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

Is that a BONZ bar clamp set? He makes some nice stuff. I should start listing for sale all the parts I didn't use or took back off when I found the works parts... in case you are interested.

Some more HRC goodies came in.. and these last few parts were rather hard to find so I am quite happy to finally get my hands on them.

Here is an HRC ignition advance button made from a 2-piece aluminum housing. The wiring ran down the front of the frame cradle and connected to a sensor mount in the HRC transmission cases just in front of the gear shift lever input shaft, as well as wired to the ignition. The rider would push the button on the starting gate and it would advance the ignition a few degrees. This increase cylinder pressure and torque for a stronger launched off the gate. When the rider shifted into third gear, the senor would tell the ignition to retard the timing back to its base setting.



The US and MXGP factory teams used this button along with an OEM Honda kill switch, however, the Japan factory team adapted a second HRC ignition advance button as their kill button. I only had one HRC button so I reused the replica button I had made last year as my kill switch. This looks close to the original Japan factory set up until I find a 2nd HRC button.

Here is an HRC rear brake pedal I will be installing today. It has the height adjusting bolt and the lever is wider near the pivot then the OEM pedal. Unlike the HRC pedal on my CRF450 which is billet and has a titanium tip, the HRC pedals in this period were cast with steel tips. This HRC pedal requires a special short return spring that is much shorter than the OEM spring so I will have to fabricate that.




HRC also made up these nice little mounting tabs for the rear brake snake wire. It mounts on the bottom engine mount bolt.

Got the pedal mounted up but it required fabricating a return spring that is 1/3 shorter than the OEM spring which is already very short. Final modified spring looks OEM.




The HRC pedal is beefier than the OEM pedal near the pivot and hugs the frame/ engine cover closer than the OEM pedal. Of course there is the HRC standard height level adjuster bolt on the back.


I also got an NOS HRC brake snake kit for the pedal.. looks like they just used a new clutch cable wire cut to size for the snake.


I thought this disclaimer that came with an NOS HRC part rather humorous considering that only the factory mechanics and top riders in the world hired to win championships could ever get close to these parts in their day.

There are a few places where the Japan factory machine used plain old OEM parts such as the chopped up countershaft sprocket cover, front brake line guide and the front axle spacer cover. In all 3 areas, I have chosen to replace these OEM parts with later year HRC parts even if not 100% period correct. Gives me something more interesting to look at and it is HRC. Here is a NOS HRC front axle spacer. The cover/ spacer is one piece and the cover is machined very thin unlike aftermarket axle spacers which are much thicker aluminum or the OEM part which is 2 pieces.



The titanium pegs are almost finished and it has been a long road for this ambitious project. Here are the titanium bodies freshly machined for 5 sets of pegs which will be exact replicas of the original HRC pegs. The next step is to weld the titanium cleats picture above around these foot peg bodies. These big hunks of freshly machined titanium should be impressive thanks to Corne van Ballegooy.



While the foot pegs themselves are the same for 1st to early 3d generation aluminum framed RC's, each of the 3 generations has a different design mount. Corne had 2 sets of the 1st gen mounts machined, 2 sets of the 2nd gen mounts and 1 set of 3rd gen mounts machined. It is very expensive to machine all this titanium as it wears out the bits quickly. Unlike the HRC engine covers or clutch perches which are hard enough to find even though they fit many models over the years, a set of these early titanium pegs is even harder to find because the mounts only fit one model.

The final pegs should look just like the original HRC pegs pictured below except they wont have 20 years of tarnish and wear on them.. they will look like they just came out of the Honda R&D machine shop!

a few more pics of the freshly machined part..

The Honda teams of the period often extended the shroud graphics across the aluminum frame so I got some 3M gloss black vinyl and did the same as the Japan factory team. From 2002 on, Honda emphasized minimal plastic and graphics to show off the frames more



NOS HRC front wheel spacer. It is not period correct as the factory team used the OEM plastic cover on the spacers and this HRC spacers was used from the mid-2000s to the present day. More to look at than the OEM plastic cover so I used it.



New engine guard..


The HRC replica titanium foot pegs are finished with machining and welding and should have them soon. They look just like the original item if not better.

I have quite a few very nice parts left over from this build.. I first restored the bike with NOS and a few trick parts and then decided to rebuild again as an RC250M with genuine HRC parts so I ended up with a lot of extra parts. I posted this parts in the Bazaar section.. https://www.vitalmx.com/forums/For-Sale-Bazaar,26/2000-2001-Honda-CR250…

The bike is a 2001, but it is a replica of the 1999 and 2000 season Japan RC250M's. I combined what I liked best of the subtle differences between the 2 seasons. Japan ran the FIM designated green number plates for their Pro class up to 1999 then switched to red number plate backgrounds in 2000. The 2000 RC250M also had red triple clamps while they were silver on 1999 and placement of a few of the decals were slightly different between the 2 seasons. At the end of the 2000 season, they also changed the shroud graphics only on Atsuta's bike where was part of the development of the new 2002 graphics. In 2001, they ran both the second and third generation aluminum frame models side by side on the race team as they usually do to evaluate the newer model against the old one. Only one or two of the factory team members get the newer model. The primary job of a big 4 factory rider in Japan is to evaluate the new machinery in real race conditions for the race teams in the US and Europe where the championships are more important, as well as for production. Of course winning a championship in Japan is great too, but for most of Japan's factory riders, it is testing and development.

