MXA RACE TEST: THE REAL TEST OF THE 2020 HUSKY TC250 TWO- STROKE
MXA’S TC250 RACE TEST GOALS
Half of learning to live with and love your bike is understanding how it works—and how to make it better. Here is a quick guide to things that a 2020 Husqvarna TC250 two-stroke owner should know.
TUNING THE TC250 POWERBAND
Husqvarna, in its infinite wisdom, realized that two-stroke owners come in a wide variety of shapes and riding styles, thus the engineers made the TC250 engine tunable via the power valve. The power valve is a movable flap located in the cylinder’s exhaust port, where burnt gases are flushed out of the cylinder. At low rpm, the flap is held closed to make the exhaust port smaller. This helps the engine generate torque at low speeds. As revs build, the flap gradually opens, expanding the size of the exhaust port for greater top-end power. The ability to vary the size of the exhaust port gives your two-stroke engine broad and usable power from bottom to top.
Husqvarna’s powerband can be controlled by the power-valve adjuster. The main power-valve spring’s preload can be altered by turning the “Robertson head” adjuster in the center of the power-valve spring cap. Adjusting the preload on this changes when the power valve opens. Want more hit? Turn the power-valve adjuster counterclockwise for an aggressive hit and maximum top-end power. Want mellower power? Turn the adjuster clockwise for smoother power and a broader range of tractable low-end power. You do not need to loosen the two screws that hold the brass adjuster to the engine (unless the dial is stuck). Oh yeah, ignore where your owner’s manual says not to adjust the power valve—obviously the adjuster was put there to adjust.
SOLVING THE MYSTERY OF THE ROBERTSON WRENCH
Did you notice the reference to a “Robertson head adjuster”? Yeah, we don’t have a Robertson wrench either. In a pinch, you can use a flat-bladed screwdriver that is the same size as the square adjuster. It is important that the flat blade be a perfect fit in the brass dial, because the brass is very soft and can be scarred by a loose-fitting screwdriver. Plus, if you use a screwdriver, the proper size Robertson wrench, which is available from KTM, Husqvarna and Nihilo Concepts, might never fit again. Even better, Kreft Moto sells an adjustable power-valve adjuster called the Power Dial that allows you to make instantaneous adjustments (even on the side of the track) by hand. You get started by turning the power valve adjuster all the way out (counterclockwise) and then turning it in 1-1/2 turns. Most riders should find the sweet spot between 1 and 2 turns out.
SPRINGS OF MANY COLORS
Your Husqvarna comes with green, yellow and red auxiliary power-valve springs. Changing the small auxiliary springs can make your exhaust flap snap open quicker (red spring) or open slower (green spring). The yellow spring is the stock spring. While the larger-diameter main power-valve spring determines when the power-valve flapper begins to open, the smaller color-coded auxiliary springs determine how fast it opens and at what rpm it will be fully open.
As a rule, most MXA test riders prefer to stick with the stock yellow auxiliary spring; however, we love to adjust the power valve by turning the adjuster. The power-valve adjustment is very sensitive. We turn it in 1/8-turn increments, always keeping track of which way we turned it. Be willing to turn it both clockwise and counterclockwise just to ensure that you are getting what you want. The full range of the Husqvarna power-valve adjuster is six turns. When you find the best spot on the dial, mark it with a paint pen so you can find it easily.
HOW TO SWAP IGNITION MAPS
For some unknown reason, the 2020 Husqvarna TC250s comes from the factory with a click-style switch that allows TC250 owners to access two different ignition maps, while KTM owners don’t get the map switch (although they can access the second ignition map by unplugging one wire). Located under the fuel tank is a wire that is fitted with a white male/female plastic connector. Since it is the only white connector under the frame, it is easily identified. If you unplug the KTM’s white wire, you get the “Mellow Map.” If you plug it in, you get the “Aggressive Map.” But that is neither here nor there, because we aren’t talking about the 2020 KTM 250SX two-stroke here.
The Husqvarna has a two-position map switch on the right side of the handlebars. It has two settings; one hash mark is the “Aggressive Map” and two hash marks is the “Mellow Map.” If you activate the Mellow Map, the power delivery will be smoothed out for ease of use. For most motocross racers, the Mellow Map would only be used on rock-hard or slippery surfaces, because it takes the bark out of the engine; however, because of the massive midrange hit of the TC250, running the Mellow Map is more common than you would think. The Aggressive Map is really the stock map. Every MXA test rider prefers the Aggressive Map, and that is the way the bike is shipped from the factory.
