Spark plug modification.

Nate D

Nate D

New Member
Hello everyone, I'm new here. I have a great mod which especialy helps with the torque on the low end of the power band. As an ex-street racer I know the difference a good plug makes so I went looking for a performance one for my new 80cc. I could not find one so I decided to mod my own. Here is what you do. Take out the plug. bend the tip up with pliers so you can work on it. use a dremmel tool with cutting wheel attachment and cut about a 1/16 in groove in the middle of the metal contact tip. Bend it back but angle it so the double tips are closest to the contact node, this insures the spark does not contact farther down getting only 1 spark. make sure the tips are evenly spaced from the contact node. This will make the spark contacts the 2 points giving a more powerful ignition, better torque for dirt trails and hills, plus easier starts!!! enjoy the free mod. Let me know if anyone wants me to post a pic of the modded plug for reference :)
 
Last edited:
Re: Ways to increase Horse Power

Be careful bending the electrode. If it breaks in use you will have a gouged cylinder.

The stock plug is poor quality. I have had the electrode come off just trying to set the gap.

After a big movement like described it would be a case of not if but when, even with a quality plug.
 
Re: Ways to increase Horse Power

wildemere said:
Be careful bending the electrode. If it breaks in use you will have a gouged cylinder.

The stock plug is poor quality. I have had the electrode come off just trying to set the gap.

After a big movement like described it would be a case of not if but when, even with a quality plug.
Click to expand...

wildemere those are good points, while spending money for mods is great and sometimes the only option let us not forget the value of learning and sharing free mods & tweaks. As a dsm tuner I can tell you we have shared many free mods on the turbo charged cars, some giving up to 15 hp gains at no cost. I have been using this plug for 4 tanks already and no sign of wear. To ensure you do not snap the electrode make sure the plug is not cold. Room tempurature is fine or let it warm up in the sun bit. Metal can break when cold as it is brittle, when metal is warm it becomes maluable and can be worked with out losing structual integrity.
I just picked up the NGK BP6HS plug I heard about on a forum I will install and provide everyone feed back on a comparison of the 2. :)
xct2
 
Last edited:
Re: Ways to increase Horse Power

freewheeling frank said:
ya post a pic i wanna see this puppy
Click to expand...

Here is a pic, bear with the resolution just snapped em with my Helio ocean 2mp.
Also a comparison next to the stock plug non-modified.
 

Attachments

  • 0625090003.jpg
    0625090003.jpg
    116.5 KB · Views: 1,376
  • 0625090005.jpg
    0625090005.jpg
    91.3 KB · Views: 1,430
  • 0625090006.jpg
    0625090006.jpg
    87.3 KB · Views: 1,430
Re: Ways to increase Horse Power

Nate D said:
Here is a pic, bear with the resolution just snapped em with my Helio ocean 2mp.
Also a comparison next to the stock plug non-modified.
Click to expand...

OK I am back from a test run using the one I hear people buying the NGK BP6HS and the custom modded stock plug. Here are my findings. Feel free to try the 2 yourself and add your thoughts or feed back.

The NGK plug has a thicker core with a higher energy requirement so I found at low idle the spark wants to fade out due to the low electrical power produced during lower revolutions. You can kick the idle up however in an attempt to remedy this. This plug also extends slightly more which does 2 things, displaces space and increases compression. I found this slightly increased compression seemed a little more powerful on the low band (torque). Hear is the con, since the plug displaces more it lowers the actual displacement of the cylinder reducing the over all CC's of the motor. It was definately lacking power at the high end or top speed.

The Modded plug can idle better at lower rpm, still has significant torque and power increase at lower end of power band and also feels more powerful at the higher rpms.

Here are my thoughts. If you are going to be doing a lot of hill climbing or rough terrain and will not be going faster than 20 use the NGK and up your idle.

If you want good all around performance and plan to hit 30 every now and then, street and light trail riding then use the modded V tip stock plug.

I like to ride on the street, occasional hills, and hit the dirt bike trails now and again so the modded plug felt better for my needs. Yours might be different. As always, consider advice but make your own conclusions and try things for yourself. If you happen to try the free mod or come up with your own new design to try please share with the rest of us. Happy modding..trk
 
Last edited:
Re: Ways to increase Horse Power

well why dont you tell us what type of plug to use i use the ngk bp6hs and i have now problems give us some ideas thank
 
Re: Ways to increase Horse Power

Please explain how a spark plug can alter an engines cubic capacity?

Its bore x stroke that determines capacity.

Plug reach would make a minute difference to compression ratio.
 
Re: Ways to increase Horse Power

wildemere said:
Please explain how a spark plug can alter an engines cubic capacity?

