250-500cc wr300 seized after 500kms

My 2010 wr300 seized after only 500kms . I followed the running in procedure running a tank of 32/1 through it before going to 40/1 ( IMHO 50/1 is to lean but lets not get into that argument .) . the carb is still stock from bike shop with a 420 main.
so why .
here,s my only reason i can think of for this to happened . the tank doesnt have much of an overhang below the frame like my ec300 had and other makes lile KTM and TM do and as i ride on tight forrest trails the fuel slushes around the tank a lot more . if the level in the tank goes below the pick up tube on the fuel tap it should be moved to reserved because the bike should run out of fuel . but with all the tight turns it must slush over the pick up tube enough to fill the float on the carb but not enought to fill it completely. this makes the bike run on the lean side as when i stop after doing 75 or so kms ,the bike is idoling high, a sure sign it is running lean as all 2 stroke run faster just before the run out of fuel . my gasgas just ran fast for about 20 seconds then completly stop and i needed to go to reserve .even when riding on the tight trails
1 ride before the seizure i got back to the car after riding around 90 kms the last 20 or so with out stopping .the bike was idiling fast when i pulled up but hadn't cut out. when i checked the speedo and seen i had done 90 kms( yes my one is still going ) i thourght surely i would of needed to go to reserve about 15 ks before . i pulled of the fuel pipe to the carb and no fuel came out , i then turned it to reserve and put a measuering jug under the flow and all i got out of the tank was 200ml . so the bike had been running lean for some time . I haven,t got the bike back from the shop yet but when i do i will check the fuel tap to see it has a leak below the pick up pipe or the vacume caused by the carb is enough to pull a small amount of fuel through the reserve hole .
with a 5 speed gear box your up and down the gears and its sometimes hard to tell if the bike is running lean . particuly when your racing and chasing other riders.
this is my first 2 stroke seizure in 30 years of riding and i use castrol tts premix for the last 20 .
one reason for this post is to let all husqvarna owners with the new black 2 strokes tanks to be cautious it could be a contributing factor or even the main reason for it to seize .
forgot to mention when it seized the bike bike just died like the kill swicth had been pressed no squeaking or funny noises engine didnt even lock up. in fact i didnt realise it had seized until i went to kick it and it had no compression .

So you stuck your rings or holed your piston.
I've done that and didn't hurt the plating, hope you're lucky.
420 main was too lean for me, unless you have a richer needle.
You could have one of those leaky reed blocks.
A leakdown test would be good to rule out any mechanical leaks.

i seized my 2009 WR250, you could be onto something, i'd check the jetting wasn't too lean to start off with.

i thought seized ment seized? no compresion is a different thing aint it? still stuffed and i wouldnt be happy!

yeah, get it right lol.

A lean seize will cause the piston to lock up in the bore, some people have been lucky and managed to get it goin again after letting it cool down.

You have no compression so something in the cylinder has died.

Ant yours is sort of a seizure caused by component failure.

went to bike shop to look at damage

the piston seize against the bore .
as you sit on the bike there is one score mark on the bore at 10 o'clock and one at 2 o'clock the ring grove on the piston was closed holding in the rings . the score on the 2 o'clock mark is half way down the bore and the size of a 10 cent piece . the other score mark at 10 oclock is all the way down the bore and about 1,5 cm wide. there was a low amount of compressoin but not enough to draw in any fuel as the spark plug was dry when i looked at it after trying to restart the bike .
the standard factory main jet is 380 but the importer over here changes it for a 420

Hi Pcah,
You shoulda stuck with the 360 or at least pulled the Keihin out (remember ya from TT forum).

Anyway, very strange that you suffered a lean seizure with only 500kms wondering if you have a faulty carb float?

Jay

i run a 430 main. recommended by PSC husky, been fine. 360 is too lean.

Id say it wasnt a jetting issue, possibly a blocked jet, or float, leaky reed block as mentioned earlier.

Hopefully they find what caused it so it dont happen again.

