Building a DRM 400

[LWC82PE]

yes it can be done. there is an article in issue 30 of VMX magazine of a DR 400 in a PE 400 frame. it looks to have the lower cradle changed though. so the 80-82 PE 250 and 400 frames are all the same (except for 81 and 82 having 2 extra frame loops instead of an alloy bash plate as on the 1980 model) and these frames are the same basic dimensions as a RM 250 T and probably RM 250 N as a RM 250 motor is same as the bottom end of a PE 250 and 400.  i would say if you had a 79 or 80 RM 250 frame or a 80-82 PE 250 or 400 frame you could do it but welding will be involved!

[David Lahey]

For what it is worth here are pictures of my RM250C/SP370/400 taken in about 1980. It is still the same now but looks a bit neglected after 28 years.

[David Lahey]

Side view

[oldfart]

Dr 400 frame 1980 with added brackets to take Rm 250-400T NOS side covers .
    remove all unwanted factory brackets and tidy up thier welds
    Beef up the frame foot peg mounts as they are not to strong ( re weld and add a fillet )
    Leave the muffler bracket on as you will need this to mount the exhaust to
    Cdi unit is mounted on Rhs behind frame cover ... tags welded on frame next to frame cover
    Steer stop added addd at head
    Tank frame mount relocated at head
    Coil mount changed to suit Rm 125 b tank

[oldfart]

 Tank Rm 125 b     Seat Rm 125 b             swing arm  Rm 250 c2        Frame covers Rm 250 -400  T
 
 rear wheel Dr 500     -  Front  Dr 400        Rear shock    Dr 500   ( usa )

[LWC82PE]

I reckon ive got some photos of some trick modified DR 370/400’s somewhere. I think I got a photo of the white brothers modified DR 400 and FMF DR 370. I will see what I can find and scan it

[LWC82PE]

oldfart, are those stock KYB DR 500 shocks? they look a lot like the french DeCarbons.

[GMC]

You may be a bit harsh on Graeme Boyd as it is his Hallman frame that I have to jig from. It appears to be NOS, never used but very rusty.

MX250, pity you didn't throw your SP stuff my way
I would like to get hold of some engine cases, head & barrel. Empty cases, any condition so long as the all engine mounts are in good condition.

Yes Oldfart that was the frame we were comparing with several suzuki models. I only got to see your DRM briefly but it looked like you had done a proffesional job of it. I was going to came back for another look/chat but the 3 days just went too quick.

[GMC]

Your proposal is certainly interesting GMC since the Hallman frames essentially is rebuild -74 Husqvarna CR frames. Shouldn't be too hard finding one of those since I live in sweden...

Yes the Hallman frame is very similar to the HL frame which was styled from the Husky frame allthough I beleive it was more likely a 76-77 frame.
Hallman also had a Honda version available.

[Tony T]

I would like to get hold of some engine cases, head & barrel. Empty cases, any condition so long as the all engine mounts are in good condition.

Geoff, I have plenty of SP engine parts spare if you need for jigging. Email sent............. 

[Jens]

Thanks for all the input mates!

Now, one final (atleast on this stage) question for you Oldfart. Do you know the length of those shocks? I intend to use a couple of Ohlins shocks I have laying around, I know they are of the same lengt as the stock Suzuki 125 -80 shocks but I believe they are longer than the DR´s? So out with the old folding ruler lemme know! I suspect I´ll have to make new upper mounts for the shocks.

Thanks again and cheers!

[JC]

This is an interesting thread in a direction I've been considering myself.

Can anyone tell me how heavy a standard SP370/DR400 frame is?

Also Oldie, how heavy is yr completed DRM?

[LWC82PE]

also Jens  you can fit longer bottom eyelets to you ohlins to make them longer.

[mx250]

MX250, pity you didn't throw your SP stuff my way

You'll be pleased to know thet went to a good and deserving cause and they are been used in a 'get to work' hack.

I didn't think that they were 'in demand' bits - XT, XR etc yeah, but the old dreary SP370 . But I'm pleased they went to a worthy cause and are actually being used.

[oldfart]

Shocks are KYB 3329
Length of shock eye centres  = 397
Weight of bike ...  not known ,  a hell of a lot lighter than it started out at 

Turns into corners fine, you  hardly need to use the brakes due to engine compression . Rear suspension is to my liking but the front needs sorting out as I have it too harsh ( trying a different set up this weekend )
I have a sister bike on the go at the moment using  a Dr seat and tank combo finished in Rm T( 1980 ) colours
using a Sp 370 motor with a lager bore     seems to rev harder