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rear sprocket


wild foamy
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hi everyone

am looking to gear my DT50 up a bit more, but i am running the smallest possible sprocket on the back and i still want to go smaller, i remember another member saying they had a Yam RS100 sprocket on their DT, would i need a specific year to fit the sprocket onto my original hub? and is it even possible?

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hi everyone

am looking to gear my DT50 up a bit more, but i am running the smallest possible sprocket on the back and i still want to go smaller, i remember another member saying they had a Yam RS100 sprocket on their DT, would i need a specific year to fit the sprocket onto my original hub? and is it even possible?

can you go 1 up on the front? that roughly equals 3 on back

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up as far as it will go on the front, still only getting 40 on the flats, dont want to put a big bore on it for more speed because then it will just rev its nuts off and self-destruct

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up as far as it will go on the front, still only getting 40 on the flats, dont want to put a big bore on it for more speed because then it will just rev its nuts off and self-destruct

You will only gain more speed down hill with a tailwind, up hill you will have to change down a gear so wont be any faster, might even be slower, ask blackhat about his Garelli! that would blow away an FS1E (back when jesus was a boy), but when top gear selected it would die a death, i remember it well! If youre going to continually seek a higher gear, sooner or later youll need more power to cope with it!

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Companies are lazy, now modern motorcycles need fancy this that and doodah to sell. Back 'when jesus was a boy' as there are only a couple of chain sizes they generally kept the pcd on a wheel hub the same so they could use it for say, the 50, 80, 100 maybe even 125/75. Just look at suzuki, within reason all the oil cooled bandit stuff swaps with GSXR stuff wheels everything. Then all they had to do was lace it to a different rim, manufacturing cost zero.

If i remember right ( i may be wrong it came from a breakers ) it was a rs100 rear sprocket on the back of my dt50, i know i couldnt pull the biggy on the front with it and i could get 65ish (clocked at 64) in PERFECT conditions reving its b@lls off , realisticly it was more like 45-50, with i think a 14 but in really windy stuff i was better running a 13 maybe even a 12 cos the engine was so peaky.

You really need a friendly breaker who will check or better still you do it. Again back in the day breakers you could actually go to were pretty common now its all online. And health and safety cobblers means NO BODY will officially say it will work in case you sue.

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okay, well im also having a malossi 70cc kit on it, new reeds and a few other bits and pieces to get it running nicely :)

even in its current state it will pull top gear up a hill nicely, but it will sit at 40 revving its balls off and i want to birng hte revs down a bit and get some more speed out of it.

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okay, well im also having a malossi 70cc kit on it, new reeds and a few other bits and pieces to get it running nicely :)

even in its current state it will pull top gear up a hill nicely, but it will sit at 40 revving its balls off and i want to birng hte revs down a bit and get some more speed out of it.

Must have missed that bit, well yes then, youve got room to change the gear ratio again.

One other thing though, make sure your brakes are kept in top class condition, because all this extra speed will need them to be good, theyre drums are they?

Jetting as well, but you know that.

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yeh, i thought it looked better on the left, so i flipped the image...

... OG thought my L plate was on upside down :P

just been down to probike and the RS100 sprockets are 80mm and my DT ones are 60mm (hub size) so its not going to work :(

may just get a suzuki TS or something a bit faster :P

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less teeth = higher top speed

more teeth = quick take of but lower top end

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thats for the back sprocket. front sprockets work the other way as i understand it.

there was a question about that in my RAF Airmen Selection Test today, it showed two gears and a series of answers.

a small gear turning a larger one, the correct answer was "the smaller gear turns faster and in the opposite direction to the larger gear"

i got 9/9 on the mechanical skills section, and i qualified to be an aviation mengineer XD

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thats for the back sprocket. front sprockets work the other way as i understand it.

there was a question about that in my RAF Airmen Selection Test today, it showed two gears and a series of answers.

a small gear turning a larger one, the correct answer was "the smaller gear turns faster and in the opposite direction to the larger gear"

i got 9/9 on the mechanical skills section, and i qualified to be an aviation mengineer XD

Well done Steve :thumb: you will make a great engineer with all that tinkering you do. ;)

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just been down to probike and the RS100 sprockets are 80mm and my DT ones are 60mm (hub size) so its not going to work :(

Sorry mate, i honestly thought it was from a RS. It was quite small and i ran it with a 14 i'm sure as the 15 was too tall and got a LOT more than 40mph. I did have the dt50m not the MX (similar to a TY)so maybe that is a difference. Either way if you dig around i'm sure you will get one that fits that is the right number of teeth. Don't just limit yourself to yams either. No reason to exclude other manufacturers.

There is a lot more to gearing than just the sprockets, but ultimately you want as small as you can realisticly get on the rear for road performance and use different front sprockets to match it up right.

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im running a 45 on the back, smallest i think is a 44.

and a 12 on the front, largest is a 14.

so i just need to find a 60mm sprocket with less than 44 teeth at 420 pitch...

shouldn't be hard :P

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im running a 45 on the back, smallest i think is a 44.

and a 12 on the front, largest is a 14.

so i just need to find a 60mm sprocket with less than 44 teeth at 420 pitch...

shouldn't be hard :P

Steve, you might find this useful, gear ratios with different sprocket combos

Gear Ratios - Motorcycle Front/Rear Sprocket Combinations

------14---15---16---17---18---19

49- 3.50 3.27 3.06 2.88 2.72 2.58

48- 3.43 3.20 3.00 2.82 2.67 2.53

47- 3.36 3.13 2.94 2.76 2.61 2.47

46- 3.29 3.07 2.88 2.71 2.56 2.42

45- 3.21 3.00 2.81 2.65 2.50 2.37

44- 3.14 2.93 2.75 2.59 2.44 2.32

43- 3.07 2.87 2.69 2.53 2.39 2.26

42- 3.00 2.80 2.63 2.47 2.33 2.21

41- 2.93 2.73 2.56 2.41 2.28 2.16

40- 2.86 2.67 2.50 2.35 2.22 2.11

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im running a 45 on the back, smallest i think is a 44.

and a 12 on the front, largest is a 14.

so i just need to find a 60mm sprocket with less than 44 teeth at 420 pitch...

shouldn't be hard :P

Crikey man if you have a 12 on the front no wonder you are getting 40mph, get the 14 in soonest then find a long hill and see what you get up and down, and you could get a 15 once upon a long time ago so i don't see why not now if need be,

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Probike said all they had was a 13, so im'a try and find a place where i can get 14 or bigger.

will going down 1 tooth on the back make any difference at all?

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Probike said all they had was a 13, so im'a try and find a place where i can get 14 or bigger.

will going down 1 tooth on the back make any difference at all?

It wouldnt be worth the money spent on it, the front will make more difference and be cheaper

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thought as much.

even if i am still getting 40 out of it with a 14 on the front i would feel happier riding it at 40 because currently it will get up to 40 and then i can really feelt he vibrations through the handlebars and footpegs, which makes my feet and hands go all giddy.

plus, lower revs = longer lasting engine :)

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