dori Posted October 12, 2007 Share Posted October 12, 2007 My bike cries! :'( The bike in question is a 1982 XS400 Seca in an apparent great condition. I want to bump up the cond even more. It runs fine, yet, it produces a bad sounding noise. Let me describe: 1. Seems like it is dependent on ambient temperature as it is more likely to happen if it is cold (and it started happening all the time now). The speed at which it starts seems to be lower the lower the temperature. First few times it happened it rained heavily so I assumed it might be dependent on water, but last few times it was just cold. 2. It is not directly rev dependent. It starts around 40-60km/h (depends on air temp) and keeps at it even when I pull the clutch in or stop the bike... It stops with a dying sort of fluctuating pattern after a few seconds after I stopped (about 20 secs after I pull the clutch in.. total). 3. If I was to describe it, it would be either a wet rubber belt rubbing on metal squeaking somehow, OR a blown up balloon letting air out while holding the lips apart (and having the inside slightly humid) I try to describe as accurately as I can. 4. I cannot make the sound start while stopped (neutral/clutch) and reving the engine. Please diagnose or suggest something. Make my baby stop crying (I wanna ride it through the winter, so it is very important). Thanks! Darie PS. Main issue is that it seems to run fine ... no impairment of performance while making that sound (could it be some filter, tube, wet thing, transmission?) EDIT: I should mention that I recently (500km .. last weekend) changed the oil to recommended for under 15 degrees Celsius usage. It was a synthetic one Pennzoil 10W40 or 10w30 ... the proper one. And the bearings do not make noise, I don't seem to find any vibrating loose screws either. I eliminated the possibility that the chain might be making the noise as noise persists when the cycle is stopped. It really seems to be something to do with the internals. Link to comment Share on other sites More sharing options...
Moderator drewpy Posted October 12, 2007 Moderator Share Posted October 12, 2007 My bike cries! :'( The bike in question is a 1982 XS400 Seca in an apparent great condition. I want to bump up the cond even more. It runs fine, yet, it produces a bad sounding noise. Let me describe: 1. Seems like it is dependent on ambient temperature as it is more likely to happen if it is cold (and it started happening all the time now). The speed at which it starts seems to be lower the lower the temperature. First few times it happened it rained heavily so I assumed it might be dependent on water, but last few times it was just cold. 2. It is not directly rev dependent. It starts around 40-60km/h (depends on air temp) and keeps at it even when I pull the clutch in or stop the bike... It stops with a dying sort of fluctuating pattern after a few seconds after I stopped (about 20 secs after I pull the clutch in.. total). 3. If I was to describe it, it would be either a wet rubber belt rubbing on metal squeaking somehow, OR a blown up balloon letting air out while holding the lips apart (and having the inside slightly humid) I try to describe as accurately as I can. 4. I cannot make the sound start while stopped (neutral/clutch) and reving the engine. Please diagnose or suggest something. Make my baby stop crying (I wanna ride it through the winter, so it is very important). Thanks! Darie PS. Main issue is that it seems to run fine ... no impairment of performance while making that sound (could it be some filter, tube, wet thing, transmission?) EDIT: I should mention that I recently (500km .. last weekend) changed the oil to recommended for under 15 degrees Celsius usage. It was a synthetic one Pennzoil 10W40 or 10w30 ... the proper one. And the bearings do not make noise, I don't seem to find any vibrating loose screws either. I eliminated the possibility that the chain might be making the noise as noise persists when the cycle is stopped. It really seems to be something to do with the internals. AARRHH you used synthetic with a wet clutch. that noise could be the clutch slipping as the oil is too slippy. what's your acceleration like? You need at the most semi synth, Link to comment Share on other sites More sharing options...
