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fishugly

Which inverted forks will fit the DRZ?

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I'm considering inverted forks. To increase my odds of finding a used set from a parts bike, I'd like to know which bikes I should look at... like older RMs, etc.

Thanks.

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RM125/250 from 2001 until they were discontinued (2009?). Now that I think about it, the 1999 and 2000 forks should work, too. You'll need the triple clamps to match the forks. Me, I'd try to source a complete front end.

Edited by ptgarcia
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Posted (edited)
1 hour ago, ptgarcia said:

RM125/250 from 2001 until they were discontinued (2009?). Now that I think about it, the 1999 and 2000 forks should work, too. You'll need the triple clamps to match the forks. Me, I'd try to source a complete front end.

Thanks. Will the DRZ brake caliper work with those forks? Or is that whey you suggested a complete front end?

 

 

Edited by fishugly

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16 minutes ago, ohiodrz400sm said:

The best regarded inverted forks are the KYB SSS forks found on 06 and later Yamaha YZ/WRs.  I have no idea how simple or hard it would be to transplant the Yamaha front end 

Thanks. I'm still whipped from my Husqvarna shroud retro project... so, any transplants for a while will need to be easy. 😁

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By going the "entire front end" route you'll only have to deal with a cut or custom turned head bolt. There's always the possibility that the existing bolt can be pressed into the donor lower t-clamp. That's the way it goes with custom builds...sometimes it's easy...sometimes you're scratching your head for a few months.

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1 hour ago, fishugly said:

Thanks. Will the DRZ brake caliper work with those forks? Or is that whey you suggested a complete front end?

 

 

I'm pretty certain the DR-Z caliper will bolt right up, but I can't say for certain because I haven't done it. Based on my research and experience with wheel swaps I'm 95% positive it will, though. My front dirt wheel is from a 2006 RM and it bolts right up to my 2006 S model. The brakes rotors are interchangeable, as are the spacers, so I've deduced the caliper will be, too.

I recommended the complete front end just in case, so you're not kicking yourself in the ass when trying to find that one part that doesn't swap over.

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21 hours ago, ptgarcia said:

I'm pretty certain the DR-Z caliper will bolt right up, but I can't say for certain because I haven't done it. Based on my research and experience with wheel swaps I'm 95% positive it will, though. My front dirt wheel is from a 2006 RM and it bolts right up to my 2006 S model. The brakes rotors are interchangeable, as are the spacers, so I've deduced the caliper will be, too.

I recommended the complete front end just in case, so you're not kicking yourself in the ass when trying to find that one part that doesn't swap over.

Thanks. I just found out about an entire RM (minus the engine and plastics) 10 miles from me that recently sold for $45! Yes, $45 dollars!!! Ah, man!!!!:banghead:

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3 minutes ago, fishugly said:

Thanks. I just found out about an entire RM (minus the engine and plastics) 10 miles from me that recently sold for $45! Yes, $45 dollars!!! Ah, man!!!!:banghead:

Damn, that would have been an awesome score!

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Just now, ptgarcia said:

Damn, that would have been an awesome score!

No kidding! It's one of those things that I wished I wouldn't even have discovered... especially on a Friday. Damn! If only I had found it sooner....😭

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How about the DRZ400SM models? I see that they have inverted forks. Wouldn't be any question then, as far as fit. But... is there a reason I wouldn't want them? Are they not valved, sprung, etc for offroad use?

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The SM forks are no different internally than the  2002 and newer S and E forks. Other than looking more modern, it’s a pointless change. RM and Showa forks offer a performance improvement.  

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1 hour ago, Gary in NJ said:

The SM forks are no different internally than the  2002 and newer S and E forks. Other than looking more modern, it’s a pointless change. RM and Showa forks offer a performance improvement.  

Thanks. My bike is a 2000, and as I understand, the forks were improved after... but to what extent and how, I don't know. So, there would be some improvement swapping mine out for SM forks. Maybe not enough to justify the effort though... unless I got them super cheap. ?? What fork changes were made after 2000?

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I'm going to explain dirts bike suspension very simply and in laymen's terms

The SM forks are the exact same thing found on RMs and CRs in the late 90's to early 2000s.  It's a Showa Twin Chamber fork.  It's a closed cartridge design and is essentially early 90's Works technology. It basically a sealed fork within a fork that separates the cartridge oil from the air and oil outside of the cartridge.

