2001 CR250 $pecial Restoration Part II - Recreation of a 1999-2000 Japan Honda Factory RC250M

Hi Rich,

Would really like to ride it on the track, especially to try out the suspension. I also would like to try out the 20"/18" tire combo. I really liked the 20"/19" on dry tracks and think this would have an even better feel. Actually wouldn't mind riding anything right now.. haven't been able to ride all year because I haven't been able to get the surgery done on my shoulder from the skiing injury last season due to covid, I can still use a wrench though

mike

Here is the newer style HRC ignition advance button next to the older style with the 2 piece aluminum housing. The older style was used on the factory Honda's from the 2nd half of the 1990's up to 2000. The newer style was used on the Honda factory 2 stroked and 4-strokes from 2001 to 2008. Here are some pics of the newer style switch on Katsuya's 2004 RC250 2 stoke, McGrath's 2005 Factory CR250, and Brayton's 2008 factory CRF450. I am looking to trade this newer style HRC switch with the older style. It is in like new condition.

Another project for the holidays... HRC magnesium rear hub, NOS HRC 6 bolt rear brake rotor and special titanium bolts, NOS HRC rear sprocket made specifically for the HRC hub by Renthal. The HRC wheel originally came with a 19 inch rim, but I am in the process of rebuilding the wheel with an 18” rim like the Japan team used in 2000. The rear hub I am using now is a rare Martin Honda CNC hub which is much more interesting to look at, but I figured I should grab the correct rear wheel while I still know where the parts are and they are still available. These parts were hard to find initially, but getting harder now that several guys are building 1997-2001 era RC250s..





The 2 most complex parts are the triple clamps and their very special sized bearings and the rear hubs. That is why these are the 2 easiest HRC parts to find, relatively speaking.

Some of the HRC parts bolt right on. The front hub takes all oem parts, but the rear HRC hub requires all special HRC parts to make it work.. special rear sprocket, brake disc, six M6 titanium disc bolts, concave spoke washers so the spoke ends don’t wear on the magnesium, asymmetrical width wheel spacers are all specially made to fit the hub. Renthal made these specially machined rear sprockets of the Honda factory team to fit the works rear hub which requires a larger machined center. They have a sticker on them that states "Sponsorship products only".





The 1999-2001 RC's represent the last of the really unique looking HRC parts, in my opinion because, for example from 2002, all the Honda works bikes have used very similar looking hubs which don't look very different from what you can get from the aftermarket. There are differences in manufacture though. I have identified about 3 or 4 different rear brake calipers on the 1999-2001 bikes as Honda was developing the much smaller rear brake caliper and master cylinder with the integrated reservoir which has been mostly unchanged on all OEM and works Hondas from 2002.

The rear HRC hub was the last of the old magnesium works technology. The magnesium hub is simply painted silver, while the front HRC hub is rather different being made of drop forged aluminum with a machined center section. I originally thought these HRC front hubs were CNC'd from billet, but they are not and was a step away from the old magnesium works hubs, but not quite reaching the fully CNC'd hubs of today.

The HRC rear hub uses 36 spokes compared to the 32 spokes found on the oem Honda MX bikes since 1989 and uses these special steel concaved seats (shown below) so the spoke ends do not ride directly on the magnesium. The front HRC wheel doesn't use these special steel seats/ grommets. Also, unlike the oem rear hub which uses 2 different length spokes, the HRC rear hub uses only one length spoke on both the sprocket and brake disc sides of the hub.




I also picked up an NOS 110/100-18 Dunlop D739 rear tire for this rear wheel project. These old knobby patterns look fairly different from the grooved knobs on today's Dunlop MX tires.




The rear 18" rim and some HRC titanium is also on the way, but have been lost in the USPS system for a few weeks now. Hope they get it straightened out soon.

Hi Mike, The rear magnesium hub is drop forged like the front aluminum wheel. Although you have to be careful because magnesium is a flammable material, it can be CNC machined, but CNC machining was still in its early days in the era of these HRC hubs, just on the cusp of when CNC'ing started to become cheap and easy. The CNC's parts on these 2nd gen RC were the titanium footpegs, titanium kickstart knuckle, aluminum clutch perch, triple clamps, fork lugs, front brake caliper hanger, some of the titanium bolt heads, and a few other aluminum doo-dads that I can think off of the top of my head. There were quite a few sand cast pieces on these RC's like the Nissan works brake master cylinders, brake calipers, engine covers, etc.

