hi, i have a gilera dna 125 4 stroke model, i bought it with a scorpion exhaust fitted. i did not buy it long ago and since i have had there had been a problem. The problem is that once the bike has warmed up and and the bike is idling(ticking over) the revs will drop from about 1800rpm-1900rpm to about 500rpm and then will come straight back up it will sometimes do this when cold aswell but it isnt very often. Also sometimes you can see the rev needle moving quite a bit and it is not the instrument panel because you can feel the rev change. Since this problem was there i suspected it may have been a fueling problem e.g. to lean or rich, so i decided to fit a performance ramair air filter and rejetted the carb and the problem still persists. I have also noticed that it is considerably slower than many standard dna 125's as i have done some 'Drag races' with them. Also when starting alot of the time it can take quite a while to get it started and sometimes will decide it doesnt want to start atall.
if you require any more information i will be happy to provide it
thanks alot
martyn

martyn, February 2007

got a dna 125 the silencer is blowing by the head shoud there be water coming out

christopher, August 2010

air in your lines

david, September 2008

ye it maybe that, but how much lighter ? and wouldnt that reduce the top speed which is lower than the average dna already ?
thanks

martyn, February 2007

Don't you need lighter vario rolls when fitting this exhaust?

This is the info I found at the product page on a German webshop:

'SIP-TIP! New, lighter vario rolls, harder clutch springs, new spark plugs, main jet 5% larger.'

Dodgey, February 2007

hi i have changed the jet from a 135 to a 140 and in a way it seems that the problem is a bit worse when ticking over, it might just be me but it feels worse

martyn, February 2007

i currently have a 135 in, but that is because i have fitted a performance ramair air filter, i was considering maybe fitting a 140. I do not think it is the jet though as it was happening before when it had the standard air box and standard jet which was a 108 i think. although maybe the scorpion exhaust was causin reduced comprssion and maybe making it lean ?

martyn, February 2007

what size main jet have you got in it ?it may be weak or lean as you suggested

adam bike doctor, February 2007

i replaced the diaphragm and the problem still seems to be there, could it be anything else ?

martyn, February 2007

no no collant deposits on the spark plug as far as i know

martyn, February 2007

well its a problem with the carb i would say for sure ,other probs they have is head gaskets blowing and they drop valves too but thats not the problem with yours unles you get coolant deposits on the spark plug? then the head gasket may well be in trouble

adam bike doctor, February 2007

hi i will have a look at some point thanks for the feedback. Any other causes of these problems?

martyn, February 2007

is the diagphragm in the top of the carb in good condtion as these areclasic symptoms of a split rubber diagphragm.ok

adam bike doctor, February 2007