shortwaveradio
New member
Hi All
I'm new member that recently acquired my first Beemer a few months ago; I'd been wanting an airhead for quite a while, and I'm loving it so far. Bike in question is a 1985 R80 that had been converted a few owners ago from an RT to a naked bike, and has been well taken care of as far as I can tell. Mileage is currently just over 29.5k, of which I've put a little over 600 so far. Only issues to this point I've had to address are a leaky oil pressure switch, and an idle that would get a little high after the engine got warm (more on that later) that is, until I went for a ride on Sunday. I'll try and be brief as possible and lay out the scenario, and hopefully someone can tell me where I either screwed up or how to remedy the situation (or both).
I haven't yet done a valve adjustment on the bike (perhaps one area where I screwed up) but I didn't know if the mileage of the bike necessitated one quite just yet. However, I noticed shortly after getting the bike that the idle would climb to a little over 2k, and occasionally just shy of 3k after getting warm. It would even occasionally climb while sitting at stoplights. I ruled out the mechanical timing advance mostly because it wouldn't come unstuck when attempting to "drag" the RPM down with the clutch, and it would still remain high after cutting the engine off and restarting, as well as the fact that it would climb while stopped without any throttle input. Having done that, I focused my attention on adjusting the butterfly plate on the carbs with a friend who isn't an airhead expert by any means, but knows motorcycles pretty well. It was a pretty minor adjustment, and we did it after a good 20+ mile ride while the engine was good and hot, and it got the bike idling right around 1k no problem. After the carb adjustment, we went out for a longer, 40 mile ride where the bike performed well, though on occasion when clutching out for stops, the bike would come close to stalling without ever doing so, and I chalked it up to needing to tweak the throttle cable tension just slightly. With the throttle open and riding along, I noticed no loss of power or stumbling. That was last Sunday.
I rode the bike during the week, and it cold started fine, but after the carb tweak I needed to keep the enrichener on for a bit longer; before the change I could flip it off after maybe 30 seconds or so in 60-ish degree weather. Afterwards, I noticed it needed a minute or two longer to wake up, but figured this was normal. Idle was still better than it had been, and bike rode just fine, but on Friday I noticed that if I removed ALL throttle input, the idle would drop to below 1k, and die every time. It didn't affect rideability, and if I put just a hair of throttle on, and I mean, like a mm of cable pull, the bike would idle fine at 1k, fat and happy. No stumble, no loss of power. I again figured that this must be a cable tension issue, but when I got back Friday it was dark and cold, and figured I'd get it warm and ride it around on Sunday and make the adjustment then.
This past Sunday I took the bike out and it again started fine with a little bit of extra enrichener. It was a nice 25 mile ride with no symptoms of poor performance that I could tell, but the bike would still want to die when totally off throttle and the plan was to adjust the throttle cable when I got back home, because it idled fine with barely any twist. Towards the end of my ride I was crusing through a local sleepy downtown not too far from home at around 25 MPH when I noticed what felt like the bike needing to be put on RES. I was a little alarmed, because I had just filled up mid week, and while I had been suspecting that my gas mileage isn't necessarily amazing, I should have had plenty of gas. Before I could put it on RES, the bike died on me, and I coasted to a stop on a side street. I checked the fuel level, and found that I did in fact have gas, and tried to get it fired again, to no avail. It would crank fine, occasionally turn over very briefly and immediately die, and it actually backfired on me a couple of times but it never completely caught. I checked the carb bowls, found them full of gas and free of crud, and after letting the bike cool for a couple of hour thinking it might be ignition related, I found it still wouldn't turn over. I've since loaded the bike in my truck and brought it home.
I know that a bike with valves set too tight won't turn over, but am I correct in thinking that a degradation in performance would have been noticed long before any sudden engine cutout and subsequent starting issues? I'm also aware that my carb tweak may have exacerbated an underlying issue or be the root cause of my current problem, but I'm a little stuck as to what I should check first, or troubleshoot. Any guidance, wisdom or constructive public shaming is appreciated.
