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Old 11-24-2007, 07:31 PM   #1
davidc83
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16 T front sprocket

Well, changed my front sprocket to the 16 T today. Since I had bought the C50 back on October 6, I had only rode the little gz250 (new name: little bit) only about 12 miles. I decided to do a little tlc on little bit today. I changed the oil, changed the front sprocket to the 16 T, performed chain maintenance, washed and wiped her down. 40' F but I decided to ride to town (10 miles each way) and see how the sprocket changed the performance. Sorry, but didnt see any. First gear was maxed at 12 mph, 2nd gear had to be changed at 22-25mph, 3rd was wound out at 35, 4th was done at 45mph. I ran 5th gear at 55 mph but on country roads with dear out, didnt want to go any faster. These are basically the same speeds/gear changes I have done with the 15 T front sprocket. At 55mph, 5th gear/engine sounded the same to me as the 15 T.
It was still fun (wind chill very cold :rollriding little bit. I can ride little bit completely different than the C50. You all have a good weekend.



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Old 11-24-2007, 10:52 PM   #2
jonathan180iq
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You may not have noticed a difference since you haven't been on the GZ in a while.

The changes aren't mindblowing but they are definately noticeable. The biggest noticeable change is in the 45-55mph range. Also, side by side, my 16T bike can out run my buddy's 15T bike. There just isn't enough gearing for the 15T to keep up. Up the 55-60 miles per hour, the 16T bike is quicker and does so at lower RPMs.

However, above 55 mph, the 15T equipped bike can pull away from the 16T bike. The internal gearing of the bike, combined with the increased gearing of the 16T sprocket is too much for the GZ to handle. I can only break 70mph if I'm drafting on the interstate. When my bike was stock, at 15T, I could reach 80 with no problem. Now, I'm relegated to 65 max. (without drating)
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Old 11-24-2007, 11:33 PM   #3
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I will find out if my top end speed is greatly reduced the next time I ride the Interstate. When I commute to work, I have to ride Interstate and if I cannot maintain the 70-75mph range, I will go back to the 15 T. I put 11,300 miles on little bit this year, so I can tell there is no significant difference. My max in 4th gear is same as for the 15 T; 45-50mph. I will see.



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Old 11-25-2007, 02:41 PM   #4
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HowTo Turn 5 Gears Into Four

I recently replaced the chain and sprockets on my GZ250. Having read many favorable comments in the various GZ250 Internet forums about increasing the size of the front sprocket from a 15 to a 16 tooth sprocket I decided to give this a try. To say I was disappointed would be an understatement. If I had a 15 tooth sprocket to switch back to I would have changed back the first day. After considering it for a while I decided that I was being unfair about the whole thing and that it was possible that I just needed to get used to it. I've had the 16 tooth sprocket for 2000 miles including one 700 mile road trip and I still don't like it. I have ridden more than 20,000 miles on GZ250s. I own two of them. One with 15T sprocket and one with a 16T sprocket making comparisons quite easy.

Before the 16T sprocket I used 5th gear on a regular basis. Now its practically useless. The big surprise came on a recent road trip while riding on a highway with a 65 mph speed limit in hilly country I shifted into 5th gear going down hill at about 65 mph. With the throttle wide open going down hill my speed slowly decreased until I had to down shift into 4th. It wasn't a very steep hill and there may have been a slight amount of head wind. The pavement was a bit rough which increases rolling resistance. However, a 15T sprocket would have easily maintained 65 to 70 mph under these conditions. In order to use 5th gear on the highway at all I had to contend with constantly shifting up and down between 5th and 4th gear. I conditions where your are riding with the throttle wide open this is difficult at best.

At lower speeds around town 5th gear is only useful in certain near perfect conditions. Smooth pavement, flat or down hill, no wind, and little or no traffic. At 45-50 mph the in 5th gear the engine is so far out of the power band that any tiny change in speed lugs the engine. This can't be good for it. Our other GZ250 with its 15T sprocket will easily run around town in these conditions.

With the 16T sprocket 4th gear is OK but it can't maintain 70 mph on the highway. Its much like riding with a 15T on a windy day when you have to ride in 4th gear to maintain 65 mph but with less vibration. Annoying!

