MXA RACE TEST:
INSIDE THE 2009 HUSQVARNA TC510
There is a theory (that is more old wives’ tale than fact) that the modern 450cc motocross bike makes more horsepower than anyone but AMA Pro-level racers can fully utilize. This isn’t true, for several very obvious reasons: (1) If you have ever turned the throttle wide open on your 450, then you know that you wanted more power. (2) No one says that you have to turn the throttle wide open; the power can be metered out. (3) When you ride a slow 450, you know it (and you wish it was more powerful).
In truth, what most 450cc motocross bikes need is more power! You may say that we are crazy, but going bigger than 450cc does not have the effect you think it does. While it is true that going up from 450 to 470, 488 or 510 does translate into increased horsepower, the real benefits come in the form of torque. Horsepower, for all its acclaim, isn’t as important as torque.
The MXA wrecking crew has an affinity for over-450cc production bikes. The KTM 505 (really a 477.52cc engine) has a much more usable powerband than the KTM 450. Bolting an Athena 488 kit to a CRF450 makes it much more tractable on a race track. Which led the MXA wrecking crew to the 2009 Husqvarna TC510.
Q: WHAT ARE THE LATEST UPDATES TO THE 2009 HUSQVARNA TC510?
A: For 2009, the TC510 has received the same updates as the 2009 Husqvarna TC450.
Frame. The TC510 received a new steel frame designed to improve the overall feel of the chassis. The frame is one kilogram (2.2 pounds) lighter than last year’s frame and is more rigid. There are new guards to protect the engine on both sides of the bike.
Exhaust. The TC510’s titanium exhaust system has been tuned for more progressive engine response. It is an AMA/FIM-legal, 94-dB exhaust system.
Brakes. All the 2009 Husqvarna motocrossers are equipped with new, scalloped-style brake rotors, which are designed to improve performance under extreme
Suspension. The Marzocchi Shiver forks and Sachs shock settings have refined valving.
Gearbox. Shifting action has been improved by adding a new steel gear change linkage, steel fork driveshaft and new gear selector.
Lubrication. The oil filter and timing chain tensioner have been revised to help improve the efficiency and reliability of the Husky’s engine. The TC510 now has an oil circuit pressure relief valve, which is designed to improve starting when the bike is cold.
Graphics. The 2009 bike has new colors and graphics.
Q: WHAT’S THE DIFFERENCE BETWEEN THE TC510 AND THE TC450?
A: The TC510 isn’t bored, it’s stroked. The TC450 and TC510 share the same 97mm piston, but where the TC450 has a stroke of 60.76mm (for a displacement of 449cc), the TC510’s stroke is 7mm longer at 67.8mm. Although it’s called the TC510, its displacement is really 501cc. The only other differences between the 2009 TC450 and the TC510 are taller gearing and one pound more weight on the 510.
Q: HOW DO YOU START THE 2009 HUSQVARNA TC510?
A: The Husky has a manual and an automatic compression release. The manual is activated by a trigger above the clutch lever and can easily be mistaken for a hot-start lever. The actual hot start is down in the old-school position on the carburetor. MXA’s seasoned test riders, those who were around back in the days when men were men and four-strokes wouldn’t start, had no troubles starting the TC510. They simply brought it up on top-dead-center, pulled the manual compression release, nudged the kickstart lever slightly over TDC and gave it a full and amazingly slow kick. Voila! It fired every time.
The younger test riders pumped away on the kickstarter like it was a Honda Kick ‘N’ Go. More often than not they used the manual compression release as a hot start. This Kick ‘N’ No Go scenario was all wrong. You can’t cut corners on the starting procedure, misuse the mechanical aids, or kick it halfway through its stroke.
Q: HOW DOES THE TC510 ENGINE RUN?
A: The short answer is that it runs like a much bigger TC450. The long answer is that it has a broad, slow-revving and potent powerband. It is very torquey in the low-to-mid range, but has the wherewithal to rev deep into the upper ranges.
A Husqvarna TC510 rider won’t be rewarded for letting the engine shriek. This is a torque curve engine to the max, but thanks to the rev, a rider can still wait to shift if he is so inclined.
In TC450 testing, some MXA testers complained about the slow-revving powerband, especially in racing situations. When raw horsepower was needed, it could be a chore to get the TC450 up to speed quickly. Conversely, the TC510 has the same, tractor-like powerband, but the massively increased torque curve negates the desire to get through the low rpm range quickly.
Q: IS THE TC510 A 450 KILLER?
A: The TC510 doesn’t exactly gun down 450s, but it can definitely eat up the gap between the 450s in front of it and increase the gap on the ones behind. It’s not sheer power that helps the TC510 gain ground, it’s the torque that helps it hook up early and gain speed while 450 riders are still searching for traction.
Q: HOW IS THE TC510 GEARED?
