2016 Honda CRF250R Project Build

Triple Air Chamber? Try Quadruple Air Chamber!!

Normally we bike builds are exciting when lots of small changes add up to big results. Well, this bike’s story is pretty much the opposite of that. We made a few big changes that didn’t make for a wholly different bike, but it didn’t end up worse than stock either.

Right after the shootout, we went to work on the Showa SFF-Air TAC fork, which was the only real demerit the bike had since it did take home a silver medal. While the bike turned well, the fork just seemed like it was mad at us – it was unforgiving and harsh. Naturally we went on a crusade to find comfort, only to be thwarted by confusing feedback. The first change was to drop the stock inner psi from 156 to 153, which didn’t do much. Then we consulted the manual which said the lowest the fork should be set to was 141 psi. So, at the lowest operating pressure, the fork gained some comfort at the beginning of the stroke but the fork seemed like it was sitting too low in the stroke which upset the turning of the bike and it blew through to the bottom to quickly which also made it feel harsh. At the same time we went from 7 clicks out on compression to 14 clicks which contributed the low ride height and bottoming problems.

After some head scratching we left the inner chamber psi at 141 psi, lowered the outer pressure to 10 psi, decreased the balance chamber to 153 psi but went back to 7 clicks out on the fork compression. We decided this was the best stock setting we were going to find for the fork. With the lower air pressures, the fork was a little freer to move without diving too much since the compression was set at the stock setting. After all this we sent the fork and shock to Enduro Spec to work their magic.

Honda CRF250R
The stock CRF250R got second place in the 2016 shootout.Photo By Sean Klinger

At first my goal was to get a spring conversion kit but when I talked to Enduro Spec (who are one of the few suspension companies that do SFF TAC conversions) they suggested that I try the new MX-Tech TAC-r system. I was told that for the track, this was their top-of-the line suspension system that gives a ton of adjustability and performance. They also told me that it would essentially be changing the TAC (triple air chamber) fork into a quadruple air chamber system.

Honda CRF250R
We wanted to see what some suspension and minor motor work could do.Photo By Sean Klinger

With a hint of reluctance, I agreed and this is how the TAC-r system was explained to me. According to MX-Tech, the stock fork is too progressive and they wanted to make the action more linear. There is a new high pressure region (250 psi) positioned above the main pressure region (167 psi) with a separation piston that starts to compress as the main pressure region increases, slowing the rate at which the volume change accelerates. I’m not a suspension guru so I’m not entirely sure how this works. There is also still a low pressure region (18 psi) and a balance chamber (152 psi). To fill the high, mid, and low pressure regions, MX-Tech had to change the fork cap to have three valves, but they are smaller than regular Schrader valves and female rather than male, so they also require the use of what MX-Tech calls their Bone Tool that allows you to use a normal fork pump.

Honda CRF250R
We swapped the dually exhaust for a single-sided FMF setup.Photo By Sean Klinger

Before heading out on the track, I set all the pressures which takes longer even than the regular TAC system, which I wasn’t a fan of to begin with. You have to remove the valve caps with an Allen key, then install the Bone Tool and check the pressure. One thing to note is that with the high pressure region, I lost about 40 psi when I removed the tool. That meant that I had to pump it up to 290 psi to account for the pressure loss. I asked Enduro Spec if that was normal and they said the faster you unscrew the tool, the less air you’ll lose.

Honda CRF250R
Enduro Spec Suspension took both the fork and shock to work on. Notice the new adjustment cluster on the shock.Photo By Sean Klinger
Honda CRF250R
MX-Tech sent Enduro Spec their R-TAC system that turns the TAC (triple air chamber) Showa SFF fork into a four chamber system.Photo By Sean Klinger

Did all of this work pay off? The short answer is yes-ish. The stock fork had a harshness that I just couldn’t tune out with different air pressures and clicker settings. Yet the first thing I noticed with the TAC-r fork was that my wrists and shoulders got much less of a shock on hard square edges and slap-down landings. And the fork felt like it moved more in the stroke than the stock set-up, which felt like it was stuck in place. The psi’s recommended by Enduro Spec were definitely on the performance (not comfort) side of the spectrum and I asked which chamber I should lower to get more comfort. After being informed I should drop the mid chamber, I set it 3 psi lower and this took some of the shock out of fast hits. I noticed that the CRF250R turned the same as stock, which was good for me since I like the way Honda’s handle.

