Yamaha R125 2009 No Start

[slownotsteady]

I've got a Yamaha 2009 R125 with a replacement Engine with roughly 3500 miles on it. I went out for about an 2 hour ride after filling up with the highest octane Shell Vpower available at select stations - specifically called race fuel as I wanted to try it out. The bike seemed alright that day but I did notice the revs bogging down a little bit while I was holding the throttle completely open in the higher gears.

Other than that, it made it home for the night and in the morning I went to take it to work. I made it about a mile from home, got to the A6 and I was going up through my gears after coming off a roundabout, got to 6th and 8000 revs and suddenly they dropped by 3-4000 revs. The bike didn't die straight away, it managed to stay alive until I'd brought it to a natural stop before the next roundabout. I didn't notice any engine noise or blowing up as I was both wearing headphones and my exhaust/the road was loud as fuck. I tried to start- nothing, tried to bump, nothing but a metallic clicking sounding noise. Sounds like a little bit of compression too. I've tried spraying Engine Easy Start in the airbox/straight into the header through the spark plug hole but that didn't start the engine at all so I'm guessing it's not a fueling problem. I've done a compression test, cold start obviously as the bike doesn't run, and it read as pretty much 0PSI. The needle barely climbed at all, and after pouring a teaspoon on oil down the spark plug hole it read about 25psi, which is roughly half what the bike should be for a cold start.

What are the potential causes for no compression other than piston rings (which is my belief, hotter running fuel burnt through the rings?) and head gasket? Do you think it could be a bottom end problem at all if the bike didn't lock up in any way? This is the first time I've had my bike break down so I'm a complete noob to this and any advise is welcomed other than:

'Take it to a garage' 'sell it and get a real bike' ect. I'm going to take the Engine out on Wednesday most likely as that's my next day off and I need to know what to have a look for. Garages aren't an option as there's a 4 week waiting time for any of them and it's going to cost me about a grand for any kind of engine work which I'm not prepared to pay. I'll take it out myself and take it to someone that can help me take the engine itself a part and rebuild (probably going to just whack a 180 header kit on the bike that comes with the fuel commander as they're cheaper than the original header kit. FYI this isn't a 'hurr durr there's no point buying a 180 kit buy a real bike hurrrrr'.

Soooooooo, is there anything basic I should check before taking the engine out I haven't done? What should I look for once the engine is out other than fucked rings? and is it wise taking the engine completely out before working on it or will that cause problems?

[Nobby the Bastard]

4 stroke? I'd look at the valve clearances.

Wasted money, buying high octane fuel for that, btw.
____________________
trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Sprint ST 1050

[slownotsteady]

Yes mate four stroke, and it's literally a quid or so extra for a full tank and I did so as my friend had already done so and since he was leaving me behind on the exact same engine :L Bikes with no power do increase in performance a fair bit from the small things!

I'll have a look at that. Thanks for the heads up.