1999 RC250M;






2000 RC250M







New shroud graphics at end of 2000 season

The HRC titanium replica foot pegs and mounts are finally done.. it was a long road getting these machined, but they came out great.. 100% exact replicas of the original HRC peg shown in the middle. Period correct HRC replica titanium mount bolts and pins were included.




Corne from VintageHonda made these beauties and I am really happy with the way they turned out. As the machining of the billet titanium was quite expensive, Corne is thinking of making a few more sets in stainless steel for those who need pegs for their HRC replica projects, but are on more of a budget. HRC parts are hard to find to begin with and this generation HRC pegs are extremely rare as the mounts only fit a few years bikes, so to have a freshly machined set of exact replicas is a blessing to be able to finish off any RC replica bike project. Here are a few pics of the pegs on the bike...





The bike has come a long way this year after unexpectedly finding quite a few more nice period correct HRC parts..

Thanks Bandit... while there are quite a few 4-stroke HRC parts floating around these days.. the last of the 2 stroke HRC parts are getting scarcer. It is a long journey to find what is left out there and what you cant find, you have to make. I did notice recently a lot more people starting to do very high quality replica parts in limited runs for 80's and 90's RC builds for a lot less money than the real item. It is great that people are bring these old cool parts back to life.

A few more shots of the bike as it sits today. While the bike could hit the track tomorrow, it is now destined to be an expensive dust collector although I do get a lot of enjoyment checking it out whenever I step into the garage.

Haven't really thought about it as I have no plans to sell, but I would be losing a lot of money at anything less than $15k as I probably have closer to $20k in just parts and not considering lots of hours. The NOS Kevlar silencer, the titanium foot pegs and the forks are $7k right there for just 3 parts. I would recoup more money by selling the works parts off the bike and selling the bike separately as just a resto. I have seen a few 100% original and complete RC250Ms sell in the $25k to $40k range among collectors.. the parts off these bikes are worth even more, but a true enthusiast/ collector would never part out an original championship factory bike, so it is actually quite a deal when you consider what is inside the bike. An HRC crankshaft for these old bikes is big, big money and absolute works of art! My bike is a lot of works parts bolted on to a very clean production CR250.

The important thing is that people are putting a lot of time and money into keeping these old works parts and bikes of a bygone era alive for future generations to look at.

mike

Here are some technical details on the 1997-2001 RC250Ms that I picked up during this build that may be of interest to other geeks like me that like to read about the technical details of these factory bikes and their parts;

• While a 2 stroke is quite a simple engine, HRC developed ways to further fine tune the power band of their works engines beyond just different exhaust pipes, carburetion, ignition and port timing. A picture below shows how they facilitated adjustment of the effect of the exhaust valve. While the production unit just uses a simple bolt with a machined tip to hold the exhaust valve assembly in place, HRC developed this 2-piece retainer design which was a slotted bolt and a flange nut (see pic below). The tuner could tighten the bolt ever so slightly against the rotating shaft of the exhaust valve to delay opening momentarily.
• Also in the picture below, you can see an exhaust valve cover spacer. HRC has several spacer thicknesses. The thicker the spacer installed, the softer the hit when the exhaust valve opened.


• The most expensive piece for HRC to manufacturer was the crankshaft and polished tungsten steel connecting rod. These cranks were not only balanced extremely well for almost no vibration, but HRC also drilled extra holes in the crank which could be fitted with either plastic or a heavy metal to change the rotating inertia of the cranks and thus change the powerband and engine braking characteristics.

• The front wheel hub was drop-forged ergal aluminum. Only the center of the hub was machined and the sides of the hub were left as a raw drop forging. This provided the greatest strength where the ends of the spokes sat on the hubs. While the center of the hub was left as a raw machined aluminum finish, the sides of the hub (around the wheel bearing) were painted silver. These hubs rode on a floating axle which has 2 pieces compared to the 1 piece OEM axle.

• Unlike the aluminum front hub, the rear hub was a cast magnesium piece that was completely painted silver. It used a special brake rotor that required six bolts instead of the 4 bolts used for the OEM wheel. The diameter of the pad for the rear sprocket to mount was also different from OEM, and the Renthal sprockets they used had to have their bores machined wider to fit the HRC hub. Also unlike the OEM rear wheel spacers which were both the same width to make it idiot proof, the HRC rear wheel used two different wheel spacers that were different thicknesses for each side.

• The tip of the Kevlar silencer where it slipped into the exhaust pipe was titanium as the silence used an aluminum tube that would bend/ wear too easily. The titanium tip was a good compromise between steel and aluminum.