Honda CRF250R
The new suspension set up didn't hamper the Honda's great cornering characteristics.Photo By Sean Klinger
Honda CRF250R
The CRF250R feels light and flickable. See above.Photo By Sean Klinger

With all the changes to the fork it is easy to overlook the changes to the shock. Enduro Spec did a revalve, put an MX-Tech compression adjuster (which is easier to adjust than stock), installed their Merge Knuckle that changes the motion ratio, and a stiffer spring. I actually really liked the new shock’s performance which felt a lot more planted and progressive without losing comfort or bottoming. I could OJ something without fear of the tire kissing the fender or swapping side to side.

Honda CRF250R
The FMF single-sided exhaust system slowed down the rev rate of the bike. Some testers liked it, some didn't.Photo By Sean Klinger

Overall, if you are a serious racer and are committed to the air fork system and want even more adjustment than three chambers, this is a better fork than stock. But not leaps and bounds better, which is a bummer since it is more complicated, time consuming, and math-requiring to set up. In the end, I was personally happier riding with the TAC-r system, just not stoked about setting it up.

In the motor department we wanted just a little more power everywhere (who doesn’t?) but especially in the top end since that is where the Honda was a little flat. We went with the FMF single sided Factory 4.1 with a MegaBomb header which did give us more power at the bottom and in the mid, but actually took away some of the top end and over-rev where we wanted more power. On tight, jumpy tracks, it was better than stock, but on most tracks that have any straights or hills, it left us wanting more and shifting more than stock. The pipe also seemed to slow down the revs of the engine, which some people liked and some didn’t. For those that did, the bike seemed to have better traction and be suit a short-shifting, lugging style. For those that didn’t like it, the motor lost some excitement and snap that they preferred.

Honda CRF250R
The Vertex piston really freshened up the motor.Photo By Sean Klinger

The main take away from this project build is that aftermarket parts and mods are not one-size-fits-all. Pipes don’t always work the way you want and sending suspension away doesn’t mean you automatically get a factory-feeling bike. As we send off our ’16 Honda CRF250R into the grey mist, we are looking forward to the empty slate that will be the 2107 model.

Honda CRF250R
We also threw in an EBC clutch pack and springs to keep the power flowing right.Photo By Sean Klinger

Second Opinion: Kris Keefer Vet Pro The Honda CRF250R engine is not the fastest of the class in 2016. With the engine and muffler modifications that our test bike received, I feel like it gained some bottom and midrange, but lost some top end. The increase in snap and throttle response is very noticeable out of corners, but shifting into third gear and trying to let the CRF250R rev out was something that it didn't like as much. When ridden on tighter style tracks the bike shined. When riding longer, faster types of tracks like Glen Helen the Honda felt somewhat flat on top end.

The Enduro Spec/MX Tech suspension had some performance gains, but was difficult to find a good setting that was consistent on different types of tracks. The TAC-r four chamber system fork had great hold up. We also lowered the air pressure, but nothing really helped the comfort on the initial part of the stroke. On light bump (acceleration) the fork felt harsh and deflected on square edge. When I got past initial part of the fork's stroke the action of the R-Tac felt better, but having all of these chambers to play with to me is overkill. What I get in performance and comfort doesn't outweigh all of the work I have to do with setting all of these air chambers. Yes, I have a ton of adjustment at the tips of my fingers, but I just didn't get the results that I wanted on the track from these adjustments.

The shock felt like it could handle square edge better (than the fork) and I enjoyed the comfort and traction I received from the rear end. It also had enough control on g-outs and squatted nicely coming out of corners. I do feel the suspension is somewhat unbalanced for me as I would want the fork to have increased comfort like the rear end did.

Honda CRF250R
Next Components levers and Mika Metals Hybrid Bars spruced up the controls.Photo By Sean Klinger

Parts List:

Enduro Spec Suspension work featuring MX-Tech's TAC-r System
Mika Metals Hybrid Bar, Front and Rear Sprockets, and Chain
EBC Clutch Pack and Springs
Factory Effex Graphics Kit
FMF Factory 4.1 RCT Carbon Cap Muffler and MegaBomb Header
P3 MotoFlex Skid Plate
Vertex Performance Piston Kit
Next Smart Brake and Clutch Levers