Husaberg Motorcycle Wear – Red Alert

This information is generally accepted for all Husaberg motorcycles. This section covers wear items that are considered Red Alert. For additional wear items, reference the Amber Alert section for Husaberg motorcycle wear.

Main Bearings

Over the years from 2004 to 2006 the three models: 450, 550, 650 have had rare occasions when the ball-race main bearings have failed. The factory changed to roller mains which require more accurate alignment in the cases. It appears that a cure is to go back to ball-race mains OR to have the bearing mouths align machined using an arbor (Lineaweaver). As soon as this was done however, dealers like DCR in the UK converted all engines back to ball race. However the Australia bikes didn’t have this vast privilege and they continue to fail heavily in that corner of the world. The ball-race bearings though can be evil to place and replace however (Orangeberg).

In Lineaweaver’s opinion, and it’s one we trust here at Husaberg Forum, you must have the cases checked and bored if need be for alignment, the housings themselves are often undersized by several microns making either type of bearing a force fit causing problems in themselves. The counter-balancer should be removed and a wider (20mm roller instead of 16mm) roller bearing be fitted with the appropriate spacer made to suit.

Another rule is to get the axial tolerance right. Around 0.3 – 0.4mm for 2 x ball, 0.5 – 0.6mm for a ball and roller mix, 0.6 – 0.8mm for a double roller crank (Enginehardwear of Sweden) use 1.0mm. With the counter-balancer removed, the engine should be re-balanced to a factor of 70% + – 10% (Lineaweaver).

Arbor Tool for Husaberg Main Bearing
Lineaweaver’s Arbor Tool for Husaberg Main Bearing

It would appear that engines were built with a lack of end float at the crank. Most of the ’04 and ’05 problems will have worked their way through the system by now but JBS uses a 9-ball instead of 8-ball race bearing. See Engine Tuning. In Engine Upgrades, we discuss the merits of ball versus roller and what to use.

Bearing Notes: The NJ6206 series bearings have a rpm maximum of 11000 rpm but only if they are in an oil bath mounted in the horizontal position. When in the vertical position, the maximum for this bearing is 20% less, or 8800 rpm to be exact, but only if the bearing is at least 30% submerged in oil. (NSman) Ball-race bearings have a max load factor of 19KN while the NJ206 roller bearings have a load rating of 42KN and should easily be able to handle the crank loads.

Mains WR450 ball 29kn 6306  Mains Husaberg drive side sperical roller 68kn wo cb 22206   Mains Husaberg ball 19.3kn 6206  Mains Husaberg 16mm roller 45kn 206

16mm ball vs 20mm roller 20mm spherical roller for drive side.

Thanks to Weed for the charts and pictures!

For Ben Ballard’s JBS racing engine, Ben removed the balancer and instead took the chance to beef up the drive side bearing from 16mm width 44kN OEM Husaberg to 20mm width 55kN rating.

It would further appear that the crankshaft is slightly inbalanced in the way it is held by the two mains. The one on the right is against the flywheel cheek while the one on the left sits some 16mm away – outside of the counter-balancer bearing. The crankshaft is ‘adequete’ but slight oscilation in an unsymmetrical way occurs. The roller bearings when fitted can be an improvement but it has been found that sidefloat tolerance is critical. The rollers can catch a ringlip and start chaffing the edge, the chippings cause spawling and the rest – as they say – is history!

Another problem would appear to be the bearing housings themselves within the cases. These are machined too tight and sepecifically on the right-hand bearing (Lineaweaver). The best approach for meticulous preperation would appear to be to use the arbor method (Lineaweaver) and use the extra material in order to machine a straight line.

The bearing should be a slight interference fit into the housing. The bearing will be 62mm dead to -10 microns, while the housing should be 62mm +2 to +11 microns for a good fit. Try to heat the cases in the oven whilst chilling the bearings before having them pressed in evenly.

Primary Crankshaft Gear

This was thought to be specifically a 2004 model problem however there are occasional bikes that still have the problem. The gear breaks due to the locknut tightening down onto the crankshaft shoulder after the thread has stopped (Lineaweaver). The loose and oscilating gear then eventually snaps. If you’re lucky you lose drive, others smack the front out of the crankcase. The broached keyway in the gear is the weak link. The Intermediate shaft and drive gear were revised somewhere along the lines of 2003 in an effort to ensure the retaining nut shouldered the gear as opposed to that of the shaft. (Lineaweaver)

The sharp corners (i.e. lack of a root fillet) is largely responsible hence suggest shot peening of said area. Dale personally prefers the taper drive pinion gears of the earlier model Husaberg. (Lineaweaver)

Husaberg cracked primary drive sprocket
Husaberg cracked primary drive sprocket (TheEngineer)

Tuliped Valves

The inlets of both the small and big valve heads tuliped and sank into the head if raced or revved sustainably. After market items found as well as turning to KTM items helped.

Husaberg Tuliped Valve

This is what a tuliped valve looks like. You can just about suss out that the sides are about 20 degrees only. Major destruction was imminent. (Taffy)

Husaberg Not so flat intake valve seats
Not so flat intake valve seats (Weed)


This is for motorcycle up to 2006. Wears very quickly. Aluminium shavings in oil: Probably the chain wearing against the water outlet in the head. Overal length for a 550 = 0.375 x 66 = 24.750 C-C (628.65 mm) (Neil E.)