dori Posted October 12, 2007 Author Share Posted October 12, 2007 no, I had the noise before changing the oil too... I do know what you are talking about (it being very slippy), but I find it makes the gear changes smoother and quicker... the only time it is bad is when I rev it up too quickly while releasing clutch too slowly... it slips as in it revs up quicker then it should without making the bike move much (not enough rezistence). It is a small power bike, so even doing hard acceleration, the clutch grips fine. I went on a 500km trip last weekend and tried everything and ran fine. The noise comes on only some days, when it is cold... for all I know I could start it up right now and it might be fine. Link to comment Share on other sites More sharing options...
jrhendryx Posted October 13, 2007 Share Posted October 13, 2007 no, I had the noise before changing the oil too... I do know what you are talking about (it being very slippy), but I find it makes the gear changes smoother and quicker... the only time it is bad is when I rev it up too quickly while releasing clutch too slowly... it slips as in it revs up quicker then it should without making the bike move much (not enough rezistence). It is a small power bike, so even doing hard acceleration, the clutch grips fine. I went on a 500km trip last weekend and tried everything and ran fine. The noise comes on only some days, when it is cold... for all I know I could start it up right now and it might be fine. hrm, this probably isnt your answer, but since it only seems to happen in cold temps, heres a maybe.... cold air makes things shrink up, so fittings arent as tight as they might have been before. in a truck or car, this can cause the dashboard to rattle. maybe whats happening is that your airbox is developing a slight leak, so you get a whistling noise, like you would hear with a car window that is open slightly? maybe the cover isnt seating as tightly in cold air, but its pulling harder at higher rpm/kph, so maybe thats whats happening? or it could be something else that the wind is whistling through strangely on cold days... the entire rest of the bike would experience the same flex between cold/warm temps. probably not whats happening to you, but a thought. Link to comment Share on other sites More sharing options...
Moderator drewpy Posted October 13, 2007 Moderator Share Posted October 13, 2007 no, I had the noise before changing the oil too... I do know what you are talking about (it being very slippy), but I find it makes the gear changes smoother and quicker... the only time it is bad is when I rev it up too quickly while releasing clutch too slowly... it slips as in it revs up quicker then it should without making the bike move much (not enough rezistence). It is a small power bike, so even doing hard acceleration, the clutch grips fine. I went on a 500km trip last weekend and tried everything and ran fine. The noise comes on only some days, when it is cold... for all I know I could start it up right now and it might be fine. Its the polymers in the oil with synths, your not supposed to use full synth. sounds like you are getting some clutch slip and it will get worse as the cork on the clutch starts to go as they are not designed with synth in mind!! your choice of course I wonder if an outer bearing seal is becomming brittle and when cold becames harder? maybe a crank/camshaft seal if it is revs dependant. A trick is to use a long screwdriver and listen like a stethescope for the loudest part. Link to comment Share on other sites More sharing options...
dori Posted October 14, 2007 Author Share Posted October 14, 2007 I got the impression it comes from the front so I took the front wheel off... bearings seem to be nice and well lubed, but the tachometer gear seemed really dirty and actually noisy when I turned it manually... I cleaned it and lubed it and will test soon... It might have been the mechanical tachometer cable inside not being properly lubed. Stay tuned. Thanks all for the suggestions (it might be true that the tachometer gears contract in cold making the noise nastier or maybe the bad leftover lube in the cable becomes hard and facilitates noise). Does synth oil do permanent damage? If so I will switch of course. Thanks It is speed dependent, but not rev dependent... I realized the noise frequency varies slightly with speed, and I can't do the stethoscope because it only happens at over 40km/h ... it would be a little dangerous Right now I am suspecting the internals of the spedometer/tachometer. Weird problem I would say, but I think I will have to somehow open that up and lube it. Link to comment Share on other sites More sharing options...
dori Posted October 14, 2007 Author Share Posted October 14, 2007 Solved! Problem was a little washer wore off and slipped through the speedometer cable and left the square/tapered end of the cable vibrate as it spun and making the whole display casing make that horrible noise. I put the same washer back, and covered the square end with a bit of paper tape to make it thicker and amortize buzzing if it should arise. Link to comment Share on other sites More sharing options...
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