Chain and sprockets

Uber_Beluga

Hi,
I want to get a new chain and some new sprockets for my DT. I don't really know what I'm buying though.

Sprockets:
I understand the concerpt of cog teeth and ratios, but I'm concerned that there may be something else I need to worry about, presumably I can't just go out and buy any kind of sprockets? What about the inner teeth, or are those standard?
What are the standard teeth numbers for the DT? I could go count mine, but after what I've seen on my bike so far, I don't trust the previous owners

Chain:
Also, can I buy any chain or do I need a certain type? O,X,Z ring... what? Presumably they need to be different lengths for different swingarms etc.

NINJA

@Uber_Beluga I believe that the stock sprockets are 16T and 46T, with a 428 chain. I 'm not exactly sure which type the stock chain is, but I believe that it's an 'O' ring. You can change the sprocket sizes dependant on which type of set-up you prefer? Eg. more top-end or faster accelation? A Haynes manual should list the exact sizes under the specs section.

You can also get 520 chain kits which include the sprockets to match. Obviously the 520 is a beefier set-up and should reduce chain stretch over time. WeMoto and B&C Express sell individual parts as well as kits.

http://www.bandcexpress.co.uk/pages/home/advanced-search.htm?search=dt125&search_new_bikes=yes&search_used_bikes=yes&search_products=yes&search_pages=yes&match=any_word&submit.x=0&submit.y=0

http://www.wemoto.com/bikes/

Just select your bikes year to bring up the correct parts list.

Calum

The chain you should be able to buy any 428 pitch chain. The rear sprocket should be fairly universal, only other than the bolt hole pattern. However the front sprocket needs to fit onto the output shaft and requires the correct Z index.

That said, you can't really go wrong, B&C Express should help if you want to just follow their recomendations.

AndyYam

Plenty available on ebay or wemoto by searching for DT125R. Personally i'd stick to stock unless you've modified the bike in some other way to compensate for the difference. Yamaha made the DT125R...they know what they doin'!

Calum

@AndyYam They also made it to a budget.

You always hear that when modifying stuff. Don't you thinj Mr Toyota knew what he was doing.

It's like yeah, selling a car to make a profit. Corners must be cut.

Uber_Beluga

Thanks for the help guys,

I've sent a question into B&C about one of those anodized rear sprockets. I got distracted by the pretty colours. Here's hoping they can do one for my DT.

I'm just getting the bike into good running shape for now so I want to stick to stock spec.

Mightyman

Anodised sprockets have always seemed a bit pointless to me. The nice coating on the teeth wears away after a few miles of use, and then you end up with a half anodised sprocket.

AndyYam

@Calum said in Chain and sprockets:

@AndyYam They also made it to a budget.

You always hear that when modifying stuff. Don't you thinj Mr Toyota knew what he was doing.

It's like yeah, selling a car to make a profit. Corners must be cut.

Point taken but I was referring to sprocket ratios.

Uber_Beluga

I hadn't thought about wear, probably not worth it then, I'll still try one and see how it goes.

B&C are saying that I could change my chain pitch to a larger number. Is this a bad idea for any reason?

NINJA

@Uber_Beluga A thicker grade of chain is obviously heavier and stronger, which aids durability, reduces stretching and therefore increases it's lifespan. However, some people say that a heavier chain requires more energy aka rpm to get it moving. Which in turn suggests that there's a slight reduction in horse power? I've not seen any evidence to support this theory myself, but there's probably an in-depth study posted somewhere?

So it's really all down to a personal choice, my ole DTR had a 428 chain on it and I was unable to assertain which make? But it stretched a lot and needed adjusting every few weeks, but that may have been down to it being a cheap make? So I guess really it's a choice over increased maintenance over a more durabilie drive train???

Darty

Standard sprocket size should be 16-57T 428.

DT doesn't need a 520, It has no torque anyway. just a added rotating mass that still stretches a bit. It's strange, Aprilia's 125 range all ran 520 stock though.

A side note - Although people seem to be pedalling the price of these haard! That Alloy good good saves 4kg.

http://i.ebayimg.com/images/g/Jd4AAOSwLF1X48le/s-l1600.jpg
http://www.ebay.co.uk/itm/Yamaha-DTR-200-125-DT125-R-200-R-WR-Alloy-Swing-Arm-Shock-Suspension-Linkage/222258223763?_trksid=p5411.c100170.m2943&_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20140131123831%26meid%3D33e65d4d464c4fddb7154d6e29dd177d%26pid%3D100170%26rk%3D4%26rkt%3D15%26sd%3D222256378036

Uber_Beluga

Alright, that's a no to the higher pitch in that case.

Doesn't look like I'm going to get any of this stuff before the weekend now. I have a whole heap of new stuff that I'm dying to get on the bike, so the drivetrain stuff is going to have to wait I think.

If I can get the bike running this weekend I'll place an order for one of those anodised renthal rear sprockets, a 428 chain and a standard front sprocket. I'll probably come back and ask about chains then.

Here's hoping I can get a spark this weekend.

DT125R FORUM

Chain and sprockets