Word of caution about engine knocks. - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
Engine / Exhaust / Cooling
\ From the radiator, through the case and out
the exhaust. If it has to do with the cooling,
engine or exhaust, discuss it here!

Reply
 
LinkBack Thread Tools Display Modes
post #1 of 29 (permalink) Old 11-11-2011, 12:25 PM Thread Starter
Member
 
Join Date: Sep 2011
Posts: 33
iTrader: (0)
 
Word of caution about engine knocks.

Just wanted to offer a word of caution to those of you out there dealing with engine knocks. In my case I acquired a 2002 750, with under 4700 miles, that had a " rapping" sound that seemed to be coming from the upper portion of the front cylinder. I got a lot of advice about acct's. valves, etc. and did a lot of checking to try and determine the cause. After finally deciding to remove the engine, I removed the front cyl. head and cyl. exposing the front piston and found that it had obviously spun the connecting rod bearing. Just wanted to let you know because the longer an engine runs like this, the more the damage will be.
dodger is offline  
Sponsored Links
Advertisement
 
post #2 of 29 (permalink) Old 11-11-2011, 12:51 PM
Linkmeister Supreme
 
OlHossCanada's Avatar
 
Join Date: Aug 2008
Location: Lethbridge, Alberta, Canada
Posts: 7,960
iTrader: (8)
   
Thanks for the word of caution dodger. We always want to believe that a problem noise is something easily and inexpensively fixed. Your experience shows that we are not always so lucky, and a complete engine teardown is required. Good luck with the repairs.

Gordon

1991 VN 750 -"Cosmic Lady" or "Bad Girl"?
Purchased May 16, 2008
Approx.19,300km (12,000 miles)

H-D windshield
Relocated R/R
MF-AGM battery
Fiamm Freeway Blaster horns
F&S luggage rack and engine guard
Kury Offset Hiway pegs
July 13, 2016, Riding on the DARKSIDE now, Classic Radial 165/80-15


TOP TEN THINGS A NEW RIDER/OWNER SHOULD DO. Click on link.
https://www.vn750.com/forum/11-vn750-general-discussion/9127-top-ten-items-you-would-suggest-new-owner-do-his-new-ride.html
OlHossCanada is offline  
post #3 of 29 (permalink) Old 11-11-2011, 01:20 PM
Calif Rider
 
weh44att's Avatar
 
Join Date: Jan 2006
Location: Petaluma Calif
Posts: 725
iTrader: (0)
 
The previous owner must have really over torgued the engine. At 4700 miles the engine was not even broke in yet. Sorry to hear about the damage, to bad it was not something
simpler.

2004 25,500 miles
Led tail light enhancement
Homemade floor boards
Headlight modulator
Extra heat sink on R+R
R+R relocation
Homemade driver's backrest
Fused Stator
Mcct conversion-cost 4.50
Ride-on in tires
crash bar with home made hyway pegs
iridium plugs
home made fork wind deflectors
coil pickups adjusted.
Kenda kruz tires 110/90 170/80
weh44att is offline  
 
post #4 of 29 (permalink) Old 11-11-2011, 09:21 PM
Members who have donated towards server costs
 
Join Date: Nov 2007
Location: Chandler, Arizona
Posts: 2,850
iTrader: (0)
 
Could have been a defective bearing. But how did you determine it was the con rod bearing without splitting the cases?

I am a motorcyclist, NOT a biker.


1997 Vulcan 750, purchased about a week ago
2006 Sportster 1200 Low
2013 Royal Enfield Bullet 500, converted to carb
2001 Yamaha XT225, heavily modified
2004 Honda Rebel 250
1979 Vespa P200E
2002 Vulcan 750 parts bike
1994 Yamaha XT225 parts bike
VN750Rider/Jerry is offline  
post #5 of 29 (permalink) Old 11-11-2011, 11:48 PM Thread Starter
Member
 
Join Date: Sep 2011
Posts: 33
iTrader: (0)
 
Jerry: Once the cylinder (Lower portion) is removed, both connecting rods are visible where they connect onto the crankshaft journal. The front connecting rod was extremely loose and able to be moved up and down. The damaged bearing had been mulled up between the rod and crankshaft. After I split the case and removed the connecting rod, what was left of the bearing was paper thin.
dodger is offline  
post #6 of 29 (permalink) Old 11-12-2011, 06:56 PM
Members who have donated towards server costs
 
Join Date: Nov 2007
Location: Chandler, Arizona
Posts: 2,850
iTrader: (0)
 
Ok. I have never had a Vulcan 750 engine apart. So did it destroy the crankshaft? I noticed a new crank is $650.

