

One definition of "overdrive" is "to be used at highway speeds to allow the engine to turn slower".
Your observation that it feels like it is needed above 50 fits that definition pretty good, I think.
It is not a real overdrive but it functions pretty much like one.

And yes, the effect is more pronounced with a 16T front sprocket as you don't feel the need to use 5th in most city situations (below 40-45 mph).

How's that, WW ? :cool:

JWR 03-23-2009 09:42 AM

Re: 5th gear - overdrive?
 
Hey Easy, is someone else on your computer????

Easy Rider 03-23-2009 09:50 AM

Re: 5th gear - overdrive?
 
Quote:

Originally Posted by JWR
Hey Easy, is someone else on your computer????

Why do you ask?
(Maybe I don't want to know!) :roll:

alanmcorcoran 03-23-2009 03:25 PM

Re: 5th gear - overdrive?
 
Seems like you are taking your medication again! :whistle:

(can I get some?)


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