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ULTIMATE FRONT END CONVERSION FOR CRF230F


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I do realize there have been quite a few threads on this subject and the necessary parts and machining needed to get it done.

I thought at first that going to a CR80/85 or CRF150R front end would be the way to go but then I find a few threads where folks have used CR125/250 or CRF250/450R forks, even non-Honda forks and/or front ends.

 

None of the conversions are a direct bolt on but the larger forks from the bikes which come with a 21" front wheel to begin with look to have fewer downsides and need fewer parts to make work.

 

Looks like the bigger bikes use the same front brake caliper as the 230F.

Can use the original front wheel from the donor bike, not sure what it would take to make the 230F wheel work.  Same diameter rotor?

 

The stem has to be modded regardless or can a spacer just be used on some of them?

 

Would a company like RaceTech modify the larger forks for 9.5" of travel down from 12"?

Is using spacers on the top out spring and shortening the fork spring the way to go about this?

If I did this mod, I'd probably procure some forks or a whole front end or a whole donor bike, send the forks to a pro to be resprung and revalved.  Looks like you can spend alotta money on tuning and aftermarket valves, mid-valves etc.  I'd like to have a plan before I start gathering parts.

 

I'd like to relocate the ignition key switch on my 230F regardless, it isn't easy to get to and once it is turned on, I keep it on for a whole day of riding, not necessary to turn the key off when riding and stopping.

 

So, this thread is to summarize what front end swaps folks here have done and how it turned out.

Determine what fork, bar none, would be the best candidate for a swap.

Who would be the best shop for modifying the forks, respring, revalve, etc.?

 

Seems like regardless of how good or bad any year of fork was from the factory, they can all be made as good as the others with proper upgrades and tuning.

 

Yes, this would be lots more expensive to do but for me, dreamy suspension is very important as is the 230F's size and power delivery.  If yer gonna do it right, you need to know the range of options available.

Edited by MetricMuscle
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None of the conversions are a direct bolt on but the larger forks from the bikes which come with a 21" front wheel to begin with look to have fewer downsides and need fewer parts to make work. 

I agree

 

Looks like the bigger bikes use the same front brake caliper as the 230F.

Can use the original front wheel from the donor bike, not sure what it would take to make the 230F wheel work.  Same diameter rotor?

Axle size will be the problem. Some can be acommodated by swapping bearings.

 

The stem has to be modded regardless or can a spacer just be used on some of them?

Unfortuneately, but there are solutions such as All Balls special bearings and/or adapter sleeves.

 

Would a company like RaceTech modify the larger forks for 9.5" of travel down from 12"?

I think they do shorten forks, but Ive done my own.

 

Is using spacers on the top out spring and shortening the fork spring the way to go about this?

I used PCV spacers in the forks but depending on fork type you may also need to move the spring perch.

 

If I did this mod, I'd probably procure some forks or a whole front end or a whole donor bike, send the forks to a pro to be resprung and revalved. 

Do your own, lots of help on TT.

 

Looks like you can spend alotta money on tuning and aftermarket valves, mid-valves etc.  I'd like to have a plan before I start gathering parts.

Do Your own, I have had help from world wide knowledgable riders on the Suspension Forum.

 

I'd like to relocate the ignition key switch on my 230F regardless, it isn't easy to get to and once it is turned on, I keep it on for a whole day of riding, not necessary to turn the key off when riding and stopping.

I added a 230F ignition switch to my CRF250X based on Rick Ramsey web site, so relocating can be done.

 

So, this thread is to summarize what front end swaps folks here have done and how it turned out.

I have 89 RM125 front end on an earlier RM, very good conventional cartridge forks that have become my standard for other forks.

I have CRF150R forks on a XR200R, not as good as the 89 RMs but lighter.

 

Determine what fork, bar none, would be the best candidate for a swap.

Twin chamber Showa used on late CR250R and CRF250/450/R/X, with appropriate valving and springs.

 

Who would be the best shop for modifying the forks, respring, revalve, etc.?

My advice is do it your self, or find a local RaceTech shop.

 

Seems like regardless of how good or bad any year of fork was from the factory, they can all be made as good as the others with proper upgrades and tuning.

But the above mentioned Showas are very tuneable and they are rigid, might be overkill for a CRF230F.  IMO the KYB conventionals from a 89 RM 125 might be better (but difficult to find).   I have a CRF150R front end with RT Gold valves on my XR218 and they are good, a big improvement over the stock damper rod forks like the 230s use, and much lighter than stock or the the big Showas. 

