Q&A
1982 Kawasaki GPZ 1100
Q: Hello CMM, from Gabriola Island, Canada! This is my 1982 GPZ1100 (see below). I purchased this bike with 14,000km from the original owner. She has always had fuel injection issues. Would the issue be the computer? I have purchased off of ebay four control units for the FI but none of these worked! When running on the original computer unit it runs fine for 15 minutes but then loads up and quits running and when I look at the plugs they are black and sooty. Should I convert to carbs? It’s a shame as the bike is as new. Derrill Shuttleworth A: I do not think you need to convert the system to old-fashioned carburetors as there probably is not much wrong with it. I am assuming yours is a B2 model, which has the superior digital fuel injection system which replaced the earlier (and less successful) analogue set-up. I do hope you haven’t thrown away the Electronic Control Units you bought as you have successfully proved there is nothing wrong with them. The bike has now had five different ECUS fitted, all producing the same effect so either all five have the same fault (unlikely) or there is something else wrong. The fault is almost certainly down to a faulty sensor or wiring to a sensor, and you should see the warning indicator light illuminating in front of you when you ride (if it is working). The engine is fitted with sensors measuring both air and engine coolant temperatures and throttle position so your first step is to check that the contacts are clean and undamaged. If that does no good, you will need to get hold of a workshop manual (preferably the Kawasaki one which consists of the Base and Supplement volumes) as things now get a bit more complicated. Take the bike out for a run and when it starts playing up, without turning the engine off, lift the seat and have a close look at the ECU (I think you should know by now where it is situated – in the tail unit!). Just next to the big connector you will see a little hole and inside is a green LED, which should be flashing, using a code of long and short flashes to indicate what is wrong. By following the manual you will isolate the fault and be able to rectify it. And put your collection of ECUS back on ebay.
1979 Suzuki TS250
Q: Hello Mark. I read with interest your article on restoring plastics. I have got a similar problem; the actual plastic front mudguard is not split or broken but is out of shape. How do you go about straightening it? I cannot find a replacement as tin ware (as you call it) on these bikes is very rare! I live near Cheltenham do you know of any firms near-by who could do this for me? Merv Martin A: I don’t think the restoring plastics article was one of mine, but I can tell you what to do in this case. Plastic parts such as mudguards are great on bikes as they are light, relatively cheap and do not rust, but as you have found out they can warp, particularly if a force is exerted on them for any length of time. One typical example is a front mudguard accidentally being pressed against something nearby when the bike is out of use and semi-forgotten about during its (or the owner’s) winter break. If you just grab hold of the mudguard and start bending, you will probably find that does not work and you might then put just too much force on it and break it, so a more considered approach is needed. What you need to do is find a way to heat the plastic. It does not need to be melted or even nearly so but rather in a slightly more pliable state, with the correct temperature depending on the type of plastic. Two ways of applying heat which you will have at home are to immerse the part in very hot water or to use a hot air gun on its low setting. Rather than heating the part and then bending, the recommended approach is to carefully bend the part to the right shape, hold it there (quite how you do that is up to you) and apply the heat. Then let it cool down and release the clamping arrangement – and with luck the part will now be correctly shaped. That is the theory, so good luck!