84 replies to this topic

[BrooC TT Member]

Hi KVG, thanks for the local info . ..  my reason for trying to search out an OEM part was that (IF it had been available ex stock) it could have been cheapest & quickest to source (esp as I was getting good prices as part of the bike purchase deal). . . & various folks were saying "Oh, the YZ or F ones will fit", but not mentioning that they were using brands not locally available here, rather than OEM . .. & I've been quoted 3 months for local supply of Renthal .. others not having em listed, yada yada yada .. . I'll go try Linton / Dirt Action 2moro. WhereaBOUTS IN uNZud are you .. . ?

[kvg TT Member]

BrooC said:

Hi KVG, thanks for the local info . ..  my reason for trying to search out an OEM part was that (IF it had been available ex stock) it could have been cheapest & quickest to source (esp as I was getting good prices as part of the bike purchase deal). . . & various folks were saying "Oh, the YZ or F ones will fit", but not mentioning that they were using brands not locally available here, rather than OEM . .. & I've been quoted 3 months for local supply of Renthal .. others not having em listed, yada yada yada .. . I'll go try Linton / Dirt Action 2moro. WhereaBOUTS IN uNZud are you .. . ?

Hi BooC I'm in Christchurch,Dirt Action's closed till next week but he will be able to help then he had mine there in a couple of days, also got a rear of him  I'm now running 12/45 for short road trips and offroad and 13/45 for longer road trips, got Linton quite interested in the wr250r he can sorce many other parts like the twin air filters, bashplates
etc..he's also a suspension specialist so hoping to mine in there soon for him to have a play with that to.

[djmamayek TT Silver Member]

Anyone tried a 428 conversion yet?

[Toddwr250r TT Bronze Member]

Expound on that some, what do you mean exactly by 426 conversion?

[chris7521 TT Bronze Member]

Toddwr250r said:

Expound on that some, what do you mean exactly by 426 conversion?

He means going from a 520 chain to a 428.  It's a smaller chain and you'd have to change sprockets as well.   People convert to have a lighter chain for quicker response and more power.   I don't know if it would work out on this bike or not.

[Toddwr250r TT Bronze Member]

Oh ok i see, that only stands to reason, less rotating weight and all

[BrooC TT Member]

... but its not a 'race' bike, so why not just go for an 'F' model that already has more grunt anyway. . . .?  BrooC  ;-))

[SteveRed TT Member]

It stands to reason that if a good combination is a 13/46 that you could also run a 14/49 or 14/47 to the similar effect. Then you could swap out the front to a 13/47-49 for much better off road ability when you need it. No need to go down to such a tight front sprocket in this scenario.

[BrooC TT Member]

Mebbe, but I dont find 12/43 or 13/46 to be a 'significant' change, whereas now I find 12/46 to suit me, & even then I had to add a link to get a fit, so 13/47-49 would need even more links. . . . . & there goes the supposed weight saving on a lighter chain, nevermind the cost, & as I weigh mebbe 200 dressed to go I dont really get to excited about 'weight savings', eh! YMMV of course!

Cheers
BrooC DownUnder ;-))

[djmamayek TT Silver Member]

BrooC said:

Mebbe, but I dont find 12/43 or 13/46 to be a 'significant' change, whereas now I find 12/46 to suit me, & even then I had to add a link to get a fit, so 13/47-49 would need even more links. . . . . & there goes the supposed weight saving on a lighter chain, nevermind the cost, & as I weigh mebbe 200 dressed to go I dont really get to excited about 'weight savings', eh! YMMV of course!

Cheers
BrooC DownUnder ;-))

420 series chains are quite substantially lighter than 520 series chains.... Adding links would not be enough to make up the difference.

The reason I didn't get an F is that I didn't want to deal with short service intervals and jumping through hoops to legalize it.

I actually am planning on running 14/48 or 14/49 gearing. I think having a 14T front will provide a much wider variety of gearing options when I go turbo.

