In a few hours, a mate will be bringing his ZZR 250 around so that I can find and hopefully resolve the problem he has been experiencing. The bike in a 1994 ZZR-250 which claims to have done about 50k kilometres, although it’s possible that it’s been around the clock. A few months ago, his mechanic replaced the cylinder head and conducted a full service. Thus, all the basic trouble points – carbs, valve clearances etc – should be ok, but the details of the service I do not know much about. I put a new battery in it myself a few weeks ago. When cold, the bike will start and idle fine (using the choke to begin with). However, when trying to take off, the engine stalls as the clutch is engaged. I had a shot on it the other day: it didn’t matter how hard I revved it, there was just no pulling power whatsoever. However, my friend has been able to get moving by rolling the bike until he has enough speed to click up into second gear. At that point, the bike becomes responsive. Once it has warmed up a bit, he is able to stop and take off as normal. Given these symptoms, I’m thinking about a weakness in the ignition system. I already plan to replace the spark plugs. As the bike fails when cold, I don’t think the problem is the ignition coils – coils tend to fail when hot. But the ignition system is where I plan to start. For now, I’m just looking for some more ideas about what could cause this that might help guide my approach. Thanks!