THE NOMENCLATURE OF DIAPHRAGM CLUTCHES
Not every Husqvarna has the same clutch installed at the factory, although they are all Belleville washer-sprung diaphragm clutches. The FC350, FC250 and TC125/150 have Diaphragm Steel (DS) clutches, while the FC450 four-stroke and TC250 two-stroke have Damped Diaphragm Steel (DDS) clutches. What’s the difference between DDS and DS? The DDS clutch has six rubber dampers that sit inside the inner clutch hub to lessen the jolt of sudden acceleration and rapid shifts. The DS clutch doesn’t have the rubber dampers because Husqvarna’s engineers don’t feel that the lower power output of the smaller engine needs the added safety of the cush-hub dampers; however, the rubber dampers do wear out over time and create an annoying jerky feeling. It is important to replace the rubber dampers before the 40-hour mark.
THE PLASTIC AIRBOX KILLS THROTTLE RESPONSE
Although the FC250, FC350 and FC450 got the optional vented airbox cover, the Husky two-strokes did not. This is too bad. Even though Husqvarna’s definition of venting is a far cry from MXA’s understanding of venting, at least some air gets in through the four-stroke’s vents. Why is this so important? The TC250 airbox is sealed so tight that the engine is suffocated. Don’t believe us? Take the airbox cover off of your Husky TC250 and ride it for a lap. You’ll notice the difference. The choked-down airbox makes the power build slower and mellower than on the identical KTM engine (even though KTM didn’t vent its two-stroke airbox cover either).
The solution is to drill holes in the airbox cover with a Craftsman drill (make sure that the holes are behind the air filter, not directly next to it or above it). But, before you go drilling holes in the airbox to get free pony power and added low-to-mid grunt, make sure you want more power. Some riders prefer the mellower power transition from low-to-mid that comes courtesy of the closed-off airbox. We know many riders who like the 2020 FC450 power the way it is. If after you ride with the airbox cover off you decide that you like the stock power better, you can put the drill down.
PLAYING BOTH SIDES AGAINST THE MIDDLE
The Husqvarna motocross bikes (TC and FC) get Brembo master cylinder brakes, while Husqvarna off-road models (FX and TX) get Magura components. Both of these systems produce excellent stopping power, and there is no need to fear the Magura parts, but in the case of the TC250, it is all Brembo.
PLAYING RUSSIAN ROULETTE WITH THE PRE-MIX RATIO
In 2017 when the Mikuni carb was introduced, Husqvarna’s engineers insisted that we run our TC250 premix at a 60:1 gas-to-oil ratio. The MXA wrecking crew was reluctant to change from our preferred 40:1 Maxima mixture, but we set up a special fuel test at the track and ran both ratios with the stock brass in place. Surprise! The 60:1 ratio ran crisper and cleaner than the 40:1. We still didn’t want to switch to 60:1 because of our lifelong trust in 40:1, so we fiddled with the brass to get 40:1 to work. Paradoxically, Husky switched the TC125’s recommended 60:1 ratio back to 40:1, while still demanding 60:1 for the TC250. If you don’t want to switch from 32:1, 40:1 or 80:1, you might have to make a few changes to the air screw, needle position or brass.
TRY GEARING IT UP TO BROADEN THE POWER
Gear it up. Last year, Husqvarna’s stock gearing was 14/50. In 2019, we recommended that racers change the gearing on the 2019 TC250 from 14/50 to a taller 14/49. Surprise, for 2020, Husqvarna switched the stock gearing combo to 14/49. The taller ratios smooth out the power, lengthen the gap between gears and make the TC250 pull further in the rpm range, requiring the rider to shift less.
THE TWO-STROKE HUSKYS DON’T GET THE “VET VALVING” OF THE HUSKY FOUR-STROKES
Off the showroom floor, the WP XACT air forks are going to feel a lot stiffer and harsher than they will after a couple hours of break-in on the seals, bushings and shims. They start to come into their own after two hours of riding time. Lots of riders never give their stock WP forks a chance to settle in. They send them out for a re-valve before they know their capabilities.
Unlike the Husqvarna four-stroke models, the two-strokes did not get the plush valving of the FC250, FC350 and FC450. This isn’t a deal breaker, but the key to getting the WP Xact air fork to work well is to ignore the recommended air pressure settings. Most riders find the Husqvarna air pressure settings to be too firm. After all, air forks allow an infinite number of spring rates, and one psi setting does not fit everyone. Husqvarna’s recommended psi setting is 146 psi. Most riders, even MXA’s Pro test riders, run the stock air pressure; however, light riders and slower riders often go as low as 135 psi. This is how air forks are supposed to work. The advantage of an air fork is that the pressure can be changed to fit different track conditions, rider weights and skill levels.