I'm new member that recently acquired my first Beemer a few months ago; I'd been wanting an airhead for quite a while, and I'm loving it so far. Bike in question is a 1985 R80 that had been converted a few owners ago from an RT to a naked bike, and has been well taken care of as far as I can tell. Mileage is currently just over 29.5k, of which I've put a little over 600 so far. Only issues to this point I've had to address are a leaky oil pressure switch, and an idle that would get a little high after the engine got warm (more on that later) that is, until I went for a ride on Sunday. I'll try and be brief as possible and lay out the scenario, and hopefully someone can tell me where I either screwed up or how to remedy the situation (or both).
I haven't yet done a valve adjustment on the bike (perhaps one area where I screwed up) but I didn't know if the mileage of the bike necessitated one quite just yet. However, I noticed shortly after getting the bike that the idle would climb to a little over 2k, and occasionally just shy of 3k after getting warm. It would even occasionally climb while sitting at stoplights. I ruled out the mechanical timing advance mostly because it wouldn't come unstuck when attempting to "drag" the RPM down with the clutch, and it would still remain high after cutting the engine off and restarting, as well as the fact that it would climb while stopped without any throttle input. Having done that, I focused my attention on adjusting the butterfly plate on the carbs with a friend who isn't an airhead expert by any means, but knows motorcycles pretty well. It was a pretty minor adjustment, and we did it after a good 20+ mile ride while the engine was good and hot, and it got the bike idling right around 1k no problem. After the carb adjustment, we went out for a longer, 40 mile ride where the bike performed well, though on occasion when clutching out for stops, the bike would come close to stalling without ever doing so, and I chalked it up to needing to tweak the throttle cable tension just slightly. With the throttle open and riding along, I noticed no loss of power or stumbling. That was last Sunday.
I rode the bike during the week, and it cold started fine, but after the carb tweak I needed to keep the enrichener on for a bit longer; before the change I could flip it off after maybe 30 seconds or so in 60-ish degree weather. Afterwards, I noticed it needed a minute or two longer to wake up, but figured this was normal. Idle was still better than it had been, and bike rode just fine, but on Friday I noticed that if I removed ALL throttle input, the idle would drop to below 1k, and die every time. It didn't affect rideability, and if I put just a hair of throttle on, and I mean, like a mm of cable pull, the bike would idle fine at 1k, fat and happy. No stumble, no loss of power. I again figured that this must be a cable tension issue, but when I got back Friday it was dark and cold, and figured I'd get it warm and ride it around on Sunday and make the adjustment then.
This past Sunday I took the bike out and it again started fine with a little bit of extra enrichener. It was a nice 25 mile ride with no symptoms of poor performance that I could tell, but the bike would still want to die when totally off throttle and the plan was to adjust the throttle cable when I got back home, because it idled fine with barely any twist. Towards the end of my ride I was crusing through a local sleepy downtown not too far from home at around 25 MPH when I noticed what felt like the bike needing to be put on RES. I was a little alarmed, because I had just filled up mid week, and while I had been suspecting that my gas mileage isn't necessarily amazing, I should have had plenty of gas. Before I could put it on RES, the bike died on me, and I coasted to a stop on a side street. I checked the fuel level, and found that I did in fact have gas, and tried to get it fired again, to no avail. It would crank fine, occasionally turn over very briefly and immediately die, and it actually backfired on me a couple of times but it never completely caught. I checked the carb bowls, found them full of gas and free of crud, and after letting the bike cool for a couple of hour thinking it might be ignition related, I found it still wouldn't turn over. I've since loaded the bike in my truck and brought it home.
I know that a bike with valves set too tight won't turn over, but am I correct in thinking that a degradation in performance would have been noticed long before any sudden engine cutout and subsequent starting issues? I'm also aware that my carb tweak may have exacerbated an underlying issue or be the root cause of my current problem, but I'm a little stuck as to what I should check first, or troubleshoot. Any guidance, wisdom or constructive public shaming is appreciated.