Is my engine seized?

**Doowrag** · 07-07-21

Hi all, 2008 model with about 200 hours on it.

When I try to start it just clicks and won't turn over. Brand new battery and even with the spark plug out it still won't turn over. Tried roll starting to force the engine to turn over with plug out and won't budge. Removed starter motor and it spins fine when not mounted in place...

HELP please!!!!

**Tims1572** · 07-07-21

I would pull either side case and see what is going on to possibly see why it won't turn over.

**bello650** · 07-07-21

Sometimes there is a problem with the decompressor lever on the exhaust camshaft #414

https://advrider.com/f/threads/2011-...674140/page-21

http://www.bmw-etk.info/parts-catalo...554/11/11_4246

#2 Set decompressor

**Doowrag** · 07-07-21

I assume the decompressor lever reduces the compression to allow easy start, so given the spark plug is removed wouldn't the compression be far less anyway?

**bello650** · 07-07-21

Yes you remove the compression but the two camshaft are connected on the timing gears wich is drived by the crankshaft.
http://www.bmw-etk.info/parts-catalo...554/11/11_4245

Try to push the bike forwards AND backwards and check if the wheel gets stuck in both directions. You might hear a click around the left side valve cover.

**Tims1572** · 07-07-21

First of all remember these engines physically rotate backwards to the normal rotation of nearly all other dirtbikes. Another words standing on the right hand side, looking at the crankshaft/clutch cover removed. The engines normal direction of crankshaft rotation is counterclockwise. So with that out of the way.

I would avoid pushing the bike backwards in gear to see if the engine will rotate or turn over and here's why.

As you can see from the parts drawings provided by Pascal from BMW parts catalog and also looking at the short video clip from ADV rider. You can see how the decompressor is fitted to the camshafts slot. The video shows that the spring that holds the arm is not pushing the decompressor arm outwards like its supposed to because the spring is damaged.

The way the decompressor arm is fitted to the camshaft, it's offset and is positioned in a way that when the cams lobes open the exhaust valves, by gradually ramping up to full lift, acting against the valve buckets. The decompressor arms contact face simply follows the highest point of the camlobe with the valve now already open, thereby extending the left exhaust valves opening event, leading to reduced compression.

If the engine is turned backwards from the closed position of the valve. The offset of the decompressor arm connected to the cam lobe (even though the retreating side of the decompressor arm is chamfered) will come around and make contact against the face of the still partially closed valves bucket, before it reaches maximum lift with little to no more assistance from the cams lobe ramping effect. At that point the engine becomes very tight.

This can cause the decompressor arm and or its shear pin to be damaged unless the decompressor is physically pulled out by hand away from the valve bucket, as the engine is rotated backwards in the opposite direction of normal rotation.

The first time I noticed this myself was when rebuilding one of my 2 engines. The decompressor arms offset geometry, designed to come into play just past the peak of the cam lobe is very simple, yet effective in its design. Then centrifugal force just makes it swing out of the way against the pressure of it's spring.

However the decompressor arms geometry when viewed while it's rotated backwards. Along with the contact of the valve bucket against the arms chamferred angle not really being rounded off or smooth. It made me cringe just looking at it. Its obviously made to only go 1 way.

**Doowrag** · 07-08-21

I'm not crying! I've been cutting onions...

**bello650** · 07-08-21

Originally Posted by Doowrag

I'm not crying! I've been cutting onions...

No comments, always the same issue : https://youtu.be/3bWtoYm563M

**Doowrag** · 07-08-21

So whats the best course of action here? Is it just a matter of replacing the stator or will the flywheel need replacing also? And how likely is it that metal fragments have entered the bottom end?

**Tims1572** · 07-08-21

Its hard to tell if the flywheel is damaged without seeing the loose flywheel bolts and copper debris being cleaned out of it.

The copper windings from the stator coils being grinded up can usually be cleaned out enough to be able to run the bike successfully again if you can find a replacement stator coil assembly.
Sometimes the stator can be rewound by a cycle electrics service, for much less than purchasing a new one. But yours looks to be damaged beyond that being an option for you.

To flush out any remaining debris, lean the bike over on its side stand or over towards the left side. Pull the 2 cartridge screen strainers out of the forward 2 holes next to the oil drain plug (remove the drain plug too) and clean them well.
You could flush any resultant material out with some gas (flame solvent) real cleaning solvent, or even some diesel, etc. before installing a replacement stator in the side cover. Use loctite on those screws as well.
Then after fastening it all back together, replacing the oil filter and filling it with the proper oil go ahead and ride it and change the oil again right away after running it for about half an hour or so.

You can occasionally find stators for sale used on eBay or possibly 1 of the 2 "BMW G450X or bmwg450x" owners pages on Facebook. You can also look for one from the 449/511 owners Facebook page or the CCM GP 450 owners Facebook pages. I see them occasionally, however when they come up you need to respond fast. As they are spoken for in a matter of minutes. The dealer parts networks are getting more and more difficult to be able to find factory new stator assemblies as they are currently listed as back ordered or flat out unavailable.
If you are lucky enough to find a new one through the BMW or Husqvarna parts network they are only sold as a complete assembly that includes the flywheel with the stator coil and ignition trigger assembly.
Later versions of the 449/511 Husky's had an updated flywheel that uses a 5mm rather than a 3mm thick woodruff keyway. This would only be an issue if your flywheel is damaged and it needs to be replaced. These later engines also had a crankshaft with a wider slot in the cranks stub shaft for the thicker keyway to match. They do not interchange. Get a later model stator assembly and flywheel you just use the old flywheel if its not damaged. If it is damaged, you will have to change the crankshaft. If you have a engine that has had a complete overhaul and you buy or get a early model stator and flywheel and now have the later style replacement crankshaft you will have to find a later style flywheel to go with it. Otherwise a competent machine shop will have to re-broach the flywheels woodruff key slot to 5mm from its current 3mm.
I know this seems like a lot of information you may not think you need but its better to be informed of what you may be facing as it has become the reality.

**Doowrag** · 07-08-21

Thanks Tim. A few years ago I had the stator rewound in Melbourne after it burnt out. I'm not sure this one is saveable though. I'll see if I can find a new one.

**Doowrag** · 07-08-21

Yep so as you said, no new stators available worldwide with no expected timeframe for availability

**bello650** · 07-09-21

Originally Posted by Doowrag

Yep so as you said, no new stators available worldwide with no expected timeframe for availability

Indeed bad news, maybe you can try with BMW classic : https://www.bmwgroup-classic.com/en/...c-partner.html

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**Tims1572** · 07-09-21

Its a damned shame. I myself and many others have been advising owners to replace their 6 factory flywheel screws with replacement hardware (M6 x 1.0 pitch x12mm long in 10.9 or better yet 12.9 hardness hardware torqued to approx. 14 newton meters using red permanent Loctite) on this forum for over 10 years now.
The same has been done with the Husky 449/511 owners pages on Facebook.
It seems, that I just continue to see 1 owner after another owner who hadn't got the word yet or ignored the advisory all together to take 30-45 minutes to swap those bolts out about twice a month now.
The Facebook G450X and the Husky 449/511 and CCM GP450 owners pages are full of pictures of this same thing happening every month.
The supply of new stators has dried up on planet earth it seems.
We have even tried to get other owners to try to find an alternative stator from some other bike that could be modified minimally to work as a substitute in its place with no luck so far.