HOW TO FIND YOUR PERFECT AIR PRESSURE
Put a zip-tie around the right fork leg and then set the air pressure to 146 psi. Go out and ride a couple laps at full speed. Then, look at the position of the zip-tie on the fork leg. If it is nowhere near bottoming, decrease the air pressure by 2 psi, push the zip-tie back up, and go back out on the track. Keep doing this until you get the zip-tie within 1-1/2 inches from bottoming. That air pressure will be your personal air pressure. Why should you leave 1-1/2 inches of travel in the fork? Because at some point during a race, you are going to jump too far, jump too short or suddenly develop talent that you didn’t know you had. The 1-1/2 inches is play room.
MXA’S 2020 HUSQVARNA TC250 FORK SETTINGS
Once you have found your personal air pressure, do all of your tuning with the compression clicker. As a rule of thumb, most MXA test riders turn the compression out. How far out? The standard settings are 12 out on compression. We like to start about 20 clicks out to get a baseline feel for minimal compression damping, then turn the compression clicker inward until it lands on the sweet spot. For hardcore racing, we recommend this fork setup for the 2020 Husqvarna TC250.
Air pressure: 146 psi (for Intermediate and up), 135 psi (for slower or lighter riders)
Compression: 12 clicks out (for Intermediate and up), 20 clicks out (for slower or lighter riders)
Rebound: 12 clicks out
Fork height: 2nd line
Notes: The stock settings are stiff. Vet test riders lowered the stock air pressure and went out significantly on the compression clicker.
MXA’S 2020 HUSQVARNA TC250 SHOCK SETTINGS
The Husqvarna shock settings are workable for 2020 (and not much different from the 2019 shock). All you need to do is set the sag at 105mm to get the bike balanced fore and aft. Shorter test riders should lower the sag to 107mm and slide the forks up in the clamps to the third line to keep the same balance but with a lower feel. For hardcore racing, we recommend this shock setup for the 2020 Husqvarna TC250 (stock specs are in parentheses):
Spring rate: 42 N/m
Hi-compression: 1-1/2 turns out
Lo-compression: 16 clicks out (15 out)
Rebound: 14 clicks out (15 out)
Race sag: 105mm
Notes: If you weigh over 185 pounds, you might need to up the spring rate to 45 N/mm. Take it easy on the preload ring. It wears out quickly. We use a long flat-bladed screwdriver, hook the tip of the blade in the preload ring slots, and use the frame as a fulcrum to pry the preload ring while turning the spring with our other hand.
FINDING YOUR HAPPY MIKUNI PLACE
No one was happy when Husqvarna and KTM switched from the Keihin PWK carb to the 38mm Mikuni TMX carb in 2017—and with good reason. We had jetting issues in 2017. The carb switch created a jetting nightmare. In 2018, the stock jetting was improved. We only had to change the pilot from a 45 to a leaner 42.5 and go out a turn and a quarter on the air screw. For 2019–2020, the TC250 could run its box-stock jetting without any major hiccups. Obviously, there will be some air screw, needle or pilot adjustments needed for your local elevation, humidity and temperature. Here’s what we ran in our Mikuni TMX carb:
Main jet: 450
Air screw: 1-1/2 turns out
Notes: If the bike feels boggy off idle or wants to go “wah” before the power kicks in, try tuning the air screw. Have a friend hold the throttle setting at 1800 rpm while you turn the air screw in and out. When the engine’s idle reaches its highest peak rpm, that is where it should be.
HOW DOES IT RUN COMPARED TO THE YZ250 OR KTM 250SX?
We like that the TC250’s powerplant is more manageable than its crisper KTM 250SX stablemate. If you expect a 250cc two-stroke to explode in the middle and rev until the cows come home, that isn’t the TC250’s modus operandi. This is a kinder and gentler two-stroke—sort of. The power is at its best from low to mid. After that, it signs off very quickly. In back-to-back tests against the 2020 KTM 250SX, the two powerbands felt very different. The KTM’s output was livelier, hit harder and rushed through its spread, while the Husky TC250 was more controlled and metered. Neither engine pulled very hard past 8200 rpm.
The Husqvarna TC250 slots in between the top-end-focused YZ250 powerband and the explosive low-to-mid power of the 250SX. That leaves the 2020 Husky TC250 as an in-between powerband. It’s not as violent off the bottom as the KTM 250SX and not as high revving as the Yamaha YZ250. It is a lot like Mama Bear’s porridge.
