ADVrider

Go Back   ADVrider > Bikes > Thumpers
User Name
Password
Register Inmates Photos Site Rules Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
Old 11-17-2012, 11:47 PM   #1
Eddieb OP
Studly Adventurer
 
Eddieb's Avatar
 
Joined: Nov 2006
Location: The Tron, New Zealand
Oddometer: 875
Keep it in the family, DRZ250 Cartridge forks onto a DR650

It's been done before, but no seems to have ever documented it. Seeing as I am doing it now here's my experience, with pics even.

The DRZ 250 uses 43mm Cartridge forks with adjustable damping and rebound that outwardly look very similar to the DR650's Damper rod units, so I purchased a pair taken from an '02 model DRZ 250 off Trade Me (our local version of Ebay).

As these share the 43mm measurement with the DR 650 the 250 forks slide straight into the DR650 clamps and in fact use the same axle, spacer, speedo drive and caliper as the 650.

The one main difference is that the DRZ250 uses a 250mm disc and the DR650 290mm, plus the disc offset is approx 1-2mm different. This means you need either the 250 wheel and disc or to get an adapter bracket made up which spaces the caliper out 20mm and makes up for the extra 1-2mm offset to take the 650 wheel and disc.

I decided to go this route because:

Ease of fitment:
The 250 forks are the same size as the 650 forks though are a little longer so as already mentioned they slot straight into the stock 650 clamps/wheel etc. Being that they are the same size they are obviously up to the job structurally. The 250 springs do need changing to suit the heavier weight but the stock 650 springs aren't up to the job either so that is something that needed to be done anyway. More than likely you'd need to respring any other forks you got, for example the RM-Z 450 weighs ~112kg vrs the ~147 of the DR650 (both dry) so the 450 forks would be further out than the 250 ones.

Cost and availability:
You only need the 250 fork legs and a caliper bracket. In NZ this is a far cheaper option than buying say a complete DRZ-400 front end including wheel, disc, clamps, headlight mounting brackets etc etc, or buying a complete front end off something not Suzuki and having to make all sorts of steering head adapters, pressing out stems, making new ignition barrel and speedo brackets or whatever to make it fit. Suzuki 450 front ends rarely come up for sale here and when they do sellers want their weight in gold for them.

Impact on future mods:
I'm intending to do an outback Australia trip on this bike next year for which I'm intending to fit a Safari 30 ltr tank to cope with the huge distances involved. If you go much wider than the stock clamps you can get steering lock issues where the clamps hit the Safari tank. So you can loose some maneuverability at full lock, and potentially have to remake your steering stops to stop the safari tank being damaged in a crash.
__________________
05 DR650 - 86 BMW R80 with Velorex Chair - '67 Ducati 250 Mark 3 Narrow Case - 94 Beta Techno 250

www.AdventureRidingNZ.co.nz Free GPS tracks for New Zealand & more
www.FlyingtheChair.co.nz - NZ sidecar forums

Eddieb screwed with this post 11-18-2012 at 12:02 AM
Eddieb is offline   Reply With Quote
Old 11-17-2012, 11:57 PM   #2
Eddieb OP
Studly Adventurer
 
Eddieb's Avatar
 
Joined: Nov 2006
Location: The Tron, New Zealand
Oddometer: 875
I only bought the forks and am using the DR650 wheel and disc so a visit to my local friendly engineer resulted in this...


With a brake caliper bracket fitted and everything lined up I fitted the forks to the bike for about 500km on the road to see how they behaved. Overall they are a bit soft on the road spring wise as expected but seemed to have less brake dive.

Depending on who you believe the stock 250 springs measure at .37-.39 vrs .40 stock for the 650. While the 250 springs were softer than the 650 ones I did like the action of the forks. I didn't do anything with the valving due to the soft springs but it seemed to be a nice ride.
__________________
05 DR650 - 86 BMW R80 with Velorex Chair - '67 Ducati 250 Mark 3 Narrow Case - 94 Beta Techno 250

www.AdventureRidingNZ.co.nz Free GPS tracks for New Zealand & more
www.FlyingtheChair.co.nz - NZ sidecar forums

Eddieb screwed with this post 11-21-2012 at 01:34 AM
Eddieb is offline   Reply With Quote
Old 11-18-2012, 12:01 AM   #3
Eddieb OP
Studly Adventurer
 
Eddieb's Avatar
 
Joined: Nov 2006
Location: The Tron, New Zealand
Oddometer: 875
I swapped the stock 650 forks back on the bike so that I can open up the DRZ250 forks and try fitting some new springs.
While I had the 650 forks off the bike I removed the Intiminators I had fitted and refilled the stock forks with 15 weight oil to see what that did. My advice, don't do this. It makes the fork action horribly Jarry over even small bumps on the seal.

Here's the 650 forks and the 250 forks side by side, 650 forks in the center, 250 forks on the outside. Aside from the height, which isn't much, you can see differences in the caliper mount.

__________________
05 DR650 - 86 BMW R80 with Velorex Chair - '67 Ducati 250 Mark 3 Narrow Case - 94 Beta Techno 250

www.AdventureRidingNZ.co.nz Free GPS tracks for New Zealand & more
www.FlyingtheChair.co.nz - NZ sidecar forums

Eddieb screwed with this post 11-21-2012 at 01:34 AM
Eddieb is offline   Reply With Quote
Old 11-18-2012, 12:09 AM   #4
Eddieb OP
Studly Adventurer
 
Eddieb's Avatar
 
Joined: Nov 2006
Location: The Tron, New Zealand
Oddometer: 875
Digging around on the internet indicates the DRZ 250 springs are somewhere around 40mm shorter than the 650 springs. Further research indicated the Eibach .47 650 springs are about 10mm longer than the 250 springs, as both are a 43 stauncion the springs are the same diameter.

No one seems to advertise springs for the DRZ 250 so I decided the bite the bullet and go for the .47 Eibachs for the DR650 from Procycle figuring at worst I will end up with 10mm of preload from the slightly longer springs.
__________________
05 DR650 - 86 BMW R80 with Velorex Chair - '67 Ducati 250 Mark 3 Narrow Case - 94 Beta Techno 250

www.AdventureRidingNZ.co.nz Free GPS tracks for New Zealand & more
www.FlyingtheChair.co.nz - NZ sidecar forums
Eddieb is offline   Reply With Quote
Old 11-18-2012, 12:44 AM   #5
Eddieb OP
Studly Adventurer
 
Eddieb's Avatar
 
Joined: Nov 2006
Location: The Tron, New Zealand
Oddometer: 875
Disassembling the DRZ250 Cartridge forks.

Undo the bolt in the bottom of the forks which also houses the adjuster.
Once that is removed you can unscrew the fork cap and remove the cartridge which will leave you with this.

__________________
05 DR650 - 86 BMW R80 with Velorex Chair - '67 Ducati 250 Mark 3 Narrow Case - 94 Beta Techno 250

www.AdventureRidingNZ.co.nz Free GPS tracks for New Zealand & more
www.FlyingtheChair.co.nz - NZ sidecar forums

Eddieb screwed with this post 11-21-2012 at 01:34 AM
Eddieb is offline   Reply With Quote
Old 11-18-2012, 12:51 AM   #6
Eddieb OP
Studly Adventurer
 
Eddieb's Avatar
 
Joined: Nov 2006
Location: The Tron, New Zealand
Oddometer: 875
At the top of the unit the rod screws into the fork cap. The rod requires a 14mm spanner and the fork cap a 16mm.



Undoing those leaves you with the fork cap and adjuster rod



I've removed the spring here as well.
__________________
05 DR650 - 86 BMW R80 with Velorex Chair - '67 Ducati 250 Mark 3 Narrow Case - 94 Beta Techno 250

www.AdventureRidingNZ.co.nz Free GPS tracks for New Zealand & more
www.FlyingtheChair.co.nz - NZ sidecar forums

Eddieb screwed with this post 11-21-2012 at 01:34 AM
Eddieb is offline   Reply With Quote
Old 11-18-2012, 12:53 AM   #7
advNZer?
Beastly Adventurer
 
advNZer?'s Avatar
 
Joined: Dec 2008
Location: Wellington,New Zealand
Oddometer: 2,686
nice wee project eddie
__________________
aka BMWST?
advNZer? is online now   Reply With Quote
Old 11-18-2012, 01:01 AM   #8
Eddieb OP
Studly Adventurer
 
Eddieb's Avatar
 
Joined: Nov 2006
Location: The Tron, New Zealand
Oddometer: 875
I laid the stock DRZ250 and the Eibach .47 DR650 spring out next to each other, Eibach .47 for the DR650 on top, Stock DRZ250 at the bottom. You can't tell from this pic but the left hand ends are lined up evenly.



It turns out 2mm is all the difference!
__________________
05 DR650 - 86 BMW R80 with Velorex Chair - '67 Ducati 250 Mark 3 Narrow Case - 94 Beta Techno 250

www.AdventureRidingNZ.co.nz Free GPS tracks for New Zealand & more
www.FlyingtheChair.co.nz - NZ sidecar forums

Eddieb screwed with this post 11-21-2012 at 01:34 AM
Eddieb is offline   Reply With Quote
Old 11-18-2012, 01:08 AM   #9
Eddieb OP
Studly Adventurer
 
Eddieb's Avatar
 
Joined: Nov 2006
Location: The Tron, New Zealand
Oddometer: 875
Reversing all the disassembly steps resulted in a DR650 .47 Eibach fitted to a DRZ250 cartridge.

__________________
05 DR650 - 86 BMW R80 with Velorex Chair - '67 Ducati 250 Mark 3 Narrow Case - 94 Beta Techno 250

www.AdventureRidingNZ.co.nz Free GPS tracks for New Zealand & more
www.FlyingtheChair.co.nz - NZ sidecar forums

Eddieb screwed with this post 11-21-2012 at 01:35 AM
Eddieb is offline   Reply With Quote
Old 11-18-2012, 01:36 AM   #10
warewolf
Tyre critic
 
warewolf's Avatar
 
Joined: Oct 2004
Location: Nelson, New Zealand
Oddometer: 2,300
Looks like a great mod, Eddie!
__________________
Cheers,
Colin
KTM LC4 640 Question? Check here first --> KTM LC4 (640) Index Thread
Quote:
Originally Posted by Steve McQueen
All racers I know aren't in it for the money. They race because it's something inside of them... They're not courting death. They're courting being alive.
warewolf is offline   Reply With Quote
Old 11-18-2012, 08:03 AM   #11
Foot dragger
singletracker
 
Foot dragger's Avatar
 
Joined: Dec 2006
Location: chico,just below rag dump(nor-cal)
Oddometer: 12,298
Trading forks is usually a good thing,DR forks are pretty basic. I would guess a DRZ250 fork is about the same as a DRZ400 cartridge fork. I had a DRZe 400 and tried to make the forks work decently,they are harsh on rocks and dive even with stiffer springs/revalving,they dont seem like real great forks.
I think the cartridge emulator/resprung stock forks on my DR650 work pretty darn good after playing with them a little.
Is it really worth the trouble to swap forks over?
__________________
Some bikes around at times
Foot dragger is offline   Reply With Quote
Old 11-18-2012, 05:27 PM   #12
Eddieb OP
Studly Adventurer
 
Eddieb's Avatar
 
Joined: Nov 2006
Location: The Tron, New Zealand
Oddometer: 875
Quote:
Originally Posted by Foot dragger View Post
Trading forks is usually a good thing,DR forks are pretty basic. I would guess a DRZ250 fork is about the same as a DRZ400 cartridge fork. I had a DRZe 400 and tried to make the forks work decently,they are harsh on rocks and dive even with stiffer springs/revalving,they dont seem like real great forks.
I think the cartridge emulator/resprung stock forks on my DR650 work pretty darn good after playing with them a little.
Is it really worth the trouble to swap forks over?
I'll find out whether it was worth it when they are all back together and have been on the bike for a while.
At this stage the caliper bracket is the only thing I've done thats any more trouble than doing springs and emulators in the stock forks, and fitting emulators requires full disassembly of the stock forks and drilling holes in them doesn't it? and if you don't like that you're stuck with damper rods with large holes in them.

If in the end I don't like it I can swap the .47 springs into my stock forks and re sell the DRZ250 forks, potentially with the caliper bracket for another 650 rider to try them and I'm not hugely out of pocket.
__________________
05 DR650 - 86 BMW R80 with Velorex Chair - '67 Ducati 250 Mark 3 Narrow Case - 94 Beta Techno 250

www.AdventureRidingNZ.co.nz Free GPS tracks for New Zealand & more
www.FlyingtheChair.co.nz - NZ sidecar forums
Eddieb is offline   Reply With Quote
Old 11-18-2012, 05:34 PM   #13
Gryphon12
Beastly Adventurer
 
Gryphon12's Avatar
 
Joined: Aug 2006
Location: Carnation, WA USA
Oddometer: 1,194
The stock DRZ-250 spring pictured above looks like it is progressively wound, while the Eibach spring looks to have a uniform spring rate. Any comments on how moving from progressive to uniform affects the handling in the DR-650 application? (I'm assuming that the stock DR-650 is a uniform spring rate. Can anyone confirm this?)
__________________
1990 Honda NT-650 Hawk-GT

Never doubt that a small group of thoughtful, committed citizens can change the world;
indeed, it's the only thing that ever has. - Margaret Mead
Gryphon12 is offline   Reply With Quote
Old 11-18-2012, 07:31 PM   #14
jessepitt
Ride More
 
jessepitt's Avatar
 
Joined: Oct 2008
Location: Redmond Oregon
Oddometer: 993
Stock DR650 springs are progressively wound.
jessepitt is offline   Reply With Quote
Old 11-18-2012, 09:42 PM   #15
eakins
Butler Maps
 
eakins's Avatar
 
Joined: May 2002
Location: Fort Collins, Colorado
Oddometer: 17,189
Quote:
Originally Posted by jessepitt View Post
Stock DR650 springs are progressively wound.
indeed and rated at .40.
i think the drz250 springs are .37/.38
i use .47 on my 650 and weight 175lb. that rate is ideal for me.
.50 are good for 200lbs and .55 for the big boys.
http://www.procycle.us/bikepages/dr650.html#suspension
__________________
Butler Maps - motorcycle maps for riders by riders -
Alaska
AZ map COBDR AZBDR IDBDR South East map
http://www.advrider.com/forums/showthread.php?t=598717
Cycle World Adventure Rally:
http://www.advrider.com/forums/showthread.php?t=956350
eakins is online now   Reply With Quote
Reply

Share

Thread Tools Search this Thread
Search this Thread:

.
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump


Times are GMT -7.   It's 11:30 PM.


Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright ADVrider 2011-2014