Ignition pick-up coils gapped at 0.018". WHY? - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
Electrical
Where does this wire go?
Includes Electrical mods, Lights, Stator,
Rectifier, Diagrams, etc

Reply
 
LinkBack Thread Tools Display Modes
post #1 of 22 (permalink) Old 05-15-2009, 08:18 PM Thread Starter
Linkmeister Supreme
 
OlHossCanada's Avatar
 
Join Date: Aug 2008
Location: Lethbridge, Alberta, Canada
Posts: 7,960
iTrader: (8)
   
Ignition pick-up coils gapped at 0.018". WHY?

I believe at least two active members here, fergy and lance, have narrowed the gap on their ignition pickup coils down to 0.018". I think fergy also put in a relay controlled, 12 volt line direct from the battery to the cylinder ignition coils. I`m curious about how much benefit these mods have given you in terms of easier starting, reliable running, fuel economy and anything else that you may have noticed?

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  
Sponsored Links
Advertisement
 
post #2 of 22 (permalink) Old 05-15-2009, 08:33 PM
The Professor
 
lance328's Avatar
 
Join Date: Feb 2008
Location: BUFORD, GEORGIA
Posts: 3,147
iTrader: (15)
   
Closing the gap gives you easier starts and quicker throttle response. Running the coils directly from the battery gives you about 1.0v more, which will increase the coils output voltage for a hotter spark and a more complete burn.


85 VN700 "Old Yella"

REBUILT ENGINE
CUSTOM PAINT
VANCE & HINES CRUZERS
EAR SHAVED AND RE-JETTED W/K&N'S
DUNLOP ELITE K591 FRONT & REAR
VOLTMETER
SYNTHETIC BRAKE FLUID
SYNTHETIC OIL & GEAR LUBE
PLEXISTAR 2 WINDSHIELD
SPLINES LUBED
ACCT'S GREASED W/TOC SPRINGS
COASTERD
LEATHER SADDLE BAGS
LEATHER TOOL AND ROLL BAG
PICKUP COILS GAPPED AT .018"
NGK CAP, WIRES, IRIDUMS
BARNETT FRICTION PLATES & SPRINGS
CUSTOM GRIPS, MIRRORS, LEVERS
ORIGINAL STATOR & R/R 14.5v
DEKA MF AGM ETX15L

Best Auto/Moto Insurance | Motorcycle Protection Today | FREE Trade-In Quote
lance328 is offline  
post #3 of 22 (permalink) Old 05-15-2009, 08:49 PM Thread Starter
Linkmeister Supreme
 
OlHossCanada's Avatar
 
Join Date: Aug 2008
Location: Lethbridge, Alberta, Canada
Posts: 7,960
iTrader: (8)
   
Thanks lance, that`s about what I remembered from reading about it several months ago, but wanted confirmed before I put that mod on my list of to-do stuff on the bike.

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/showthread.php?t=9127
OlHossCanada is offline  
 
post #4 of 22 (permalink) Old 05-16-2009, 04:37 AM
Members who have donated towards server costs
 
Join Date: Nov 2008
Location: Finland
Posts: 369
iTrader: (0)
 
Quote:
Closing the gap gives you easier starts and quicker throttle response.
This could be an interesting topic..

As I understand it, the pickups just give timing information to the igniter. A too big cap could reduce the signal too much for the igniter to operate, but how does reducing the gap improve performance? The voltage generated to the pickup coils is not square wave, so the gap does affect the timing - but how much? I would imagine that the factory gap gives the optimal timing. The only reason to reduce the gap I can think of is the aging of the timing magnets. By reducing the gap you could compensate the weakening of the magnetic field.

Well, that was just my theory, not having any real knowledge about the subject. But I'd like to hear (read) a plausible explanation why changing the gap would give any benefit.
pappa is offline  
post #5 of 22 (permalink) Old 05-16-2009, 06:51 AM
The Professor
 
lance328's Avatar
 
Join Date: Feb 2008
Location: BUFORD, GEORGIA
Posts: 3,147
iTrader: (15)
   
Quote:
Originally Posted by pappa View Post
This could be an interesting topic..

As I understand it, the pickups just give timing information to the igniter. A too big cap could reduce the signal too much for the igniter to operate, but how does reducing the gap improve performance? The voltage generated to the pickup coils is not square wave, so the gap does affect the timing - but how much? I would imagine that the factory gap gives the optimal timing. The only reason to reduce the gap I can think of is the aging of the timing magnets. By reducing the gap you could compensate the weakening of the magnetic field.

