RM 125 B forks & alloy swingarm

[KTM47]

Has another purchased a set of RM 125 B forks through eBay from the US.  Are there any pitfalls? I have an RM 370 B and I know that it was common practice in 1977 to change to the 125 B forks. Are there any available in Australia.

Also does anyone know where to get an alloy swingarm from.  I know that they were available through Suzuki in 1977 but for some reason MA has not approved them. Where do you get the Thor ones from?

Kevin

[Davey Crocket]

Kev, the alloy 125 B arm is OK, I don't know if it fits the 370 as the axles are different sizes and the length may be shorter....talk to Johnny Kittle....it's probably easier to get a thor arm or DG.....the DG ones are quite a bit lighter.

[KTM47]

Thanks John. What about the forks have you had any experience with them?

[Davey Crocket]

There's forks around, Johnny will know what springs to use.

[oldfart]

Kevin .... I have a set on my 250 B and 370  and it is a straight forward job if you use  a 125 B triple's as well, as  Rm 250/370  have tapered forks   36mm bottom x 35 mm top clamp.
 If you set up a jig you could reem or drill/ mill the top clamp out to 36mm.

Take the 125 springs out and replace them with 250 / 370  .... job done 

[Husabergpete]

Kevin,

Not sure why you would change 77 RM370 forks out for a set of 77 125 B model forks.

I have a 370 and have owned RM 125 A and a pair of C's. The C had an alloy swingarm.

I know 370's have been fitted with the later model RM 125 C from 1978 front forks. But it is said that it makes the bike illegal for Pre 1978 racing.

Perhaps the Suzuki race guys could set us straight.

Pete

[09.0]

I think it's because the 125 is leading axle.

[JohnnyO]

All the B models have leading axle forks, the 125B forks are better than 250/370 forks that's why the pros used them on their 250/370's back in the day.
Kevin I'm using nos harder S&W springs bought from the US in my forks but I can get harder springs to suit locally. I have original DG and Thor swing arms on my 370 & 250 again from the US, if you look hard you'll find one..

[KTM47]

Thanks everyone for your replies.  Back in 1977 it was common for the dealer supported riders to use the 125 B forks. They have a longer section below the axel so they are probably stronger.  In another post there is photos of Anthony Gunter's 370 B with them on.  He also has a factory alloy swing arm, it is painted black.  They are a genuine Suzuki item, but there is a post http://ozvmx.com/community/index.php?topic=24891.0 that says MA does not except them as legal.  Does anyone know if this has changed.

Also has anyone purchased 125 B forks from the US and is there any pitfalls.

[Davey Crocket]

The 125"B" optional alloy arm is OK Kev, talk to Tanner if your worried....I have never seen for sale a 250/370 optional alloy arm (gen Suzuki). If you buy a set of forks out of the states, get them to pull them apart so the package is smaller...probably pay 100 bucks for a set and the same for shipping....they do come up for sale here now and again. I'm thinking the arm on Gunters bike was a works one....they where more square on the sides than the optional one. 

[TM BILL]

Kev I have a genuine optional alloy arm for 250 / 370B complete with brake lug and still some of the black paint on it , could be convinced to sell it .

I also have a PDI swinging arm of the Gods I could be convinced to move on for the right offer 



125 B forks are better than 250/370 B forks .

[maico67]

Hey Kevvy ,
I've got a pair of 125 B forks , if you what to buy them , they'll need totally restoring though

[Montynut]

The RM125B forks had more travel than the RM250/370 from '77 they can also be adjusted to give the full Pre78 legal 9" of travel which the RM250/370B can not. That is what I have been told

[JohnnyO]

Any of those forks can have the travel amount adjusted with spacers or different length top out springs, they're all much the same inside.

[Slakewell]

Kev I have a genuine optional alloy arm for 250 / 370B complete with brake lug and still some of the black paint on it , could be convinced to sell it .

I also have a PDI swinging arm of the Gods I could be convinced to move on for the right offer 



125 B forks are better than 250/370 B forks .

Hey Bill are those KYB shocks?
I have a manual for those if want a scan?