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MOTOBRICK.COM => The MBdotCOM Community Center => Topic started by: kman on June 29, 2015, 06:27:41 PM

Title: Noisy Engine?
Post by: kman on June 29, 2015, 06:27:41 PM

I'm new to K bikes, like 1 month new. I'm not new to 2 wheels, I have been shaking around on top of V Twins for a while. My question to you is this. I have an "87 K75 with 41K on the clock. How quiet are these engines at idle? Mine seems to rattle a lot at idle, but smooths out with a little gas. The motor is extremely smooth while running. Do I have a legitimate concern or should I just shut up and ride.

Title: Re: Noisy Engine?
Post by: johnny on June 29, 2015, 06:33:02 PM

greetings kman...

post up audio of that engine... wanna take a listen... im thinking its getting ready to grenade any minute...

j o

Title: Re: Noisy Engine?
Post by: kman on June 29, 2015, 06:48:22 PM

I'll try to get a good audio with my phone tomorrow. Thanks

Title: Re: Noisy Engine?
Post by: Chaos on June 29, 2015, 10:18:06 PM

this is a small gold mine of information http://www.ibmwr.org/ktech.shtml  You noise could be worn out alternator drive dampers (monkey nuts) fairly common on old k's.  If let go too long alternator stops spinning and more parts need replacing http://www.motobrick.com/index.php?topic=6067.0

Title: Re: Noisy Engine?
Post by: motodude on June 30, 2015, 10:02:43 AM

+1 for monkey nuts.  Check 'em.

Quote from: Chaos on June 29, 2015, 10:18:06 PM

this is a small gold mine of information http://www.ibmwr.org/ktech.shtml  You noise could be worn out alternator drive dampers (monkey nuts) fairly common on old k's.  If let go too long alternator stops spinning and more parts need replacing http://www.motobrick.com/index.php?topic=6067.0

Title: Re: Noisy Engine?
Post by: The Mighty Gryphon on June 30, 2015, 03:07:19 PM

My 94 K75 has a clanky rattle between 1200 and 2000rpm.  Noise is not there when the engine is run without the alternator.  New alternator, monkey knutz, and drive dog(the splines on the old one stripped out for some reason) and the damn noise is still there.  Been there for the 14,000 miles I've put on the bike. 

I am beginning to think is may be the bearing in the intermediate section or possible the anti-backlash spring in the starter drive.  In any event, it doesn't appear to be hurting anything, so I am going to wait until this winter to get into the engine to check out these parts.

Title: Re: Noisy Engine?
Post by: kman on July 01, 2015, 06:03:49 PM

Here is a video/ sound track of my engine at idle. The noise seems to be all in the top end. Have a listen and let me know what you think. By the way, I know what a numb nut is, cause somebody said I are one, but what is a monkey nut.  :dunno2:

https://youtu.be/pqvC23v8Frk (https://youtu.be/pqvC23v8Frk)

Title: Re: Noisy Engine?
Post by: johnny on July 01, 2015, 06:10:47 PM

greetings...

i have heard the same before... its not good... not good at all...

its in really bad shape... i wouldnt ride it utill you getts a new engine in there...

j o

Title: Re: Noisy Engine?
Post by: TimTyler on July 02, 2015, 01:17:13 AM

Oh, Johnny...

Sounds to me like you might need to balance your throttle bodies or maybe have the injectors cleaned.

Try the Johnny prescription first: no-corn fuel with a bottle of Techron and long, hard riding.

Title: Re: Noisy Engine?
Post by: mystic red on July 02, 2015, 02:33:21 AM

Seriously.  There is nothing wrong with that engine. Don't listen to Johnny. It's fine. Take Johnny's favorite advice..."cheap oil, good tyres and run it till it won't move."