The HRC brake pedals on the 1997-2001 RCs were cast parts, but the HRC brake pedals on our more modern CRF450's are CNC'd parts.

The only other thing that I notice that is different on the works Renthal sprocket besides the special machining of the center opening, is the way the part number is stamped on the sprocket. I have a standard Renthal sprocket on the Martin Honda hub and the part number is neatly formed into the part in a couple of spots on the sprocket, whereas the works Renthal sprocket looks like someone used a die to hammer in the part number on one spot between 2 sprocket bolt holes. The standard sprocket part number is 154U while the works part number is 239U, "U" denoting it is Renthal's Ultralite model.

Here is part number stamping on the standard Renthal sprocket. The number of teeth is stamped on a different part of the sprocket;


And here is the stamping on the Renthal works sprocket all in one spot;

While the Japan factory Honda’s used a lot of titanium all over the bike, they retained the oem steel for most of the linkage bolts during these years as I guess they were still figuring out which ones could get away with titanium. The lower linkage bolt would usually be the first to bend. A few years later, most of the factory Honda machines were using titanium for all the linkage bolts except the lower right linkage bolt they continued to use steel. It’s no fun looking at oem steel so I picked up a few more pieces of titanium for the linkage.




Some of the HRC parts such as the pipes and rear magnesium hub have exact dates of manufacture to the day imprinted on them. I suppose this helped them keep track of older parts as the continually refined the newer versions. On this HRC rear hub, we can see the date of manufacture was November 2, 2001. This would mean it was probably the last bath of magnesium hubs before they changed over to the red anodized aluminum hubs for 2002.



The HRC rear hub uses a dark blue anodized bearing retainer ring on the sprocket side and a red anodized bearing retainer ring on the brake disc side for some reason. HRC dimpled the hub on 4 corners around the retainer ring to keep it from coming loose. On the red retainer side, I haven't greased it up or installed the dust seal yet, but you can see that the part numbers on all 3 rear wheel bearings are the same as oem, as are the seals. The bearing distance spacer is HRC though.


After staring at parts in so many pics of these old factory Honda's, I have noticed some minor variation in the parts they used on the same bikes. Most of the 6-bolt rear rotors had a slot shape machined in the ring, but others had a triangle shape machined in them. Not sure if it was because they used different vendors for some reason or what. The slotted discs were more common.

slot;


triangle;

I always enjoy reading the details on the parts and set up of the RC250 works bikes in the Japan magazines. Few US magazines ever covered these true works bikes in any significant detail. The following translated Japanese magazine article was taken from the February 2000 edition of Dirt Sports magazine. In the article, Hiroyuki Sasaki (former Honda factory rider) does a test session on Yoshitaka Atsuta’s 1999 season RC250M which was the debut of the 2nd generation aluminum frame and bodywork. The MX track is the Motosportsland Shidoki MX track in Iwaki, Fukushima prefecture.
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I will continue the translation every few days, as time allows.
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RC250M HRC Factory Machine - #5 Yoshitaka Atsuta

Will beefy aluminum frames and wide tires become standard for the CR’s of the 21st century!?

Hiroyuki Sasaki test rides what may resemble the 2001 CR250 model.





Yoshitaka Atsuta continued to prove the fighting power of HRC alone when his teammate dropped out of the championship due to injury. Right up until the end of the championship he demonstrated the fighting potential of the RC250M which was the same as Odagiri’s machine. Sasaki test rides and brings the details to light.
The stiffness of the suspension speaks to the high level that this bike is meant to be ridden.

I have ridden Kazu Odagiri’s machine every year for the last several years. In comparison, while Yoshitaka Atsuta machine this year doesn’t look very different, the differences become apparent when actually riding the bike. It was much better. The engine (power) is smooth and doesn't have a torquey feel. The (engine) setting were developed specifically for Atsuta. As the rpm’s increase, the engine responds and has a smooth, flat feeling as it accelerates.
While there is no sudden surge of power through the rpm range, the performance is undeniable and the throttle feels directly connected to the engine output.