• The air filter bolt was a special trick titanium piece. There were 2 different HRC designs for 97-99 and 00-01. Here are pics of both designs;



• For many of the normally mundane bolts that screw everything together, HRC often designed unique titanium pieces for things like the triple clamp bolts, seat bolts, subframe bolts, etc. Here is a picture of the special grommet HRC made to help keep the rider’s boot from getting caught on the rear exhaust mount. You can also see the unique titanium triple clamp bolt design in the pic below.




• The HRC triple clamps use a titanium steering tube that is narrower in diameter than the OEM piece. The bearings are also different so OEM parts won’t fit here.

• HRC used different DOW coatings to protect their magnesium ignition and clutch covers from the elements. DOW used to be a number one producer of magnesium and developed these coating in-house. I believe HRC used DOW 17, 18 and 19 coatings which differ slightly. When you look at the HRC covers from different years or different pics in the same years, sometimes you will see the covers could be a dark green, dark gray, medium gray or even light gray. I believe DOW 17 is the dark greenish-gray color. These coverings help keep the magnesium from “rotting”, but the riders boots would quickly wear the coatings off.

• It is sometimes hard to tell an HRC pipe from an OEM pipe at first glance until you look very closely and realize it is totally different. The welding is different and the HRC pipe uses a thinner metal. Most telling is the way the HRC pipes exit the cylinder and bend around the front cradle. The OEM pipe simple turns 90 degrees left out of the cylinder and then cuts straight across the front of the frame cradle. All the HRC pipes I have seen for this era RC250M have a more intricate bend in front of the frame cradle. You will notice that when it turns left out of the cylinder, it turns more than 90 degrees so that it comes closer to the left side frame rail of the cradle than the OEM pipe. It then swings out toward the front wheel with a gradual bend that is not perpendicular to the front of the frame like the OEM pipe does. Although HRC had several different designs for this particular bike, they all share this characteristic in terms of how they exit the cylinder and sweep across the front of the frame cradle, and distinguishes them from the OEM design. The US team seemed to prefer a different design pipe than Japan and Europe. The US designed pipe required the team to run a 97-99 style kickstart lever on their 00-01 RC250M’s to clear the US style pipe. Japan and Europe ran 00-01 OEM kickstart levers with titanium knuckles.

• The HRC shift lever is steel and is very heavy compared to the aluminum OEM shift lever. The irony here is that HRC did not paint the levers black as most people might think. The black coating is actually a process called “passivation” which is lighter than paint but quickly wears off.


• The HRC front brake rotor cover and brake caliper mount only fit the HRC specific lugs on the works forks. They will not fit OEM forks. The mounts are very different.

• The front and rear brake caliper pistons are titanium.

• Because of the technology of titanium suspension springs was still somewhat in its infancy back then, while HRC had titanium rear shock springs available, they instead chose to run a special alloy steel spring on their race bikes that had less coils and was lighter than the OEM shock spring as they didn't want to risk losing a race win due to spring breakage..

• While the OEM ignition cover used a rubber seal, HRC used a paper gasket for a better seal. You could tighten the ignition cover bolts more securely with paper without the gasket squeezing out like with the OEM part.

• HRC developed many new parts designs that were quickly adopted by the aftermarket parts companies. One such example is the adjustable clutch lever which allows rider adjustment while racing. HRC’s first attempt was the 3-step clutch used from 1996 to 2000 (see below). HRC replaced this with a new design in 2001 which is the design we still know today. Here are pictures of both HRC designs,



If you read through all the above details, you can probably declare yourself an HRC parts geek!

You may be tired of pics of this bike, but I had my son who does freelance photography, take some better pics of the finished Japan RC250M build. All the previous pics were iPhone pics. The build gives you a good idea of what Japan Honda's RC250 build looked like in the 1999 and 2000 seasons. It is built with a lot of the original HRC pieces from that period, many of them NOS or near NOS condition. I did make a few minor stylistic changes that I think makes the bike more of a knockout to look at in the man-cave. It is a piece of history recreated in the present. Enjoy.

Here are some close up pics of the NOS Martin Honda MXGP hubs. They are CNC'd from 7075 aluminum and the machining is absolutely beautiful. These where made at a time when CNC aluminum hubs were just coming on to the MX scene at the works level. They are designed with a very fat diameter in the center section but are completely hollow so they remain very light. These huge shiny hubs are a big standout on the bike.

Here is the front hub. The HRC front aluminum hub center section was 78mm in diameter while the Martin Honda hub is 72mm.. both huge compare to anything before or since on an MX bike. The HRC hub was a 7075 drop forging with only the center machined and the sides unmachined and painted silver to provide the strongest support for the spokes. Very strong, and perhaps over done, but not quite as pretty as the polished Martin Honda hub.





Here is the Martin Honda MXGP rear hub. It uses a 4 bolt rear disc rotor with smaller bolts than oem while the HRC rear hub required a special 6 bolt rear brake disc. The Martin rear hub is 7075 aluminum like the front while the HRC rear hub was a magnesium casting painted silver and used special grommets/ seats on the heads of the rear spokes to keep them from pulling through the hub. OEM nor Renthal sprockets fit the HRC hub and the center hole had to be machined larger to fit. Conventional sprockets fit fine on the Martin Honda hub so the team didn't have to keep a supply of special machined rear sprockets on hand.