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'89 CR250 forks on the way...advice for tuning?

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Okay, so I just purchased a complete '89 CR250 front end to bolt on to my XR200R, so that I can have inverted forks, and a disc brake.. I know that these forks have a reputation for being way too harsh... I am told that it is due to being over dampened and undersprung. I have thought about giving Racetech a call, but I am afraid that they will sell me more than I really need.

I am approximately 130 pounds, but likely to be around 150 in the future. I mostly do trail riding over rediculously big rocks, so suspension setup is important for a comfortable ride. Then again, these forks are going to be the best I have ever had, so I don't need for them to be perfect. My bike already has the long travel, older XR200R suspension, so it won't be completely lopsided, but maybe a little. The most I have ever done with suspension is change fork oil, and find good deals on Ebay for better components.

My questions are: How much of this can I do myself? What should I be doing in the first place? Any other tips or advice?

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I hope you like fishing because you just bought yourself a can of worms.

These forks are the first generation of USDs and are frought with design infancy issues. Poor bushing land design made stiction a real issue. I bet if you were to examine the inside of the alloy uppers you will find that the anodising has worn through where the lower triple clamp locates. The upper cartridge bush tends to wear easily allowing fluid to be expelled through the top of the cartridge itself. Given that your forks are near 18 years old I would examine everything for signs of wear and fatigue. My advice is to call RaceTech and get some Cartridge Emulators for your stock forks. Conventional forks will always outperform USDs in trail / rocky situations.

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"How much of this can I do myself?"

I would hate to guess your knowledge tools and skills.

"What should I be doing in the first place? Any other tips or advice?"

I would completely strip them down and check EVERYTHING. They are 18 years old as Terry Hay said.

Terry Hay: :"The upper cartridge bush tends to wear easily allowing fluid to be expelled through the top of the cartridge itself."

Would that be the damper rod bushing? What affect does the oil going through the top of the cartridge have?

Thanks.

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I hope you like fishing because you just bought yourself a can of worms.

These forks are the first generation of USDs and are frought with design infancy issues. Poor bushing land design made stiction a real issue. I bet if you were to examine the inside of the alloy uppers you will find that the anodising has worn through where the lower triple clamp locates. The upper cartridge bush tends to wear easily allowing fluid to be expelled through the top of the cartridge itself. Given that your forks are near 18 years old I would examine everything for signs of wear and fatigue. My advice is to call RaceTech and get some Cartridge Emulators for your stock forks. Conventional forks will always outperform USDs in trail / rocky situations.

Just for the record....this is mostly for the trick factor and disc brakes. I have ridden the same terrain just fine with a '75 Yamaha that had 4 inches of harsh travel, so I'm not completely worried about performance here.

I am well aware of all of this...but thank you. Racetech has "ultra-slick" busings that I think I might try. The forks also get gummed up, because the springs wear and turn into a gunk, from what I have been told. According to my research, aftermarket springs that are hard anondized are the cure for this. I was thinking that the whole inner tube will have to be anondized, but not according to one guy I talked to, so I may or may not end up having to do that later. According to the seller, the bike was ridden very little with one owner, so maybe I will be lucky, and they won't be worn too bad, but I will have to see when they arrive.

Next question: I don't understand how gold valves help.....and why are they so damn expensive?

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Conventional forks will always outperform USDs in trail / rocky situations.

Terry - Does this apply to new trail bikes like the crf250x? If so why do they use them?

.

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Terry - Does this apply to new trail bikes like the crf250x? If so why do they use them?

Obviously, I'm not Terry, but I'll give you my 2 cents on this subject: Yes.

As good as the Showa TC USD forks are, they still transmit more feedback over sharp hits than a pair of RSU forks with the same build quality. I know, I own a 250X.

Scott Summers is very aware of this.

I'll wait to hear Terry's reply but my experience is that the RSU fork is a superior design for off-road than the USD fork. The inherent characteristics of the two designs make the RSU fork my choice for off-road use.

The reasons have been discussed here many times.

My favorite fork? The Showa TC RSU fork from the 96-98 RM's. I have several sets.

Second favorite? The 46mm KYB RSU forks from the 89 KX's. I also have several sets of these.

Why do they use them?

My guess is two factors:

1. Cost - It's much cheaper to buy the same design for all the major off-road bikes than to single out the X's for RSU's. Maybe they could work it out where the X's and the XR650 all get the same fork to help with cost.

2. Marketing - Don't think this isn't a biggie. My understanding is this is why Suzuki finally swapped back even though their RSU forks were better (and probably KTM's reason, also). Joe Rider wanted his bike to look like the factory bike.

:thumbsup:

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.....my experience is that the RSU fork is a superior design for off-road than the USD fork.

It's my understanding that RSU forks don't respond to handling as well as USD forks. This is due to the flexiness that makes the RSU feel softer than the USD.

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you should be able to do the whole swap yourself. I am 16 and have done a complete kx fork swap on my kdx. I had websites to read about this on but the basics should be no differnce.