Ran 20 mins of TTS at 40:1......never again, the old dt200 ran fine on it but the husky ran terrible/wouldn't rev out ect. I would try a more modern oil when you go again. Also mates ktm300 did in the little end in 1000k's from new on tts

any possibility the 2010's are also affected by the potentially leaky reed block?

you burned up your bike cuz it was too lean. pure and simple.

tank didnt have anything to do with it. doubt the reed block did either. that low pressure leak is usually negated to a large degree when the slide goes up and the vacum drops- path of least resistance thingy.

you need to, after rebuilding both top AND bottom ends, verify your jetting.

start by going up at least 2 steps on all jets, AS 1.5 turns out, needle middle slot.

go WFO in 3rd till it tops out, chop the gas, hit the kill switch and read the plug-DONT LET IT IDLE!. dark brown? that will get you in the park for the main w/ needle in middle postition. the rest is trailside/super easy "by ear" response-test tuning.

start way rich, then lean it out SLOWLY.

read the plug. use fresh ones each time!

once you get a recipe WRITE IT DOWN, write it on the float bowl. then, when you go up or down in elevation youll only need to change the main, in almost all cases, once your baseline recipe is established.

riding around with an engine that runs-on, pings, diesels etc. is a sign of dangerously lean jetting and if you keep riding it like this you will burn up a bomb-proof motor, everytime in no time. i've ran bikes out of gas a millions times, never seized or burned one down on the trail like that....on the track? diff story.

i've also yet to see one off-road two stroke that was even close to ready to ride, jetting wise from the factory. makers dont cover burned up engines for a reason.
read the owners manual for more info.

reading the plug is the single most important thing you can do on a 2-stroke, and, it's so easy there is no excuse.

if you bike does not run 120% PERFECT spot on bitchen- STOP!!! read the plug.

take jets on the trail in case something goes haywire. take a plug or two as well. i see all these"i burned up my motor " threads and not one has pics of a plug with corresponding jetting recipe's.

a two-cycle engine only requires one thing- the opperator knowing how to jet it. if you dont know how, find someone that does or get out your wallet.

read the OM and................

READ THE PLUG GUYS! and, let me know if any of youz ever need some help. PM, e-mail, whatever- gimme a jing and i'll always give ya some good dope or whatever if ya need something!

premix not at fault

CAstrol TTs is now 100% fully synthetic and has been for some time . I ran my Gasgas ec300 on it for 2 years before getting the WR and if it was as bad as some of you say i think there would be more complants about it than there is so it's not the pemix. nor is it jetting Why would Husqvarna release a bike with to lean jetting when they are offering a 1 year parts and labour warranty. elevation is not an issue either as the highest we ride is about 300m above sea leave and thats just a hill we go up before going down the other side its not like we ride at that elevation all day . spark plug is a coffee colour and there is plenty of oil resadue inside the pipe and around the crank . i agree the bike has run lean but not due to lean jetting from stock . if it was lean jetting from stock don.t you think husqvarna Australia would have a rash of seized 300's. the float bowl is ok . i have to turn off the fuel tap if the bike is on a steeper lean than when it' son the side stand or fuel leaks out the over flow pipe.

oi!

if yer plug was dark brown during a verifcation test as i indicated you were good to go and it was not lean, on the main. it may have been detonating causing a glow-plug effect and spiraling piston overheat as a result- this can be caused by the needle being too low/lean low speed jet/ leaned out AS. its not an oil issue. bikes are shipped with stupid jetting for a number of reasons. mine was. it would start and idle, that's it. period. not rideable as was. i had to rejet it.

always verify yer recipe with a test before hitting the trails.

if it surges or pings etc anywhere from off idle to 3/4 WO you are too lean on the slow and mid-speed circuits. those wont usualy show on the plug as once you hit WFO it kills the "tell". if it runs-on (gin-ging-ging-ging!!!) at idle it's WAY lean somewhere and cooking the piston. too low a needle has melted more motors than too small a main.

go up ti my post above and re-do the jetting starting rich etc....

the wrty covers defects, not meltdown unless ya have a bad crank seal and its sucking air but then the plug would indicate same in most cases, esp WOF.

all bikes can piss out the overflow when parked on the side stand or a hill, that's normal (as the engine is no longer drawing in fuel compensating for the full level etc) and it's better to have a slightly too high bowl level then too low! i too turn of the tap if i stop for more than a minute. if your needle valve and its seat are good, so are you.

unless you have a MAJOR air leak it's probably a jetting issue. these WR motors are bomb-proof hammers. check your crank seals to make sur ethey aint damaged in anyway, one can leak air the other oil and sucking in trans oil can actually make it lean but usually fouls the plug first. either failed will make it really hard to start. you can do an easy pressure test to verify but be VERY careful and keep the pressure VERY VERY VERY low. all you want to do is see if it leaks down any then find same and fix it. if you pump it up more than the seal is made to hold, its toast and the test is invalid. i dont know the pressue spec for same (upitite will)on this bike but use caution as you can damage the seals, easily.

sorry yer having issues mate, again, not here ta bash ya, id like to help my husky brother in any way i can. any pics of the piston?

how did you go mate?