Full Showa USD fork/RM125 shock conversion

Questions and comments about converting to beefier forks..
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Re: Full Showa conversion

Post by SS109 »

Friedom wrote:I'm actually a member of that meetup group already I think, and went on a Reddington ride this year. Was late to the party, though, and with two other late comers we did some single track, went down to frog hollow, waited around and finally passed the group in the Italian springs/trap area on our way back.
Cool! I hope you make it out again sometime soon.
Friedom wrote:So you're saying the H series KDX machines have significant suspension improvements over the E series from the factory? I guess I'll never know if yours has USD showas and mine will have conventional dual stage showas. I really should read up on this stuff so I know what on earth in talking about.
Nope, the '89 through '06 KDX 200/220's, other than the '93-'94 models, all had the same basic suspension. I have swapped mine to upside down forks. The Suzuki forks that we were talking about are conventionals that look like the stock KDX forks except way better.
Friedom wrote:I used to ride the PowerLine roads north of Tangerine with a buddy. IT250K and a TDub 200. Learned a whole lot real quick trying to keep up with my friend that practised on his brother's cr500. But I live near Reddington now, yet don't get out much.
Those powerline roads are part of the Marana riding area but we normally stage further North. I live closer to Redington now (just East of Davis-Monthan) but still prefer to drive to Marana to ride.
Friedom wrote:Hopefully the kdx will improve my experience when I do make it out.
I'm sure it will! :supz:
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Re: Full Showa conversion

Post by Friedom »

Ok I see a set of 96 rm250 forks, triples, wheel (with good pirelli rubber!), axle, new spacers for about $260 combined.
Last thoughts? USD sounds cool, but I've never rode competitively and don't expect to. As it is this will be a solid setup, yes? I realize revalving may be in the works, but I'll consider that separate for now.
Anyone can confirm that my existing stock 92 dx200 caliper will work with this setup?

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Re: Full Showa conversion

Post by Friedom »

Hey SS, what did RB have to do to your triples?
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Full Showa conversion

Post by SS109 »

Yes, those should be some good forks. Not sure about the caliper. If yours doesn't match up I might have one that does or you can pick one up from Ebay. RB took the KDX stem and pressed it in to KX250f lower. This makes the forks a bolt on deal and you still use the KDX bearings.
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Re: Full Showa conversion

Post by Friedom »

So I'm reading up on the swap.
I guess the KX swap is more common, is one better than the other? Sounds like I'll have to knurl the bottom of the kdx stem and shim the top to make this fit right? Then re route the brake line, raise the forks in the triples 1". Bleh.

Maybe I'll change my existing seals and run stock for a little to get a feel for it. Though I do like having rebound damping.

Maybe I'll shop for some USDs like you have. Bolt on solutions are my friend.

You still had to get an axle/wheel/spacers to accommodate the forks, right?

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Re: Full Showa conversion

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Friedom wrote:So I'm reading up on the swap.
I guess the KX swap is more common, is one better than the other? Sounds like I'll have to knurl the bottom of the kdx stem and shim the top to make this fit right? Then re route the brake line, raise the forks in the triples 1". Bleh.

Maybe I'll change my existing seals and run stock for a little to get a feel for it. Though I do like having rebound damping.

Maybe I'll shop for some USDs like you have. Bolt on solutions are my friend.

You still had to get an axle/wheel/spacers to accommodate the forks, right?
Some need knurling, some don't. Rerouting the brake line isn't a big deal at all. You don't have to raise the forks if you have them internally shortened to match the stock KDX forks.

Yeah, I would suggest running the stock forks for a while to see if they will work for you. If you aren't crazy like me you just might like them. On the other hand, you can't go wrong with the upgrade!

If you do a fork swap you will always want to get the wheel, axle, and spacers from the same bike the forks came from. That makes it a real simple swap.

Since you're local I can help you if you need it. I have built so many bikes, street and dirt, it's ridiculous.
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Re: Full Showa conversion

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Some need knurling, some don't. Rerouting the brake line isn't a big deal at all. You don't have to raise the forks if you have them internally shortened to match the stock KDX forks.
Pardon my ignorance. How do you shorten forks internally? Shorter preload spacer?

Also, some posts state that the 96-99 rm125/250 forks are the money. Others say it's 97-99. Which is it, as I'm looking at a set from a 96?


Yeah, I would suggest running the stock forks for a while to see if they will work for you. If you aren't crazy like me you just might like them. On the other hand, you can't go wrong with the upgrade!
The stock ones have blown seals. Are these standard rebuild ones? Drain oil, remove forks, remove dust seal, remove snap ring, hammer out old seal, use protection and install new seal, ring, dust and oil and pop em back in? Or do bushings get damaged and the whole thing needs revamped for $100 in parts and you need a 10' one-off tool to tighten down the bottom nut job? (Did I say that out loud?)

Since you're local I can help you if you need it. I have built so many bikes, street and dirt, it's ridiculous.
This gives me confidence enough to know I have backup that I probably do it. :win

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Re: Full Showa conversion

Post by 6 Riders »

Friedom wrote: Pardon my ignorance. How do you shorten forks internally?

Also, some posts state that the 96-99 rm125/250 forks are the money. Others say it's 97-99. Which is it, as I'm looking at a set from a 96?


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96-99 are the same forks. The fork swap is worth it, so don't discount it, just make sure your willing to dump the money into it. Also, if you ever upgrade your kdx to a newer one, the whole set up will swap right over.
I had mine lowered, it involves springs and other "technical" blah blah.....here's a link.....http://www.lt-racing.com/html/susp ... onLowering
This is the guy that did my 93 forks and my RM forks.....haven't ridden on the Showa's yet, but I trust that they will be better than the 93 forks.
Also give a thought to swapping on a 93 and up KDX front end, if you can find one cheap enough to justify it. Again you will need the brakes as they are different than the 92 and older forks....Thinking of that, the 92 brakes will NOT swap onto very many, if any, modern forks and any brake swap that you do (in conjunction with the forks) will be a huge upgrade.
newbbewb wrote:^what he said.
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Re: Full Showa conversion

Post by Friedom »

6 Riders wrote:
Friedom wrote: Pardon my ignorance. How do you shorten forks internally?

Also, some posts state that the 96-99 rm125/250 forks are the money. Others say it's 97-99. Which is it, as I'm looking at a set from a 96?


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96-99 are the same forks. The fork swap is worth it, so don't discount it, just make sure your willing to dump the money into it. Also, if you ever upgrade your kdx to a newer one, the whole set up will swap right over.
I had mine lowered, it involves springs and other "technical" blah blah.....here's a link.....http://www.lt-racing.com/html/susp ... onLowering
This is the guy that did my 93 forks and my RM forks.....haven't ridden on the Showa's yet, but I trust that they will be better than the 93 forks.
Also give a thought to swapping on a 93 and up KDX front end, if you can find one cheap enough to justify it. Again you will need the brakes as they are different than the 92 and older forks....Thinking of that, the 92 brakes will NOT swap onto very many, if any, modern forks and any brake swap that you do (in conjunction with the forks) will be a huge upgrade.
Sounds like putting the forks higher in the triples is easier, faster and cheaper.

Good point on the brakes - if I'm making it go fast better, it's worth making it stop faster.

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Full Showa conversion

Post by SS109 »

There really isn't much difference between the '89-92 and '95+ forks. They are both KYB 43's. Only the brake caliper mounts and, maybe, the axles are different. The '93-'94 KYB 41 USD forks aren't worth messing with as parts are getting very hard to find for them and you still only have compression adjustment. Don't waste your money on either unless dirt cheap.

The problem with raising the forks in the triples is sometimes you can't get them high enough because they hit the bars and/or you can risk bottoming the wheel against the bottom of the fender/lower triple clamp causing you to be thrown over the bars. That said, mine are just slid up and I have never had a problem.

The only plus from using the '95+ front end might be they have less hours on them (ie; wear and tear) and they do use the larger brake caliper. If you want, I have a set from my '98 I pulled off you can have for $25 and I'll throw in the caliper, wheel, and axle. Yes, they need to be serviced but Donnie at ZR1 is very reasonable on his work and might get them setup for you pretty cheap. If you're interested let me know.
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Re: Full Showa conversion

Post by Friedom »

That's a mighty offer, man. Thanks for that. I want to go with the Showas, though. Let's see what these puppies can do!

So is there not a short and simple answer for how to shorten the forks internally? Fork shortening for noobs?

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Re: Full Showa conversion

Post by SS109 »

Friedom wrote:That's a mighty offer, man. Thanks for that. I want to go with the Showas, though. Let's see what these puppies can do!

So is there not a short and simple answer for how to shorten the forks internally? Fork shortening for noobs?
No problem. You'll like the Showas much better. Unless you're familiar with working on forks I would suggest letting a pro shorten them. A lot of factors come in to play like the springs, spring preload, and the valve stack migt need to be altered.
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Re: Full Showa conversion

Post by Friedom »

Maybe I should get a shorter dog bone instead.. Can't lower the front? Raise the rear!

I'm perplexed by the 'some need knurled, some don't' phenomenon. Sounds like a significant variance in production. No matter, it'll work out.
Time to check ebike again..

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Re: Full Showa conversion

Post by Friedom »

So if I pick up a caliper, does it need to come with matey cylinder and hose, or can I use those from my kdx?

(Just ordered forks and wheel from a 96 rm250)

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Full Showa conversion

Post by SS109 »

Why some stems need to be knurled is production variance and different years of triple clamps.

Your master cylinder should be fine. Hose might need to change due to the metal fitting on the caliper end not positioning the hose correctly. I made my hose work with the '96 KX125 forks I put on my E-series. The only way to know is try it.
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Re: Full Showa conversion

Post by Friedom »

Cool. Do you recommend RB designs for the stem work, then?

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Re: Full Showa conversion

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Friedom wrote:Do you recommend RB designs for the stem work, then?
Absolutely! I have used him many times. Stem swaps, head mod, and carb. Good guy to deal with and fast turnaround.
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Re: Full Showa conversion

Post by Friedom »

If it's all you're doing, is it worth the shipping? I feel like a local machine shop can press a stem.

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Re: Full Showa conversion

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Friedom wrote:If it's all you're doing, is it worth the shipping? I feel like a local machine shop can press a stem.
It's not just the pressing. It is also the special bushing/spacer RB makes. You won't find anyone to make one for you even at twice what he is selling his for.
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Re: Full Showa conversion

Post by Friedom »

Huh, first I've heard of this. Is that to make the top triple fit the stem?

Edit: I see the details on their page, though they look like they only specify doing it for a kx swap. Should I just email them about doing the RM work? Also, do you have an extra kdx stem around I could purchase? I want to send one in to match up with the rm setup, but I also want to have one so I can bolt on the whole stock front end, either while I wait, or for the fun of it. [emoji14]

Did a ride on Reddington today with Chris. Apparently he made it out on a ride with you guys in Marana once. Said you're fast. We were "just exploring" the road that connects Camino Cascabel to the beginning of the singletrack area across from the Three Feathers entrance.
A few spills, could use a lighter bike for that kind of stuff. What to do..

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