Well, that was just my theory, not having any real knowledge about the subject. But I'd like to hear (read) a plausible explanation why changing the gap would give any benefit.
As I stated above the results were faster and easier starts and a very noticable difference in throttle responce. I have done this mod to my bike and two others I have repaired with the same results. Granted all bikes had a Deka/Big Crank MF AGM battery and Irridium plugs, which will help with starting. The difference in throttle responce did not occur untill the gap was changed. The age of the bikes varied from 85', 97' 03', I have another vn750 comming next week for an engine rebuild and I will do the same "MOD" on that bike.

Apparently I am not alone since I found the pick up coil "MOD" on this site in the Archives, you are more than welcome to test the "MOD" yourself. It could very well be due to aging magnets on the rotor, I won't dispute that. If that is the case it is great to know there is a "FREE MOD" that will regain or improve performance.

If I have to give an educated guess on why it would be because with any magnetic field the further you move the source the weaker the field. If you move the pickup closer to the source the quicker it will recieve the signal. Although I have no data to support this theory but from the results I would say it Advances the Ignition timing curve. By advancing the ignition timing you create more cylinder pressure resulting in more power at the crank.


85 VN700 "Old Yella"

REBUILT ENGINE
CUSTOM PAINT
VANCE & HINES CRUZERS
EAR SHAVED AND RE-JETTED W/K&N'S
DUNLOP ELITE K591 FRONT & REAR
VOLTMETER
SYNTHETIC BRAKE FLUID
SYNTHETIC OIL & GEAR LUBE
PLEXISTAR 2 WINDSHIELD
SPLINES LUBED
ACCT'S GREASED W/TOC SPRINGS
COASTERD
LEATHER SADDLE BAGS
LEATHER TOOL AND ROLL BAG
PICKUP COILS GAPPED AT .018"
NGK CAP, WIRES, IRIDUMS
BARNETT FRICTION PLATES & SPRINGS
CUSTOM GRIPS, MIRRORS, LEVERS
ORIGINAL STATOR & R/R 14.5v
DEKA MF AGM ETX15L

Best Auto/Moto Insurance | Motorcycle Protection Today | FREE Trade-In Quote

Last edited by lance328; 05-16-2009 at 09:51 AM.
lance328 is offline  
post #6 of 22 (permalink) Old 05-16-2009, 08:33 AM
Senior Member
 
skalding's Avatar
 
Join Date: Jul 2008
Location: Miami, FL
Posts: 409
iTrader: (4)
 
I've been curious about this for awhile. How do you actually narrow the gap? I thought the coils were sealed units?

Edit - found it. https://www.vn750.com/forum/showthread.php?t=875

Scheherazade
'86 VN750
MF Battery, Iridium Plugs, RR relocated, Voltmeter, 170/80/15 Kenda Kruz rear tire, DIY Samsonite hard bags, DIY shaved seat with Beaded seat pad ('cause that's how I roll) and the dreaded STATOR CHANGE.

Shining Black Bess '86 VN750, retired for parts after a fried stator and being knocked (kee-runch) in her parking spot.

Last edited by skalding; 05-16-2009 at 08:40 AM.
skalding is offline  
post #7 of 22 (permalink) Old 05-16-2009, 12:43 PM
Members who have donated towards server costs
 
Join Date: Nov 2008
Location: Finland
Posts: 369
iTrader: (0)
 
Yes, reducing the gap would obviously advance the ignition, but why didn't Kawasaki alredy do so if it improves the performance? Could it be that advancing the ignition gives better performance, but at the expence of the engine durability?
pappa is offline  
post #8 of 22 (permalink) Old 05-31-2009, 11:01 PM
The Professor
 
lance328's Avatar
 
Join Date: Feb 2008
Location: BUFORD, GEORGIA
Posts: 3,147
iTrader: (15)
   
Originaly posted by Wwicker in another post.


Hot start problems VN750 2002 12500 miles. Solution: There are 5 proposed fixes in the verses. I applied 4 of them in sequence as follows:
1) Installed new battery. Old battery was still in acceptable range but not knowing its exact age I chose to switch it out. Sealed type battery of course.
2) Relocated the Regulator/Rectifier to side(per Forum sketches/pictures)
3)Put in new Iridium plugs. $7 a piece from Advace Auto Parts
4)Adjusted the pickup coil gaps. The top coil was at .030 and the bottom was over .040...which was probably the culprit. This solved my problem.

