2009 Tmec 200cc w/ Street Package Setup Sprockets

[Cbohannan0513]

I know that there are like 15 different forums about this subject... But I have yet to catch my exact bike with a sprocket swap. I have the 17T counter sprocket that came OE and don't plan to change it because of limited availability and possible clearance issues. The rear sprocket is a 56 tooth and I run a 140/70/17 rear wheel/tire setup. I've been sorting the bike out engine wise... But prior to the rebuild I am performing, the bike was topping out at what I presume to be 45mph (my speedo needle was broken before the restoration). I want the bike to be able to run at 60-65mph with out straining so badly. I have done the math and compared numbers from JT-Sprockets which leads me to want the gear range produced by using a 48T rear sprocket. That is a 2.82 gear ratio instead of the stock 3.29 ratio. I live in a busy suburb just north of Atlanta which means I am basically a rolling speed bump at the stock gear ratio. Has anyone been able to purchase or have a counter sprocket made for this bike? I have several sources of where to have one made, but what hick-ups might I run into as far as fitment? I bought my bike with no counter sprocket cover so I'm not sure what the outcome would be in terms of clearances.... I have a sprocket cover on the way though!!! I am just impatient with parts. Thanks for any help guys!

[Weldangrind]

A new countershaft sprocket would be an easy find.

I'm not so sure about the rear sprocket; if it was my bike, I'd remove the rear wheel and measure the sprocket. Once you have specs, you can begin comparing it with Japanese models, and we can help.

[jjn]

Culcune has experience with rear sprockets on the TMEC. It seems TMEC went with a rather odd rear hub. There are sprockets available, but they are nothing common.

[Weldangrind]

Perhaps, but measurements will allow us to confirm. You never know if there was a production change.

[SpudRider]

One can hope.

[Cbohannan0513]

So The largest I counter sprocket available that I have found is the 17T that I already have.

17T - 20mm ID - 7mm thick - 428 Chain Size - 18mm from L bolt hole center to Rbolt hole center.

The rear I think I found the Derbi Senda-R 125cc sprocket will fit. All of the specs appear to be identical: 56T to 48T - 6 Bolt holes which are paired in 43mm spaces - 103.55mm inner diameter.


http://www.jtsprockets.com/catalogue/model/3348

[Weldangrind]

Are the bolt holes on your rear sprocket grouped in pairs like that? Do you have a pic of your rear sprocket?

[Cbohannan0513]

They are grouped like that...

[Weldangrind]

Congrats on finding a match! How long did that take you? I've perused the JT site for hours on some occasions.

[Cbohannan0513]

Thanks!
As it turns out, the rear sprocket is commonly swapped on these... But with several variations of wheel/tire sizes from the factory it became very difficult. It didn't take long thanks to the forum... But I'm still iffy in what gear ratio I want to chase.

[2LZ]

Originally Posted by Cbohannan0513

Thanks!
As it turns out, the rear sprocket is commonly swapped on these... But with several variations of wheel/tire sizes from the factory it became very difficult. It didn't take long thanks to the forum... But I'm still iffy in what gear ratio I want to chase.

Don't be overzealous on the change. I went a wee too far on my Q Link's "legginess" to try to get it better on the open road and actually lost top speed because it would fall under the powerband.

[Cbohannan0513]

See, I'm on the fence. I have the calculations of what speed matches which rear tooth / gear ratio... but rear tire is not incorporated. I want the bike to run 60 without fail, at grave digging rpm. I want 50mph as a set cruising speed since every road around me is a 45 and seeing as I am just north of ATL, everyone assumes 55mph in a 45mph.

[Weldangrind]

There is an 18 tooth available, although it's a little harder to find. Perhaps you'd care to start there. I think forum member Jibberwobble found them.

[culcune]

On my old '09 bike, I had Rebel GEARS make me a 40 tooth. It made the bike geared way too high (or low?) where I had to commute on the long 50 mph stretch in 4th gear. I then played with counter-sprockets, which are easy Honda aftermarket ones, but I never liked the gearing. I think I tried a 14 and a 15 and maybe a 16. For some reason, it seemed like that rear sprocket would rip apart chains, as I went through 3 or 4 of them. It did seem a bit narrower than the stock 56. I probably wouldn't order another custom one, but that is me and remembering the several times I was stranded with a broken chain.

For my new bike, I ordered a 48t from a place out of the UK which was the only place in Europe that would send me one to the US, as they took and trusted Paypal. That is the smallest aftermarket sprocket manufactured by JT that is a direct fit. It was easier and cheaper to use the mail order company than JT which wanted me to order via their US subsidiary who wanted to have one made and sent. Too confusing! The UK mail order place only took a week or so. It was under $50, which was about $5 cheaper than JT, and Rebel Gears.

If you go with Rebel Gears, they do have the hub design, as I sent the link to JT Sprockets. I don't think JT will allow me to send the exact page, but if you link here http://www.jtsprockets.com/catalogue and put in jtr1134 in the 'parts box' they will show you a 48, 50, 52, 54, and 56 which fit all kinds of 125cc enduros/motards we don't have in the US.

The place where I bought the sprocket is here http://www.urbanbike.co.uk/jtr113448...ket-1655-p.asp I think they still have my cheesy review, LOL

[culcune]

Originally Posted by Cbohannan0513

See, I'm on the fence. I have the calculations of what speed matches which rear tooth / gear ratio... but rear tire is not incorporated. I want the bike to run 60 without fail, at grave digging rpm. I want 50mph as a set cruising speed since every road around me is a 45 and seeing as I am just north of ATL, everyone assumes 55mph in a 45mph.

The 17/48 is still a little 'buzzy' but much better than the 17/56. I commuted with my TMEC on a 70 MPH road disguised with 50 MPH signs, and was able to keep up with the 'slow' 60 to 65 mph commuters.