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Author Topic: Noisy Engine?  (Read 7147 times)

Offline kman

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Noisy Engine?
« 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.
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  • Waxhaw, NC
  • '87 K75C, '02 Yamaha V-star, '04 Honda VT1100c2

Offline johnny

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Re: Noisy Engine?
« Reply #1 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
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  • :johnny i parks my 96 eleven hundert rs motobrick in dodge county cheezconsin  :johnny

Offline kman

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Re: Noisy Engine?
« Reply #2 on: June 29, 2015, 06:48:22 PM »
I'll try to get a good audio with my phone tomorrow. Thanks
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  • Waxhaw, NC
  • '87 K75C, '02 Yamaha V-star, '04 Honda VT1100c2

Offline Chaos

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Re: Noisy Engine?
« Reply #3 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
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  • sw ohio
1987 K75S    VIN 0231
Original owner, Original litter
200,000 miles (plus or minus) and 5 paint jobs
sold 6/23
2023 Ural 2WD sidecar (BMW's bastard step child)

Offline motodude

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Re: Noisy Engine?
« Reply #4 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
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'90 K75RT
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Offline The Mighty Gryphon

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Re: Noisy Engine?
« Reply #5 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.
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  • In my garage in Marilla, NY
  • '91K100RS White/Blue
Current:
'91 K100RS16V "Moby Brick Too"

Past:
'94 K75RT "Ilsa, She Wolf of the SS"
'92 K100RS16V "Moby Brick" (RIP, deceased in a vehicular assault)
'94 K75S Special Edition Dakar Yellow "Cheetos"
'89 K100RS Special Edition "Special Ed"

Offline kman

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  • Posts: 9
Re: Noisy Engine?
« Reply #6 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:

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  • Waxhaw, NC
  • '87 K75C, '02 Yamaha V-star, '04 Honda VT1100c2

Offline johnny

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Re: Noisy Engine?
« Reply #7 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
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  • :johnny i parks my 96 eleven hundert rs motobrick in dodge county cheezconsin  :johnny

Offline TimTyler

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Re: Noisy Engine?
« Reply #8 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.
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Offline mystic red

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Re: Noisy Engine?
« Reply #9 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."
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