 

Yes, this would be lots more expensive to do but for me, dreamy suspension is very important as is the 230F's size and power delivery.  If yer gonna do it right, you need to know the range of options available.

Compared to a CRF230F my CRF250X:

is the same weight,

4" longer wheelbase,

2 1/2" more suspension travel,

very rigid chassis,

with the CCC mods has nearly twice the HP of a 230.

 

Careful what you wish for as you can become entangled in a time robbing endeavor.

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Used 2002 cr125 forks. Had them shortened by 1 1/2 inches. Believe it requires special took to get at valve. Ergo's like a chopper, until shortening or could have done the shock or linkage to raise it 1 inch. Still had to put them up in triple clamps for level bike. Reger steering stem in cr125 triple clamps and cr125 wheel. Stock brake went on without issue.

Did this for 14 year old, now wife's bike. Would I do this again, not a chance. Replaced handlebars with open ktm ones. Bike looks great, but suspension still not great because of stock rear shock. Still not in the same league as my wr450 kyb SSS or my son 250x Showa twin chamber. If this is a bike your going to ride for a lot of years. Then do it, if semi temporary not worth it. Expensive upgrade and your should really do rear if doing right also.

The last thing I might do to this bike is buy an aggressive cr250r front fender and cut notches in the back for air flow. Ebeck did this on his before selling.

ImageUploadedByThumper Talk1415685049.308109.jpg

ImageUploadedByThumper Talk1415685121.133215.jpg

Edited by RMK800
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I have done several different suspension swaps on the four 230s that I own or have owned. I found the least expensive, easiest accomplished and  most improved performance is acheived with the XR250 conventional cartridge fork. Stem spacers and some tank triple clamp clearance adjustments were all that was needed to bolt them on and ride. Uses the 230 wheel, axle and brake system too. The XR250 forks /Works Performance or Fox Podium shock combo is hard to beat. My next project (after I ride it box stock a few feet to remind me just how crappy they are as delivered) is OEM forks with RaceTech cartridge emulators and a fork brace and some variation of the OEM shock.

ST O.D. 

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Great info, thanks for the replies.

 

Let me clear up my goals with this swap.

- Still only trail riding but the terrain 'round here can be pretty rough, rocky, rooted.

- I want a plush front end that can still handle the big stuff and of course everything in between.

- I want a fork that cannot be attained by upgrading the springs and adding Emulators to the OE forks.

- The bigger forks range from 43mm up to what, 48mm?  Weight is not an issue for me as they won't be lots heavier than the other options.

 

When you say "shortened", what do you mean, how do they go about that?

 

Conventional forks are also contenders for this swap.  They may actually be a better option in some cases, easier to disassemble than USD.

 

I already have a Hagon rear shock and it is a big improvement.  Wouldn't mind trying a Podium X if I could find one.

 

I'm not looking for any more power.  The CRF230F is faster than I ride.  Her size is perfect for my 30" inseam and Eastern Tennessee terrain.  Fuel economy and electric start are also upsides.

 

I have rebuilt and resprung the USD forks on my streetbike, Suzuki TL1000S.  I don't have the compression tool to get the forks apart but can get one or borrow one.

 

How difficult is it to tune the cartridges in a twin chamber showa?

Is there magic RaceTech or anyone else can work on forks that the DIY'er can't?

I'm all for DIY if we know how to go about it.

 

RMK800 wrote:

The last thing I might do to this bike is buy an aggressive cr250r front fender and cut notches in the back for air flow. Ebeck did this on his before selling.

 

 

Don't worry about cutting notches for air flow.  One of the benefits of the larger fender is more mud protection for the head and cylinder.  It will cool just fine with a full uncut fender in front of it.

If this still cooled then.....

1ATC200SLeftside.jpg

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Great info, thanks for the replies.

 

Let me clear up my goals with this swap.

- Still only trail riding but the terrain 'round here can be pretty rough, rocky, rooted.

- I want a plush front end that can still handle the big stuff and of course everything in between.

- I want a fork that cannot be attained by upgrading the springs and adding Emulators to the OE forks.

- The bigger forks range from 43mm up to what, 48mm?  Weight is not an issue for me as they won't be lots heavier than the other options.

 

When you say "shortened", what do you mean, how do they go about that?

I shortened Showa twin chamber forks on my CRF250X.  Pretty straitforward; used a PVC spacer inside the cartridge to limit rebound (but it needs a steel washer to protect it from the rough surface at the lower end of the cartridge) and relocated the spring perch the same distance using an aluminum sleeve.

 

Conventional forks are also contenders for this swap.  They may actually be a better option in some cases, easier to disassemble than USD.