With regard to the suspension, I had the impression that particularly the front suspension was stiff. After one lap, my arms were done.

**(I will finish the rest of the translation of the main story after the explanation of each of the pictures of the parts on this factory bike)**

Radiator;
There is not much change in appearance from last year. It has almost the same dimensions as the production CR radiator, however, a radiator cap with a different pressure rating is used to raise the boiling point of the coolant. Instead of the usual coolant, special high water with a higher boiling point is used.


Front end;
The front fork is from Showa and the handlebar is a Renthal “Huffman” bend with 5mm cut off both ends. The grips are Renthal medium compound.


Front brake;
It is equipped with a Nissin front brake caliper that has been downsized to reduce weight. The brake hose is custom made by the team and is wrapped in stainless steel mesh. The brake rotor size has also been increased.


Titanium coat and 20 inch tire;
The inner tubes of the front forks have a titanium coating to increase hardness and prevent scratches. 90/100-20 inch tire is supported by 36 spokes and an aluminum hub.


The engine:
The cylinder and crank are special works items. For gasoline, the team uses Nisseki (Company based in Saitama prefecture where the HRC office is also located) high octane. For oil, Castrol 747 mixed at 30:1. The generator (ignition) cover is made of magnesium.


Foot pegs and shift lever;
The same as last year, the foot pegs (and mounts) are made completely from titanium while the shift lever is made from steel. In terms of weight, the steel (shift lever) is heavy, but it is used to prevent a DNF.


Skid plate;
A skid plate that wraps around the lower frame rails is used.

Yup that's right, but didn't seem too popular with the smallish tip as most of the RC's of this period used the standard tip. You can also see they connected the brake snake to the main part of the pedal rather than the tip in this pic.

I have noticed a lot of one-off changes to these factory bikes as they evolved since I have been studying the pics so much. For example, these RC's had 3-4 different rear brake calipers and 4 different caliper guards during 1999-2000 as they developed the new downsized caliper that is now found on all 2002+ CRs and CRFs.

Also, in addition to the extra frame gusseting around the steering head, look at the 2 pics below and you will see a square tube welded across the 2 downward front frame rails, just above the front of the skid plate. Then there are more corner gussets if you look at the cross-rail in front of the rear shock reservoir and just below the back of the tank. Seems like way overkill even for factory rider level riding. Seeing how much smaller/ thinner the frame rails are on the latest Honda's 20 years later. I can only guess that they were afraid of the new frame design coming apart in the prototype stages.



Also check out the works front brake caliper.. it doesn't have any ribs on the back the way the oem or newer billet works Nissin calipers do.

This particular article had good pics but not as much of the less obvious details provided by the other articles I translated.

Here is a continuation of the article...






Lighter isn’t always better

New materials and lots of new parts are not the only characteristics of a factory machine. This RC250M which has been battling throughout the 1999 season is equipped with wider (than normal) tires and some of the latest new technology made from titanium. On the other hand, there are parts like the shift levers and radiators that can be used for many years without changing them.

The dry weight of the bike (weight including oil and water but excluding gasoline) is about 98kg more or less, just above the minimum weight set by regulation. It is not necessary to make it lighter than this. The reason why materials such as steel, aluminum, titanium and carbon fiber are used selectively is that the requirement for durability and strength are different for each part. It's all about the thought given to each individual part that a reliable and easy to ride RC250M machine is born.

Frame;
At first glance the 2 areas that you can see have been strengthened are the head pipe and the main spars. From the 2 modified areas seen in these pictures, we can expect that it has an effect on the way the bike rides. My guess is the strengthen areas are to prevent the frame from twisting.



Silencer
There is one part that is clearly visible where carbon fiber was used.. the silencer. If only carbon fiber were used, it would be easily susceptible to breakage so a combination of carbon fiber and Kevlar is used. This part is similar to what was used last year.


