Author Topic: RM125B suspension  (Read 4089 times)

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Offline YZAT252

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RM125B suspension
« on: September 02, 2014, 10:47:18 am »
Need to upgrade standard front suspension, forks are sagging (pretty sure it is all original), thinking of new Racetech springs (they only do one type of spring for this bike, so no hard choices to be made) and new 5 or 10w oil. Anyone suggest anything better without breaking the bank?

Offline asasin

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Re: RM125B suspension
« Reply #1 on: September 02, 2014, 11:27:42 am »
The 125B runs alot of air presure as they were a AIR OIL fork so may seem to have sad springs as they are quite light springs standard as the need to run 20 psi of air compensates, they also have a very long top out spring. they are quite different to all other RM models from the era.
If in doubt ,WIND IT OUT

Offline Davey Crocket

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Re: RM125B suspension
« Reply #2 on: September 02, 2014, 01:16:27 pm »
What the Asasin says, I weigh 92kg, run 20 psi and there fine....they are good forks std unless your a world beater.
QVMX.....Australia's #1 VMX club......leading the way.

Offline suzuki59

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Re: RM125B suspension
« Reply #3 on: September 02, 2014, 01:58:20 pm »
What the Asasin says, I weigh 92kg, run 20 psi and there fine....they are good forks std unless your a world beater.
And the  rest- lard arse  :D

mainline

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Re: RM125B suspension
« Reply #4 on: September 02, 2014, 03:01:06 pm »
They must have slid a set of scales under him when he was suspended from the ceiling in hospital

Offline Rossvickicampbell

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Re: RM125B suspension
« Reply #5 on: September 02, 2014, 04:17:59 pm »
look out Craigy has been looking at the boys again!  ::)
1974 Yamaha YZ360B
1980 Honda CR250R - Moto X Fox Replica

Offline Davey Crocket

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Re: RM125B suspension
« Reply #6 on: September 02, 2014, 04:20:45 pm »
Who pushed the homo Jaffa's button......what's a couple of kg's between mates.... ;D.....the scales where at a weigh bridge.
QVMX.....Australia's #1 VMX club......leading the way.

Offline suzuki59

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Re: RM125B suspension
« Reply #7 on: September 02, 2014, 05:19:38 pm »
Last time Ross's was sub 100kg was when he attended kindergarten :)

Offline Ted

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Re: RM125B suspension
« Reply #8 on: September 02, 2014, 05:22:24 pm »
What the Asasin says, I weigh 92kg, run 20 psi and there fine....they are good forks std unless your a world beater.

Are you insane.

YZAT....Set them up with the right springs and valving. No air.
81 YZ 465 H   77 RM 125 B

Offline asasin

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Re: RM125B suspension
« Reply #9 on: September 02, 2014, 06:23:40 pm »
If you listen to $$$ Ted you will have to completely change the internals. Find a RM B 125 manual and set them up as per the factory instructions in there and they will be as good as anything . it is basically the same a having simons forks that everybody raves about . like I said they are unique to the 125 B model and really good but they are fussy on air pressure .
 I have ridden this model since I was 14 years old , still have original bike . so I have gone from 50odd kg to over 100 kg ans still use same forks. I tried the other way and went back to standard set up.
I  even had a aftermarket alloy arm and full floating rear brake in the day which now seems to be legal.
« Last Edit: September 02, 2014, 06:46:28 pm by asasin »
If in doubt ,WIND IT OUT

Offline Rossvickicampbell

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Re: RM125B suspension
« Reply #10 on: September 02, 2014, 06:25:02 pm »
has anybody got a spare set around for sale????

Oh Craigy - missed you at the Nats?
1974 Yamaha YZ360B
1980 Honda CR250R - Moto X Fox Replica

Offline MaxPower

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Re: RM125B suspension
« Reply #11 on: September 03, 2014, 01:13:18 am »
What about running springs from a 78 RM250 or 400. They would have to be stiffer I'm thinking

Offline Tahitian_Red

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Re: RM125B suspension
« Reply #12 on: September 03, 2014, 05:31:40 am »
What the Asasin says, I weigh 92kg, run 20 psi and there fine....they are good forks std unless your a world beater.

+1   

I always buy new .46 fork springs for my old bikes, but ran the RM125B forks stock.  I bought a new set of Works Performance shocks sprung for my weight and I rode that combo to a championship.
 ;)
The "Factory Novice"
California, USA

'74 Suzuki TM100, '75 Bultaco 250 Pursang, '77 Honda XR75, '77 Suzuki RM125B, '77 Yamaha YZ400D, '79 Honda CR250RZ Moto-X Fox Replica, '83 Honda ME480RD Mugen