Yes and there are some very good conventional cartridge forks:

The  KYB 41C on the 96+ XR250R as previously mentioned is an easy swap. 

I have KYB 46C from a 89 RM125 and KX125/250 (hard to find) on a bike and they are fantastic, my fav conventionals.

Another very highly rated conventional fork is the Showa 49C used on 96-98 RM125/250 and DRZ400, this may be the best conventional forks out there.

 

I already have a Hagon rear shock and it is a big improvement.  Wouldn't mind trying a Podium X if I could find one.

 

I'm not looking for any more power.  The CRF230F is faster than I ride.  Her size is perfect for my 30" inseam and Eastern Tennessee terrain.  Fuel economy and electric start are also upsides.

 

I have rebuilt and resprung the USD forks on my streetbike, Suzuki TL1000S.  I don't have the compression tool to get the forks apart but can get one or borrow one.

I bought a MotionPro tool for removing the cartridge and base valve.  Used a ratchet strap to compress the fork, but I didn't like the sudden release action. So I made a compression tool from a light duty bar clamp by thinning one arm so it would fit into the axle hole.  A bench vise with soft jaws, or lined with a rag to protect the fork.    Digital calipers to measure shims, torque wrenches for assembly, Loctite blue, a digital camera and notepad. 

 

How difficult is it to tune the cartridges in a twin chamber showa?

TC forks are more difficult to work on than open chamber forks but not by much, and the cartridges are all very similar. Lots of tuning help on TT.

 

Is there magic RaceTech or anyone else can work on forks that the DIY'er can't?

I'm all for DIY if we know how to go about it.

There are 4-5 shim stacks in each fork that need to be assembled correctly, some stacks have float, some are multi stage, the valve bodies are directional, etc; so lots of details but info is available and taking thorough notes  & pics help.

The only work that is difficult is shock, they seem more complex because of the seal head, bladders, purging air, and pressurizing.

 

Don't worry about cutting notches for air flow.  One of the benefits of the larger fender is more mud protection for the head and cylinder.  It will cool just fine with a full uncut fender in front of it.

If this still cooled then.....

1ATC200SLeftside.jpg

My experience with  fenders that block air flow to engine is different but maybe it is the terrain. e.g. I have Vapors on most of my bikes and while riding one with a large watercooled type of fender on a long steep climb in the mountains I saw cylinder head temps at the spark plug of over 400 degrees.  I know from dyno runs that above 400F bad things can happen to an air cooled engine but in this case engine speeds were lower and mostly light-medium  thottte.  The climb was in the mountains,  several thousand feet of elevation change in a mile or so with lots of switchbacks and stair steps, in the summer, and it was a continious run with no idle time and only one stop to wait for a riding partner.  Next year I rode a XR with the stock short XR fender and the cylinder temp styed well under 400F.

Edited by Chuck.
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My experience with  fenders that block air flow to engine is different but maybe it is the terrain. e.g. I have Vapors on most of my bikes and while riding one with a large watercooled type of fender on a long steep climb in the mountains I saw cylinder head temps at the spark plug of over 400 degrees.  I know from dyno runs that above 400F bad things can happen to an air cooled engine but in this case engine speeds were lower and mostly light-medium  thottte.  The climb was in the mountains,  several thousand feet of elevation change in a mile or so with lots of switchbacks and stair steps, in the summer, and it was a continious run with no idle time and only one stop to wait for a riding partner.  Next year I rode a XR with the stock short XR fender and the cylinder temp styed well under 400F.

 

+1 on this topic.  I also have a Vapor and temperatures at the plug can get very high when riding in the summer on slow technical trails, even with the mild stock compression ratio.  I have seen temperatures over 350 and, at times, close to 375 under severe conditions.  Conventional motor oils begin to break down near the 400F mark.

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+1 on this topic.  I also have a Vapor and temperatures at the plug can get very high when riding in the summer on slow technical trails, even with the mild stock compression ratio.  I have seen temperatures over 350 and, at times, close to 375 under severe conditions.  Conventional motor oils begin to break down near the 400F mark.

I assume this was with the factory CRF230F front fender so the temps will still skyrocket even with unblocked air flow to the head.

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When you say "shortened", what do you mean, how do they go about that?

I shortened Showa twin chamber forks on my CRF250X.  Pretty straitforward; used a PVC spacer inside the cartridge to limit rebound (but it needs a steel washer to protect it from the rough surface at the lower end of the cartridge) and relocated the spring perch the same distance using an aluminum sleeve.

 

 

Did you document this somewhere?

Is there a good thread on how to go about it?

Did you cut or change the fork springs?

