VIDEO- clutch problem, name that noise!?

so i've taken about a month off from the norton, returned to it tonight. Put the primary on, and put the clutch together. but i've got a NASTY noise from the clutch area when i put it in gear, hold the clutch in and spin the rear wheel. It sounds like it's coming from the plates? somewhere in that area for sure, doesn't make any noise while in neutral, and also has some slight drag when spinning the wheel in gear, not smooth like in neutral. I did roll the bike around while holding the clutch in and it wasn't as noisy/noticeable. no adjustment i make changes it. could this be some sort of stack problem? Listen to the video, i spin the wheel a few times, then jerk it a few times where the sound gets more clunky.
http://www.youtube.com/watch?v=dOjXdxQC ... e=youtu.be

kevbo82 said:

so i've taken about a month off from the norton, returned to it tonight. Put the primary on, and put the clutch together. but i've got a NASTY noise from the clutch area when i put it in gear, hold the clutch in and spin the rear wheel. It sounds like it's coming from the plates? somewhere in that area for sure, doesn't make any noise while in neutral, and also has some slight drag when spinning the wheel in gear, not smooth like in neutral. I did roll the bike around while holding the clutch in and it wasn't as noisy/noticeable. no adjustment i make changes it. could this be some sort of stack problem? Listen to the video, i spin the wheel a few times, then jerk it a few times where the sound gets more clunky.
http://www.youtube.com/watch?v=dOjXdxQC ... e=youtu.be

Click to expand...

Sounds like your rear drive chain is hitting the primary case or crankcase somewhere

Yes sounds like links rattle noise on inner case. Basket can rub inner case but that is more a scrapping sound. Eyeball light behind inner case to see what ya can. May have to space inner case out some with the center bolt shims but not too much w/o compensating the front mounts.

if it was the chain it would do it in neutral no? dead quiet in neutral when i spin the rear wheel. that was my first thought when i heard it, but then i took it out of gear and the rear wheel spun free with no noise at all. When i put my ear right up against the clutch i can hear "friction" inside there

Sounds like the dry clutches on my Ducatis! As you noted, can't be chain noise since it would happen in neutral as well if it was. It really sounds to me like dry clutch rattle (which is normal on a Duck). Did you change stack height/clean all the plates so that they are now totally dry? I'm just wondering if that's all it is - more clearance than previously with the clutch lever pulled in (more room to rattle) plus the dry plates/friction discs as opposed to having oil in there to dampen everything.

mike996 said:

Sounds like the dry clutches on my Ducatis! As you noted, can't be chain noise since it would happen in neutral as well if it was. It really sounds to me like dry clutch rattle (which is normal on a Duck). Did you change stack height/clean all the plates so that they are now totally dry? I'm just wondering if that's all it is - more clearance than previously with the clutch lever pulled in (more room to rattle) plus the dry plates/friction discs as opposed to having oil in there to dampen everything.

Click to expand...

yes Mike, i didn't change any components but i did clean all the plates. This is the first MC i've ever worked on, so in turn the first MC clutch i've ever had any experience as well. should i be putting any type of lubricant on the plates? I'm basically going by the manual and it didn't mention anything :?:

No - no lubricant on the plates - they will end up "lubricated" anyway from the primary chain case oil. And I can't say for sure that the rattle is really caused by dry plates in this case, it just sounds a lot like the sound a dry clutch in a Ducati makes. A Norton clutch is not a dry clutch due to the chaincase lube. There are folks here with belt drive primaries that have no lube in the chain case - and therefore essentially have dry clutches (same clutch, just no oil in the case) - perhaps one of them will advise if they have a similar noise. It just sounds so much like both of the Ducatis I previously owned that I struck me that way. But I suppose it could be something else.

The Norton service manual suggests cleaning the plates periodically but I have never done it on any Norton and never had a problem with clutch slippage so I can't say from experience that cleaning the plates could result in that noise. OTOH, if it does, it will go away as the chaincase lube works back into the clutch.

I ran dry belt primary but wet the new Barnett plates with ATF as they recommended to prevent chattering on initial bedding in. Peel belt primary did not rattle wet or dry plates. Clutch center splines can get waves of wear and cultich teeth worn to points might be a factor. Maybe the clutch locator circlip is over whelmed by the fixing nut tightness so pack ain't as tight as should be. Might try removing chains to see what is heard then. My Cdo's go in an out of silent rolling d/t rear hub alignment and chain slack to sleeve bushes on main shaft allowing basket weaving. With some terrible wear in these components while riding around pretty hard I don't think there's much dangerous to run it a bit and see how that goes.

i think i need to investigate/replace some of the parts in the clutch. It's a 73 750, but it's got the 5 bronze friction plate setup. god only knows when and how my dad converted it, i was reading some info on old britts about the thickness of all the different parts, maybe he's still got the stock 750 pressure plate on there or something? the clutch pull is also VERY hard, like breaking rocks with your hand, and again no adjustment has seemed to help that too much.

Hobot, i used the later electric start circlip, i put two bolts into the clutch center and a lever between them to tighten the nut down, i used a torque wrench and only put about 30LBS on it, so i don't THINK i would have put too much umph on the circlip.

kevbo82 said:

if it was the chain it would do it in neutral no? dead quiet in neutral when i spin the rear wheel. that was my first thought when i heard it, but then i took it out of gear and the rear wheel spun free with no noise at all. When i put my ear right up against the clutch i can hear "friction" inside there

Click to expand...

As mike996 says it's simply the plates rattling as they are dry.

In gear, with the clutch lever pulled in, the driven (friction) plates will be spinning inside the clutch when the rear wheel is turned as they will rotate with the mainshaft and clutch centre when the box is "in gear".

In neutral, the mainshaft is isolated from the sleeve gear and layshaft therefore the driven plates do not rotate when the wheel is turned so you don't hear the sound.

kevbo82 said:

i think i need to investigate/replace some of the parts in the clutch. It's a 73 750, but it's got the 5 bronze friction plate setup. god only knows when and how my dad converted it,

Click to expand...

A 1973 750 would normally have had the 5 bronze plate clutch. (apparently fitted to 750's from serial 212278)

Many people, particularly Ducati type, concider the rattle of a dry open type clutch to be quite sexy and exotic. I fall into that group.

Can be a head turner at stop lights.

Yes...on my Ducks it was rattly with a bit of a "ringing" kind of sound. Add the ventilated clutch cover and it's a LOUD rattly-ringing sound!

thanks for all the input guys, it just sounded rough and worried me, especially since like i said i have zero experience with MC's. so as far as the hard clutch pull, should i play with adding a plain plate to make that a more human type pull?

Yes the stack height makes or breaks the clutch ease and control so mix and match plates till big spring just slips in its groove w/o any pushing or near-y any slack - is how this hick gets sweet spot w/o measuring tools fiddle, then I measure sometimes just for fun. Wiggle clutch basket, if any visible then likely that's adding to the rattle proneness. Rattling parts are like too loose a fit in sex acts, so those that have it, have to make up excuses why they prefer it that way, while the more snug fits just smirk in knowing silence.

hobot said:

Rattling parts are like too loose a fit in sex acts, so those that have it, have to make up excuses why they prefer it that way, while the more snug fits just smirk in knowing silence.

Click to expand...

Are you sure about that "BIG" guy?

Any of you dry clutch people care to comment on hobot's assessment?

I will just say that noon is a little early for him and he hasn't had his fifth cup of coffee yet, or maybe hair of the dog, or morning pull on the hookah. Probably all the above!

Hey Mike 996, I'm guessing that you have a ST4s Duc?

Bruce MacGregor