pretty concerning problem i have with my very well maintained used 07 900. I started it yesterday in pretty cold weather. I hadnt ridden it in a week, and it had been left outside under cover. I think it was about 8 degrees out. I warmed the engine up for an hour previous with a space heater under a tarp, and it fired up right away. Anyway, once i sat with it in idle until the motor got up to 100, i tried riding it around in 1st and 2nd, but i immediately noticed it sounded a lot deeper and when i went to throttle it, it required half the throttle in 1st to get up to 20 km. going into second was not much better, and after 20 min of riding, it seemed to perform the same. it seemed like the engine was struggling a bit, and i stopped riding it after. anyone ever had issues like this?
First off there is nothing wrong with starting an engine from cold and riding it, you don't need to first warm it up, most wear occurs on start up whatever temperature, and leaving it in idle is not the best thing to do as it takes far longer if the engine is not loaded and there is more chance of introducing condensation and acid based contaminates into the oil during long warm ups. Modern engine materials and machining practices are designed for startup and go treatment, so you far better off just riding, as for the performance you will always find that initially in cold conditions the engine will sound different as the air is denser so a richer air fuel mix is used whether FI or carb, also if water cooled and EFI there is a cold start that the ECU will only come out of once the coolant temperature has got to a pre determined temp so there will be an over rich condition until this is reached so throttle position will not be the same.
As said running on idle doesn't benefit it really. Careful use of the throttle and riding off nearly straight away is the best plan. Do some fundamental checks and just ride it
There is nothing actually wrong with warming up an engine before driving/riding though & some bike like the Honda VFR 800 are famous for running rough if they don't get a few minutes of warm up, including the current model VFR. Plus, it doesn't address the issue that Johndoeish seems to have with the engine actually struggling despite going through his usual warm up. I'd suggest giving the bike a quick once over. After all, Suck, Squeeze, Bang, Blow is a pretty simple process. First thing I'd do is throw some injector cleaner in with your next full tank of fuel, as they do a surprising amount to help keep an engine happy. If you can, have a look see if there is any rusting inside the fuel tank (Or check the fuel filter if you have one). As Callumity suggests, give the air filter a check & clean/replacement. Inspect your spark plugs, see if they're on the way out & check the clearances. Bigger job, but you could do a valve clearance check/get one done. Is the same problem happening regularly, or is it an occasional thing? Or just the once? It could simply be the colder temperatures as it does have an effect. Air & fuel are both more dense when cold, it could be something as simple as your fuel is warm & is interacting with very cold air is having an effect on the air/fuel mix & the ECU hasn't adjusted things. In fact it may well be that all the air/exhaust sensors are telling the ECU everything is at the right temperature for the current fuel/air mix & you've then headed out into very cold air & has had the effect of creating a overly lean mix because there is a lot more air for the same volume being drawn in.
Idling for long periods can lead to bore wash where the cylinder walls lose lubrication by being washed by the fuel. Once reason not to buy a van off a milkman (or similar use).
The airflow metering (not sure what this bike uses hot wire or MAP and air temp sensor if used) should take care of the correct fueling for the air temp and density, however if the lambda is going faulty it will cause a permanent rich mixture by default, there is also the coolant temp sensor as mentioned if this is faulty will also cause a permanent richer mix a result which will cause bad throttle response.
Only really an issue with older carbureated engines where base fueling is set too rich or choke left on.
