Spark plug modification.

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Down_South

Down_South

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Aug 28, 2008
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Nate D has posted a good mod here and I'll have to try it some time. Just put a BPR6HIX on it and watch the thing buzz! I have fooled around with standard plugs and a grinder and it will make a difference if you taper the electrode. Have fun, be safety minded and don't grind the ground electrode too small or it could get too hot, fall off and blow the engine. OOPS LOL.
 
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Bryan Smith

Bryan Smith

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Dec 1, 2008
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Summerville, South Carolina USA
Bryan Smith said:
I was hoping to increase my compression without shaving the head.
I have a Starfire 50cc Gen II engine. (They come with slant heads). The other day I bought a Bosh 7818 plug which is the replacement for the NGK BPR6ES and BPR6EY (according to the packaging). It has twice the length of threads as the stock plug. I pulled the head and tried it in the hole and it cleared the piston at TDC. I put everything back together and put some anti-seize on the plug threads. I drove the bike and i can tell it has more top end power than before adding a couple of mph to the bike. So far it looks like a keeper mod for me.
Click to expand...
I wanted to give a progress report:
It's been over a year since I put this longer plug in my bike. I pulled it out the other day to clean it. I had no problems from the threads fouling when I removing the plug. I was warned before putting it in that carbon would build up on the longer threads and prevent it's removal, but I have had no such problems. I HIGHLY RECOMMEND THIS MOD if you have a slant head and want to boost power by increasing the compression without having to shave the head... just make sure your piston clears the tip of the longer plug and a little anti-seize on the threads doesn't hurt either.
 
stuartracing

stuartracing

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Dec 9, 2008
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Gainesville FL.
Nate,
I just got done modding my plug like you discribe and have to admit, WOW....Holy Moly dude....I slpit the strap a little more than you and accidently put a groove in the electrode....Still runs VERRY smooth, idle is right on, throttle response is nice.and acceleration is perfect....My motor idles like it`s got a cam in it, just has that nice rap pap pap pap,pap tone to it........
Thanks for the info...
Paul.....
 
john8460

john8460

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Aug 16, 2009
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do you cut a slice so there are two separate contact tips or just make a groove so that there is still just one contact tip
 
stuartracing

stuartracing

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Dec 9, 2008
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Gainesville FL.
john8460 said:
do you cut a slice so there are two separate contact tips or just make a groove so that there is still just one contact tip
Click to expand...
Straighten out the strap a little and the split the strap to just where it starts to bend into the plug body.....Sorta like a snakes tongue....It`s just one with a split at the last half of the ground strap....
There is a picture in this post towards the beginning.....
 
bikebum1975

bikebum1975

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Aug 18, 2008
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Saw someone made a mention about the Platinum plus 4 from Bosch I used those in a car once made it run like crap I wonde if the Accell ugrove plug would work in the 2 strokers Also had a car that didn't like platinum plugs all that much me personally I would stay with a good copper core plug the mod sounds interesting though worth killing a plug for. Only thing I would worry bout is it running to hot and possibly burning out the piston.
 
stuartracing

stuartracing

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Dec 9, 2008
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Gainesville FL.
I wonder if an extended tip plug plus the split strap mod would make any difference....The extended tip plug#BPR7HS has quit a bit of electrode extended out of the plug itself....Ifa regular NGK plug is good for a compression point, then this plug has got to be good for a couple.....Check one out....
 
J

JTinFL

New Member
Feb 4, 2010
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Port Charlotte,Florida
Does anyone have any experiance with this type of plug.One came stock in a Skyhawk 80/66cc Slant Head kit.The engine has a lot of power compared to a straight 80/66cc.Do'nt know if it's due to slant head,plug,or both.I got some B7HS NGK's.Would they be ok in a 80/66cc and a Skyhawk Slant Head 48cc.Any help would be appreciated.Going bonkers trying to choose best plug without damaging the engines.
 

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Allen_Wrench

Allen_Wrench

Resident Mad Scientist
Feb 6, 2010
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Indianapolis
My bike runs great on a basic NGK copper core plug. I worry (very much) that a platinum plug would be a bit much for a mostly aluminum engine. And I shudder to think how long it would live with an iridium plug. And whenever I've tested those multiple electrode plugs, it seemed like only one spark would jump the gap at any given time. Getting them to spark to all electrodes is beyond my skill.
And how does one safely bounce a spark off the head of a piston? Safely?
 