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It's my understanding that RSU forks don't respond to handling as well as USD forks. This is due to the flexiness that makes the RSU feel softer than the USD.

While this is true for the small tubes on like on a TT'R, and XR 250, the XR650R and DRZ are a very good "off-road" fork. If you are doing triples then you may/will prefer an UDS fork.

Alot of people have a pre-concieved notion brought on by the rags bagging on RSU forks...it's all about looking cool. Before they swing a leg over the bike they are already convinced they won't steer as well...

Another concern is the underhang of the lower leg at the axle. That is the biggest downside to RSU forks. The DRZ forks are by far the best mass-produced out there with 49mm tubes, 28mm cartridge, 12.5mm cartridge rod. Good stuff! :thumbsup:

I have a buddy that put a set of DRZ forks on his 03 WR 450. He rides alot of rocks and you just can't beat a RSU fork for that! :ride:

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It's my understanding that RSU forks don't respond to handling as well as USD forks. This is due to the flexiness that makes the RSU feel softer than the USD.

KTM-Lew has pretty much nailed it for you. :thumbsup:

However, it's not the "flexiness" that makes them feel softer, it's the flex pattern.

An RSU fork wants to bend where the bottom triple clamp holds the upper tube. This allows the lower leg to remain parallel with the upper leg with no bushing binding or "stiction".

A USD fork is more rigid at than point and instead wants to drive the lower leg through the back of the upper leg before it moves. This causes it to momentarily "stick" before moving and is what you feel when going over sharp-edged obstacles.

While it is true that by inverting the fork it results in a more rigid assembly, the trade-off is initial ride quality. This is more important to the off-road crowd than trying to carve a surgical line on a perfectly prepped bowl turn in front of 75,000 people.

The right tool for the job. :ride:

Lew: I don't keep up with the DRZ's (I guess 'cause I'm straight :applause: ), but do they all have that fork or just the dirt-only model? It wouldn't surprise me if the DS version had a less sophisticated fork.

:applause:

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Right on KTM-Lew & SC_Spode :thumbsup:

I'll second that on those late '90's Showa 49MM TC RSU forks SC_spode. Even the USD 49mm's weren't bad and were the basis for those $5000 Works forks from PC I think.......

doc

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Lew: I don't keep up with the DRZ's (I guess 'cause I'm straight :ride: ), but do they all have that fork or just the dirt-only model? It wouldn't surprise me if the DS version had a less sophisticated fork.

:applause:

Can't remember right off the top of my head but I worked on one of the DRZ's (DS I think) a few weeks ago and it had the old damper rod style fork. The shock is revalvable but has no external rebound adjustment.

doc

PS......sorry forgot this thread was about the '89 CR Showa fork so like everyone else.... :thumbsup: is all I need to say :applause:

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In 2002 or 3003 all the DRZ400's went to the "good" version of that fork.

A few months ago I bought a set of those 2000 49mm RM Showa's and never got them. My first official eBay screwing!

Don't deal with Jruskie from Ringold Ga! I think his name is Joe Larue or Laruskie? Fake phone number, welll it is apparently a fax number, and email that bounces! Supposedly from North Georgian Powersports...no such place! :applause::ride:

I would LOVE for someone to find this :thumbsup: and give him a $150.00 tune-up! :applause:

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Sorry to hear you got ripped off. Actually, it was jrueskie. As you spelled it, was some feedback of 1 seller.

Thanks for the warning, though with his feedback, I wouldn't buy anything from him anyway.

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you should be able to do the whole swap yourself. I am 16 and have done a complete kx fork swap on my kdx. I had websites to read about this on but the basics should be no differnce.

Yeah I will have no problem with the swap....I have done it before. I just haven't torn a fork leg completely apart before....

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I know that these won't be the "perfect" forks, but I really don't give a crap. Once you have ridden a '75 Yamaha with 4 inches of harsh travel on this really nasty terrain, most forks feel real good...

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I know that these won't be the "perfect" forks, but I really don't give a crap. Once you have ridden a '75 Yamaha with 4 inches of harsh travel on this really nasty terrain, most forks feel real good...

I just put a set of 1993 XR 250R forks on my girlfreind's XR200, and the improvement just from the disk brake was worth the work alone, regardless of how the forks felt. These were still conventional damper rod forks, no shimstacks or any sort of digressive valving setup. We did it mostly for the brake setup and the more rigid forks were simply a side benefit, really. I would have killed for a set of USD forks...

ANYTHING is better than the stock spindley little things that came stock on those XR200s. My suggestion with the CR250 fork you have now is to revalve it much much softer and then worry about spring rates. Those years were to my knowledge notoriously softly sprung, so for your weight on the the little XR they mgith be in the diamond if not in the ballpark.

The frames on theose little XR's are also flexxy enough to take some of the harshness out of a stiffer fork, too.

You will likely end up removing shims from the valving, but you should do so in stages. Like I said, ANYTHING is better than the stock boingers on those bikes - my DH mtb has larger stanchions thatn those came with stock!

Just my $.02...

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