Building My Flat Track Ready 250R

I once owned an HRC 250R in the 1980's and ended up trading it for a car in college, but always wanted another race bike. So, I built another one for one purpose in mind......crush the competition. Keep in mind that racing is dangerous and this is simply a collection of race tricks that Honda and other companies did to make the 250R fast on the track. Build your bike the way you see fit, and don't ride beyond your ability.

Let me apologize for slow updates on this page, but the bikes are stored in NY so it's tough to get new pics, but if you have questions, I will try to get back to you.

 

This is what my bike evolved into after 7 years of change. It's an ESR330 powered R that's built to win.

Building an ice racer:

TRACTION (A number one...numero uno...most important thing for ice racing):

Tires, tires, tires! Tires and studs are even more important than anything I could do for my bike. A common misconception is the thinking that if you stud your tires, you'll have a fast bike on the ice. I chose to save my expensive tires for summer riding and opted for a good ice tire. This goes back to the 1980's, but is still the best option today for any ice racer is the CHENG SHIN C-826 18"-9.5"-8" tire. For racing I WILL NOT BUY ANY OTHER TIRE! I've had friends buy the 20" version thinking they'll get more top end speed, but ended up with overbearing traction and poor maneuverability on the track. In the case where they ran a 250cc motor, the bikes couldn't turn 6th gear at all. The 18" tire is the only one I will buy. It was dubbed the "ice racing tire" for a reason. It's a hard compound, tightly knobbed tire that's relatively inexpensive. I bought a couple sets on rims for $130 shipped per pair. The studs were another $50, but I'd have spent that anyway.

For traction, I use the Kold Kutter studs. My rear stud pattern in the is set up like this: \\-----\\ axel \\-----\\. I tried to go against the direction of the turn with the side stud pattern. The front tire is more simple. I have a random stud direction with 2 studs in each of the three center knobs. Some people go crazy on their front tire, but I don't notice any difference. What I have is perfect.

CHASIS (sorry, but I do race the bike so there are some grease and rub marks on it. This is not a show bike):

Building a race bike is not cheap and is not as simple as you think. Most people put a pipe and reeds on their R and they think they have a fast bike. However, I knew if I was going to have a really fast bike for the track, I needed more than a quick motor. I knew that a more important thing was to improve the stability of the bike, so I used what I knew about my 1980's HRC R as a starting point in the build. Most of the parts I used in my bike are still available, but some parts such as the suspension and short track tank are becoming very difficult to find.

To improve stability, I first widened the stance of the bike: I used the Durablue 2+2 on a couple different bikes over the years and am happy with it, but there are a couple manufacturers that offer axels today. The extra 4" makes a huge difference. On my spare ice bike, I have 3+3 wheel spacers, but prefer an extended axel over the spacers any day. It just depends on your budget and what you're looking for. For example, the 3+3 spacers are perfect for my spare bike because I mostly ride it in the woods. I like having the stock axel when I get into tight spots in the woods.

The next thing I focused on was lowering the bike for flat track / ice racing. Most people will make common mistakes that really hurt the handling of the bike. First mistake is DO NOT USE A TIE STRAP TO LOWER YOUR REAR SUSPENSION!! This is not only dangerous, but it actually limits your bikes handling greatly. I bought a Durablue adjustable rear strut to lower the rear (no preference, that's just who I used). I allows you to raise and lower your ride height easily.

The next mistake is that people lower their bike as low as possible without thought about suspension. The more you lower your bike, the less suspension travel you have. The adjustable strut helps a lot, but you still need a workable suspension. I didn't end up lowering my suspension too far from stock. Through trial and error, I ended up with about 8" of travel in the rear (without me sitting on it, 5" with me on it) and 6" in the front.

The front suspension is very easy. Honda built in a cool feature. On the 1985 model 250R, they had 2 stage springs: one short set and one long. I simply removed the small spring and it set my bike at the perfect height. My bike is an 86R, so I searched Ebay and ended up finding a set of two stage springs for $5. I don't know how Honda decided which springs to put in each model because I've come across 86 R's with 2 stage springs too. Whatever. The only way to find out was to remove the top fork bolt and see which set I had.

I tried raising the fork tubes in the tree, but found for my preference, I liked it at the stock shock level with the small spring removed. If I lowered it too far, the tire (with sharp studs on them) would dig into the pipe on turns and if I hit bumps. It didn't help handling enough to warrant replacing dull studs every race.

The last major piece in the chasis was the HRC Short Track Tank Kit. This is an elusive animal . I've watched bidding reach over $500 for a complete kit on Ebay. I got lucky and bought mine a couple years ago for $250 in the box. The kit consists of the following: The tank and radiator shrouds, new radiator brackets, new radiator hoses and a wider angle triple tree.

The last part of the chassis is the miscellaneous stuff that people miss but do improve performance:

Yes, I know, the rear sprocket is very small, but I am running 18" tires and a fully modified 330 motor. The object was to get the tires spinning as fast as possible, so I put in a powerful motor and geared it as tall as I could. Prior to the 330, I was running an FTZ250 motor, which was no slouch, but the gears got a little too tall when topping out in 6th gear. The 330 handles it nicely. For the 250, I probably should have run a 34 or 35 rear, but chose to stick with the 15/33 sprocket combination.

The next thing of interest is the bearing carrier. I use a tapered bearing carrier in my 86 and a double row in my 85. The funny thing is that on my 85 R it didn't improve the longevity of the bearings that much. I got another year or so out of the bearings, but i thought I'd get more. Just a note before others spend the $150+ to buy a new carrier. The tapered carrier is still perfect, but it only sees ice racing so I can't say how durable it is.

If you notice in the top right corner of the left picture, you'll see a gold springed shock. I was lucky enough to call Sudco a few years ago and bought front and rear Mugen suspension for $200 total. I think everyone found out about it and they sold out before I got another set for my 85R, but I didn't worry about it. It's great to have new, fully adjustable suspension, but for flat track racing, it's not as critical as if you were clearing 30' double jumps in MX. This will not ruin a flat track racers day.

Finally, there are a couple of random parts that I like, but didn't need. First is the aftermarket rear disk. My old one was getting thin. The next addition was a good idea. I bought a locking rear axel nut. I used to tighten and tape the stock bolt, but it would eventually come lose from time to time. Now I never have to worry about it again. The last nicety is the TM designworks chain slider. It's thicker and more durable than stock. Since I was running a 15 tooth front sprocket, I thought that a wider slider would be a good idea.

MOTOR:

I don't know what to say here. It is constantly evolving. As it stands now.....a TRX9 ported ESR330 motor with a 19 cc dome, Pro-Lite piston, a PVL digital ignition, K&N air filter, taperbored 40.5mm to 42mm PWK A/S, highly modified KX500 Rad Valve with carbon fiber reeds that's matched to the carb, 1/2" intake spacer plate, 89 long rod with 5mm spacer plate, lightened counterbalancer, PT Hi-Rev pipe and Fat Boy Silencer, Vortex clutch basket, Veshra clutch and an 89 clutch upgrade kit. I don't know if this is the best motor setup, but it's fast. I will continue to work on it as time goes on. It changes.

Proposed changes ???: More torque. I'm going to try to machine a wieght for the flywheel and put a stock counterbalancer in the motor. The bike needs more torque on a smaller track. I have to shift too many times. I need to leverage the torque of the big motor more so I can pull a taller gear through the turns more........any suggestions? Let me know......