XR400 rear frame support.
 

Can anyone suggest the best way to add extra bracing to the rear frame of an xr400 1998 model to support extra weight. I have a set of panniers that I will have to make a rack for but I think the rear frame wont hold alot of weight. Thanks Ernie.

Hi Ernie. I've not got any direct experience of a XR400 but I've faced the same problem on a XR600 and did eventually manage to load quite a bit onto it without anything breaking - pic below shows what I took on one trip


http://i145.photobucket.com/albums/r...Africa0034.jpg


It involved making up a "subframe to attach to the subframe" to spread the load into the main part of the frame rather than having it all hanging on the end bolts and reinforcing the original Honda welding - particularly the area at the end of the subframe where the plastics attach. You'll also need to consider cross bracing to cut down on side to side movement.

This is a good idea as this is where a XR400 rear frame usually gets bent, even without extra luggage.
If you look at it, from the top, you'll see 2 tubes connected by two other tubes at 90 degree. You only see squares and as you know you need triangles, for a construction to be stable.

if it help's I have had my xr400 from new ,bought it in 2006.

It's done 30,000 and as yet I have not strengthend the sub frame.

it's been used fully loaded and also used for two up trail riding.

i need to keep an eye on this tread, i just stripped my xr400 '96
and am waiting for some welding on the side stand.

Weld a lug on to either side of the frame, just above the swingarm pivot and then extend the pannier mounts forward to bolt on to the welded lug. You could just drill through the lugs prior to welding them but on the DRZ below, I also tapped them to 8mm and then used a Nyloc on the rear to locknut them in place. You'll need to ensure that the longer bolt doesn't interfere with the chain run or hit the swingarm when the suspension compresses.

http://possu.smugmug.com/Motorcycles...06_VZrMR-L.jpg

http://possu.smugmug.com/Motorcycles...56_sJcX6-L.jpg

More pics here:
DRZ PANNIER FRAMES - Steve's Photos

I also extended the mounts to the pillion pegs and then forwards to the welded lugs for additional bracing. The bike's recently returned from a 4 month / 14,600 mile trip through South America with no issues at all.

That's really important. I looked at a DRZ to replace my XR600 and it looks like it has a much stronger subframe than the XR - you can see the really spindly subframe tubing on the picture I posted earlier, so considering how the weight of the luggage is going to impact on the frame is even more important on the XR.

If you look carefully in the picture you can just about see where I welded a lug onto the frame and the pannier mount tube going to it. Without the extension tube taking the stress forward to the main frame all of the luggage weight is hanging on two 6mm bolts originally intended just to support the mudguard and rear light.

Great looking rack btw. Not surprised it made it round SA without problems.

I see you're in Oxford, there's quite a few of us off various forums & the TRF in the area who are all in to bike travel, offroading, spannering etc. Let me know if you want to meet up. We normally meet up monthly in a pub near Benson.

Hi Steve

I'm actually in Thame but there's no point in putting that in my profile as no ones heard of it !

Be great to link up with others of like mind. The Benson meet sounds like a good place to start - could you pm me some details.

Thanks for your suggestions. The motors comming out this week for a rebuild so will have a good chance to strengthen rear then.
Ernie.

We normally post up on UKGS'er in the Thames Valley forum, most of the group frequent this forum, Advrider, UKGS'er & the UK KTM forum.

1st one for 2011 - ::. UKGSer.com .::

Just keep an eye out, see you there.

here is my setup
http://img812.imageshack.us/img812/4061/foto0148y.jpg
By beat_ at 2011-04-21
as you can see i cut the subframe and attached it higher to the frame
this way the panierrack van attach to the original mounting holes of the subframe.
where the tank and sadle meet, i welded a "u" piece to it to bolt the frame on
the two sides are connected with a tube over the number plate and a piece of "flat" steel folwing the arch of the subframe under the fender. a can attach the to arches together with a bolt