 

Are all of the twin chamber Showa CRF250/450R forks the same over the years?

Is there a better year to get?

 

Is there any advantage to USD vs. Conventional or vice-a-versa?

USD look more racer but in the muddy woods, the sliding part of the fork is closer to where the front wheel flings stuff and is less protected than conventional with gaiters.

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Did you document this somewhere?

Is there a good thread on how to go about it?

Did you cut or change the fork springs?

 

Are all of the twin chamber Showa CRF250/450R forks the same over the years?

Is there a better year to get?

 

Is there any advantage to USD vs. Conventional or vice-a-versa?

USD look more racer but in the muddy woods, the sliding part of the fork is closer to where the front wheel flings stuff and is less protected than conventional with gaiters.

 

One of the benefits of USD forks is that the larger-diameter components of the forks are in the triple tree.  This results in a much more rigid configuration (i.e., less-flexible).

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One of the benefits of USD forks is that the larger-diameter components of the forks are in the triple tree.  This results in a much more rigid configuration (i.e., less-flexible).

 

Yes indeed!  Rigidity is on my list of expectations/goals.

 

The more I investigate this swap/mod/upgrade the key issues to making it fit start to stand out.

Looks like the stem is the main interface between the CRF230F and any other forks.

I'm not clear on what issues a CRF250/450 stem will pose, is it just the longer length?

Will the bearings interchange or can the right bearing make the stem fit in the 230F neck?

I wouldn't mind there being a spacer gap between the neck and top triple clamp, I would like the added height.

 

Steering stops.

Do any of the lower triples have stops which can be modified?

ebeck did an awesome job on his 230F but had to make his own steering stops it looks like.

He started with a 2000 CR250R triple and forks.  Do the later CRF250/450 triples have stops built in?

I found a couple of old threads which touch on this issue but the pics don't load so not real clear what he ended up doing.

 

Looks like the later twin chamber Showa use lots stiffer fork springs than previous USD forks, some even more than what is working well for me in my OE 230F forks, 0.46kg/mm.  By comparison, my old '93 KX250 had 0.38kg/mm.

Do the newer forks use less compression damping and rely more on the spring?

Do the newer forks use less fork spring preload therefore need a stiffer spring to start with?

 

Can the CRF250/450 top clamp hold the forks lower than where they did originally or are the twin chamber Showa tapered and not designed to be clamped except in certain areas?  Most of the ones I've seen pics of look to be a consistent diameter the entire length.

 

What is the difference between a CRF230F front wheel and one from a CRF250/450R ?

Is the rotor size the same?

 

I'm gonna try and take my time with this project, figure out how to go about it, what parts are best to go with before gathering them all up.

I'm still gonna fiddle with and tune my OE forks and Emulators to get them as right as possible.

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@MetricMuscle

While damping can influence effective spring rate the biggest influence will still be bike weight, rider weight, riding enviroment.

Since most of the Showa TCs are factory set up for MX they will be much stiffer in damping and springs than a trail bike, so plan on changing damping and springs. 

 

Rotor size is the same, front axle is 20mm vs 15mm.  Don't know about rotor offset or if a bearing swap will accomdate axle/wheel swapping.

 

All of the Showa USD have tapered sections that restrict triple clamp adjustments. But the handle bars probably are the limiting factor on moving the forks up. The Showa 37 USD have reduced diameter between the triples, the 47 USD have a smaller upper triple with a long taper between.  

 

My X steering stops are two bosses cast into the top of the lower triple that contact the sides of the frame at full lock. 

 

Steering head bearings;  The twin spar aluminum frame was a fresh design and uses larger head bearings than most of the steel frame bikes.

 

Same bearings top & bottom; Honda #91015-425-832  (26x47)  $24 x 2= $48 :

87-00 CR80

96-02 CR80RB

03-07 CR80

03-07 CR80RB

82-92 CR125

82-91 CR250

82-83 CR480

84-01 CR500

03+ CRF150F

07+ CRF150R/RB

03+ CRF230F

81-07 XR200R/250R/350R/400R/600R

82-90 XL200/250/350/500/600

 

The Showa TC forks use a larger bearing  91015-KZ4-701 (can't find my notes on size)

 

Did you document this somewhere?

Is there a good thread on how to go about it?

Did you cut or change the fork springs?

 

Are all of the twin chamber Showa CRF250/450R forks the same over the years?

Is there a better year to get?

 

Do a search in the Suspension forum on shortening forks.

Did not cut the springs, that would increase their rate.