If we had our druthers, we think that the perfect powerband would be the KTM 250SX’s low-to-mid power mated to the Yamaha YZ250’s top-end. Don’t take our desire for more power on top as a negation of what the 2020 Husqvarna TC250 is capable of. This is still a fast 250cc two-stroke, and the path that Husky went down (somewhere between the low road of the KTM and the high road of the Yamaha) is just about perfect for riders who are scared by the orange bike’s bark and unimpressed by the muted roll-on of the low-to-mid blue bike.
IT DOESN’T DO ONE THING WELL; IT DOES EVERYTHING WELL
When it comes to handling, the Husky frame is a standout. All a racer has to do is get the chassis balanced with the proper race sag and fork height, and the frame goes on autopilot. It is sweet handling. You don’t have to muscle the handlebars to get it to turn—just look that way and it will follow. No oversteer. No understeer. No wig, wag or wallow. No fear.
(1) Airbox. Husqvarna, under KTM’s reign, has always suffocated the Husky motocross bikes with restrictive plastic airbox/subframe combos. Engines are actually air pumps. They pump air in and they pump air out with the byproduct being horsepower. The Husqvarna doesn’t let as much air in as it is capable of letting out. That is easy to fix.
(2) Spokes. The spokes come loose. Check the one next to the rim lock if you are in a hurry; if it’s tight, you’re all right.
(3) Bodywork. The two-piece side number plates make little or no sense—especially from an aesthetics standpoint. Come on Husky, enough with stupid design aesthetics. Be practical and mold them in one piece.
(4) Muffler. The Husky TC250 is on the long side. Run an FMF or Pro Circuit muffler, they add power and save weight.
(5) Frame color. There are 100 shades of blue—this tone is not on our short list of blues we would choose.
(6) Triple-clamp protector. We love the bottom triple-clamp protector that is integrated into the front number plate, but we have to wonder why it only protects half of the triple clamp from roost.
(7) Compression clicker. Last year’s three-prong compression clicker has been changed to a two-prong clicker. Guess what? Two is not better than three. We need longer prongs, not fewer of them.
(8) Graphics. How much do we have to pay to get the other half of the radiator shroud graphics?
(1) Brakes. They are awesome, incredible and delightful.
(2) Hydraulic clutch. The Husqvarna’s Belleville washer-activated hydraulic clutch is self-adjusting. We have always been leery of the seal in the Magura slave cylinder, but Magura fixed it this year and it hasn’t failed in 2020— we only ever suffered seal problems on the FC450.
(3) Air filter. KTM and Husqvarna have the greatest air-filter cage design in the sport. It is plug and play with little to no chance of messing it up.
(4) Hour meter. The 2020 Husky TC250 has an hour meter mounted on the top triple clamp.
(5) Radiator cap. Husqvarnas and KTMs comes with 1.8 raditor caps, most Japanese bikes come with a weak 1.1 cap.
(5) Power-valve adjuster. We love that we can adjust the power valve but hate the weird square tool needed to do it. Buy a Kreft Power Dial and live happily ever after.
(7) Handlebars. Every test rider liked the Pro Taper handlebars.
(8) Lock-on grips. We like the ease of use of Husqvarna’s ODI lock-on grips. They are firmer than glue-on grips, but we like the ability to fix a torn grip without having to wait for the glue to dry.
(9) Counterbalancer. The Husqvarna TC250 engine has a counterbalancer that cancels out engine vibration by rotating on the off beat. Very sweet.
THE FINAL BREAKDOWN
In most four-stroke engine sizes, you have six motocross brand choices, but when you go looking for readily available 250cc two-stroke motocross bikes, you only have three choices. We aren’t discounting TM, Gas Gas, Sherco or Beta, but we consider them to be boutique brands that are less of a choice and more of an adventure. Thankfully, the differences between the Yamaha YZ250, KTM 250SX and Husqvarna TC250 cover the full spectrum of what’s possible with a 250cc motocross bike. The 2020 KTM 250SX is hard hitting and aggressive (maybe even a little angry when you are on the pipe). The 2020 Yamaha has a slow-developing powerband that gives up 4 horsepower out of a corner but takes it all back at the end of the next straight. And then you have the 2020 Husqvarna TC250. Without being condescending to the TC250, it is the safe choice. It doesn’t kick like an Army mule or make you wait for the power to build; it is Mama Bear’s 250 two-stroke.