Honda ST1100 Section > Honda ST1100 General Questions
Damper shaft bearing
saaz:
A couple of possibilities - the last one may be of the most interest if the damper unit is a possible problem (I have not had the ST apart enough to check the damper unit at the front of the shaft) (all of this from the now archived www.my-mc.com) (note to Diesel - may be worth saving some of this while we are still collecting relevant information - I have saved a lot of this sort of information over the years , some of which is still readily accessible, some not):
Another possibility: (Service Manual item number)
The (20) Clutch outer (clutch basket) has slots that contact the tabs on (14) clutch frictions. If there are wear notches in the basket, the friction plates can hang and then release, causing a clunk. This would happen at mild or heavy throttle. This has not a problem for me, but had glazed frictions (slipping clutch) 40K miles ago.
If this occurs only at a heavy throttle, it could be something else, there is a primary damper deep in the engine, but have not heard of a problem in there.
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the primary shaft is the diagnosis that Martin reached ages ago. There was a recent thread with a picture of it somewhere...It has a cam that is spring loaded, and so is meant to give at times to protect things.
My 1100 would do this clutch chattering thing, usually during warm up before everything is fully up to temperature. I also noticed it was more frequent directly following an oil change. At 150,000 miles the problem developed to the point where it was doing it hot or cold and slipping at the same time. Fresh friction plates and springs solved it for the 15,000 miles or so that I rode it after that before it was sold.
I'm not sure what causes it but it was much worse with certain oils in the sump. Motul coming to mind as the worst one. My theory is weak clutch springs allowing the chatter.
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One thing I have not seen mentioned here is the possibility of the noise coming from the damper unit on the front of the drive shaft. Last year I had a loud snapping noise when I let out on the clutch. It was very infrequent and would only do it when the bike was rolling. I checked everything from motor mounts to the rear end. I needed to grease the swingarm bearings anyhow, so I pulled the swingarm and driveshaft out and disassembled the front damper unit. I found the seal had failed, all of the gear lube that was supposed to be in there was long gone and everything was dry and starting to rust.
There is a collar behind the seal that was coming into contact with one end of the driveshaft/damper and scored pretty bad. This was causing the one part of the damper unit to hang up, then let go, causing the snap noise.
I bought a new seal and collar, cleaned everything up and reassembled it. It now works very smooth and doesn't make noise at all.
Greencan:
Morninin' Saaz et al...
I cave replaced the clutch...made a composite unit from one I had at home and the 'bits' I removed rom this bike in question.
"If there are wear notches in the basket, the friction plates can hang and then release, causing a clunk. This would happen at mild or heavy throttle. This has not a problem for me, but had glazed frictions (slipping clutch) 40K miles ago. "
Yep agree with that.
[i"]the primary shaft is the diagnosis that Martin reached ages ago".[/i]???
Not sure what this is...the shaft that connects the clutch assembly to the gear box is called the damper shaft...the input end at the clutch holds the roller bearing for the clutch assemble and is accessable after the outer basket and oil pump driver gear has been removed.
It is this bearing I have inquried if anyone had cause to replace. And why?
The bottom line is I think that the engine I am dealing with is simple noisey due to having a hard life...I aquired the bike in 2003 from it's second owner who, though having it for little over a year the log book with the bike indicates that he seldom rode it...the bike was first reg'd in early 2000 and and 152,000km on the clock when I got it.
The bike still rides well now even with a 'rattly' engine at idle, when hot and not under load.
There is a plus side which is I have another two engines at home that were recently give to me, so when I get time I'll build another engine if and when needed.
Thanks again.
Ciao, the can :)
saaz:
The primary shaft is the one that connects the clutch to the gearbox. There is a cam like arrangement that is meant to give if there is too much stress in the drive train. It is spring loaded, so tends to give a 'clack clack' sound if it disengages then engages again. I have not heard of anyone having to replace the bearing or the damper arrangement.
Mine also is a bit rattly but this is relative, as it sounds really quiet compared to my GS1000 Suzuki clutch rattle! Part of this is I think due to a bit of wear in the clutch (may be those notches but I have not had it apart) and the gear for the timing belt that is keyed onto the right hand camshaft as you look from the front is noticeably loose. If you have a spare engine or two have a look to see if one of them has a tight interference fit for the gear onto the canshaft. It is not an uncommon problem but not fatal, just annoying on an otherwise quiet engine. Once the interference fit is loose it seems it is hard to tighten up. Just in case you have not come across this, all the camshafts in 96 and before (at least for Australian models) have slightly more aggressive cam profiles in terms of lift and timing, so it would be best to match the cams from a donor bike as the 2000 model cams will be different to 96 and before cams.
Good luck!
Greencan:
Arvo Saaz et al...
"The primary shaft is the one that connects the clutch to the gearbox"
Point taken...noted that term is used in the parts listing and as a 'damper' in the service manual
"and the gear for the timing belt that is keyed onto the right hand camshaft as you look from the front is noticeably loose."
Yes I have heard that sometimes noises are generate from the timing driven pulleys, often within 10 to 20k of a belt replacement...though the key is a woodruff key and I would have think that this wear could be shimmed out?
Anyway, ta again.
Ciao, the can :)
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