RETRO REBOOT
Kar Lee re-invents the original Honda CBR900RR Fireblade.
Q:
This bike had a brand new battery fitted as part of a service just before I purchased it. I last rode it last weekend and left it filled with a full tank of (new) fuel. Today I went to start her up to go for a quick spin and the following happened: 1. Engine span up, she immediately tried to fire (for about 1 sec) unsuccessfully but did not start
2. Tried to start again, starter motor turning the engine no problem – but not a hint of her firing up
3. I left bike for about five minutes and tried starting again. Same result – plenty of juice in the battery, motor turning, but no hint of firing up. She’s started immediately every time. (One difference today if relevant is air temp – around six degrees, probably eight to 10 degrees colder than when I have started her before). Is the fuel system or ignition system at fault? I am thinking common components like fuel pump, fuse or pump relay, or the fuel pump itself might be the cause. I’m not suspecting spark plugs/coils as I think if one of those had packed up she’d still have tried to fire up on three cylinders. Any ideas? Graham Roper
A:
I think the basic problem must be that either fuel/air mixture is not being drawn into the engine, or the sparks are not appearing to set it on fire. Your thinking is absolutely right as a failure of all four carbs or both coils would be highly unlikely to happen, so I think the first thing to do is to quickly check that all the fuses are in working order and then follow the traditional route by extracting a spark plug (or an easier way is to take off a plug cap and fit a spare plug to it), earth it and see if you have sparks. If not, it could be the ignitor unit, but before you shell out for a replacement, the good news is that with luck it might be something less expensive such as a bad connection to it or possibly the pick-up coil or throttle position sensor. If you do have sparks, as you say, suspect the fuel pump or its supplying relay and also the associated level sensor. Also, don’t forget the side-stand switch.