Rear suspension
Similar to the front, a Showa rear shock is used with a titanium coated shock shaft. The (rear) master cylinder is a one-off Nissin unit that has been downsized and the mounting position changed. The (rear shock) uses a special lightweight spring with wider spring pitch (spacing) between the coils.


Rear wheel
A wide 120/90-19 rear tire is fitted. The (rear) hub is made of painted magnesium. The rear axle is the same diameter as used last year. The rear brake caliper has been downsized.


Other changes;
• Titanium parts
Titanium is used extensively for bolts that don’t require tightening to high torque levels.
• Air cleaner box
Has additional openings to let in more air which are covered with aluminum mesh to prevent rocks and other foreign objects from entering.
• Safety wiring
In addition to the oil drain bolt and oil filler cap which are required to be safety wired by regulation, the hand grips, brake pedal and steering stem nuts are safety wired to prevent loosening.
• Personal preferences
Basically the 3 RC250M machines are similar, but there are personal difference for the 3 HRC riders. Atsuta and Takahama use Showa suspension while Odagiri uses Kayaba. In addition, Atsuta uses hand guards, while Takahama prefers a ribbed seat to prevent slipping and Odagiri uses frame guards to improve his feeling for holding on to the bike There are other various small differences for the personal tastes of each rider.

Here is the complete translation of the main text. I was hoping for more technical details in the article, but it was more overall riding impression. I have an Italian article that I will also translate as it seems to have more on the technical side.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
I have ridden Kazu Odagiri’s machine every year for the last several years. In comparison, while Yoshitaka Atsuta machine this year doesn’t look very different, the differences become apparent when actually riding the bike. It was much better. The engine (power) is smooth and doesn't have a torquey feel. The (engine) setting were developed specifically for Atsuta. As the rpm’s increase, the engine responds and has a smooth, flat feeling as it accelerates.
While there is no sudden surge of power through the rpm range, the performance is undeniable and the throttle feels directly connected to the engine output.

With regard to the suspension, I had the impression that particularly the front suspension was stiff. After one lap, my arms were done.

However, it is not so stiff that it seems strange and works better the faster the bike is ridden. The bike is set up to work better the harder it is ridden. In other words, the (suspension) setting matches the rider's level and intended to provide Atsuta maximum control when he is at high speed. However, despite feeling stiff, it makes it very easy to enter corners and never made the bike difficult to handle.

The (suspension) doesn’t quickly find its limits and seems to made to work with the position of the handlebars on Atsuta’s bike making it easy to move into a standing position.

In summary, the front end felt very composed with a particular emphasis on cornering. I felt the bike would always go exactly where I intended it to go. In other words, whether it is entering a rut or a corner, the front end provided quick feedback to provide this (controlled) feeling. I felt that maybe this was influenced by the fact that the brakes worked so well along with the wide tires and one inch smaller (front) wheel. However, when not cornering, the front had a bit of a floating feeling and the steering was on the heavy side. Perhaps this is an intended characteristic built into (the settings).

My overall impression is the bike has a smooth engine with a very controlled feeling. The suspension is very effective at competitive speeds providing a balanced package that is designed to win (races). Maybe we can expected to see the wide tires and beefed up frame reflected in the 2001 CR (production) model.

I know.. "liar, liar, pants on fire".. I really did think I was done with the build and had stopped actively looking for parts, but some how more parts found me, and hard to say "no" since opportunity for rare old HRC parts usually doesn't knock twice.

Lots of updates coming... these HRC titanium foot pegs will saute in 91% isopropyl alcohol for 72 hours before going on the bike. Makes 22 year old titanium nice and shiny again. The replica Ti pegs I had on there gave up little to the genuine item except these were made by HRC. Almost impossible to tell them apart even side by side, but I feel the need tp keep the bike as 100% genuine as possible at this point. They have very little wear on the cleats and cleaned up nice.. will share pics after another 48 hours in the alcohol bath.


HRC used a lot of special looking heads on their titanium bolts and no RC build would look accurate without these special looking bolts... here are the HRC rear sprocket bolts I just picked up. The other special bolts that are essential for an accurate build are the triple clamp bolts, rear subframe to main frame bolts, seat bolts, front and rear brake rotor bolts. There are other bolts that will not look right unless you get the actual HRC bolts or have exact reproductions made after copying the actual HRC bolt.


