Rough running low down and high idle when warm

FrankenDesmo · 20-03-2020, 09:43 PM

I appreciate the the write-up utopia, always good to hear from those that have been there and done that a few times. This was my first time doing a valve clearance check on any vehicle, and I'm fairly sure it's the first time I've ever use feeler gauges in anger. I know that the principle is for there to be a small amount of 'drag' and for the feeler to go in without being forced (or even encouraged), but you know what they say about theory and practice. I'll go through the checking process again tomorrow. Also I can't believe I didn't think of a mirror! I ended up getting what would seem to be a very flat tile from B&Q but a mirror has a much better chance of being true.

I am, however, very tempted to leave them well alone for now - if the impact is on efficiency and less than perfect low RPM running, then I'll take the hit for now while I sort out the more acute low-RPM running issue I've been facing (which I don't think is likely to be caused by valve clearances given it wasn't anywhere near that bad before being parked up over winter). I think at this point I run more risk of getting it wrong, which puts the bike out of action for longer. Whereas over the winter I can take my time with it (and possibly get a shim kit ready from emc ahead of time). Also - I really, really want to ride the bloody thing! I've owned it for 6 months and have barely ridden it - I'll happily do the things that require attention right now, but I am willing to put off those tasks that aren't a pressing issue at the moment.

Going off of the link that flip has shared, it seems that I should be aiming for the assembly tolerances? I do want this bike to last 'forever', however that would mean a full re-shim if my measurements are correct. I think I'd like to take the heads off for that, and do it in the off-season.

Am I being too impatient? Is it silly to leave the valves as-is (for now) if my measurements are correct?

20-03-2020, 09:43 PM	#21
FrankenDesmo Member Join Date: Sep 2019 Location: Glasgow Bike: M900 Posts: 108	I appreciate the the write-up utopia, always good to hear from those that have been there and done that a few times. This was my first time doing a valve clearance check on any vehicle, and I'm fairly sure it's the first time I've ever use feeler gauges in anger. I know that the principle is for there to be a small amount of 'drag' and for the feeler to go in without being forced (or even encouraged), but you know what they say about theory and practice. I'll go through the checking process again tomorrow. Also I can't believe I didn't think of a mirror! I ended up getting what would seem to be a very flat tile from B&Q but a mirror has a much better chance of being true. I am, however, very tempted to leave them well alone for now - if the impact is on efficiency and less than perfect low RPM running, then I'll take the hit for now while I sort out the more acute low-RPM running issue I've been facing (which I don't think is likely to be caused by valve clearances given it wasn't anywhere near that bad before being parked up over winter). I think at this point I run more risk of getting it wrong, which puts the bike out of action for longer. Whereas over the winter I can take my time with it (and possibly get a shim kit ready from emc ahead of time). Also - I really, really want to ride the bloody thing! I've owned it for 6 months and have barely ridden it - I'll happily do the things that require attention right now, but I am willing to put off those tasks that aren't a pressing issue at the moment. Going off of the link that flip has shared, it seems that I should be aiming for the assembly tolerances? I do want this bike to last 'forever', however that would mean a full re-shim if my measurements are correct. I think I'd like to take the heads off for that, and do it in the off-season. Am I being too impatient? Is it silly to leave the valves as-is (for now) if my measurements are correct?