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Discussion Starter #1
Bought some time ago a JT 42 tooth sprocket for the back.

I still have the stock in the front. How is the 42 going to help me on the road, I ride mostly road.

Thanks



PS Cannot do a search on this site for words less than 4 characters
 

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If the 42 tooth will pull you, you'll probably be able to cruise at about 90. If you do a google search like this "site:tw200forum.com oil", it will search the forum for you with less than 3 character words.
 

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42 tooth sprocket will be fine, downhill, with a tailwind, drafting a semi. Other than that, no.
 

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I had 15/47 for a while. It worked on flat ground, but uphill, or too much head wind, and there was NO torque to keep the bike moving at highway speeds. (it slowed down going up & over the overpasses) Now that I have 15/50 I have enough torque for holding the bike at 60 or so on all but the steepest hills. I might go with a larger rear sprocket, but I'll never go back to anything smaller than a 50.



Using a 14 front sprocket, the closest equivalent to my current setup would be 14/47. I think any ratio lower than that gives up too much torque. Your 14/42 would be like a 15/45. While the engine will theoretically red-line at higher speeds with a smaller rear sprocket, in reality you are less likely to get up to those speeds. Unless you are going downhill, with a tailwind, or drafting a larger vehicle.

 

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Discussion Starter #5
I am 200lb, 6 foot high. No, I was not drunk when I bought the 42 sprocket.

Can you recommend something else? Like 44 or 45?

What chain tool should I buy for the chain on a 2008 TW? Is there a specific size of the pin or space for the tool?

Tx
 

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Sorry, I can't help on the chain tool. I used a Dremil and a punch to shorten the 130 link chain I bought. Then put the master link on using needle nose vice grips. I edited my previous post with my personal preferences on sprockets.

 

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The stock sprockets are good for 75mph @ 9500rpm, which the stock engine won't pull, anyway. 14/47 or 15/50 sprockets will allow a little more runout in lower gears, a little less vibration on the highway, but no real gain in top end unless running downhill, 9500rpm about 79mph. 14/42 yields 9500rpm @ 88mph. I expect there are not many long enough, straight enough downhills to run that fast in the U. S. of A.



Other than a few people who traverse long downhills in the mountains, most street riders eventually end up with a 14/47 or 15/50 sprocket set as the best all-around choice. Many people who ride dirt roads (as opposed to hard core off road) in addition to pavement also settle on the 14/47 and 15/50 sprocket sets as the best all around choices.
 

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Discussion Starter #8
For a 15/50 setup would the stock chain need to be modified (lengthened) ?

I am at the first notch, it's a new bike. I cannot lengthen the chain by shortening the distance between the sprockets anymore, am I correct?

tx
 

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I run 14/45. Did a 14/50, 14/47, and 14/45 on previous tw and 47 was better than the 50 but still not enough for me. I like the 45 on back better. You have to decide which you prefer as there are plenty of folks using all sorts of ratios. If you are swapping the rear sprocket, get a new o-ring chain and put it on with the sprocket swap. That is a choice most will agree on.
 

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Ive been running a 42t for almost 2 years. Im 90% street so I wanted to be able to stay above 60mph without the motor screaming. I'm @230lbs and when I hit the highway I just hold it wfo which usually has me around 72mph. Wind is not your friend and neither are hills. With a strong headwind my top speed sometimes drops to 65mph, add a big hill to that and I have to drop it into 4th to maintain 60mph. Fortunately I dont deal with many elevation changes on Long Island. If I ever change the rear sproket id go with a 47 or 45.
 

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Don't worry about a TW engine screaming its guts out. It won't. Some people complain about the sound of the engine at high rpm on the highway, but that's more of a problem for the rider's ears, not so much a problem for the engine. The TW's carb throat is so small it's almost like running at half throttle when the throttle is WFO. The cam is so mild the engine will stop making power long before you break anything. It is the samll crab and mild cam that give the TW its wide powerband. Don't be afraid to use it all. Gearing too high just lugs the engine, overloads the clutch, transmission, and final drive, and ruins higway performance. It's a weakly tuned 200cc engine. Gear it for a 75mph redline and ride it like you stole it--won't hurt the bike a bit. Gear it for a 90mph redline, and you'll invite driveline problems and make it harder to maintain speed. If the vibration in the bars bothers you, $10 worth of gel grips will solve the problem. Ride the bike as it was meant to be ridden--don't try to make it lug along like a KLR or a Harley.
 

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For a 15/50 setup would the stock chain need to be modified (lengthened) ?

I am at the first notch, it's a new bike. I cannot lengthen the chain by shortening the distance between the sprockets anymore, am I correct?

tx


15/50 uses the stock length (122 links) with plenty of adjustment room left over. I haven't had to adjust the chain since putting it on. It hasn't stretched enough to go slack.
 

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I'm going to try a 15/52 this summer. We'll see how it does. Parts are ordered. It's halfway between a 14/47 and 14/50. Hoping to keep up better against windy conditions at highway speeds and still keep 1st useable for the street. Theoretical top speed will be a hair over 76mph with this setup so that'll keep me happy for the commute to work.



Really debated going back to 14/50 but decided to try something new. Haven't seen many 15/52's out there.
 

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I have a 14 tooth front. I just replaced my rear sprocket with a JT47 and cut a new o-ring chain at 122 links and it fits fine, right in the middle of the adjusters.
 

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Discussion Starter #16
Did a front sprocket with 15 T and the bike runs way better. 1 st gear is usable, I can reach 90km/h in 5th and 80 km/h in 4 th.

Definitely worth the 17 CAD for the sprocket and the 3 hours invested in changing it.

Wondering how it would be with a 16 T in the front and stock 50 T in the back or 15 T in the front and 47 T in the back. Can you guys let me know?

I am 220 lbs and trying to ride roads more and light trails sometimes.

Tx
 

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Here is a chart showing the TWs HP and Torque vrs rpm. There is a better graph in the Maintenance Manual I believe. This is for Sea Level Conditions.



For those of you on paved roads, flatland and sea level a smaller rear sprocket will work much better than for those riding off-roading, hilly/mountainous terrain at high elevations (where re-jetting the carb might also be necessary, as well-but that's another topic).



But, as Qwerty already stated "Keep the Revs Up" on the TW. The chart shows why.







Hope the chart helps, wish I had a better one to share, maybe someone else does.



As perviously mentioned for most of us the 14/50 or a slightly taller 14/47 works quite well. And those doing more trail riding will most likely enjoy a 55R.





Mike
 

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So if i live @ 7000 ft and ride 100% street with my bitch on the back dont get the 50 tooth? I just need a lil more gogo.



should i put the full fmf on as well or just change the sprocket ? altitude is kinda the devil for my tw.
 

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So if i live @ 7000 ft and ride 100% street with my bitch on the back don't get the 50 tooth?


No problem. The TW's monster 13.5 rear wheel horsepower is only trimmed slightly to about 9 HP at 7000 feet. Load your girlfriend on the back, hitch up that trailer, and head up into the mountains. I'm sure it will climb like a Sherpa on steroids.



Chip
 

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So if i live @ 7000 ft and ride 100% street with my bitch on the back dont get the 50 tooth?


I hope you are talking about your female dog here. Or else I hope your bitch has a nice name for you, too.



You might want to keep in mind that this is not a men-only forum. Welcome, btw.
 
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