My daughter has recently bought a 2nd hand Gilera DNA 125. It's only done 6000 miles but was laid up for 12 months previously. The acceleration is very poor and the bike struggles to reach 50mph. I have replaced the spark plug and cleaned out the carb bowl, jets etc with compressed air. When revved on the stand it struggles to get up to 9000 rpm. Any ideas?

Dave Robertson, July 2006

hi try this i brought a dna 125 with the same problem on full throttle it seemed to die out at 47 mph when i checked the airbox the screws had worked loose letting in too much air i put new screws in and straight away it does 70 mph hope this helps

jay dog, October 2006

sorry for the late response most people dont bother replying,its not too bad to do the timing is pretty straight forward there are two sets on marks on the camshaft one set for the two valve model and one set for the 4 valve model(your one).you may need to undo the main engine pivot bolt at the front of the engine to get access to the cylinder head.make sure the crankshaft is on top dead centre when you take it apart to help with re assy.i would suggest getting the head skimmed if you have a local machine shop to take it to.dont take too much off though the valves poke out as it is!you will need to take the valves out before it can be skimmed too.hope it all goes ok good luck.

adam bike doctor, July 2006

Thanks Adam. No, I didn't look through the jets. There has been some leakage from the coolant bottle so you could well be right. Is it a difficult job and will the head need skimmed? I'm a competent DIY mechanic.

Dave, July 2006

The thing that is most likely to be the problem is the head gasket leaking .It is very common on all of the piaggios and aprilias ect...that use this leader engine.this will cause loss of compression and usually the water bottle under the tank cover will blow a bit of coolant out or be a bit low on coolant level if the head gasket has gone.did you actually look throught the jets in the carb after you blew them out to see if they were clear?adam

adam bike doctor, July 2006