i have just been riding my bike, and at around 9000 revs aprox 65 mph it begins to misfire and the power dies. if i let of the throttel and re-apply it after around 2 seconds its ok. but does it again if i reach the same speed. i recently put on a performance air filter, could it need re-jetting as the fuel to air ratio may be wrong. also would a new performance exhaust fix the problem (i dont think it would as it is a 4 stroke) in the mean time i have to stick to about 40mph please help, as 40 mph is to slow LOL.... Any suggestions welcome at djsnitch88@hotmail.com

James, June 2006

my dna 125c was running gr8 still starts everytime ater a look at it myself the ht lead has become loose and eventually come away from the spark plug socket i cant get the other end off that goes 2 the coils so does it screw on or pull off coz cant do either lol any help welcome

lewis, February 2010

my gilera runner 125 its 05 i was drivein it and it just died any ideas

richiemurray, September 2009

scrap it and buy a car.

fred, January 2009

i have a gilera runner 125 sp
and it has an exshuast an air filter , and a dellorto 25mm carb and wen i give it full throtle it sounds like its four strokein gettin to ,much petrol and have been told i need to get smaller mainjet can any one help me

and tell me wot main jet i need pls pls pls

jack, August 2008

i am too having the same problem with the power dying at around 60 , but i only have a 50cc dna. and also my ped wont tick over properly and dies when starting up, unless you keep the revs on. my mate seems to think that it needs rejetting but im not sure, also i plan to get a new yasuni performance exhausts and a new air filter. will these affect what size jets i need??? thanx

dan, July 2008

I also have this problem with my dna125, spoke to countless mechanics who just say its the restrictor?any other solutions?(HIGHLY DANGEROUS ON A-- ROADS)

Ryan, June 2008

hi i agree with adam running lean will literally get your engine so hot it will melt the piston and blow a hole through it
just to let you know i brought a dna 125 only did 50 mph then started to die on full throttle, when i checked the air box its very poor the screws work loose and let in too much air causing it to run lean for now just make sure its all sealed up nicely

jay dog, October 2006

ok i have seen them run dry of oil before and it wrecks the gears and the bearings.if you really want it to go well then i would suggest a polini 20 big bore kit a bigcarb from malossi and a rce pipe and gear up kit.i have dont these mods before to a dna 125 and they go like a rocket !!!in excess of 100mph try lookinng on v.e uk website and see what they have to offer you they are a good company and i have dealt with them before lots of times.p.s i have got a gear upkit in stock at the shop i work in if you need one ok mate t.c adam

adam bike doctor :), June 2006

thanks adam, your advise is greatly appreicated. ive decided to buy a new malossi carb with larger jet now, if you have msn please add me as i have a few more questions about my bike and moddifying it, i plan to spend alot of money on it and dont wish to waste my time by doing something stupid and pretty much destroying the bike. its had to have a new engine in it anyway as the previous owner let the rear hub run dry thus wearing away alot of the bearings, i was told that it was a dangerous engine and could have blown up while i was riding it, the owner before knew nothing about bikes. i cant say im any better but atleast i asked.... lol

James, June 2006

it is still going to need rejetting if the air filter has been altered from standard to a power filter!it will run too lean and could cause a hole to burn in the piston if left how it is never mind the bad running,as a rule a 125 4 stroke engine will need the main jet raising at least .2 mm from the standard size spo for instance if you have a main jet in it that is 100 then you should raise it to a 120 ,the number will be stamped on the side if the main jet which is the biggest jet in the carb and the most central one ok,please heed my warning and do this mod before you ride it as it can cause big problems to the engine it will run very hot how it is at the moment and will damage the engine badly either by holing the piston or seizing up or blowing a headgasket and warping the head itself ok.ps i am a bike mechanic by trade for the last 15 years :)

adam bike doctor, June 2006