i have a gilera dna 50cc ive just come off my tzr on black ice and smashed it up so i need too get the dna going it will start on a drill but unless you hold the back brake it revs too its full and it wont start off the electric on its own ? anybody got any ideas would be much appreciated thanks

Ryan, February 2009

mate you would be exactly right to think head gasket it will def be that they are very common and i do loads of them well done for noticing the water on the plug most people would miss that ! i would reccomend only using a genuine gasket on it and change both the head gasket and water jacket gasket around the edge of the head.dont use a pattern one they turn to bubble gum after a few weeks.good luck with that im pretty sure there is a bleed screw on the top of the head after refilling the coolant be sure to bleed out the air until it runs out with coolant only.if you need help getting a genuine gasket let me know i work in a bike shop as a mechanic.:)

adam bike doctor, February 2009

thankyou for your help mate its got it running but still off the drill i still will not start off the electric it doesnt even fire but after its been running i take out the spark plug too find that the bottems coverd in what seems too be petrol and water when its running it pisses water out the exhaust and when you take it down the road it misfires and wont pull any faster than about 20 mph ? normally does 60 im thinking headgasket ? i am a car mechanic and thats what i would say that is but im not sure when it comes too bikes ? i would appreciate a second opinion plus i just bought a yamaha dt 50 mx trail do you know how too deristrict one ? it does about 45 mph ? thanks again for your help mate

Ryan, February 2009

ryan if the throttle is stcuk in the open position (just like it is when you rev it up)then it will not start easily because the air intake is too high from cold.sort out the problem with the throttle sticking and you will solve your starting problem mate.its very common for rust to build up inside the cable and make ot stick.there a re 3 parts to the cable a toppiece and two bottom pieces one of the bottom parts goes to the top of the carburettor and into a throttle slide and the other goes into the left hand engine case where the kickstart is to the 2 stroke oil pump.you can buy a small tool called a cable oiler for a few pounds and it can be used with a wd 40 can .look on ebay for a cable oiler.ok mate adam.ps i am an actual bike mechanic so trust in what i tell you i am not just guessing at things. i know.:)

adam bike doctor, February 2009

the problem is the throttle is stcuk open and it will not start with the amount of air that is going in from cold.i would check the cable going into the carburetor and also the free play at the twist grip isnt too tight.a cold engine only want minimal air and maximum fuel ratio to start from cold so your extra air is causing the problem also it could be a problem with an air leak from the inlet manifold or even just a simple problem like the tickover screw is wound in too far and just needs undoing

adam bike doctor, February 2009

yeh the throttle is sticky ? it sticks on if you rev it ! and you have too hold the back brake too stop the thing going insane ?!

Ryan, February 2009

is throttle stuck open?

rayb, February 2009