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Buell Forum » Knowledge Vault (tech, parts, apparel, & accessories topics) » Engine » Big Mechanicals: Head, Cyl, Piston, Rod, Crank, Flywheel, Cases, Bearings » Archive through October 22, 2006 » Clunking noise from engine « Previous Next »

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Acejay
Posted on Friday, October 06, 2006 - 05:22 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

ive got an xb12 with 1500km on it and in the last 200 km it's started to make a knock or clunking noise which seems to be coming from the cylinder or head area - i cant really tell which.

its especially noticeable when cold, but is still there a little when warmed up. it starts off as single odd knocks when cold, but as it warms a little they get to be in series, like knockety-knock-knock (sorry its hard to explain). you can actually feel the knock through the pegs and the handle bars.

irs quite pronounced when its idling, but is reduced when there is a few revs, and higher than that its hard to tell if its there.

has anyone had an experience like this before?? i have no probs with the usual aircooled rattle etc, but like i say this is new and you can even feel the clunk. the bike is booked in for the first service at the end of the week, but who knows what the service will be like at the dealer.
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Jackbequick
Posted on Friday, October 06, 2006 - 08:34 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Maybe a loose alternator rotor? That is held on by the big nut on the left end of the crankshaft. It is called the compensator nut if I remember right. Has a very high torque spec on it, something like 260 or 310 foot pounds. Details on the torque spec are in the KV.

To trouble shoot it further, take piece of 1/2" wooden dowel about 15" long and hold it against the "flap" over your earhole so that it presses the ear shut. Put the tip of any clean finger in the other ear to block external noises. Then start touching the other end of the dowel to the engine and see if you can localize the noise.

Another noise I've heard that sounds a little like that was a too loose primary chain, it was slapping the inside of the primary cover a little.

Jack
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Acejay
Posted on Saturday, October 07, 2006 - 06:49 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

good advice, i was just about to go down and listen to it with a screwdriver the same way, just thought id check in here.
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Sweatmark
Posted on Saturday, October 07, 2006 - 12:16 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Any chance your clunk is associated with the primary drive?

http://www.badweatherbikers.com/buell/messages/32777/155801.jpg
http://www.badweatherbikers.com/buell/messages/3842/222585.html?1160035597
http://www.badweatherbikers.com/buell/messages/3842/4010.html

Seems there's lots of people here who have experienced this.

Mark
Oregon
un-clunk (so far) XB9
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Acejay
Posted on Saturday, October 07, 2006 - 07:23 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

the primary seems to be the problem, when i had a listen with the screwdriver last night the noise definately sounded like it was coming from behind the primary cover.

cheers,
ajay
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Jackbequick
Posted on Saturday, October 07, 2006 - 10:07 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Yeah, screwdrivers do work good too.

Sound like you have a loose stator (i.e., the compensator nut is loose) or the primary chain needs to be adjusted.

The chain should be easy to check through the inspection cover. The pretty much agreed on by BadWeb adjustment is to have a total of 3/4" of play (total, up and down) at the tightest spot on a cold chain. The service manuals call for a little tighter but the 3/4" seems to work better.

Several people have reported loose compensator nuts in the KV and on the XB board in recent months. The toque spec on that nut was raised from 215 ft/lbs to 261 ft/lbs if I remember the numbers right. And the shaft and nut need to be cleaned, degreased, and have red LocTite applied when mounting.

I don't know all the particulars on the increased torque spec and don't see it in the Tech Bulletins in the KV, maybe someone can fill us in on the details?

Jack

(Message edited by jackbequick on October 07, 2006)
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Blake
Posted on Saturday, October 07, 2006 - 10:32 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Y'all must have your ad blocker running.

Turn off your ad blocker and look for the Service Alert banner here on BadWeB. : )
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Acejay
Posted on Sunday, October 08, 2006 - 05:48 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

ive seen that ad blake, but its an 07 bike, so it shouldn't have that problem still.
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Dkennedy
Posted on Sunday, October 08, 2006 - 08:58 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Acejay, check this out. It maybe your solution

http://www.badweatherbikers.com/buell/messages/32777/155801.jpg
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