This coil adjustment procedure is really pretty simple....IF you have or purchase an impact driver (Northern Tools $12) to loosen the 3 face plate screws AND the 2 screws that hold the coils on. I did not remove the little tit/that holds the coil in place as one member did; but instead just filed down the front of the wings that the 2 screws go through and ground out the back of the screw holes (with drimmel tool) until the coils would move forward just enough to stop where I wanted them...I stopped at .022....the Forum suggests .020. Also you will need to have brass feeler guages so they will pass between the magnitized fields. I did use the blue formula locktite for the two screws that hold the coils on...as suggested by the member who wrote an excellant "how to on this procedure which I followed to get'r done. Thanks a million to whoever that was...printed it out but can't find yer name to give you credit.

OH the 5th item suggested as hot start preventative is one Fergy originated: Routing a new wire directly from the battery to the coils in the event the heat has caused the original wire in the harness to weaken over time. That was to be my next trial...but the wide coil gap was my problem.
WWicker/San Antonio


85 VN700 "Old Yella"

REBUILT ENGINE
CUSTOM PAINT
VANCE & HINES CRUZERS
EAR SHAVED AND RE-JETTED W/K&N'S
DUNLOP ELITE K591 FRONT & REAR
VOLTMETER
SYNTHETIC BRAKE FLUID
SYNTHETIC OIL & GEAR LUBE
PLEXISTAR 2 WINDSHIELD
SPLINES LUBED
ACCT'S GREASED W/TOC SPRINGS
COASTERD
LEATHER SADDLE BAGS
LEATHER TOOL AND ROLL BAG
PICKUP COILS GAPPED AT .018"
NGK CAP, WIRES, IRIDUMS
BARNETT FRICTION PLATES & SPRINGS
CUSTOM GRIPS, MIRRORS, LEVERS
ORIGINAL STATOR & R/R 14.5v
DEKA MF AGM ETX15L

Best Auto/Moto Insurance | Motorcycle Protection Today | FREE Trade-In Quote
lance328 is offline  
post #9 of 22 (permalink) Old 05-31-2009, 11:09 PM
Newb with a Bullet!
 
krebsne's Avatar
 
Join Date: Jun 2008
Location: Omaha, NE
Posts: 589
iTrader: (0)
 
Wow. Fascinating idea. I had not run across it before. Sounds like something to try when I am back on the road!

And it abuts with something I've been meaning to ask. I took my bike pretty far apart this weekend and disconnected 2 of my spark plug wires from the ignition coil. I noticed they were pretty cracked and weathered.

Obviously it would not be a bad idea to replace them. So the question is, buy the stock wires or is there actually any performance benefit to something like these-

http://cgi.ebay.com/ebaymotors/ws/eB...lenotsupported

If it's six of one, half dozen of the other I hate to pay more.
krebsne is offline  
post #10 of 22 (permalink) Old 05-31-2009, 11:41 PM
The Professor
 
lance328's Avatar
 
Join Date: Feb 2008
Location: BUFORD, GEORGIA
Posts: 3,147
iTrader: (15)
   
Quote:
Originally Posted by krebsne View Post
Wow. Fascinating idea. I had not run across it before. Sounds like something to try when I am back on the road!

And it abuts with something I've been meaning to ask. I took my bike pretty far apart this weekend and disconnected 2 of my spark plug wires from the ignition coil. I noticed they were pretty cracked and weathered.

Obviously it would not be a bad idea to replace them. So the question is, buy the stock wires or is there actually any performance benefit to something like these-

http://cgi.ebay.com/ebaymotors/ws/eB...lenotsupported

If it's six of one, half dozen of the other I hate to pay more.
Those wires are better than and cheaper than stock, check his site he has more. I just had Asbrand buy those.


85 VN700 "Old Yella"

REBUILT ENGINE
CUSTOM PAINT
VANCE & HINES CRUZERS
EAR SHAVED AND RE-JETTED W/K&N'S
DUNLOP ELITE K591 FRONT & REAR
VOLTMETER
SYNTHETIC BRAKE FLUID
SYNTHETIC OIL & GEAR LUBE
PLEXISTAR 2 WINDSHIELD
SPLINES LUBED
ACCT'S GREASED W/TOC SPRINGS
COASTERD
LEATHER SADDLE BAGS
LEATHER TOOL AND ROLL BAG
PICKUP COILS GAPPED AT .018"
NGK CAP, WIRES, IRIDUMS
BARNETT FRICTION PLATES & SPRINGS
CUSTOM GRIPS, MIRRORS, LEVERS
ORIGINAL STATOR & R/R 14.5v
DEKA MF AGM ETX15L

Best Auto/Moto Insurance | Motorcycle Protection Today | FREE Trade-In Quote
lance328 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