I've written about this problem before here. You can read my previous posts and replies at THREADt1 and THREAD2. If this problem intrigues you, some info in the initial posts will give you a better understanding of the symptoms as this problem unfolded. This is more a report on what made the noise than a request for help, but if you wish to comment, feel free.
Briefly, my ST 1300 developed a clunking noise when shifting between 4th and 5th and letting out the clutch. This then progressed to the noise being heard and felt when the clutch was engaged after any shift (usually up). Then, after my winter layup, I heard a rattle - like loose gravel in the clutch housing at idle (and only idle). This noise faded away as the rpm's increased and was affected if I pulled in the clutch (at idle). There was no other sign that anything was wrong - the bike ran great, gas mileage was not affected, performance showed no change that I could see, hear or feel.
Last fall, just before winter layup, the local dealer had pulled the front cover off and changed the primary drive shaft. He heard and felt the clunk and thought the shock absorbing spring was weak. They charged me a bundle and were wrong. The mechanic told me he heard the same noise after the ?repair? in his test ride. This spring, after my layup, I heard a loud rattle from the clutch. I took the bike to Kevin (see LINKY 2). Due to his work load, he suggested I see what the dealer would say. To be fair, the bike did not exhibit the ?rattle? when I idled it for the dealer. After reviewing his notes, the dealer's mechanic suggested, "I'd replace the whole damn clutch" - I ran as far and as fast as I could.
I liked Kevin?s approach to diagnosing this - he used a stethoscope to localize the noise, checked the bike over, listened while I revved, it, squeezed the clutch, etc.. He thought it was the primary drive gear - a two piece gear with springs between the drive side and the driven side - and said the springs could be broken or weak. I suggested it might be the water pump chain or timing chain since he had isolated the sound to the front clutch cover area.
The answer: Kevin took the bike apart and found:
1. The clutch basket was 'loose' that is, it would turn back and forth with hand pressure. He removed the clutch and looked at the primary drive gear. As said above, this gear is a two piece assembly with springs between the two parts. (The clutch basket should be held tightly by a properly preloaded primary gear).
When the clutch basket (Honda?s name is ?clutch outer?) is reinstalled, one is supposed to preload the springs in the primary drive gear by inserting a screwdriver into a slot in this assembly and lever the front gears one tooth, compressing the springs The clutch outer is then engaged to the primary drive gear. My dealer did not do this when he reassembled the clutch last fall; Kevin found no preload on the springs and the clutch basket therefore would turn back and forth until the slack between the gears and the springs was taken up. This is what caused the 'rattle' or 'gravel in the clutch' sound I heard.
2. He also felt that the looseness and subsequent shock loading on the water pump chain by the clutch caused the water pump chain to stretch so that was replaced. (I put in excess of 500 miles on the bike after the dealer?s failed attempt to fix the ?clunk? so the clutch had no preload for this time.)
3. The clutch basket seemed to wobble a very little bit on its shaft. There is a needle bearing inside the clutch basket that rides on a bushing. This bushing was worn (it measured out of spec) and and this caused the little 'wobble'. Kevin said that the needle bearing almost never wears and it is not a separate part (the clutch basket costs about $200+ w/ the bearing). After replacing this bushing, the clutch outer was significantly tighter on the new bushing/shaft.
4. He played with the water pump and was not happy with the way it felt. In the end he replaced the bearing (not the seal) and with the bearing out, felt a little roughness when you turn the races. This was a judgment call and I have to play with the bearing for several minutes before I feel the roughness.
The bike went back together and Kevin took it out for a test ride. No gravel noise and a quieter bike. We talked more about the ?clunk?. A second test ride yielded this noise (it is intermittent) and he took it back to the shop, put it on the center stand, and with a helper blipping the throttle and by using his stethoscope, he was able to isolate the sound to the joint between the final drive and the swing arm. He said he has a few Gold Wings that make this same noise ? it is the loading and unloading of the splined joint in the drive shaft. It was late in the day, time was short, I was on my way to pick up the bike, and he said it was not serious.
Next winter, when I replace the rear tire, I?ll remove the 4 bolts that hold the final drive to the rear of the swing arm and pull it apart. Then I?ll lube the spline as he suggested with either Permatex copper anti seize or moly paste. He said he has a customer who has had the same clunk for well over 100K miles.
My dealer never found this problem. The dealer?s mechanic?s technique was to listen to me, test drive the bike, formulate a diagnosis and begin. He did check the final drive and U joint for play (basically a static test as described to me) and said he did not think the clunk originated there. I do not know if he did any other diagnostic tests or investigating. He was open about not knowing what the problem might be, said this was a gamble but it was his best guess. After he replaced the primary shaft and heard the same clunk, he offered to take the rear wheel/final drive, driveshaft out to investigate. He did drop the oil pan and examined the underside of the crankcase/transmission. And I understand the last guy benefits from those who were wrong before and will be called a genius when he fixes the problem. However, his mistake in reassembly made the problem worse and might have caused wear on the chain and bushing. Who knows?
However, Kevin listened to me, and prceeded in a methodical manner to diagnose the problem ? he looked at the shop manual clutch section, listened to the bike, used his stethoscope, and found and corrected the problem. He told me he was a trained mechanic, worked primarily on Gold Wings with a smattering of other bikes and had worked on very few ST?s. In the end, not all mechanics are created equal.
