Help RS125 NF4

**husaberg** · 8th July 2012, 16:36

I have been driving myself nuts searching the Web for the dimensions for the spline of a RS125 Honda.
Does Anyone Know or have one they could measure.
I am trying to find a suitable sprocket to match these dimensions but only in 415 or 420.

The closest i can find in a suitable size is this but it will need some careful hacking.

**Yow Ling** · 8th July 2012, 16:42

Originally Posted by husaberg

I have been driving myself nuts searching the Web for the dimensions for the spline of a RS125 Honda.
Does Anyone Know or have one they could measure.
I am trying to find a suitable sprocket to match these dimensions but only in 415 or 420.

The closest i can find in a suitable size is this but it will need some careful hacking.

The spline is the same as cr125 and rg150,

**husaberg** · 8th July 2012, 17:08

Originally Posted by Yow Ling

The spline is the same as cr125 and rg150,

Thanks for your reaponse but i am now even more confused.
So are you saying the RS125 NS4 is the same spline as a RG150 (which i can't get the measurements for I do see Rg125 though) and an early 80's Cr125? Which seemed to change nearly every year according to a catalogue.

**Yow Ling** · 8th July 2012, 17:11

Originally Posted by husaberg

Are you saying the RS125 NS4 is the same spline as a RG150?

yes plus 7 char

**RDjase** · 8th July 2012, 17:27

Originally Posted by husaberg

I have been driving myself nuts searching the Web for the dimensions for the spline of a RS125 Honda.
Does Anyone Know or have one they could measure.
I am trying to find a suitable sprocket to match these dimensions but only in 415 or 420.

The closest i can find in a suitable size is this but it will need some careful hacking.

Just measured a JT548 off the KR150 (same as RG and FXR, 428 chain) it the same spline size as JT546.
A RS sprocket fits on the KR150 shaft but the RS125 is 18mm at the inside of the spline not 16mm like the JT548,

JT wont fit on the RS shaft, RS sprocket held on by a 8mm cap screw and concave washer, KR sprockets use the splined plate with two 6mm cap screws (like Honda XL and XR, think they are the same size as well)

Lucky I have a KR150 sitting in my front room and a RS engine awaiting its frame to return next week

**RDjase** · 8th July 2012, 17:40

Originally Posted by RDjase

Lucky I have a KR150 sitting in my front room and a RS engine awaiting its frame to return next week

Front room = Winter workshop

not

**husaberg** · 8th July 2012, 17:43

Originally Posted by RDjase

Just measured a JT548 off the KR150 (same as RG and FXR, 428 chain) it the same spline size as JT546.
A RS sprocket fits on the KR150 shaft but the RS125 is 18mm at the inside of the spline not 16mm like the JT548,

JT wont fit on the RS shaft, RS sprocket held on by a 8mm cap screw and concave washer, KR sprockets use the splined plate with two 6mm cap screws (like Honda XL and XR, think they are the same size as well)

Lucky I have a KR150 sitting in my front room and a RS engine awaiting its frame to return next week

Thanks for that so whilst not ideal i might get away with the RS sprocket on a NSR125 spline then i will have to retain the sprocket for which there is no holes for the XL/XR style retainers. I have previously and successfully done this before with circlips.

Plus a bit of filing as well to get the splines out to 5mm

**quallman1234** · 8th July 2012, 17:46

Originally Posted by RDjase

Just measured a JT548 off the KR150 (same as RG and FXR, 428 chain) it the same spline size as JT546.
A RS sprocket fits on the KR150 shaft but the RS125 is 18mm at the inside of the spline not 16mm like the JT548,

JT wont fit on the RS shaft, RS sprocket held on by a 8mm cap screw and concave washer, KR sprockets use the splined plate with two 6mm cap screws (like Honda XL and XR, think they are the same size as well)

Lucky I have a KR150 sitting in my front room and a RS engine awaiting its frame to return next week

Are the NX4 and NF4 splines both the same?

What are you getting done to NX4 frame?

**RDjase** · 8th July 2012, 17:49

Originally Posted by husaberg

Thanks for that so whilst not ideal i might get away with the RS sprocket on a NSR125 spline then i will have to retain the sprocket for which there is no holes for the XL/XR style retainers. I have previously and successfully fone this before with cirlips.

I used two circlips (were thinner than the groove so used two) to hold a 16 tooth front on the KR at a gearing change at HD Tri Series as a temparary fix till I got a 2 hole sprocket, was still on there after the South Island Nats, PMCC and Taupo Nats final with no problems

**husaberg** · 8th July 2012, 17:55

Originally Posted by RDjase

I used two circlips (were thinner than the groove so used two) to hold a 16 tooth front on the KR at a gearing change at HD Tri Series as a temparary fix till I got a 2 hole sprocket, was still on there after the South Island Nats, PMCC and Taupo Nats final with no problems

Bodging is great and factory.
The KTM50's which have a half round hole too rather than a spline. Only have a circlip too.

**quallman1234** · 8th July 2012, 18:03

Circlip should be fine, my KDX200 has a circlip holding the front sprocket on.

**Bert** · 8th July 2012, 18:17

I'm sure one of us will have one or ten (NF or NX). Sort out something tomorrow.

What actual pitch are you after? 415, 420 or 428?

I had a few issues with my TZR spline (found that a YZ80 fitted 428 though) then the boys surface ground it down to 415 for me.... but I was told not to come back...

**husaberg** · 8th July 2012, 18:40

Originally Posted by Bert

I'm sure one of us will have one or ten (NF or NX). Sort out something tomorrow.

What actual pitch are you after? 415, 420 or 428?

I had a few issues with my TZR spline (found that a YZ80 fitted 428 though) then the boys surface ground it down to 415 for me.... but I was told not to come back...

Wanting to fit a 415 as preference (as i have a number of 415 sprockets)
I could live with 420. but not 520 which is STD.

This is the STD NSR125 Front Sprocket

Are you sure you machined a 428 to 415 and not 420 to 415?
I thought the rollers or bushes were different diameter (as below) even though the pitch is the same?

**RDjase** · 8th July 2012, 18:50

Originally Posted by quallman1234

Are the NX4 and NF4 splines both the same?

What are you getting done to NX4 frame?

Nothing much, Just replacing the rivnuts that hold the coil on as the bolt that holds the earth wire/coil fell out at Manfeild last month, DNF ;-(
Been getting the KR's ready for sale so left the RS at work so I had some room. One KR sold today

**Bert** · 8th July 2012, 19:55

Originally Posted by husaberg

Are you sure you machined a 428 to 415 and not 420 to 415?
I thought the rollers or bushes were different diameter (as below) even though the pitch is the same?

you could be right there; can't be assed walking out to the shed to look at the box that it came in.