OzVMX Forum

Clubroom => Tech Talk => Topic started by: Stewy138 on June 17, 2011, 08:55:06 pm

Title: RM125A/B 4 Stroke
Post by: Stewy138 on June 17, 2011, 08:55:06 pm
Hey I was wondering if there an 'easy' (relatively) 4 stroke engine conversion/implant for an RM125A/B ?

Cheers,
Stewy.
Title: Re: RM125A/B 4 Stroke
Post by: mainline on June 17, 2011, 09:33:28 pm
are you nuts? some sort of bike-wrecking heathen? how can you even think such a thing? ;D
Title: Re: RM125A/B 4 Stroke
Post by: Stewy138 on June 17, 2011, 09:44:32 pm
That bloody old song...to dream the impossible dream... is playing inside my head.  ;D

Of course it would be a lot easier to just go original  :-\, if only I could find an engine  ::)....but where the fun and frustration in that hey  :D?
Title: Re: RM125A/B 4 Stroke
Post by: cyclegod on June 17, 2011, 09:49:02 pm
XL185/XR200 fits in there I've seen afew in NZ.
Title: Re: RM125A/B 4 Stroke
Post by: Marc.com on June 17, 2011, 11:56:06 pm
Hey I was wondering if there an 'easy' (relatively) 4 stroke engine conversion/implant for an RM125A/B ?
Cheers,
Stewy.

Good for you mate, nothing like a good 4 stroke special, though there is an easier path..... grab a DR400 and RM C bits like the swingarm and do your self a DRM400 special. BTW TT500 engine fits RM frame but needs a lot of hacking about. Works better with RM400 N or T frame.

(http://i245.photobucket.com/albums/gg71/marcFX_photo/rmframett.jpg)
Title: Re: RM125A/B 4 Stroke
Post by: Tahitian_Red on June 18, 2011, 01:44:12 am
Will the DR motor fit in the RM N&T frames?
Title: Re: RM125A/B 4 Stroke
Post by: Marc.com on June 18, 2011, 10:17:26 am
Will the DR motor fit in the RM N&T frames?

Realistically it is too tall, easiest option  is direct bolt up of RM suspension to DR frame. RM250C swingarm goes straight on, N/T forks. The DR400T or S was good enough starting point that frame swap is pointless.

(http://i245.photobucket.com/albums/gg71/marcFX_photo/DR14.jpg)
Title: Re: RM125A/B 4 Stroke
Post by: cyclegod on June 18, 2011, 01:16:34 pm
Buy this instead...

http://www.ebay.com.au/itm/TT-500-SPECIAL-/380347204677?pt=AU_Motorcycles&hash=item588e75c445
Title: Re: RM125A/B 4 Stroke
Post by: Stankflapper on June 18, 2011, 01:20:33 pm
Could someone point out the advantage of doing this?
Title: Re: RM125A/B 4 Stroke
Post by: Marc.com on June 18, 2011, 02:46:14 pm
Could someone point out the advantage of doing this?

Should be lighter and better suspended than the original TT frame which wouldn't take too much. Like I said earlier and you can see from the RM370 carve up, TT motor into RM ABC frame requires major surgery and there are better frames for the job, like a Husky one.... 4 stroke specials have been there as long as MX has been there, in fact really scrambles, MX started out as 4 stroke special racing.

(http://i245.photobucket.com/albums/gg71/marcFX_photo/CCM.jpg)
Title: Re: RM125A/B 4 Stroke
Post by: Slakewell on June 18, 2011, 03:56:30 pm
I going to do an XR 200 special as my next big project , you may not be at the front on one but you will be smiling  ;D
Title: Re: RM125A/B 4 Stroke
Post by: Marc.com on June 18, 2011, 10:35:28 pm
I going to do an XR 200 special as my next big project , you may not be at the front on one but you will be smiling  ;D

They were good little bikes in their own right and popular in their day, any thoughts on frame, CR125 comes to mind. OR keep the original frame as there was not much of it anyway and do something with the suspension.... heres one I did with $100 XL250 wreck

(http://i245.photobucket.com/albums/gg71/marcFX_photo/MarcsFrame012.jpg)

Title: Re: RM125A/B 4 Stroke
Post by: Colin Jay on June 19, 2011, 08:50:26 am
Could someone point out the advantage of doing this?

Should be lighter and better suspended than the original TT frame which wouldn't take too much. Like I said earlier and you can see from the RM370 carve up, TT motor into RM ABC frame requires major surgery and there are better frames for the job, like a Husky one....

(http://i150.photobucket.com/albums/s120/coljay/SR500mx-81.jpg)

The only / slightly difficult part is making an oil tank.

CJ
Title: Re: RM125A/B 4 Stroke
Post by: Nathan S on June 19, 2011, 10:15:19 am
There was a KLX powered RM125C(?) at CD6. Pretty bike, apparently went well with 310cc kit in it.
Its been mentioned before on these forums, I think the owner even popped up.
Dunno what it achieves compared to a mildly modified KLX as a race bike, but a modded KL engine in an RM-B frame could have potential as a pre-78 race bike.
Title: Re: RM125A/B 4 Stroke
Post by: Davey Crocket on June 19, 2011, 08:22:14 pm
Hey MarC....maybe you should have spent $200 and got a front end for it......looks a bit hard to ride with one wheel and no handlebars.....
Title: Re: RM125A/B 4 Stroke
Post by: Stewy138 on June 25, 2011, 08:27:16 am
Hey DC I think there is some detail you cant see in that photo - the stand has wheels.

Thanks guys, got my enthusiasm running for this one. Except Mainline of course.

Stewy.
PS I love TM Bill more !