Its bore x stroke that determines capacity.

Plug reach would make a minute difference to compression ratio.
Click to expand...

No problem, its simple mathematics my friend. Displacing volume in the chamber lowers the over all displacement. Do not take my word for it. This is also quoted by SBP, a company from what I understand on these posts is a very repspected and trusted company. Quote "with an extended tip,it centers the spark in the combustion chamber and actually displaces volume, effectively increasing compression ratio."

reference link
Sick Bike Parts
 
Re: Ways to increase Horse Power

skyliner said:
well why dont you tell us what type of plug to use i use the ngk bp6hs and i have now problems give us some ideas thank
Click to expand...

Hey skyliner, thanks for posting on this thread. The plug mentioned is the stock plug that comes with the engine. I shared a free mod you can do. Instructions and pics at the begining of post.

Thanks.

Until they come out with a bosche platinum 4 for the little china girl I'm going to keep experimenting with performance tips. :) call me crazy but hey im seeing some power gains
 
Last edited:
The plug end in the combustion chamber is not enough to consider. When you talk about compression ratio, you are really figuring volume ratio.
The height of the ex. port makes more difference. As the volume should be figured from the top of the ex. port. The book shows 6 to 1 compression ratio. A lot of power can be gained by upping the compression. Chuck it in a lathe and remove some metal where it contacts the cylinder. Or Weld it up a little. Piston to head clearance is critical and should be checked. Put a little clay on the top of the piston and turn it over once then remove the head and measure.
 
Nice really good mod :)

Im going to do the mod at the stock spark plug. i have a NGK B7HS right now. What you think?
 
Re: Ways to increase Horse Power

Nate D said:
No problem, its simple mathematics my friend. Displacing volume in the chamber lowers the over all displacement. Do not take my word for it. This is also quoted by SBP, a company from what I understand on these posts is a very repspected and trusted company. Quote "with an extended tip,it centers the spark in the combustion chamber and actually displaces volume, effectively increasing compression ratio.
Click to expand...


Vicsvw and Wildemere are correct, the plug has virtually no effect on displacement. Nate is confused over it's effect on compression vs displacement. The statement "displaces volume" has little to do with decreasing total displacement. It refers only to volume at TDC.

Although it sounds like a good idea, multi-spark plugs have been shown to be pretty much useless. Total energy and time profile of the spark counts far more than how it's physically distributed. Thank god for CDI. :)
 
Re: Ways to increase Horse Power

xlite said:
Vicsvw and Wildemere are correct, the plug has virtually no effect on displacement. Nate is confused over it's effect on compression vs displacement. The statement "displaces volume" has little to do with decreasing total displacement. It refers only to volume at TDC.
Click to expand...

Exactly correct.
 
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.
 
OMG, i just finished the mod of my stock spark plug, and jeez, what a difference... the accleration is REALLY improved, now runs very sweet..and top end i think that improves too.

thanks guys, now im gonna do the mod to the NGK B7HS :)
 
Do not run the 6ES "E" Plug as it is longer then the "H" The extra threads sticking into the combustion chamber will carbon up and then when the plug is removed will strip the threads in the head. The same length plug is very important.
 
Nate D said:
Hello everyone, I'm new here. I have a great mod which especialy helps with the torque on the low end of the power band. As an ex-street racer I know the difference a good plug makes so I went looking for a performance one for my new 80cc. I could not find one so I decided to mod my own. Here is what you do. Take out the plug. bend the tip up with pliers so you can work on it. use a dremmel tool with cutting wheel attachment and cut about a 1/16 in groove in the middle of the metal contact tip. Bend it back but angle it so the double tips are closest to the contact node, this insures the spark does not contact farther down getting only 1 spark. make sure the tips are evenly spaced from the contact node. This will make the spark contacts the 2 points giving a more powerful ignition, better torque for dirt trails and hills, plus easier starts!!! enjoy the free mod. Let me know if anyone wants me to post a pic of the modded plug for reference :)
Click to expand...
Hey could you send us some of those pics? sounds pretty simple just wanna get it right. cheers.
 
Those of you running a b5hs or a b6hs please give a b7hs a try. 2 cycle motors love cold plugs. I do a plug mod too but it's kind of the opposite of a splitfire. I file the grounding electrode to a semi point. It exposes more of the firing area of the plug and lets you run a colder plug with no fouling. Oh and Pablo.. Loving the new shift kit. Ordered Tuesday evening, was here Friday. Losing the left side chain and sprocket was great. The solider engine mounting has almost eliminated my vibrations. Shifting gears is just tooo cool.
 
Last edited:
You must log in or register to reply here.
Back
Top