Outrunner

Outrunner

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Dec 27, 2008
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Atlanta, Georgia
Allen_Wrench said:
My bike runs great on a basic NGK copper core plug. I worry (very much) that a platinum plug would be a bit much for a mostly aluminum engine. And I shudder to think how long it would live with an iridium plug. And whenever I've tested those multiple electrode plugs, it seemed like only one spark would jump the gap at any given time. Getting them to spark to all electrodes is beyond my skill.
And how does one safely bounce a spark off the head of a piston? Safely?
Click to expand...
Allen, Can you explain what you mean by Platinum or Iridium spark plugs being "a bit much," A bit much of what?? I know for a fact, that the Iridium plugs require less voltage and amperage to create a very strong spark, thus making the demands on the ignition system much LESS, which INCREASES the longevity and reliability of the whole ignition system! The piston is aluminum in a chrome cylinder, the spark only fires from the spark plug tip to the spark plug electrode, it never "bounces" off the piston.
 
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Allen_Wrench

Allen_Wrench

Resident Mad Scientist
Feb 6, 2010
2,784
26
36
Indianapolis
Outrunner said:
Allen, Can you explain what you mean by Platinum or Iridium spark plugs being "a bit much," A bit much of what?? I know for a fact, that the Iridium plugs require less voltage and amperage to create a very strong spark, thus making the demands on the ignition system much LESS, which INCREASES the longevity and reliability of the whole ignition system! The piston is aluminum in a chrome cylinder, the spark only fires from the spark plug tip to the spark plug electrode, it never "bounces" off the piston.
Click to expand...
Ah, I had hoped for a response from someone like a elite member, or somebody who'd "been around the block a few times. My concerns with the platinum and iridium plugs were that they may be a higher heat range that was not recommended for these China girls. With your above clarification, I feel more at ease about that.
As far as bouncing a spark off the piston: I read in an earlier post that a builder had removed the electrode from his plug so that the spark would theoretically jump to the piston at TDC. I'm not sure what to think of that.
 
M

matesrates

New Member
Feb 6, 2010
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sydney
Down_South said:
Nate D has posted a good mod here and I'll have to try it some time. Just put a BPR6HIX on it and watch the thing buzz! I have fooled around with standard plugs and a grinder and it will make a difference if you taper the electrode. Have fun, be safety minded and don't grind the ground electrode too small or it could get too hot, fall off and blow the engine. OOPS LOL.
Click to expand...
hi there

I am planing to buy a bpr6hix
Is it still running good??? Same plug??
Did you do any mods on this plug??.shft.
Thanks for your help
 
M

matesrates

New Member
Feb 6, 2010
93
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0
sydney
JTinFL said:
Does anyone have any experiance with this type of plug.One came stock in a Skyhawk 80/66cc Slant Head kit.The engine has a lot of power compared to a straight 80/66cc.Do'nt know if it's due to slant head,plug,or both.I got some B7HS NGK's.Would they be ok in a 80/66cc and a Skyhawk Slant Head 48cc.Any help would be appreciated.Going bonkers trying to choose best plug without damaging the engines.
Click to expand...
hi there i have same engine
The motor is jerking...
Have you had this problem???

Or anyone eles have advice????

Thanks for your helpzpt
 
W

wildemere

New Member
Feb 12, 2008
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Newcastle
Considering that the optimal HTspark timing is between 5 to 10 degrees beforre TDC, removing the elctrode and hoping for a spark of the piston crown at TDC is a questionable exercise.

These rare metal plugs are made for high performance race motors and/or extreme long life situations like the rear bank of some front drive V6 cars where the plug change involves 4+ hours labour, jacking the motor of its mounts and hands like a monkey.

A iridium plug can last over 100,000 miles in a car engine, probably more than 20,000 in a 2 stroke.

1 irididum plug would last for many HT motors.

Thats why a platinum or iridium plug it is over kill for for a Ht because it will outlast the engine by a large factor.

The engine will be toast but the plug look like new

All the while you got 1% more power from your fancy high dollar plug.
 
Outrunner

Outrunner

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Dec 27, 2008
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Atlanta, Georgia
As far as bouncing a spark off the piston: I read in an earlier post that a builder had removed the electrode from his plug so that the spark would theoretically jump to the piston at TDC. I'm not sure what to think of that.(Quoted by Allen_ Wrench)

Allen, for someone to post such a ridiculous claim, had to be joking, or was giving false
information deliberately. A spark plug must have the electrode to complete the required
plug gap, which jumps a spark from the + positive voltage (plug wire) to the - negative ground, which is the spark plug body itself. That's why there are spark plug gap recommendations which for our engines, is around .018"- .022" depending on the type of spark plug being used. You're wise in questioning what you were led to believe, that"s why this forum is very useful for getting the correct answers, at least most of the time.
 
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J

jauguston

New Member
May 1, 2010
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Bellingham, WA
The only reason there is so much discussion about sparkplugs in my opinion is it is one of the few things a person with no mechanical skills can screw with. A spark plug is a simple device and there is no magic plug that will make a big difference in power. If it comes out a nice tan color when you look at it it is doing its job.

Jim
 
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