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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: Backroad Bob on March 25, 2012, 06:28:53 AM

Title: 1992 K 100 RS 4V Final Drive very hot, noisy
Post by: Backroad Bob on March 25, 2012, 06:28:53 AM: Hi Guys,
I recently lubed the splines on my K100, and re-assembled. A few days ago,after a short ride I decided to feel if the FD was hot. It was! Very!
So I put the bike on it's centre stand and with the engine running and the bike in third gear, the FD is making a bit of banging and clanging. I have yet to pull the FD, and was wondering if it is the universal joint that is the culprit, and if it is, would it heat the FD to the point that it's almost too hot to the touch?

It is possible that I may have re-assembled the drive onto the shaft incorrectly, or mis-aligned when putting it all back. I did not pull the FD apart. Just lubed the splines, including the clutch spline, and re-assembled the tranny and swing arm.
As I did not check the temp of the FD prior to the lube, it may have been like this for some time.

This coming week I will remove it from the bike, but in the mean time I thought I would ask the question of you good folks to see if I am overlooking something. I am currently reading up the Clymer manual that came with the bike.

Cheers, Rob
Title: Re: 1992 K 100 RS 4V Final Drive very hot, noisy
Post by: frankenduck on March 25, 2012, 09:34:36 AM: Did you remember to put gear oil in it?
Title: Re: 1992 K 100 RS 4V Final Drive very hot, noisy
Post by: Backroad Bob on March 25, 2012, 09:37:43 AM: I did. Castrol 80w90 gear oil. That was the first thing I checked. It is level with the top of the filler.
Title: Re: 1992 K 100 RS 4V Final Drive very hot, noisy
Post by: frankenduck on March 25, 2012, 09:49:31 AM: Is the rotor hot too or just the FD itself?
Title: Re: 1992 K 100 RS 4V Final Drive very hot, noisy
Post by: DRxBMW on March 25, 2012, 09:57:40 AM: Quote from: frankenduck on March 25, 2012, 09:49:31 AM
Is the rotor hot too or just the FD itself?

Rear Brembo pads tend to drag, thus generating heat.

Didn't you catch a brake on fire Duck ? Or was that someone on the KBMW list ?
Title: Re: 1992 K 100 RS 4V Final Drive very hot, noisy
Post by: frankenduck on March 25, 2012, 10:10:23 AM: No, that was a dipsh*t potential buyer who I let test ride the bike and was too f'n stupid to pull over when the rear brake locked up. Eventually the rotor got hot enough to ignite the nearby final drive boot. :yow

Mystic R-o-d did one too. :neener:

Warning: If you set the rear brake lever too tightly and apply the brake hard then it will cause the piston of the rear master cylinder to get snagged on its set screw and "lock" the rear brake. Always leave a little play in the rear brake.
Title: Re: 1992 K 100 RS 4V Final Drive very hot, noisy
Post by: Rick G on March 25, 2012, 09:26:08 PM: I have seen uni joints glowing red hot before letting go so it well could be that. Probably best to have a look and be sure as the rear uni does let go sometimes and better to be safe than sorry.
Munichs in WA can do a replacement uni and you are relativly close to them.
Title: Re: 1992 K 100 RS 4V Final Drive very hot, noisy
Post by: frankenduck on March 25, 2012, 09:31:19 PM: Quote from: Rick G on March 25, 2012, 09:26:08 PM
Munichs in WA

Who/where is this? :confused:
Title: Re: 1992 K 100 RS 4V Final Drive very hot, noisy
Post by: robleyd on March 25, 2012, 11:51:48 PM: WA = Western Australia, not Washington State. Munich = Munich Motorcycles in said (Australian) state.
Title: Re: 1992 K 100 RS 4V Final Drive very hot, noisy
Post by: frankenduck on March 26, 2012, 12:05:19 AM: My bad. I live in Washington so that's what leaps to mind when I see WA.
Title: Re: 1992 K 100 RS 4V Final Drive very hot, noisy
Post by: robleyd on March 26, 2012, 02:41:59 AM: Heh; pretty much the same here - if I see SA I don't think South Africa :lol:
Title: Re: 1992 K 100 RS 4V Final Drive very hot, noisy
Post by: Rick G on March 26, 2012, 03:41:35 AM: Oops note to self dont confuse the people in other countries :embarass:
Title: Re: 1992 K 100 RS 4V Final Drive very hot, noisy
Post by: robleyd on March 26, 2012, 07:08:26 AM: Yeah, remember that the US is the world :hmm:
Title: Re: 1992 K 100 RS 4V Final Drive very hot, noisy
Post by: DRxBMW on March 26, 2012, 07:36:11 AM: Quote from: Rick G on March 25, 2012, 09:26:08 PM
I have seen uni joints glowing red hot before letting go so it well could be that. Probably best to have a look and be sure as the rear uni does let go sometimes and better to be safe than sorry.
Munichs in WA can do a replacement uni and you are relativly close to them.

Are there ANY clicking noises emanating from the UJ Bob ?

Most UJ's sound a forewarning before failure/total meltdown.
Title: Re: 1992 K 100 RS 4V Final Drive very hot, noisy
Post by: Backroad Bob on March 26, 2012, 07:44:37 PM: Follow up:

Guys, I rang Munich Motorcycles in W.A. ( Western Australia) LOL! who were quite helpful.
Said that I am going to hear a bangin' an a clangin' when the bike is in gear and driving the rear wheel with no load on it.
Well, not so much bangin' an clangin', but the drive would be noisy, but only when under no load.
I asked about the heat, and was told they do get quite warm, and not to worry unduly about that. ( we were two up at the time.)
I pulled the FD and checked the universal joint visually, and physically. Could not detect any movement, or hear any clicking. It other words, it felt tight when rotated back and forth.
I added a little extra moly to the spline which is in v. good shape, and re-assembled.
So from now on, I will be watching my FD very closely, and will post if anything changes.
One of those infra red lazer temp probe thingys would be good to use in a situation like this. I might check it out.
Thanks for the replies everyone.............appreciated.

Cheers, Rob