Saluti! I mentioned in my intro post about some issues I'm having with my S4 2001 and could do with some help please. I spoke to the former owner today and he suggested some things to do, but can't work out how or why this has happened. Whilst I have experience with carbed bikes, I'm not very familiar with fuel injection but I have a basic understanding of the working principles. The problem: engine oil stinks of petrol, can't work out why or how though. My Bandit use do this but with the absence of a fuel tap and carbs, that can't be the issue here. Bike was well maintained. Oil sight glass was full, wasn't previously. Dropped the oil and it stinks of petrol BUT when I measured it out, it's 3.5L, which is the capacity (plus oil filter extra). I need to get the oil filter off and see if there's a lot more. There is still fuel in the petrol tank, probably enough for 'reserve'. I only use super unleaded. The fuel pump does prime when you start the ignition. The bike was running well, there always has been a whiff of petrol though but couldn't locate a leak and the bike ran well. I put it down to a breather tube in the filler cap. I have regularly started it up and kept the battery charged, when not in use. It didn't get ridden until July when I took it for the MOT, which it passed without issue. It ran fine but a bit boggy like when the fuel is running out. I went to take it out in August and it ran but then kept cutting out, then wouldn't run at all. Battery was fully charged, pump was working, it was cranking. When I was doing a check, I thought I'd check the oil and out of habit (it's a bandit thing), sniffed the oil cap and realised there was fuel in the engine. I have also noticed that the coolant res is under the min mark. I haven't check the rad yet. Possibilities... questions... The bike is running too rich? I need to check the sparkplugs next. Excess fuel typically gets fired out the exhaust valves.. right? It shouldn't end up in the engine unless the piston rings are worn... yeah? Could the choke be stuck open on the injectors? Is that why it's running rich? Judging on the amount of oil, I don't think that there can be that much fuel in it but enough for it to smell. If the coolant had leaked through the water jacket/head gasket, the oil would be salad cream, right? I will check the radiator for tell tale signs of blown head gasket and top up the res. When I was under the bike, I noticed that there was a leak, which wasn't there before. I think this is from where it's overfull. It looks like it's seeping from along the clutch cover gasket, I've degreased the area and will check again. Any ideas what could have caused this and how to cure it? Thanks in advance Chao!
If it is massively overfueling it can wash the bores and get into the oil (petrol is far thinner than oil and will get past the rings). If the engine is run like this it causes wear quickly so needs to be avoided. As said above it needs a proper service/ investigation to determine what’s wrong. Hopefully something simple.
Hiya, thanks for taking the time to reply. I bought the bike last April and it had just been fully serviced, including the cam belt. I rode it May til November and then it was put away, it probably hasn't done more than 1000 miles since I got it. This year it's done 20 miles but was regularly started. I hadn't checked the coolant tbh, it just needs a top up. Looks like a right awkward thing to get to but it's on my To Do list. I can't afford to take it to a garage, so I have to do the work myself. I did a level 3 bike mechanics at college so I'm confident enough to dive into tasks, I lack the testing equipment though. I've not really worked on fuel injected bikes before or this type of engine (other than at college but that was 3 years ago), so any pointers are definitely appreciated. I need to get the tank off and learn this bikes components and locations, thankfully I have the s4 manual now and found the owners booklet. So my job today is to take the spark plugs out and check those, I fully expect them to be wet. Mentally, I'm going through a checklist of how this can happen. Just checking the mot history online, it was 10,229 in March 2023 and 10,874 in July 2024 - well that's embarrassing! Has to be rectified asap. I have a strong suspicion that it's the piston rings either worn or not correctly aligned, I'd really like to be wrong about that. I have a lot to work through. Cheers for your help.
