Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[tizone]

I just bought some new plugs for the bike and was wondering if adjusting the gap is usually necessary or whether most folks are dropping them in right out of the box.

I did some searching for info and found lots on plugs and little on gapping...

[Doc 1]

I just bought some new plugs for the bike and was wondering if adjusting the gap is usually necessary or whether most folks are dropping them in right out of the box.

I did some searching for info and found lots on plugs and little on gapping...

Always check the gap..... .038 to .042

[grc]

I just bought some new plugs for the bike and was wondering if adjusting the gap is usually necessary or whether most folks are dropping them in right out of the box.

I did some searching for info and found lots on plugs and little on gapping...

Plugs are gapped by a machine during production.  If you trust that machine, and feel confident that no one bumped the tip and changed the gap somewhere between that machine and your hot little hand, I guess you could assume that the gap is correct and just screw those bad boys into the heads.  Or not.

Always check the gap on new plugs before installing them.  I also recommend applying a light coating of high temp antiseize compound to the threads, so the steel shell doesn't develop an affinity for those soft aluminum threads in the head.  It is also a good idea to use a torque wrench to install them (15 ft lb).


Jerry

[HILLSIDECYCLE.COM]

We've seen dyno evidence of .035" gap to be beneficial in engines that carry around 185 psi ccp, and up, as the more turbulent chamber will attempt to blow out the flame.
Another thing I'll make mention of, is that you do not really want the back side of the ground strap "L", to be facing chamber, shrouding the spark kernel.
That is why God made indexing washers.
While it may seem minuscule, it all adds up.
Scott

[bigjohn]

I thought I was the only one left indexing plug..........

[grc]

Don't need to worry about gapping them or indexing them if you buy some of the whiz-bang surface gap plugs I've seen advertised.  Always amazed how the old ideas and designs keep coming back, just like women's fashions.


Jerry

[Rimjam]

OK, where can I get some indexing washers?

[Twolanerider]

OK, where can I get some indexing washers?

Local parts store likely won't stock these anymore.  Try Summit.

http://www.summitracing.com/search/?keyword=indexing%20washers&dds=1

[bigjohn]

Don't need to worry about gapping them or indexing them if you buy some of the whiz-bang surface gap plugs I've seen advertised.  Always amazed how the old ideas and designs keep coming back, just like women's fashions.
Jerry

How about those e3 plugs...........guaranteed 10 hp gain......to think all the money I wasted to gain hp and all i had to do was put those plugs in   

[Big C.]

  Would a 110 with just a drop in TW7-H cam benifit from a gap of .035"?  Or should I set them to the high or low side of spec.?

[HILLSIDECYCLE.COM]

I wouldn't think that carry's a lot of cranking pressure.
Scott

[johnsachs]

NO magic in spark plugs, unless you're over due for a change. Set the plugs at .035", and call it a day.
John

[dlaws01]

If you have access to a spark plug cleaner/tester it is better to adjust the gap to get the best spark under pressure. You can see the plug firing while under air compression through an inspection window on the tester.  As suggested before the optimum spark produced can vary from plug to plug due to several variables.  Watching the plug fire under pressure is the best method to determine the best gap for the plug. This could happen anywhere from the minimum gap setting to a couple of thousandths over the upper gap limit. When the manufacturer recommends a gap range with a spread of .004" to .006" from minimum gap to maximum gap, the suggestion is that the best optimum spark will be produced within that range. It is really up to the installer to ultimately determine where in that range the best spark is produced.

[Big C.]

  Thanks for the great education on how and why you need to set the gap.  Quick question on indexing do we want the gap opening facing between the exhaust and intake valves or more towards just the intake valve? 

[timtoolman]

The goal is in the  plug gap face in the middle between the 2 valves , but as long as the back of the  electrode strap isnt facing the chamber blocking the combustion  is the end goal