A: The primary drive of the TC450 and TC510 is the same, however, Husqvarna feels that with the extra torque of the TC510, a three-tooth smaller rear sprocket (14/47) is appropriate. Curiously, our test bike came with a 50-tooth rear sprocket. The 47 may come on the Husqvarna enduro model.
We prefered to run a 51-tooth sprocket on the rear (14/51). This tightened the gear ratios and made the bike respond quicker.
Q: HOW DOES THE TC510 SHIFT?
A: There are paradoxical forces at work on the transmission of a large-displacement motocross bike. First, the added power and torque put a greater load on the gears, a load that can often make shifting very difficult. Second, because the big engine doesn’t need to be revved, the gear lash is reduced because shifts can take place when there is less force on every gear (compared to trying to shift a bike at 11,000 rpm).
On the 2009 Husqvarna TC510, the second scenario won out. To our surprise, the TC510 and TC450 were quite happy to grab the next gear. Obviously, Husqvarna put some thought into this (since they changed the complete shift mechanism system for 2009).
Q: HOW GOOD ARE THE MARZOCCHI FORKS?
A: They are too soft for motocross. Way too soft. Luckily we had already tested the 2009 Husqvarna TC450 and knew how to fix them (we were also grateful that Zip-Ty Racing had done all the hard work before we got to Marzocchi). We sent our forks to Marzocchi to swap the 4.8 kg/mm springs for 5.0s. Marzocchi raised the oil height from 460cc to 480cc and adjusted the preload from the sixth position to the seventh position. What a difference! The Marzocchis weren’t just firmer (which was a big plus by itself), but the action was considerably better. This is the third year since Marzocchi switched from its old 45mm forks to the 50mm Shivers. They have come a long way since 2006, but they need to apply what they’ve learned in the tuning department to the production line. A little bird told us that the problem may be with how the forks are assembled in production. After our forks were reassembled, they weren’t just stiffer, they worked through the midstroke with a much more fluid and consistent feel.
Q: HOW GOOD IS THE SACHS SHOCK?
A: The linkage-equipped Sachs shock on the TC510 is a solid performer. On our best setup, we left the Sachs shock on the soft side and adjuster positions close to the box-stock positions. In this setup, the Sachs worked best through smaller bumps and choppy sections. It remained stable in a straight line and helped the rear wheel hook up under acceleration without too much deflection. This setup sacrificed a little performance over big bumps and hard landings, but we found it to be the best tradeoff.
Q: HOW DOES THE TC510 HANDLE?
The handling of the TC510 suffers more from its weight than from its geometry. This is a heavy bike. The weight is an issue, and not a single MXA test rider failed to mention that he could feel that weight in roll and
Also, while testing the gearing, we found that the TC510’s handling is sensitive to location of the rear axle. It handles much better with the axle moved forward.
Q: WHAT DID WE HATE?
(1) Starting. If you don’t do exactly what Simon says, you might not be able to get back in the race after stalling the engine.
(2) Side panels. We decided to start buying our numbers out of an R/C car catalog so they would be small enough to fit on the side panels.
(3) Weight. The TC510 is only one pound heavier than the TC450, which is way too heavy. The 2010 Husky TC250 recently graduated from Jenny Craig, and
hopefully the 450/510 will start the program in 2010.
(4) Pipe heat shield. Husqvarna went to the trouble to make an aluminum heat shield to guard your boot from the left-side exhaust pipe. Nice touch, but it would be nicer if it actually guarded your boot from the left-side exhaust pipe.
(5) Rear fender. Why does it swoop up at the end? Every test rider hit his boot against it every time he threw a leg over the TC510.
(6) Ergonomics. This is a big bike. Very big.
(7) Front axle. The front axle is held on by a 12mm Allen. A motocross bike should never use an Allen in a place where a hex-head bolt will suffice.
Q: WHAT DID WE LIKE?
A: The like list:
(1) Powerband. The TC510 makes the type of power that will get you going fast without you knowing it. The TC510 is a gentle giant.
(2) Hydraulic clutch. Although you don’t need to use the clutch very often, it feels good when you do. No adjustment needed.
(3) Exhaust pipe. It has a two-into-one header, titanium construction and quality workmanship. We think the performance could be better, but we were satisfied with just removing the spark arrestor core.
(4) Seat. Taking off the seat and getting at the air filter requires only a twist of the wrist?no tools needed.
Q: WHAT DO WE REALLY THINK?
A: In the parlance of motorcycle manufacturing, the “Big Four” is comprised of the Japanese manufacturers. The “Big Five” is all the Japanese manufacturers plus KTM. There is no such thing as the “Big Six.” Husqvarna hopes to make that nomenclature part of the lexicon of motocross in the very near future. At the moment, Husqvarna fills an exotic niche in the American moto market, but it is close to being a major player. We applaud Husqvarna for continuing to innovate.