Husqvarna wr250 2 stroke issue

[KevinJ]

How's everyone, new member to the forum. I have a 2006 husqvarna wr250 2 stroke with somewhat of an issue, was going along a forestry path recently and bike suddenly stalled, twas like as if it ran out of petrol but I had only topped it up before I went out which was only 20mins earlier so that wasn't my problem, also checked spark plug and found no issues with it nor any issue with compression, when I tried kick starting the bike it was doing savage backfiring, got the bike back how and cleaned out carburetor but can't see any problems with it, even tried a spare I had which made no difference either, the bike will start every now an then but won't fully take revs an dies about 20 seconds later, took plug out again and kick started it with the plug out and flames would shoot out the plug hole every time I kicked it, that don't sound normal does it, when the bike does start it sounds as good as it ever did with no knocks or bangs but something tells me it an internal problem more so than carburetor, then again I'm not sure at this stage, wondering if anyone could shed some light on this issue. I hope I'm posting this in the right place, apologies if not. Thanks

[Tinkicker]

Check the key on the flywheel has not sheared...

[KevinJ]

1 hour ago, Tinkicker said:

Check the key on the flywheel has not sheared...

Thanks for the reply, I'll check that tonight.

[bud]

It might be worth checking the reed valves too. Perhaps one of the reeds is cracked, or not sealing properly.

[Hairsy]

Flames while the plug is out is the biggest mystery to me

[Tinkicker]

Plug laid next to plug hole is my theory.

 

As an apprentice I took my mentors eyebrows off doing just that.  Ford crossflow in an escort van.  I asked him to see if there was a spark.  He leaned in very close to see the plug just as I spun the motor over.

Apparently cylinder one took his right eyebrow and cylinder two took his left one.

Good job he wore glasses or I'd have had his eyelashes too.

[KevinJ]

Key on the fly wheel is good, I'll check reed valves, ya the flames are a mystery because the plug was on the work bench so that rules that out, haha ya I nearly burnt me head of hair as I was leaned in over bike looking when it happened

[KevinJ]

Just looked at the reed valves and they don't seem to be sealing fully on the sides as I can see a good bit of light shine through. So hopefully a new set will solve it, fingers crossed