spark plug gapping/side gapping - Victory Forums - Victory Motorcycle Forum
LinkBack Thread Tools Search this Thread Display Modes
post #1 of 5 (permalink) Old 09-07-2012, 10:20 AM Thread Starter
Premium Member
dtmmil's Avatar
Join Date: Jul 2012
Location: Hawley MN
Posts: 4,178
Default spark plug gapping/side gapping

I have done this before on other vehicles of mine, i saw a post here somewhere about it also. In that post/link it said when doing it to reduce the gap by .010. So I tried it on my bike, but started with just over .030(my gauge doesn't have .032 on it). No noticeable difference, so I dropped to .020 like suggested, it seems to have made starting rpms slightly lower, like I almost need to rev it slightly for warmup. After its warmer it seems to idle slightly higher though. Anyone else do the side gapping, what gap did you end up with?

currently bikeless

2012 Cross Country(Imp blue)
de-badged,(self tinted) Klockwerx flare, passenger backrest, passenger touring floorboards, VictoryHID kit, Miller Mufflers short baffles,Lloyds air filter(from witchdr.)Lloyds timing wheel(6*), adjustable drop link, cut seat, removed cats, PCV w/at.
1978(2009) Honda cb750 chopper
Hawley MN(sold)
dtmmil is offline  
Sponsored Links
post #2 of 5 (permalink) Old 09-07-2012, 10:49 AM
Senior Member
RICZ's Avatar
Join Date: Sep 2010
Location: Portland,Oregon
Posts: 12,125

Not a good thing to do. If anything, you'd want to err on the gap being a bit larger than spec. Reason being, the spark corona ignites the fuel mixture that's within that gap. Hence, a smaller gap = a weak and delayed flame front. Remember, gas/air doesn't explode, it burns. When it explodes, you get "pinging."

2010 Midnight Cherry XR. 7Jurock, Lloydz AF, ATS, AFR tuned VFCIII, IAV, and T-6 and locally repacked pipes = big smiles. SOLD to a dear friend, so it's still in the family."
2017 Spyder F3 Limited - keeps this old guy in the wind and riding with friends.
Cure that ugly stand up license plate with the cheapest and best laydown bracket. Click this:
RICZ is offline  
post #3 of 5 (permalink) Old 09-07-2012, 04:24 PM
Lifetime Premium
kevinx's Avatar
Join Date: Dec 2009
Location: At Southern Motorworx. High Springs Fl
Posts: 2,646

You have to do a bunch of engine work before there is any measurable difference in side gapping. It's not like we are running low compression flat heads or full bore race motors. You can get yourself into trouble with side gapping though with the amount of advance Vic runs

I'm not an asshole...I just type that way
Check us out at Southern Motorworx on FaceBook
kevinx is offline  
Sponsored Links
post #4 of 5 (permalink) Old 09-07-2012, 04:37 PM
Senior Member
Join Date: Feb 2011
Posts: 372

Wouldn't a wide gap with a high energy spark give you more of a defined ingintion source? I thought that was the whole idea with the high energy spark systems and the wide (.060 =/-) gaps on the modern autos.
40XC is offline  
post #5 of 5 (permalink) Old 09-08-2012, 10:36 AM
Senior Member
handyhoward's Avatar
Join Date: Jul 2011
Location: FL
Posts: 545

I cannot and will not dispute anyone on their beliefs concerning the need for or the repercussions from side gapping your plugs. I will mention that I have been completely "tuning" my bike's plugs for 50 years and that I believe that the benefits are there.

First tuning the location of the spark in the cylinder... I always make sure that the opening in the gap faces the point of fuel entry so that the mist injected into the cylinder isn't "broken down" or interfered with.

Second, I have always side gapped my bikes plugs at or just slightly larger than the recommended gap.

My results are quite acceptable to me... I get a clean all at once burn and feel that I get a brisker acceleration.

My mpg's have always met or beaten what the mfg's suggest is normal... and I have used regular gas a number of times when necessary without any pinging... I use mid-level almost all the time and have no problems.


2013 Indian Vintage Chief FE... #7 of 25

2011 Victory Vision Tour Premium...
handyhoward is offline  
Sponsored Links

Quick Reply

Register Now

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

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


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

Email Address:


Thread Tools Search this Thread
Show Printable Version Show Printable Version
Email this Page Email this Page
Search this Thread:

Advanced Search
Display Modes
Linear Mode Linear Mode

Posting Rules  
You may not post new threads
You may not 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