I can go 55 mph in 3rd gear. Now this is strange. It vibrates like crazy but on my recient road trip there where several up hill stretches where I could not maintain 55 unless I down shifted to third. This is not some thing I liked.

In 2nd gear the 16T sprocket is a bit annoying. I have one of those GZ250s that will miss first gear when down shifting if you are going to slow. If you for get to check the gear and the light changes your trying to start in second. With a 15T sprocket this was not much of a problem. A little more clutch and away you go. With the 16T sprocket starting the bike in second gear is much more difficult and you may find your self stopped in the street at a green light fiddling with your shifter. If you never do this then it should not bother you, However, I start in second gear on purpose under certain conditions and had to learn not to do this. Annoying!

1st gear with the 16T sprocket is much smoother and the response in much less twitchy making low speed maneuvering easier. This improvement is not anything that you can't have with a 15T sprocket using good riding techniques such as shifting to 2nd and using a little clutch or feathering your rear brake in 1st gear and using a bit more throttle. On the down side starting a loaded bike on a steep hill is a bit more challenging. I do not like this. One of the things I really liked about the 15T sprocket was the ability to stop on any hill without being concerned at all about getting it started.

In general the the 16T sprocket causes me to need to shift gears a lot more. With the 15T sprocket my commute was pretty much shift to 4th and ride to work not having to down shift unless I needed to stop or slow for traffic. With the 16T sprocket its 4th down hills, 3rd up hills and occasionally second gear if traffic is slow. Annoying!

IMHO all switching to a 16T sprocket does is turn five gear GZ250 into a four gear GZ250. Sometime in the near future I will have a slightly used 16T sprocket for sale.

I switched back a few days ago.
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Old 11-25-2007, 04:09 PM   #5
jonathan180iq
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Bob is right about 5th gear. It is reduced to basically only an overdrive gear.

But David, that 50mph limit can't be right. Even with the 15T sprocket, 4th could carry me into the 60s. It would be buzzy, but it handles it. With the 16T sprocket, 4th gear can get me close to 65. Shifting into 5th, however, loses all momentum with the 16T sprocket.

I've found myself hating it too, on the open road. But, around town, I like the gearing on the 16T.



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Old 11-25-2007, 06:20 PM   #6
davidc83
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My fourth gear has never got me past 55mph, even down hill with a tail wind. It is just something quirky with it; but then with the 15T, I can get to 80mph on the interstate while maintaining 70mpg. When I put the 16T on, I was hoping I could get to 60mph, but nope, it was maxed at 55mph, even with WOT. I was going to do some highway riding today, but it has been raining all day with temperatures in the 40s. If I cant get above 70mph with the 16T, off it comes and my 15T goes back on. Later guys.
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Old 11-26-2007, 07:16 AM   #7
Jaime
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The problem is that Suzuki put an overdrive 5th gear in a low displacement bike. No surprise, the biggest ratio difference is from 4th to 5th. It would be perfect if it had a 19/21 instead of a 18/22 (internal gearing).
In my case, the 4 first gears are clearly improved after the 16T sprocket, but the upshift to 5th makes the mentioned difference critical, so you must run at higher rpm to have good acceleration.
I use to squeeze the gears, as I shift to 2nd at 31 mph, to 3rd at 46 mph, to 4th at 60 mph and to 5th over 70 mph. Then I can eventually top 87 mph, but not maintaining it. I cruise at 68-75 mph in 5th, only downshifting to 4th for faster overtaking from slower speeds.
Anyway, I've modified the intake system and carburetion too.
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Old 11-26-2007, 08:38 PM   #8
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Quote:
Originally Posted by jonathan180iq
Bob: If nobody else takes that 16T in the next few weeks, I will. I'll be needing one at the next chain change.
Its been spoken for. But the deal is closed yet. I'll let you know if it falls though for some reason.
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Old 11-28-2007, 01:16 PM   #9
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Originally Posted by Easy Rider
It humms along cruising at 55-65
Yeah. That seems to be the sweet spot.
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Old 11-30-2007, 10:54 PM   #10
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I wonder if the GZ will only benefit with a 16T if a smaller lighter rider is on board ?? Any comments ??
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