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Old 02-20-2009, 04:14 PM   #74
Moto Head
JDRadman's Avatar
Joined: Jun 2006
Location: In the Heartland
Oddometer: 195
Cool deal, sounds like you got it done.

I am interested in how the bike handled with those spring rates.
RaceTech's site says the Dakar's stock rate is in the .62 range but I can’t get that verified. RaceTech recommend a .83 rate on the Dakar with my street weight of 160 lbs. So the .48 springs are about half of what they recommended.

While most of us will be riding on a lot less aggressive terrain on the 650 than we would on a YZ, we are still doubling the weight of the bike (low 200lbs to low 400lbs) that is riding on the same springs.

Did you use the stock or supermoto aftermarket brake/rotor?
The BMW OEM brakes are 300mm X 5mm thick disk and the YZ OEM disk is 250mm X 3mm thick. The YZ caliper pistons are about 20/22mm and the BMW pistons are 30/32mm but I am not sure about the differences in the master cyl. I think we would be giving up significant stopping power especially when repeatedly stopping from highway speeds like in the twisties. That may not be in issue at lower speeds in the dirt.

And what kind of Beer would be good to know too...

I think I will end up at about $900 bucks in my forks but far shy of the TT $3,000 set up. When I am done, we will loose 1" travel/length to cut down on the "chopper" setup, have progressive wound - .83ish springs in front, new seals wipers and valving, stock brakes, stock wheel, new caliper hanger, new brake line and new SS axle. I may get the stock rim upgraded to make it stronger too.

The back shock is getting re-worked as we speak. Spring rate will be up about 20% and progressive wound for compliance on the street. It will also raise the rear-end a bit. This and slipping the forks deeper in the triples will help get the geometry back in check.

Overall, I will drop less than a $1,100 into the bikes suspension and I hope I am as happy with it as you are with yours.

I blame my buddy Quinn for all of this excessive spending. He bought a new 800GS last month. I didn’t want to drop the cash on a new bike but I just couldn’t sit still for that. So I had to upgrade…

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