05 FS650 bogging and shuts off while riding

I've tried to locate the fault now for a while and a little help I wouldn't mind...

This has now happened twice and after a street riding lasting like an hour or so. The bike suddenly starts to lose a bit power, starts to sound more "rough", it backfires more and starts bogging. It doesn't respond to throttle good anymore and after 20-30s of this it shuts down while still moving. It feels like it would run out of gas, though there's still half a tank left. It won't start during a roll, but right after it's stopped it fires up at the first try. It might work 95% properly for a minute, but then the problem starts again. Before this it's worked great.

When it first time happened I just limped to the garage and did these:

- carburetor taken off, checked for dirt and float needle and float level checked -> fine. Jets I also cleaned.
- filler cap airflow ok, won't help even if I would ride without it. Tried last time.
- spark plug changed
- changed also throttle cables since they were worn already
- washed the air filter and oiled it. Checked it as well.
- fuel delivery to the carburetor checked

After operations shown above I just started it and it worked great few 0,5 hour stakes and then a bit longer one hour session until it occured again after an 0,45 hour continuous riding. After second time the problem occurred I just left it to rot in the garage and started to drink beer...

Now I don't know where to start next. It delivers fuel properly to the carburetor, no kinks in fuel hoses and carburetor seemed fine + the problem starts only after a some time of riding and worked again after my operations I dunno what it coulde be? Could it still be something with the fuel delivery, something mechanical or maybe something with the electrics?

Taffy said:

Tappets?

fuel starvation? undo the cap when riding and suffering?

how much oil in the engine?

regards

Taffy

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Dunno about tappets. Don't seem like it.

Whole fuel delivery I've gone through. It works ok. Undoing the cap didn't make any difference and the valve in the cap works ok.

I've been using 0,8dl in the engine. It's maybe 0,1dl too much.

DaleEO said:

Sounds like a classic stator problem.

Since you have checked all of the fuel issues, especially the vent on the cap, it comes down to an intermittent electrical problem.

This was classic on the SEM ignitions but you had to wait a while before it would restart. Do a visual on the on the stator and look for cold solder joints on bus where the stator wiring is connected.

If you can't figure it out, send it to UHE member SPARKS in Spain. He has a test rig and can put load on it and let it run and hopefully will be able to duplicate the problem and or fix it outright and then test it.

Dale

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Starts to seem like it to me as well. I believe some part or joint starts grounding when heating and that causes problems to ignition. Also increasing backfire in the exhaust during the fault would fit to that.

Taffy said:

classic stator problem except that the bike is a 2005 and the faulty stators were fitted until 2003. so unless the bike is a very late registration I think you can count it out as being 'obviously' the problem.

regards

Taffy

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Yes, it's with Kokusan, but at least http://www.husaberg.org/wiki/index.php?title=Electrical here it's being said that also those have had problems as well. Next thing I will do is to measure it since it's possible and easy operation to do.

Also what came in to my mind was a spark plug connector. If I would have some luck a faulty disturbance eliminator could cause the problem as well. It costs like 5€ so I change it anyway.

nsman said:

Check for a broken valve spring

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I will for sure, but I believe it wouldn't work at all if the spring was broken? At least someone here in Finland had recently broken valve spring and it caused same issues, but didn't start after that at all. Mine fires up right away and after cooling works ok.

Taffy said:

they can break near the end and the bike rums fine (mostly!)

regards

Taffy

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Ok, good to know. I will check that as well when I get back to the garage.