I am a motorcyclist, NOT a biker.


1997 Vulcan 750, purchased about a week ago
2006 Sportster 1200 Low
2013 Royal Enfield Bullet 500, converted to carb
2001 Yamaha XT225, heavily modified
2004 Honda Rebel 250
1979 Vespa P200E
2002 Vulcan 750 parts bike
1994 Yamaha XT225 parts bike
VN750Rider/Jerry is offline  
post #7 of 29 (permalink) Old 11-13-2011, 12:37 AM Thread Starter
Member
 
Join Date: Sep 2011
Posts: 33
iTrader: (0)
 
There was some light scoring on the journal and connecting rod. A local machine shop has already got them back to specs. Just waiting for a bearing to arrive so they can set it up with the right clearance. Going to run around $ 350.00
dodger is offline  
post #8 of 29 (permalink) Old 11-13-2011, 12:52 AM
Old Fart
 
Knifemaker's Avatar
 
Join Date: Jun 2004
Location: Catawissa, MO
Posts: 11,634
iTrader: (4)
     
Garage
Quote:
Originally Posted by dodger View Post
Just wanted to offer a word of caution to those of you out there dealing with engine knocks. In my case I acquired a 2002 750, with under 4700 miles, that had a " rapping" sound that seemed to be coming from the upper portion of the front cylinder.
Not sure what you meant by "acquired" ...are you saying you knowingly bought a bike that made a noise like that?

Hope you got a break on the price.

If You Are Not Sure If I Am Joking or Not....I AM !!Photos:
http://www.flickr.com/photos/knifemaker1954/sets/
Knifemaker is offline  
post #9 of 29 (permalink) Old 11-13-2011, 11:46 AM Thread Starter
Member
 
Join Date: Sep 2011
Posts: 33
iTrader: (0)
 
Call me a gambler. Yes, it had the sound when I bought it. Based on the sound, mileage, and my then thoughts about Kawasaki, I didn't think it would be a rod knock. The rest of the bike is in like new condition. I'll have about $1,400 in it when finished.
dodger is offline  
post #10 of 29 (permalink) Old 11-13-2011, 11:56 AM
1986 VN750
 
thtanner's Avatar
 
Join Date: Nov 2011
Location: Dana Point, CA
Posts: 3,255
iTrader: (8)
 
Garage
Quote:
Originally Posted by dodger View Post
Call me a gambler. Yes, it had the sound when I bought it. Based on the sound, mileage, and my then thoughts about Kawasaki, I didn't think it would be a rod knock. The rest of the bike is in like new condition. I'll have about $1,400 in it when finished.
$1,400 total investment after repair? Pretty solid for the year and mileage.

My '86 with 24k miles ran me $1,100. It was fairly mechanically sound and in fairly good visual condition. I look to have to put another $200 into it, totaling it up to around $1,300.

I'd say when all is done you made out well

1986 Kawasaki Vulcan 750
NGK Iridium Plugs #7803/DPR7EIX-9
Duralast Gold ETX15 AGM Battery
Coastered & Shaved
TOC MCCTs
Metzeler ME880 [110/90-19, 170/80-15]
Balance Dampers Replaced
Tuxedo Mod
Rebuilt Forks w/ Progressive Springs
V&H Cruzers
VN750.com Grill Cover
Meanstreak Seat
Emgo 23-92411 Handlebars
MOSFET FH012AA R/R


1990 Kawasaki Vulcan 750

1998 Honda VFR800 FI

2014 Honda VFR800F

1989 Pontiac Firebird Formula 350
thtanner is offline  
Sponsored Links
Advertisement
 
Reply

Bookmarks

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

Once registered, your User Name"cannot be changed". We can make exceptions within 7 days, but after that, it is set in stone.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome