Friday, November 26, 2010

RMZ250 front end swap

It's no secret the stock DR650 suspension --both front and rear-- is comprised of pretty low budget components. Last winter I bought some stiffer fork springs:  Eibach .50 Kg/mm straight rate (stock springs are progressive .43 Kg/mm). That $100 upgrade helped to tighten things up a little, along with fresh 10W fork oil. However, there was still no compression or rebound damping adjustment, because the DR's forks are old-school, old-tech, el-cheapo damper rod forks. Suzuki was so cheap they didn't even provide preload adjusters on the fork caps, so even setting sag height required removing the caps and using a shorter or longer spacer... how convenient!

Anyway, after trail riding all year I've been toying with the idea of installing Race Tech's cartridge emulator valves, but they're a lot of work to install, and making adjustments to them once they're in place is way too much effort. Plus there's the $200 cost.

I also considered Ricor-Racing Intiminators. They're a little "gimickey" if you ask me. And I did purchase them for my last bike, the '07 SV650S... at first I thought they were great but after a few weeks of riding on them the novelty wore off and I wished I had just done the popular GSXR from end swap that all the cool SV riders do. They're pretty simple to install, but again, there's no adjustment. That's another $200 I didn't want to spend.

So I've been keeping my eyes peeled for a deal on a set of RMZ forks. After having read the details of a few folks at ADVRider who have done the swap, it's pretty much a bolt-on solution because it doesn't require any custom machining. Lots of other forks can be adapted but it usually involves pressing out the steering stem, machining the triple clamps, or other fabrication work. The RMZ is comparatively easy, much like a paint-by-numbers project. And RMZ forks are plentiful on eBay but prices are high for the ones worth buying. Cheaper ones are usually worn out, or being sold separately from the triple clamps, etc. Then I happened to run across an ad at ThumperTalk for a complete 2007 RMZ250 that was being parted out because the engine had grenaded and was going to be too costly to repair. The ad was nearly 3 weeks old and I figured the forks would be long gone. To my suprise, the seller replied indicating the entire front end was still available, even the entire front wheel assembly. And it's all in top shapre mechanically and cosmetically... The price was $500 for all of it, and he lives barely 1.5 hours away. Holy shit, this is exactly what I've been looking for.

So today I drove down there and grabbed it all. I could have re-used my DR wheel and larger brake rotor, but that would involve changing out the wheel bearings. This wheel is in perfect condition so I couldn't pass it up. I've got the complete front end, in its entirety.

I will also need to do something with the rear suspension. I've already done the rear spring (a heavier Eibach 7.8 Kg/mm). That helped a bit, but I wish there were some way to adjust rebound damping (there is a compression damping adjuster). I may send it away to Cogent Dynamics to have it re-valved and a rebound damper adjustment added. I may also just buy a Race Tech kit and install that myself. Decisions, decisions.

2007 Suzuki RMZ250 front end