Is 5th gear useless to anyone else?

[Easy Rider]

Originally Posted by tommygun

Whats the going distance before a complete engine overhaul?

Depends on what you mean by "riding it wide open".

Wide open in 5th is quite different than wide open in the other gears.

We've had a couple of guys on here that liked to red-line it in all the gears, all the time and they lasted less than 30,000 miles.

OTOH, there are quite a few approaching 50K miles and still going strong but I suspect that they never have it wound out all the way.......because it won't do that in 5th !!

[GZ250]

if you want speed, go for a 650cc or up. GZ250 isn't made for that. may be there are some individual bikes that can go faster or some mods help. i cannot go beyong 65mph. this is the maximum i can go in any situation but bike runs great.

need for speed, upgrade.

[Badbob]

5th gear is over drive.

I went on a trip a few months back. About 1800 miles half or more of this on mountain roads loaded with my 220 lbs and all me camping gear and tools. The only problem I experienced was with me not reading the road ahead correctly and being in the proper gear. This improved dramatically as the miles went by. On this trip I used 5th gear primarily in the flat country going to and from the mountains. I don't usually shift into 5th gear unless I'm going at least 50 mph.

There is nothing wrong with down shifting. To go up a mountain.

[alanmcorcoran]

I agree Bob. As my time on the bike increases, I have gradually raised the rpms in all the gears and I reserve fifth now mainly for freeways and 50+ mph. On moderate inclines I have held the bike at 60 mph in fourth gear.

I used to race to get into 5th and was typically in it by 40 mph.

In the beginning I retained my old car shifting habits (formed during the first gas crisis (77-79) where the name of the game was low rpm, high gas mileage. This may work when you have a 100-150 horsepower car, but if you want decent speed out of the GZ, higher rpms are better. I went through a similar learning curve on the bicycle - high cadence gives you the most power (and is also best for the "engine") there as well.

Now that I am used to it, I'm enjoying the thing a lot more, and I'm doing a lot better on the freeway.

[Badbob]

Originally Posted by alanmcorcoran

Now that I am used to it, I'm enjoying the thing a lot more, and I'm doing a lot better on the freeway.

I also found that I enjoyed the ride much more when I let the GZ be what it is and ride in the middle of the power band or at least what feels like the middle to me. I looked for some info on this once and was never able to find any. I would loke to see a graph of HP or torque vs rpm for this engine.

[NoMates]

I agree mine seems to love to rev so I let it do just that. Once I got over the fear of blowing it up I found my highway speeds increased and its happy buzzing away. I wouldnt say 5th gear is useless its just not as useful as 4th..

[Chris]

Hi Tommygun
Are you still looking at this post? I also ride in north Georgia and have no problems on the interstate. Let me know.

Chris, Cobb County

[mr. softie]

Originally Posted by tommygun

See now I would be thrilled to get up to 70! I have been 70mph down hill only?! does the 16t give you more torque? to maintain a top speed of 60-65?

The 16t gives you a higher final drive gear, so less torque for a given speed. However it does allow you to take 4th up to higher speed. I stay in 4th up to 65-70 on hills if I need to, with the 16t. With the 15t I would only get to 65 tops in 4th. I really don't have trouble maintaining 70mph on the highway at all in 5th, once I get there. I use 5th as an "overdrive" gear. Not much torque or power in fifth whatever sprocket you run. It is like riding a bicycle in a way. The trick with the gz is keeping the rpm's up when accelerating or hill climbing, and dropping them down when you are just maintaining a speed. Sometimes a nitrous kit would be handy. hmmm... maybe a roller cam? BTW I am using the SpitFire windshield as well . :2tup:

Don't be afraid to wind this engine out if you need to. A ninja 250 would be slow too if you never took it over 5000rpm. While the GZ does have nice usable power at the lower rpm's, it makes it's best power and torque at higher rpm's. Top torque is 18.7 Nm @ 7,000 rpm and top hp is 20.1 hp @ 8,000 rpm. The redline is about 8700 rpm and top speed is around 75mph. I have gotten mine up to 87mph! (tail wind, drafting a semi, downhill, hot day, feet on rear pegs, chin on bars) and I weigh 220lbs.

See my recent post on valve adjustment for power tips. Might be worth trying a valve adjustment to tweak a tiny bit more horsepower. I don't think changing exhaust and intake etc. is worth the trouble and expense for the small power boost you might get but you can adjust the valves for free. You can also try turning your mixture screw out a tad and raising the carb needle to get a bit more pep. Plus make sure your tires are aired up and your brakes aren't dragging. I have heard running Rotella or Castrol 10-40 synthetic oil can also give you a bit more get up and go. I am using the Rotella. Every little bit helps with the GZ.
http://www.gz250bike.com/forum/viewt...p=18790#p18790