Husaberg Camchain

Shiny chain is the standard camchain and the dull one is an early husey H/D one. Two seasons of racing and the shiny one is absolutely shagged! Note how the pins are like 3mm out of synchro! The bikes now come (from 2006) with D.I.D as standard, renowned for being the best we trust there will be no more problems.

Camchain Tensioner

In 2001 and 2002 the limited travel, alloy knob wears easily. Here’s a Lineaweaver answer: Change to stainless steel and lengthen by +4mm to 15.5mm total length. Within weeks the original camchain tensioner can become fully extended, the alloy knob then frays badly causing alloy deposits in oil. Just a tensioned steel rod from 2005 onwards with no knob on end, this shorter rod only has to push a thicker (see diagram below) stirrup balancing the dimensions out. So upgrade Camchain tensioner by removing the knob from the end. That’s right! simply remove it and you have an ’05 tensioner! to go with the better profiled stirrup from ’04 onwards. Same design as KTM now.

Husaberg Camchain Tensioner

Cam Slipper (Tensioner)

An upgrade for 2000-2002. Timing Chain Slipper (Tension Arm, Husaberg Part No. #800.36.002.000). Stepped Bushing (requires modification, Husaberg Part. No. #800.36.002.050). The two diagrams below show the early yellow and the banana black.

2002 Husaberg Cam Slipper Tensioner   2003 Husaberg Cam Slipper Tensioner

They are now superseded by the straight black on the left of the three below:

Cam Slipper (Tensioner) Differences

Latest example (left), a crooked early yellow and the standard yellow which was very weak (Weed).

I have had the camchain problems (slack) and have upgraded to better chain and steel sprockets, but I still have to change out at least one of the 3 every 6 months because the tensioner is maxed,and the chain is loose again. The difference is the shape of the chain rub surface on the tensioner arm. The 2003 is more arched up toward the upper timing sprocket. It uses all the same hardware as the old stirrup, but is keeping the chain far from the waterjacket. The steel pushbar mates perfectly.


The 2001’s were made of alloy, and if made in aluminium it’s trash… Replace with the hard steel. 2002’s were fitted with either steel or aluminium, 2003+ = steel. If changing to steel shorten the bolts or they go through the thinner camwheel and impact the head (44104).

Decomp Stop Nut and Bolt

The decomp lobe swings open quite hard and should be slightly hindered by its return spring. Alas, this weakens and so the stop bolt gets clobbered! Normally, it’s ok, but with age can fatigue and break. If it has been over torqued it will eventually snap on the nut side as the stress for the bolt is at the entrance to the nut. Later models remove the bolt completely and just let the decomp bang against the cam sprocket bolt head. We suggest that you simply remove the nut and bolt.

Rocker-Arm Roller Bearings and Pins

2000 Husaberg rocker arm oil holes are 0.155″ diagonally centered on arm in plain of arm top surface. (JoeUSA)

2000 Husaberg Rocker Arms

This is for all 2001 and 2002 machines. Upgrade VITAL. Factory modification was to increase each roller from 7.6mm to 8.0mm for 2003+ and this requires a smaller pin to be fitted. This means that all 1999 – 2002 rockers can’t be updated but must either have new follower bearings fitted or replaced. Rocker arms from the 2003+ fit. Buy the complete arm or use your old tappet screw and locknut.

For repeated procedure by mechanics etc the view is of a simple pin with punch marks etc to keep the pins from drifting during use.

Husaberg Rocker Arm End View

Follower bearings need an end float of between 0.25 – 0.30mm. This can disappear when punching the edges of the pin so be careful!

Tappet Locknut

It doesn’t even sound right to say this, a really obvious thing, BUT you must really tighten the locknut on your tappets or this will happen! Good and tight, now remember that!

Auto Decompression Issues

This was for machines through from 2001 to as late as 2003. Essentially, the decomp lobe would wear down and not lift the exhaust valve the .040″ (1mm) to release some compression while the engine turned under starting. There was also the problem that the lobe return spring would be either weak or unwound which equalled “ineffective”. This meant the engine was trying to fight full compression. The partial cure at the time was to add a ‘blob’ of weld onto the decomp and then re-profile. Husadawg has some great photos.

Your auto decompression probably looks similar to this one from my 2002 Husaberg 650. Note the worn leading tip. A common problem. (Ned37)

Husaberg worn auto decomp

The auto de-comp. bleeds only a fraction of the trapped charge engaging near 85 BTDC and closing near 15 BTDC with a peak valve lift of less than .040″. “E” Cranking compression should be roughly 130 PSI. (Lineaweaver)

In 2003, Husaberg produced a new camshaft for the 650 and de-comp lobe, they produced another cam for the rest of the range but omitted it from the parts book. The new cam profiles appear to make life easier for the valve train. It’s easier to follow by reading through an 2004 parts manual than an 2003!!!

In 2004, everything got new part numbers and a new cam again for the 650.

Husaberg Clog Decomp husaberg-clog_decomp1 2004 Husaberg Cam 2004 Husaberg Cam

Here is a boat shaped decomp – and it’s knackered. Note the tip is completely worn away!

Husaberg Boat Shaped Decomp