Stumped

[k3lv]

Hi all , I have a 2012 sinnis stealth 125 (winter hack,project bike,bit of fun) it didn't run when I 1st got it (bad starter relay) so replaced that it ran for a bit (badly) but now it just will not start at all , stripped the carbs a million times , checked the valve clearance at least 20 times an they are fine .....sometimes (completely random times) it'll start for a few seconds an die when the carb was on it would turn over an when I stopped it would make a hissing sound ....without the carb it makes a sound like a cork being pulled from a wine bottle right as it stops turning over ........any ideas? ...it has fuel,spark, compression so I'm stumped on this one literally any ideas welcomed and appreciated

[Bianco2564]

Hello.

Have you looked at a blocked exhaust?

An engine needs fuel, ignition, compression and airflow to run.

[k3lv]

Hi thanks for the reply ,yeah I've had the exhaust off and ran wires down it , everything seems to be there it's just not going ...well it ran the other day for about 5 seconds then just died if I turn the idle adjuster all the way out I can hear it trying to run but just won't catch ...then the battery dies , it back fires through the carb aswell when trying to start . 

[Mississippi Bullfrog]

Have you checked the timing?

[k3lv]

Hi ,yeah I stripped the top end down today timing is bang in and valves seem to be good , may have to order a leak down tester an see what that shows . This things got me puzzled 

[k3lv]

It lives ........after everything it turns out it was the bloody petrol , took out a mortgage an got a jerry can full of Morrisons finest premium fuel .....bike fired right up , used 2 full cans of E10 trying to get this bike to run an nothing 1st can was a couple of months old but the 2nd can was fresh that's when it tried to fire but just burbles an backfired so guessing it doesn't like E10 fuel .......thank god I never put the cheap stuff in the gsxr . Anyways thanks to all that replied an the suggestions greatly appreciated hope all are well and stay safe out there

[manxie49]

Glad you got it sorted.  I must admit that I don't go anywhere near my bike with that shite unless absolutely necessary.  Sometimes I have no option but always revert back to the super unleaded (E5) when I get chance.