TW200 Forum banner

1 - 15 of 15 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter #1
I changed the stock 50t sprocket to a 47t. Makes first gear a lot more usable. There is a definite decrease in torque and you get about 500RPM less at 90km/h in 5th gear.

I didn't change the chain to a 120link instead of a 122link, like recommended. The 122link chain still works but your cam (I don't know the right work for the thing that move's the wheel back and makes the chain therefore more tensed) is set to the position marked by a 7.

The part number for the new sprocket I put on is: JTR1842.47 (perfect fit)

Overall it's the best compromise highway-off-road if you do mostly trails and only need a little more top speed for when you need to do a little bit of highway.

36762457_1793698944050580_9199959379850297344_n-2.jpg
 

Attachments

·
Super Moderator
Joined
·
4,046 Posts
One of the guys riding the mountain trails and roads with us in Green Ridge recently didn't care for the 47 tooth rear sprocket. It was nice to have the low first gear in the technical stuff. I think I'm going 52, next time around. 47 tooth for me lost to much torque in 5th but many do like it. I guess to each his own for where and how they ride. I am running stock now, but heading up those mountain roads could have been just right with a 52, won't know unless I try and that's what it's all about trying things out, else you're in a box of your own making.
 

·
Registered
Joined
·
6,346 Posts
Kaz, I'm curious... Do you know how much top speed you gained?
I know you didn't ask me BUT I have been running a VERY similar gearing 15/50 for few years now and I would say you gain ZERO top speed. What you do gain is a more relaxed engine between 55 and 60 mph. Just my two cents.



Tom
 

·
Registered
Joined
·
1,493 Posts
"Kaz, I'm curious... Do you know how much top speed you gained?"

I don't know about the 47 or what kind of top end you get with stock gearing but I run a stock front and 45 rear which gives me a top speed of 118 km/hr (73 mph) and it will cruise all day at 110 km/hr.
 

·
Registered
Joined
·
1,861 Posts
I did the 47T swap almost as soon as I bought my TDub. If I knew how to find my frikkin mods post ("So Far") I had an RPM comparison. Bottom line was for a 50-50 bike the Yamaha engineers got it just about perfect and I recall Gary L. telling me not to bother, won't make much of a difference. Did I listen, NO of course. Just changing the rear sprocket from 50 to 47 is so minimal that the tiny loss of torque at the low-end or the lower revs at the high end are minimal, a tiny edge over stock if you still want it to be 50-50.Maybe it's 49-51 now, HaHa.

But the JT sprocket is a nicely engineered product over stock and changing to an "X-Ring" chain from the crappy factory chain was a big upgrade. So in the end those are what justifies the change for me and makes me feel warm inside.
For anyone thinking about doing it (50 to 47) I'd say don't bother. If you were going to Increase or decrease teeth substantially and primarily for street duty or trail duty... yeah, go for it.
Been down this sprocket alchemy road already years ago with a KLR where everybody was either prepping their bikes for a trip that never happened to Patagonia, Chile or Paterson, New Jersey.
 

·
Super Moderator
Joined
·
4,046 Posts
I did the 47T swap almost as soon as I bought my TDub. If I knew how to find my frikkin mods post ("So Far") I had an RPM comparison. Bottom line was for a 50-50 bike the Yamaha engineers got it just about perfect and I recall Gary L. telling me not to bother, won't make much of a difference. Did I listen, NO of course. Just changing the rear sprocket from 50 to 47 is so minimal that the tiny loss of torque at the low-end or the lower revs at the high end are minimal, a tiny edge over stock if you still want it to be 50-50.Maybe it's 49-51 now, HaHa.

But the JT sprocket is a nicely engineered product over stock and changing to an "X-Ring" chain from the crappy factory chain was a big upgrade. So in the end those are what justifies the change for me and makes me feel warm inside.
For anyone thinking about doing it (50 to 47) I'd say don't bother. If you were going to Increase or decrease teeth substantially and primarily for street duty or trail duty... yeah, go for it.
Been down this sprocket alchemy road already years ago with a KLR where everybody was either prepping their bikes for a trip that never happened to Patagonia, Chile or Paterson, New Jersey.
Paterson! You need some serious gearing there.. ;)
 

·
Registered
Joined
·
4 Posts
Discussion Starter #10
Yeah I don't have mountains in my area it's pretty flat and there's not a lot of trails so I have to travel sometimes half an hour going 90km/h to find trails..
 

·
Registered
Joined
·
7,046 Posts
I went from 50t to 55t and to be honest it didn't make much difference.

Then I tried a dual sprocket set up using a 45t and a 55t. There I could tell the difference but it really wasn't much and most certainly not worth the effort of removing or adding a short section of chain and readjusting the chain tension especially at the side of the road.

I went back to the 55t and have left it there and been happy. IIRC, 8,800 rpm is just over 60 mph and that is good enough for me.
 

·
Registered
Joined
·
112 Posts
I can tell a difference with my 47t rear. But mostly just around 45-50mph i cruise around on the backroads on, its less buzzy. Dont really notice much in in 1st gear. I like it better with the 47t. If i ever get in some real technical stuff, we'll see ...
 

·
Registered
Joined
·
1,463 Posts
To understand 47 tooth sprocket performance. looking at the opposite can also tell you what to expect.

If you plan to climb any hills I wouldn't suggest a smaller sprocket as even the stock gearing requires gearing down on longer steeper hills. Now that I run 52 off road I don't have to gear down to climb but I doubt I can't go faster then 90kph/55mph without serious redlining. I can skip 1st unless I really wanna crawl. 2nd/3rd gears are my new favorite tight trail gears. With more torque comes better climbing, wheelies, and acceleration. It is a noticeable difference that is worth the sacrifice IMO.

One thing I've yet to hear is with a smaller back sprocket, is running at lower RPMs and higher speeds will also keep your engine cooler.
 

·
Registered
Joined
·
7,046 Posts
Now that I run 52 off road I don't have to gear down to climb but I doubt I can't go faster then 90kph/55mph without serious redlining.
Get a cheap "small engine" tachometer off ebay for < $12. With the redline at 9500 rpm I bet you will have a ways to go before you reach the redline with a 52t sprocket at 55mph.
 
1 - 15 of 15 Posts
Top