Dubya made me an 18x2.5” wide 18” rear rim that looks similar to the 18x2.75” rim that HRC Japan used. Looks quite wide next to a 19x2.15” HRC rear rim in the pic below. 2.5" was the widest MX rim they had and they had to use a 36 spoke 18" Excel blank rim to do it. The blank rim was drilled for the Honda spoke pattern (each manufacturer has their spokes at a slightly different angle) and the laser-etched "Excel" logos were all removed and then the rim as re-anodized. I think it came out great.. it has that flat cross section in the middle of the rim where the spokes are like the HRC rim. Good compromise since I had no luck finding a nice, genuine 18x2.75 HRC rim that Honda used for just a few years. 19x2.15" HRC rims are much more common. I will run the same size 120/90-18 Dunlop rear tire as the Japan team did on this wide rim.



These factory bike had lots of very light unobtanium on them at the same time they had some very heavy parts. While the Kevlar silencer is feather light, the HRC shifter is a "boat anchor". The forks are also a little heavier than OEM as titanium is heavier than plastic. To win a championship, the factory team could not afford a DNF so they built some extra strength into some parts. This era RC250M was a little lighter than a production bike, but not by a lot. With the exception of the front titanium linkage bolts, the factory teams used OEM steel for all the rest of the linkage bolts. A close look at Carmichael's works 2003 CR250 reveals all the steel hardware on the linkage. Some years later, the Honda factory team felt more comfortable using more titanium on the linkage. If you look at a CRF450RW works machine, you will usually see all titanium on the linkage except for the lower rear linkage bolt which remained OEM steel. OEM steel is not so pretty to look at so I compromised using HRC titanium linkage bolts for most of the linkage, using the one OEM steel bolt in the same one single spot as the factory did in more recent years, and for the one upper rear linkage bolt that had the obvious OEM steel head on the 1999-2001 RC's, I found a titanium linkage bolt that emulated the shape of the head of the oem steel. This way it still looks similar to the old pics of the HRC set up, but is actually a little tricker with the glint of more titanium to look at.


There is an old saying; "never meet your heros" and I guess there is a little bit of the same when you dig into an "ultra-unobtanium" works bike, thinking every part was so special. While some parts are quite special, there are a lot of "factory parts" that didn't turn out to be as special as I had originally thought for the last few decades. One is the very different (from OEM) looking front brake caliper that HRC Japan and MXGP teams used. I had just found an actual HRC unit and was about to pay big money for it, when a friend pointed out that it looked exactly like the brake caliper he had in his early 90's CR500 parts bin. I compared close up pics of 4 actual HRC front calipers with old 1987 to 1991 OEM CR125-500 calipers on ebay. They were 100% the same right down to the casting numbers on the housing. It then became clear to me that HRC ditched the newer, heavier OEM calipers for the much older and lighter OEM caliper for their works bike! No sand-cast works part here... they simply filled the 14-year old OEM caliper housing with titanium pistons and a titanium slider pin. So instead of buying the old HRC part for big $$$$, I bought a nicer looking 1991 casting off of ebay for cheap, got some new gold titanium nitrided titanium brake pistons to stuff inside and I had an extra HRC titanium slider pin on hand to use on it. Presto, I now have an HRC front brake caliper set up without the HRC price tag.




Here's the old 1987 CR OEM front brake caliper on a couple of 2000 Japan RC250Ms and I know the Japan factory used the 1987 OEM brake caliper up until at least 2001..

That's right Damien.. the 97-01 aluminum works lower front exhaust mount become a standard run of the mill OEM part on the 2002 CR250. Suddenly not so exotic anymore

This era of HRC titanium pegs used from ~1997 to 2001 are extremely hard to find and the mounts differ with the generation of the frame. Here is a nice set I recently acquired that have very little wear on the cleats. I have only seen 5 complete sets of these over the last 4 years and they all happen to have the same “ F5 UO-W” code on them which indicates they are moved 5mm forward. It seems to have been the most popular option for the riders.