The 2000-2001 S used what is called a dampening rod fork. In a nut shell, it uses fixed holes in the rod to control the dampening. This is 70's MX technology. 80 class bikes used these into the 90's.  Kids and beginner play bikes all use dampening rod forks today. 

The dirt only DRZs and the later S model have an open cartridge fork. A cartridge fork passes the oil thru flexible shim stacks instead of fix holes. Open means the oil circulates throughout the fork. Basically, a cartridge design allows the dampening to be tuned to react differently depending on the speed and load.  Full sized MX bikes adapted cartridge forks by the early 80's.

Ultimately, what makes a fork "good" is setup.  Dirt bike suspension setup is a very personal thing. It needs to be tailored to the individual to perform at its potential.  Beyond being sprung for a rider's weight, it must be valved appropriately for the rider's speed and the terrain being ridden. Suspension that works for a supercross track doesn't work well for a motocross track. What works for a C class rider doesn't work for an A class riders. Same applies off-road. You need a different setup out west to ride 50 mph sand whoops than you need to ride over roots and rocks on a single track trail in Ohio.

The moral of the story is swapping the suspension from another bike isn't a silver bullet.  It will still need to be sprung and valved to work correctly for the bike, rider, and the terrain being ridden.

Edited by ohiodrz400sm
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3 hours ago, Gary in NJ said:

The SM forks are no different internally than the  2002 and newer S and E forks. Other than looking more modern, it’s a pointless change. RM and Showa forks offer a performance improvement.  

The SM fork is no different than the Twin Chambers I had on my 98 CR250 or my 06 RMZ450. 

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2 hours ago, ohiodrz400sm said:

I'm going to explain dirts bike suspension very simply and in laymen's terms

The SM forks are the exact same thing found on RMs and CRs in the late 90's to early 2000s.  It's a Showa Twin Chamber fork.  It's a closed cartridge design and is essentially early 90's Works technology. It basically a sealed fork within a fork that separates the cartridge oil from the air and oil outside of the cartridge.

The 2000-2001 S used what is called a dampening rod fork. In a nut shell, it uses fixed holes in the rod to control the dampening. This is 70's MX technology. 80 class bikes used these into the 90's.  Kids and beginner play bikes all use dampening rod forks today. 

The dirt only DRZs and the later S model have an open cartridge fork. A cartridge fork passes the oil thru flexible shim stacks instead of fix holes. Open means the oil circulates throughout the fork. Basically, a cartridge design allows the dampening to be tuned to react differently depending on the speed and load.  Full sized MX bikes adapted cartridge forks by the early 80's.

Ultimately, what makes a fork "good" is setup.  Dirt bike suspension setup is a very personal thing. It needs to be tailored to the individual to perform at its potential.  Beyond being sprung for a rider's weight, it must be valved appropriately for the rider's speed and the terrain being ridden. Suspension that works for a supercross track doesn't work well for a motocross track. What works for a C class rider doesn't work for an A class riders. Same applies off-road. You need a different setup out west to ride 50 mph sand whoops than you need to ride over roots and rocks on a single track trail in Ohio.

The moral of the story is swapping the suspension from another bike isn't a silver bullet.  It will still need to be sprung and valved to work correctly for the bike, rider, and the terrain being ridden.

Thanks. I get what you're saying. I'm just so far out of the loop since my MX days (80s)...of messing with springs, oil, and clickers. Just from what I know by feel though, I figured any newer model unmodded inverted fork would be an improvement over what I have. And as a bonus, it would appease my eyes better given the other mods I've done to my bike trying to give it a more modern look.  

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SM suspension system is shorter than an S/E and much stiffer ride for street use but you can spring and valve to your preference.Straight forward bolt up deal though.You'd need the triples and top clamp too and the 310 brake rotor because of the configuration of the fork collet.

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On 5/28/2020 at 11:44 AM, Gary in NJ said:

By going the "entire front end" route you'll only have to deal with a cut or custom turned head bolt. There's always the possibility that the existing bolt can be pressed into the donor lower t-clamp.

Can you tell me more about the bolt? Why would it have to be cut or custom turned?

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Yes, you'd have to find a lower triple with a stem with the proper diameters and length that allows you to turn down to the correct diameters in the right place to press the inner bearing races at the correct height to match the frame's outer race position.

The outer thread also has to be at the correct height so you can preload the bearings.

Or like sugested, find a triple that allows you to interchange the press fit stem post (same diameter at the press fit section).

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