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.
323095

[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?

Sent from Tapatalk. DYAC

[Jin]

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...
Yeah mine is 150Nm and if i was doing by guesswork i wouldnt do it tight enough.

[WristTwister]

I am disappoint.:weep:

Suuuurely a 250cc bike in 5th gear can manage 120. Going up 1 in front or down 2 on the rear should boost that top speed by about 10 KPHs but your bike should be capable of more than 95 at max RPMs.

Anyhoo, changing the sprockets is going to mess with your acceleration and your newtons and unless you do a lot of highway cruisin' you should put your money towards your next bike.

[Katman]

Convert it to the 520 chain.

You might gain a few horsepowers.

[djsubjective]

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.
323095

I looked into changing the front sprocket but everyone said not to bother as id never find a 17t with the same internal spline. Guess they were wrong! Thanks for that info, and the muffler info too, the previous owner drilled a few holes and then riveted them up so ill look into that too :cool:

[djsubjective]

I am disappoint.:weep:

Suuuurely a 250cc bike in 5th gear can manage 120. Going up 1 in front or down 2 on the rear should boost that top speed by about 10 KPHs but your bike should be capable of more than 95 at max RPMs.

Anyhoo, changing the sprockets is going to mess with your acceleration and your newtons and unless you do a lot of highway cruisin' you should put your money towards your next bike.



The gears have always felt to close, and the motor is pulling high revs in 5th at 90kph. Most of my riding is daily to work, and is an hr round trip mostly on open highways.
1st feels like an idle only gear
2nd isnt used much at all, feels alot like 1st
3rd is good for rolling up and through round abouts
4th is a short stop between 3rd and 5th
5th gives me about another 10kph from 4th

It feels like i need to stretch it out a bit as its clearly geared at the factory for city cruising, not highway use.

[djsubjective]

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.
323095

The headlamp is pretty lame, thats the next thing in the pipeline when i get my hands on some parts, twin headlights.

35,000kms, thats good to know, mine has only just clocked up 8,000km

[djsubjective]

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.

Cheers for that, I was getting sick of catalogues that follow models not measurements :brick: , and was precisely what I was after :clap:

[djsubjective]

a few bar and seat mods

[skippa1]

a few bar and seat mods
:sick: Gag.....sorry but but youre making a bad thing worse

[djsubjective]

:sick: Gag.....sorry but but youre making a bad thing worse

Sorry, we cant all have OC (Otara County) choppers like you :bleh:

[skippa1]

Sorry, we cant all have OC (Otara County) choppers like you :bleh:
There are usually redeeming features in most builds but what youve got there is seriously sick(in a bad way)
as for what i have, look at my history......you might feel a bit shit.....

[Madness]

a few bar and seat mods

Skippa's onto it, that's more than a bit shit. Do you by any chance rock any Sons Of Anarchy merchandise also? The SOA fleece track pants would look mean as fuck on a Lifan with upside down bars. :facepalm:

[caseye]

He might no too Skip! likely he 'will though. OP=Original Poster That's you djsubjective I sincerely hope you aint travelling an hour a day on that piece of ply, bar work, OK your choice.
Wife's first bike a Lifan LF250'(2008)could and did travel at 120-140 all day, sold it to a guy I knew in Wellington, so rode her down there too. Went OK, passed a guy in a Merc 350 SL going down the hill to Atiamuri at a clocked 150K, fastest it ever went, still going strong, great little bike.

[djsubjective]

They are reliable, but not much fun to ride as much as I have had to in the last cupla months.

Every day ive ridden into town through lots of wind & rain. i dont mind the rain, but ive hated these fine frosty mornings.

I flipped the bars for less wind drag on the frosty mornings, and easier to steer over ice on our rural road. Finished all my placements for uni so bars back to normal, but I like the lower seat, the original is like sitting on a couch.

No SOA fleecies for me, got a mate to sew some kevlar into my snowboarding threads.