Svartpilen 401 can't start

S

seb_lawrence

contributing rider
Joined
Sep 15, 2022
Messages
12
Location
Los Angeles
Hello everyone,
I just bought a Svartpilen 401 at an auction in pretty miserable shape. Stolen, grafiti all over , missing many parts etc.
In trying to restore it , i purchased all the necessary items, minus the headlight as I can't find one.

The problem is - I can't start the bike.
Engine turns over, I can see that there is a spark from the plug as I tested it and it smells like gas when I open the plug , so spark and fuel are available.
Fuel pump makes noise and I can see gas in the filter and it smells like it when i take the spark plug out.

The odometer reads CAN HLU failure and ABS failure . First is understandable as there is no headlight , the second I believe is a connection issue.
I am not sure if they have any relation to not starting. When I press the button the starter moves the engine every time, but can't fire it up. Which tells me starter the relay works.
Am I missing anything here. Fuses, other electronics?

I tried to push/roll start it , but no success - it did make a little bit of noise and it made a low bang in the exhaust twice , but that's it.

Any words of wisdom are massively appreciated!
Thanks,
Seb
 
I'm doing an auction rebuild as well. Fresh gas? Does it fire with a little starter fluid?
Google got some hits on the vitpilen forum, but unfortunately is down right now.
 
Fresh gas, pump makes the right sound ... there is fuel going in... I took the spark plug out and cranked the engine , sparks are good and there is fuel going into the chamber - I can see it and smell it...
Never done the starter fluid - it's probably a dumb question , but how does it work..? Spray into the throttle body?
Thanks!
 
yes. Just pull the air filter out and spray right into the airbox. I'm going to change my oil first before I attempt to start my bike.
 
Well, starter fluid did not work either. Any other ideas are massively appreciated. Lat resort is taking it to dealer to check codes and such. I just hoped that when I have spark it should fire.


BTW,
when changing oil - make sure the bike doesnt lean on the side stand and its perfectly vertical - the little window gauge will show no oil if leaning on the stand.
 
Looks like a ECU issue. A vit I bought a few years back needed a comp change to start after being in storage for awhile. Think it had that CAN HLU error message..
 
More development - I stuck a compression tester in the spark plug opening and was surprised with a ZERO reading.
Life just got way less fun.
Opened the cylinder head cover and on the surface everything looks ok. camshafts and valves move freely. chain is nice and tight.
What's in the chamber is a different story - valves, piston, piston rings ...
Gotta take the engine out and then decide if I want to tackle it myself or take it to the dealer.
They have 1 hour minimum for diagnosis - which should be enough to figure out the culprit.

Anyone done such extensive work before - I'd be curious to know if there any tips, specifics or insider knowledge in disassembling cylinder head and such...
Thanks much!
 
Doesn't the 401 have a encrypted key that is matched to the bike and will only start when properly matched by authorized dealer/shop? I had to confirm my address and ID before the dealer could complete the key initialization. They mentioned Husqvarna needed to match the key to the ECU for security and they couldn't do anything prior to confirming the owner to the key. Having bought thru an auction- there may simply be a call to Husqvarna and proof of your ownership. If you purchased the bike in the condition you mentioned, perhaps a call to a dealer or more investigation to Husqvarna's web site (have VIN # ready, proof of sale, etc) may get you some progress?
 
Well, so far I don't have any key , as the lock was vandalized ... any screwdriver turns it on at this point...
I can turn over the engine with no problem and every system works - spark plug is firing and the fuel pump shoots gas into the throttle ...
no compression whatsoever though and I doubt the ECU has the ability to alter that... I can see the valves moving, the piston moving... so I don't know
I'll call the dealer tomorrow to get more insights ...
 
The 701 has an automatic decompression on the camshaft to aid starting. Don't know if the 401 is the same, and if it is, does something like that mess with a compression tester?
 
seb_lawrence said:
Well, so far I don't have any key , as the lock was vandalized ... any screwdriver turns it on at this point...
I can turn over the engine with no problem and every system works - spark plug is firing and the fuel pump shoots gas into the throttle ...
no compression whatsoever though and I doubt the ECU has the ability to alter that... I can see the valves moving, the piston moving... so I don't know
I'll call the dealer tomorrow to get more insights ...
Click to expand...
Sorry to hear of all your issues. But I know the key is vital for the starting- hopefully you’ll be able to resolve. Good luck.
 
Ok, not sure if you should continue to bother you guys with the misery of this project, but here is the latest.
I opened the head cover and there is weird worn out area on the exhaust camshaft. I turned the engine over to a point where all valves are closed. I stuck the hose of the compression tested in and blew in it. I could feel the air coming out of the exhaust. this tells me there is a broken or bent valve for sure. the engine is coming off tomorrow and then I think I'll have a crack at it.. or take it to the dealer.... I'd still take suggestions if anyone has been brave enough to take an engine apart...
more to come...
 
Doing your own work is possible if you are that way inclined. I've worked on lots of motors over the years from simple two strokes to a top end rebuild on a Jap inline 4. The Svart single cylinder motor is not complicated.

Best case sounds like a bent valve stem. Worst case is the valve head has busted off and gouged out the piston, damaged the head and possibly cylinder wall also. It's the same motor as the KTM 390 and so there are likely to be second hand motors around if the damage is really bad. There is a thread on here a month or two ago about somebody replacing their Svart motor with a KTM 390.

Please keep us updated. People on here want to see you get the bike back on the road and will encourage you through the project.
 
Thanks much!
it's very close to what you describe as worst case... valve head gone, piston has heavy denting , cylinder head is pretty beat up , cylinder wall has 2 minimal dings.
It is rebuild able, but it will be close to $900 in just parts if i did the labor myself. Starting to look at parts on ebay and potentially another engine as the math lines up this way.
I don't see why not using KTM engine- it is the same thing except for the branding.
WIll report back as things progress
thanks!
 
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