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Clubroom => Tech Talk => Topic started by: justanothercgrader on August 20, 2017, 08:16:34 am

Title: 1979 RM125 N
Post by: justanothercgrader on August 20, 2017, 08:16:34 am

Hello,

Can i get some help finding a 50 or 51 tooth rear sprocket to suit a RM125 N 1979, 428 pitch.

I was hoping for an El Cheapo until i can decide on the final gearing.
Evilbay only shows 520 pitch.

What ever happened to the chain gang in Mulgrave, i used to go to his garage?

Regards Mark

Title: Re: 1979 RM125 N
Post by: TT5 Matt on August 20, 2017, 02:02:17 pm

 ;try searching pe175 for sprockets since they shared the same hub/countershaft

Title: Re: 1979 RM125 N
Post by: Tomas on August 20, 2017, 06:58:09 pm

1980 rm 125 uses 520 chain @ 51/12(4.25)stock final reduction. 1979 rm 125 uses 428 chain @ 59/13( 4.5) stock final reduction. Using 428 chain, 12t front sprocket and 51t rear sprocket you may have issues with chain clearance. Chain vs engine cases. Using 428 chain, 13t front sprocket and 51t rear sperocket will reduce lifetime of your clutch  :)
I am using 520 chain@ 51/12 on both 125N and 125T and have no issues.

Title: Re: 1979 RM125 N
Post by: Hoony on August 20, 2017, 08:05:33 pm

i think chain gand relocated to Banana land  (qld) some time ago. not sure if they are still in business


Chaingang Chains & Sprockets Pty Ltd
Sprockets - Seventeen Mile Rocks, QLD

Unit 21b/ 500 Seventeen Mile Rocks Rd, Seventeen Mile Rocks QLD 4073

Title: Re: 1979 RM125 N
Post by: Lozza on August 22, 2017, 08:33:19 am

Quote from: Tomas on August 20, 2017, 06:58:09 pm

1980 rm 125 uses 520 chain @ 51/12(4.25)stock final reduction. 1979 rm 125 uses 428 chain @ 59/13( 4.5) stock final reduction. Using 428 chain, 12t front sprocket and 51t rear sprocket you may have issues with chain clearance. Chain vs engine cases. Using 428 chain, 13t front sprocket and 51t rear sperocket will reduce lifetime of your clutch  :)
I am using 520 chain@ 51/12 on both 125N and 125T and have no issues.

Smart move there isn't any need to run a 520 chain on 125, a 415 or 428 is free hp

Title: Re: 1979 RM125 N
Post by: justanothercgrader on August 22, 2017, 06:59:29 pm

Hi Guy's thanks for your suggestions,

Only the RM125N 1979, a DR125SM and a TS185R Share the same Bolt pattern and 428 size,
50 tooth is my only off the size and luckily JT has this in El cheap steel or expensive Ally.

After i settle on the gearing i really need i will get a quality custom made up.

The phone number for the chain gang just rang through numerous times today ???
U21b/ 500 Seventeen Mile Rocks Rd, Seventeen Mile Rocks, QLD, 4073
07 33768488

Mark.