 

I added a sleeve inside the cartridge to limit rebound travel and moved the spring perch the same amount so preload would be the same as stock. Reduced oil quantity to compensate for loss volume.

 

I believe all of the TCs are the same except for valving/springs, same thing for the CR80/85/150R forks.  CRF250/450 triple clamp part numbers varied a lot for the MX bikes. Do a part fiche check on any candidate forks.     

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Does the X lower tree have steering stop bosses and the R's don't or is this a year to year thing?

 

Looks like the aluminum framed stem bearings are 4mm larger OD than the steel framed models.

Might could turn the larger stem down to fit the smaller bearing.  Better than modifying the frame or trying to find the ever elusive XR stem.

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The stem u need is the one in the lower triple from xr250 90-95. These are cheap and common as mud. This is THE stem for most fork swaps as it is the same as your 230 stem except it can be popped out. If you use conventional 41 mm forks of any kind these will slide straight into a set of these triples. Bang fork swap done in a couple of hours. Stem swap is a bit harder but gives u the option of almost any fork.

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The stem u need is the one in the lower triple from xr250 90-95. These are cheap and common as mud. This is THE stem for most fork swaps as it is the same as your 230 stem except it can be popped out. If you use conventional 41 mm forks of any kind these will slide straight into a set of these triples. Bang fork swap done in a couple of hours. Stem swap is a bit harder but gives u the option of almost any fork.

Is this stem the same length as the CRF230F or longer like the USD stem?

Can USD forks be clamped closer or does the taper prevent this?

 

I'll look for some XR250 triples again.  I actually found quite a few on eBay but most were from an 1980 something model.

 

Thanks again for all the good info!

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The late-model XR250 forks are a very good option and have been used time and time again.  I considered using them many years ago but decided to stay with the stock forks.  One thing we need to keep in mind is these forks have no external rebound damping adjustment and they have notoriously-fast rebound when using SS-7 (5w) fork oil.  They also don't do well on big square edges due to the stock piston.  My buddy will be having Bruce do his XR250 forks this winter and Bruce is not a big fan of them for the reasons just stated.

 

Are they an major improvement over bone-stock forks?  Yes.  Are they better than stock forks with properly-set emulators?  No*.  Will they be better after Bruce is done with them?  Yes.  *Do they have better resistance to twist?  Yes.

 

They are a great bolt-on upgrade but to make them right requires revalving by a professional and, of course, proper springs.  This adds up to several hundred dollars very quickly.

 

I agree with Chuck that if anybody is going to upgrade the forks GO BIG and don't stop half way.

Edited by VortecCPI
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As previously posted there are many combinations that can make an improvement in bike handling, the challenge is deciding on  cost effective improvements that suit your riding. What path and components can be as simple as a good deal on used suspension parts, or inspiration from seeing/riding someone else's  projects. That is what inspired one of my projects; riding a TT member's XR200R that had been upgraded with XR600R suspension parts and a Powroll 218 engine.  

 

Increases in front end rigidity makes a big difference in bike handling. The primary contributors to front end rigidity is fork and axle diameter. USD forks are an engineering exercise to optimize rigidity while controlling weight, and they do it well. Actually too well as the first generation of USD were univerisally critcized for their harshness, which resulted in some of the great, and large,  KYB and Showa conventional cartridge forks from 89 and on.   Today the flex, and weight, is controlled via taper in the fork tubes between the triples; some with visible taper to the OD, others with different sizes of upper/lower triple bores, others via tapers to the ID, or some combinations. I've noticed difference in steering and bike bike feel with fork size increases as small as 2mm. That was swapping from 36mm to 38mm forks on a XR200R, both KYB damper rod XR forks.

 

Triples do contribute to rigidity and I've have found Outlaw CNC uppers improved handling on the CR80/85/150R forks (Showa 37U) on my XR218.

 

Bigger axles also help, I could tell the difference when I changed from a 12mm to 15mm axle on the same forks (all internals and oil were the same, same front wheel/tire, different bearings). The steering was smoother and more precise when steering out of trail ruts.

 

Then you get to fuss with springs and damping.  Damper rod forks will be the easiest to change/adjust, and a Gold Valve according to many, will get you 90% of a cartridge fork.  Cartidge forks do have the advantage of clickers for fine tuning.  For most forks/shocks they are a bleeds for the low speed circuits (some also have high speed adjusters), low speed damping controls bike chassis motions such as when braking or traveling thru whoops.  The problem is serious damping changes require changing valve shims, which is another learning adventure, or expensive.  RaceTech's Suspension Bible is a very good book on suspension and IMO well worth the price. And I've received a lot of help revalving from the Suspension forum. 

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