[BrooC TT Member]

.. . well, with even your 14:49 being almost the same ratio as 12:43 (3.58 Vs 3.50) its a lot of putzing around (2 sprokets & a chain) to get close to the same difference as just going down to a 12.
Also, I'ld check that a 14T will fit in the front without having to sacrifice the case-saver ~ you omit that at your peril if going to a lighter chain with a turbo!
Note also that a 49 could have the bottom run rubbing on the lower guide block & wearing it thru early . .. . unless you are going to leave it off . . .. .
Your call of course . .. . .
HTH
BrooC DownUnder  ;-))

[Legalninja TT Member]

What's max size sprocket the stock chain will fit for 250x?

[mtb2104 TT Silver Member]

Legalninja said:

What's max size sprocket the stock chain will fit for 250x?

I tried with 45... no luck

so I guess 44 will be ok

[BrooC TT Member]

.. ..  not worth going just 1 on the rear, you wont notice a 2.3% change. . . ... but go down 1 on the front & the difference is noticeable ~ not HUGE mind you, but noticeable.

HTH.

BrooC ;-]]

[djmamayek TT Silver Member]

Just adding to the body knowledge:

To mount a 14T countershaft sprocket you will have to trim/grind down your case saver in order to make it fit.

I just took it to the bench grinder and took it down about 1/8th inch all the way around.

I had the opportunity to ride the bike the other day (temps finally above 40*F). Running 14/48 there is a noticeable difference in acceleration. I had no problem keeping up with my buddies Triumph Speed triple on back roads (obviously this was maintaining some semblance of legality, once speeds start getting into license loss territory he just disappears).

Most importantly I can clutch the front tire up in third gear corners and do the classic motocross wheel up, crossed up corner exit..... smiles all around

[djmamayek TT Silver Member]

BrooC said:

.. . well, with even your 14:49 being almost the same ratio as 12:43 (3.58 Vs 3.50) its a lot of putzing around (2 sprokets & a chain) to get close to the same difference as just going down to a 12.
Also, I'ld check that a 14T will fit in the front without having to sacrifice the case-saver ~ you omit that at your peril if going to a lighter chain with a turbo!
Note also that a 49 could have the bottom run rubbing on the lower guide block & wearing it thru early . .. . unless you are going to leave it off . . .. .
Your call of course . .. . .
HTH
BrooC DownUnder  ;-))

See above post on the case saver issue.

[fleetfixer TT Newbie]

Sounds like the perfect solution. What number of link chain did you find to work? Also, do you have enough adjustment range left to swap in your stock 13t for serious trail/ mx riding? (leaving the 48t in place!!)
thanks for the info!

[winterfreak TT Member]

Now I'm really confused with everyones post as what way to go.  Here is my riding conditions.

Start at 4600ft in Grand Junction, CO ride the hwy for 15 - 20 miles wide open and maxing out at 65mph maybe 70 if I have a tailwind.  I have a Fmf programmer and added fuel here and there and noticed much better throttle response.  Now here is the fun part.

My destination is at 11,000ft where my day is spent and I have to run the bike in 4th most of the day to get my top speed on the roads, and off road trying to do any climbing through the woods feels like I am way to high geared, riding in 2nd - 3rd.

I need something that is 3-4 tooth bigger in the rear, as I dont want vibration in the front sprocket. Yet I want to be able to still run good top speeds.

I am not worried about cost as I get all my parts at cost.  So what length of top quality gold renthal or DID chain 520 would I need to go with for a larger sprocket in the rear?

[Crash. TT Bronze Member]

I have a 48 tooth rear sprocket and a 112 link 520 x ring chain.  In a nut shell the lowend is improved by around 11%  and you loose 6 gear.  so just go drive the highway in 5 gear before you swap cause thats what 6 gear will feel like after the swap.
        Also go to ROCKY MOUNTIAN ATV  their sight is way easier to navigate than tt store and they have better prices.

[radianguy TT Member]

So has anyone run the 13/51 combo yet? I am thinking about going this route but would like to know if it's possible first. I currently have 13/48 gearing but am looking for a bit more grunt. Thanks for any help.