Rear sprocket swap question

[djsubjective]

Ive been riding for a few months, and living out of town means im taping out my lifan lf250 in 5th doing 90-100kph.

Standard 530 front sprocket is 16t and rear is 45t.

So my problem begins when the bike is modeled off of the yamaha virago/dragstar 250, which has an identical rear sprocket but unfortunately is a 520 chain size.

So i can either go for more teeth on the front (17t or 18t), in which case ive been told not too, because front sprockets have different splines and its much harder to machine one or find one to suit.

Ive been told the best, cheapest and most possible way is to decrease the teeth on the rear sprocket (42t or even 40t). Most people seem to do this on these bikes, but this is from info on foreign forums that get theirs machined.

So Im keen to get a rear sprocket machined, how do i go about this? same dimensions as jt sprockets jtr857, but 530 instead of 520 chain size, and 40t instead of 45t.

Im in Rotorua

[skippa1]

Get a bigger/better bike

[awayatc]

+ 1

Or smaller and better

Or same size and better

Anything other then that one really. ..


Seriously though , don't waste time or effort on it.
Save your money for other bike...

[Akzle]

yes a sprocket will increase you rpm to velocitation ratio. and they should be available through ebay and the such.

but your donk is a gutless piece of shit. and it wont thank you for it.

[djsubjective]

I see what you guys mean, but im a poor student till I graduate at the end of the year, and if its around $100 - $150 to get a rear sprocket machined, then it will pay for itself in gas savings and may stop the motor from dying due to a life of high revs.

This is a temp fix until the end of the year when ill be able to get a bigger bike,

[OddDuck]

It'll be more than whatever it costs for a swapped or machined sprocket. Don't forget that you've got to get the rear wheel off the bike and then the rear axle re-torqued on reassembly.

Either you're paying a mechanic (probably an hour's labour, say $100-ish) or DIY, in which case you need a rear stand, sockets, and a torque wrench. And a space to work in, and a second vehicle for the inevitable trip to the hardware shop or bike dealers...

As others have said - the bike's simply not worth it. You're not going to get your money back on resale, if the bucks are tight then the best thing to do is start saving now for the next bike and just run this until it drops. If the motorway's a problem, are there 70 / 80 kmh B roads that you could use?

[Jin]

It'll be more than whatever it costs for a swapped or machined sprocket. Don't forget that you've got to get the rear wheel off the bike and then the rear axle re-torqued on reassembly.

Either you're paying a mechanic (probably an hour's labour, say $100-ish) or DIY, in which case you need a rear stand, sockets, and a torque wrench. And a space to work in, and a second vehicle for the inevitable trip to the hardware shop or bike dealers...

As others have said - the bike's simply not worth it. You're not going to get your money back on resale, if the bucks are tight then the best thing to do is start saving now for the next bike and just run this until it drops. If the motorway's a problem, are there 70 / 80 kmh B roads that you could use?

Motorcycle mechanics use torque wrenches? I havent checked but id be surprised if they do it any different than car mechanics and just use a rattle gun. I just had to take my car rims off few days ago and was nearly having to jump on a breaker bar to get the nuts loose. Arseholes.

[mouldy]

torque wrenches are so you don,t leave things too loose or too tight . most modern sports bikes have alloy inner wheel spacers , over tighten them will squash them and put side thrust on your wheel bearings and on some bikes the lockring on the nut will jump a thread if overtightened thus removing the thread on your axle next time you remove the nut

[OddDuck]

Motorcycle mechanics use torque wrenches? I havent checked but id be surprised if they do it any different than car mechanics and just use a rattle gun. I just had to take my car rims off few days ago and was nearly having to jump on a breaker bar to get the nuts loose. Arseholes.

Yep, that stuff happens all the time. This kind of thing is why I do my own work, I'm sick of guys who could do it properly but just don't. Quick and easy and bill the sucker happens way too often.

For the OP though I meant that if he did it himself he'd have to purchase a torque wrench. $90-ish for a cheapie, if DIY'ing then this sort of cost needs to be factored in.

For the record I checked a Toledo a few years back and was astonished to find it within 4% through the entire range.

[OddDuck]

torque wrenches are so you don,t leave things too loose or too tight . most modern sports bikes have alloy inner wheel spacers , over tighten them will squash them and put side thrust on your wheel bearings and on some bikes the lockring on the nut will jump a thread if overtightened thus removing the thread on your axle next time you remove the nut

A mate tried retightening his rear axle a while back with a combination spanner and no idea whatever that it was supposed to go to 100 Nm... then went on tour. He got away with it but only just, it was far too loose and the alignment bolts ended up carrying chain loading. Chain was quite slack when we got back...

[Subike]

Go buy the 17 tooth front sprocket, straight on swap chain fits fine.
Look for the 17 tooth sprocket to fit a KeeWay Super Shadow. Its a bolt on change.
No torque wrench needed, no special tools, just a simple little lock tab held on by two 6mm bolts.
Bike will run comfortably at 100kph without sounding busy, all you loose is grunt when into a head wind.
Then drill four 10mm holes in the top muffler backing plate and eight 10mm holes in the bottom muffler backing plate.
Better sound and allows the engine to breath You will find the power increase doing this is small but worth it.
Take the stupid plastic headlamp off and trow it in the bin, fit an aftermarket chopper lamp. Better light at night over the std 35amp shit unit.
35,000 k on mine and still runs sweet as. Its been around the south island several times including the Brass Monkey Rally in one day from Blenheim.

[Akzle]

Motorcycle mechanics use torque wrenches? I havent checked but id be surprised if they do it any different than car mechanics and just use a rattle gun. I just had to take my car rims off few days ago and was nearly having to jump on a breaker bar to get the nuts loose. Arseholes.

they may have sensed that they were dealing with a giant fuckstick and didn't want you back.

christ only knows a shop gets one chance to put my shit on and if it ain't done with a torque wrench (that was picked up from and returned to a bench not dropped on the floor) i dont go back.

of course, when i get it back from tho shop i normally tear it down again to check that they did what i paid for and that it all goes back together how i like anyway...

[Kickaha]

Motorcycle mechanics use torque wrenches? I havent checked but id be surprised if they do it any different than car mechanics and just use a rattle gun. I just had to take my car rims off few days ago and was nearly having to jump on a breaker bar to get the nuts loose. Arseholes.

You quite often sound like a bit of a cunt so if it was me I would have loctited them as well

We use torque wrenches all day every day

[malcy25]

As expected, Yamaha have a relatively std sprocket ID and bolt spacing across different models, just differing tooth count and chain size.

Buy one of these. But check yours first for that ID etc to make sure.

http://www.jtsprockets.com/catalogue/sprocket/JTR865

"50" Chain aka 530.

[Big Dog]

Or you could just ride at 90 until you are not a poor student?

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