hello all

I have a 2004 280 pro and i am sometimes having difficulty starting it, from hot and cold. anyone else had similar problem and how did you resolve it? carb/filter is clean and plug is gapped to gasgas reccomendations.

CDI units gave trouble on 04 280 Pro. My mate's bike had the symptoms you describe. I borrowed it for a trial, rode the trial ok, parked it up and had a go on my mates Sherco. He went to try the Pro but it wouldn't start at all. Got back home, checked it over and no spark.

We phoned GasGas and they confirmed that the CDI units gave trouble. Fitted a new one (not under warranty I might add, we had to pay for it - why is it that things like this are never fixed under warranty when they are known problems, really pees me off.

With the new CDI fitted the difficulties with starting disappeared for good so maybe your CDI is the cause. No idea how to check them other than borrow one off someone else whose bike isn't giving problems and see if that cures it.

Mint, try taking it into your dealer and having him reprogram the ignition. This seems to fix CDI problems in many cases.

Doesn't sound like the CDI to me, quite common for the wires on the end of the HT lead to become burnt away and thus it only creates a weak spark, cut 5mm off the end and spread the wires out before you screw plug cap back on. Also if your petrol air mixture is incorrect i.e. not enough petrol, it will create starting problems. if when you start it it makes that out of petrol noise then this may be the case. wap the choke on and see if that helps because that'll give it less air (or is it more petrol? not sure)

when i first got bike it wouldnt start when i picked it up from shop i was told then they had a few problems with a few cdi units. do the ht leads burn out so quickly,ive only had bike a few months? will a faulty cdi cause a weak spark? when i took the plug out it was wet and black i will have to check how the spark looks.