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problems starting my XJ 900


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Hi, I'm currently having issues with my 1994 XJ900f. I've owned I for just under a year and a half now and it's served me well with little issues until about two months ago when the weather turned, since then everything has changed.

Basically when I try to start the bike its just constantly turning over and refusing to fire up and occasionally making a wering noise as if the starter is just letting go of the engine and every now and then the oil light comes on and cuts everything off.

Since I've owned it I have dropped it a couple of times but never done much more damage than breaking off the indicators, there was an issue when a fuse kept blowing for the headlights but I sorted that.

What I have done to try and combat this I replace the battery but I'm going to also replace the spark plugs. However I fear this may not be enough because when I try to start it there is a clicking coming from what I can only assume to be the cdi unit, could this be shorting? Also the oil is slightly higher than it should be so I may need to drain and replace it, could this be cutting the engine out via the oil sensor?

Ultimately electrical issues aren't my speciality especially considering this is the newest bike I've ever owned. I do know that after 20 years the engine is getting tired, the rings are beginning to stick and there's abit of smoking coming from the exhausts when i start her so a top end rebuild will be needed sooner rather than later.

Any solutions anyone can throw at me please do, I've just about had enough and am about ready to strip off all the core electrical parts and replace them but I'd rather not if I can get decent advice.

Thanks for reading and please help

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Hi Marshall, before I give you my thoughts, let me say that I have a 1992 XJ900F (32,000 miles) in the process of restoration (you can see my - slow - progress if you follow my thread). Anyway, your 1994 model is newer than mine so there might be some differences. So, I'm not convinced this is an electrical issue, although it'll do no harm changing the plugs. When you take them out, check the colour of the electrodes against the, very useful, colour chart in the Haynes manual (or online). That will show you if there are any fuel issues - as a minimum, they should all be the same colour. If not, then you could have carburettor balancing work to do. Also, with the plugs out turn the engine over and check for a spark - you are looking for a nice bright blue spark, and they should all be the same colour too. On my model, there are two coils, each firing two cylinders so if you get two good sparks and two duds, that could point to one of the coils. It would be unusual for both coils to die so if you get no spark, check all the way back to the switch - but first check the side-stand switch as they can be problematic, especially if water gets into the switch - it's low down so is prone to water ingress. 

If you have let the fuel level drop too low, there could be debris from the bottom of the tank and this can sometimes clog the carb jets, and that will cause balancing issues, which can be shown up by the plug colours, as mentioned above.

My model has the YICS (Yamaha Induction Control System) and this can often lead to fuel/carburettor issues, although if left alone they are normally fine. It's only when they get "checked" that problems arise. This is a port that runs across the engine between the carburettors and the main block. This port links all four cylinders and is designed to overcome minor carburettor imbalance by allowing fuel from one carb to cross feed its neighbour. 

Hope this helps, check those plugs first then the side-stand switch before you tackle a full blown electrics strip-down.

Good luck



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