well apperantly ive had a blown base gasket (my friend knew but didnt tell me cause he thought i knew). Ive been ridin it like this for about 2weeks now... will this affect it in the long run? it doesnt have a loss of compression, its just blown. thnx~

 

It would be a good idea to change it, even though it still runs with it blown, it will suck dirt and cool air in your cylinder and onto your piston wich might make a mess out of your rings after a while, the gasket won't cost much and won't take long to change it if it is on your 270r.

 

It's either leaking coolant or air, neither a good scenario. Fix it. Why trade a cheap, easy repair for a complicated expensive one?

 

its not leaking either, but im gonna change it anyway just to be on the safe side. My dealer told me that it can melt the piston due to too much air in the cylinder but my local dealer i full of ****!!! they always give wrong info

 

How do you know if the gasket is leaking? If gas/oil is coming out, then air could be coming in. If it is sucking air you can run lean and seize.
ERIC

 

If your base gasket was actually blown all the way through, you'd have a melted piston! Believe me, I recently blew a base gasket on my ESR310 and it immediately fried the piston. The reason is because you all of a sudden have a lean condition due to the motor sucking alot more air in.
It needs to be replaced before you ride it again, you might have gotten lucky and it's not blown all the way through yet and you haven't done any damage.

 

If the leak is along the transfer ports, it would both suck and blow. It would suck atmosphere when the piston is moving up, and blow mixture charge out when the piston is moving down. You would see a weeping of oily gas. It could also leak coolant either externally, in which case it would run fine until it lost enough coolant, or it could leak into the crankcase. If it's not doing one of those things I guess I don't consider it blown. You can't spot a blown base gasket via compression test. You could with a crankcase leakdown test, a time consuming procedure requiring some specialized equipment. Usually it's pretty obvious and any leak at all is too much.

 

What the hell does a leaky base gasket have to do with coolant? All it does is seal the center cases and bottom of cylinder!
ERIC

 

Some two strokes run coolant through the base gaskets Retro. Nearly all Rotax engines do.

 

Well a 250R does not.
ERIC