Briefly, my ST 1300 developed a clunking noise when shifting between 4th and 5th and letting out the clutch. This then progressed to the noise being heard and felt when the clutch was engaged after any shift (usually up). Then, after my winter layup, I heard a rattle - like loose gravel in the clutch housing at idle (and only idle). This noise faded away as the rpm's increased and was affected if I pulled in the clutch (at idle). There was no other sign that anything was wrong - the bike ran great, gas mileage was not affected, performance showed no change that I could see, hear or feel.
Last fall, just before winter layup, the local dealer had pulled the front cover off and changed the primary drive shaft. He heard and felt the clunk and thought the shock absorbing spring was weak. They charged me a bundle and were wrong. The mechanic told me he heard the same noise after the ?repair? in his test ride. This spring, after my layup, I heard a loud rattle from the clutch. I took the bike to Kevin (see LINKY 2). Due to his work load, he suggested I see what the dealer would say. To be fair, the bike did not exhibit the ?rattle? when I idled it for the dealer. After reviewing his notes, the dealer's mechanic suggested, "I'd replace the whole damn clutch" - I ran as far and as fast as I could.
I liked Kevin?s approach to diagnosing this - he used a stethoscope to localize the noise, checked the bike over, listened while I revved, it, squeezed the clutch, etc.. He thought it was the primary drive gear - a two piece gear with springs between the drive side and the driven side - and said the springs could be broken or weak. I suggested it might be the water pump chain or timing chain since he had isolated the sound to the front clutch cover area.
The answer: Kevin took the bike apart and found:
1. The clutch basket was 'loose' that is, it would turn back and forth with hand pressure. He removed the clutch and looked at the primary drive gear. As said above, this gear is a two piece assembly with springs between the two parts. (The clutch basket should be held tightly by a properly preloaded primary gear).
When the clutch basket (Honda?s name is ?clutch outer?) is reinstalled, one is supposed to preload the springs in the primary drive gear by inserting a screwdriver into a slot in this assembly and lever the front gears one tooth, compressing the springs The clutch outer is then engaged to the primary drive gear. My dealer did not do this when he reassembled the clutch last fall; Kevin found no preload on the springs and the clutch basket therefore would turn back and forth until the slack between the gears and the springs was taken up. This is what caused the 'rattle' or 'gravel in the clutch' sound I heard.
2. He also felt that the looseness and subsequent shock loading on the water pump chain by the clutch caused the water pump chain to stretch so that was replaced. (I put in excess of 500 miles on the bike after the dealer?s failed attempt to fix the ?clunk? so the clutch had no preload for this time.)
3. The clutch basket seemed to wobble a very little bit on its shaft. There is a needle bearing inside the clutch basket that rides on a bushing. This bushing was worn (it measured out of spec) and and this caused the little 'wobble'. Kevin said that the needle bearing almost never wears and it is not a separate part (the clutch basket costs about $200+ w/ the bearing). After replacing this bushing, the clutch outer was significantly tighter on the new bushing/shaft.
4. He played with the water pump and was not happy with the way it felt. In the end he replaced the bearing (not the seal) and with the bearing out, felt a little roughness when you turn the races. This was a judgment call and I have to play with the bearing for several minutes before I feel the roughness.
The bike went back together and Kevin took it out for a test ride. No gravel noise and a quieter bike. We talked more about the ?clunk?. A second test ride yielded this noise (it is intermittent) and he took it back to the shop, put it on the center stand, and with a helper blipping the throttle and by using his stethoscope, he was able to isolate the sound to the joint between the final drive and the swing arm. He said he has a few Gold Wings that make this same noise ? it is the loading and unloading of the splined joint in the drive shaft. It was late in the day, time was short, I was on my way to pick up the bike, and he said it was not serious.
Next winter, when I replace the rear tire, I?ll remove the 4 bolts that hold the final drive to the rear of the swing arm and pull it apart. Then I?ll lube the spline as he suggested with either Permatex copper anti seize or moly paste. He said he has a customer who has had the same clunk for well over 100K miles.
My dealer never found this problem. The dealer?s mechanic?s technique was to listen to me, test drive the bike, formulate a diagnosis and begin. He did check the final drive and U joint for play (basically a static test as described to me) and said he did not think the clunk originated there. I do not know if he did any other diagnostic tests or investigating. He was open about not knowing what the problem might be, said this was a gamble but it was his best guess. After he replaced the primary shaft and heard the same clunk, he offered to take the rear wheel/final drive, driveshaft out to investigate. He did drop the oil pan and examined the underside of the crankcase/transmission. And I understand the last guy benefits from those who were wrong before and will be called a genius when he fixes the problem. However, his mistake in reassembly made the problem worse and might have caused wear on the chain and bushing. Who knows?
However, Kevin listened to me, and prceeded in a methodical manner to diagnose the problem ? he looked at the shop manual clutch section, listened to the bike, used his stethoscope, and found and corrected the problem. He told me he was a trained mechanic, worked primarily on Gold Wings with a smattering of other bikes and had worked on very few ST?s. In the end, not all mechanics are created equal.