Genuine HRC is always nice, but I have to say that the one-off exact replicas that Corne of VintageHonda made really give up nothing in detail to the originals. These pegs are a work of titanium art.

By the way.. that is a hair from my white golden retriever on the ignition cover and not a crack. just noticed that in the pic

Another item I have been searching for ages for is the old style HRC kill switch/ ignition advance button. I had one HRC ignition advance button, but I also just picked 2 more of the kill switches which are exact replicas of the original. I had been looking for 4 years to find another and it is a part that Honda used to sell at dealerships in Europe long ago. Now it is a unicorn part. The US and MXGP teams used an OEM kill switch and this black anodized aluminum switch with a 2 piece housing for the ignition advance switch. The Japan factory team used this switch with the 2 piece aluminum housing for both the kill button and the ignition advance switch. Now I have a nice paired set for a more perfect Japan build.

The new pegs came with the mounts in the picture, but those mounts are for the 97-99 chassis so I will use the mounts from Corne. Corne had to do the same on his bike. The pegs are unicorns, but the mounts are one-eyed, 3-legged unicorns . I will be selling the 97-99 mounts to any needy souls.

I must of pissed somebody off or maybe someone doesn't like Honda's... I just got another thumbs down on the last post.

Here is a close-up of those big-ass kill and ignition advance switches on a 2000 Japan RC250. Not sure what advantages it has using it as a kill switch too over the oem.. I guess the HRC Japan mechanics just thought it looked cool.

I think we have to be patient for a little longer, Will.

Lots of additional new parts to go on this RC250M build are piling up as I work out my rear wheel situation, HRC front brake caliper, Ti swingarm pivot, Ti rear sprocket bolts, rear brake caliper hanger and NOS OEM coolant hoses. These 21 year old OEM parts are getting almost as rare as the HRC parts.. took me 3 countries on 2 continents to find a complete set of NOS Honda coolant hoses. The factory team had access to the titanium swingarm pivots, but they usually ran the oem steel on the race bikes. I have heard of a few stories about the mechanics trying to bang out a bowed titanium pivot out of a swingarm. I will use the titanium pivot since the bike is really a viewing piece.


I am on my 3rd rim and 3rd set of spokes before I found the solution, but it required Dubya to make me a custom 18" x 2.5" wide rim drilled for the HRC 36 spoke pattern, as well as Buchanan spokes to make me a custom set of polished stainless rear spokes with aluminum nipples. What happened was that I got a proper 1/2" shorter spoke set when I changes from the 19x2.15" HRC rim to the custom 18x2.5" Dubya rim, but I didn't anticipate that wider rime required notably shorter spokes. The spoke right-to-left spacing looked the same, but it is not. I have about 4 months and a few grand into building this rear wheel, but will be nice in the end. Here is the wheel laced up with spokes that are too long. Shorter spokes should arrive next week.

The Ti brake caliper pistons are nice so I picked up one for the rear brake caliper also. What I learned that in 1999-2001, only the US factory team used the 2 gen oem front brake caliper housing. The Japan factory team used, while MXGP used which I think was the ~94+ housing, and the 99-01 Japan factory team used the older 90-91 oem housing which the team filled with titanium pistons and titanium slider pins. Titan Classics makes these beautiful gold nitrided titanium brake caliper pistons. The only reason I can work out on the factory team's use of these different older oem front caliper housings is the different trade-offs between weight and strength. Each Honda team had a different notion on this.


A quality cast aluminum part can can be easily made to look like a CNC machined billet with just a little work. For the rear brake caliper bracket, I first removed all the casting lines with a small150 grit sanding drum and a Dremel tool. I then hand sand with #220 and #320 sand paper, then a 3m pad and WD40, followed by aluminum polish to bring it to a mirror finish. I only did the perimeter of the bracket and parts of the outside that you are only able to see when the bracket is mounted.



The last 2 steps are which brings out the cnc machined look... mirror polish the part, but then dull it back down again using the 3M pad and WD40. You cant go straight to the 3M pad or it wont look like this. How does this look?

Most titanium rear sprocket bolts have a domed or beveled head. The HRC titanium bolts have a completely flat head..