Spark plug replacement

Pablo

Master Bike Builder & Forum Sponsor
Dec 28, 2007
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Duvall, WA PNW
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What are the spark plugs that people have tried in these 2 stroke chinese engines. I have tried the champion cj7y, and didn't like it.
NGK B5HS works great and they are inexpensive or maybe you could try the next range cooler B6HS, but supposedly the Chinese stock plug is equivalent to the hotter B4HS...which I don't agree with....but the stock plug is slightly different than the NGK in construction and electrode tip length.

As a side note: my reckoning says a NGK BR6HIX Iridium plug would fit...not sure how it would perform.
 

paul

Well-Known Member
Dec 23, 2007
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Kalamazoo, MI
i replaced my plug and not much difference at all. the spark plug wire i changed and it made a huge difference
 

sisdavid

New Member
Mar 31, 2008
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Daytona Beach
Thanks for the help I tried the Dimon fire. That is comp "forget the number" to the Champion cj7y, and I do not like the short threads. Could get carbon build up on bottom portion of spark plug threads
 

toytime

New Member
Mar 20, 2008
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Ontario
I am now going with a Champian L86c and I love the new sound I seem to be getting.
The plug is a bit too long and I may end up with probs. when I go to remove it but it did change the sound and feel of the bike, almost as if it is running a little richer now, from the sound of things. I have also used the "40501" which is what I seem to remember being an NGK but looking at it now, there is no "ngk" marking.
 

Pablo

Master Bike Builder & Forum Sponsor
Dec 28, 2007
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I'm going to fire mine up with a B7HS - just for ****z and giggles. I got it for $1.

I normally run a B5HS with no issues, so I'll let you know how a plug two steps cooler does. (not necessarily a smart move)
 

sisdavid

New Member
Mar 31, 2008
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Daytona Beach
First picture is of Dimonfire do not know what number, but is the Cj7y champion equivaliant. Second red arrow is the stock plug. See how the stock plug reaches all the way down, and the Dimonfire does not. I get carbon on the last 2 or 3 threads which makes it really hard to screw in the regular length plug because of carbon. You would have to take the top part of your engine the part that the plug goes into and scrape carbon off to go back to a regular length plug.


 
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sisdavid

New Member
Mar 31, 2008
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Daytona Beach
I am now going with a Champian L86c and I love the new sound I seem to be getting.
The plug is a bit too long and I may end up with probs. when I go to remove it but it did change the sound and feel of the bike, almost as if it is running a little richer now, from the sound of things. I have also used the "40501" which is what I seem to remember being an NGK but looking at it now, there is no "ngk" marking.

Toy Time a longer plug may creat a sittuation that requires you to take the top part of your head off to take the plug out because of carbon.
 

sisdavid

New Member
Mar 31, 2008
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Daytona Beach
I think the CJ7Y Champion should be off of the list because if you go back with a plug with the longer threads you have to take the head off to get the carbon off
 

Down_South

New Member
Aug 28, 2008
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North Carolina
I have two engine kits. I have a 50 and an 80. The Chinese plug that came with the 50 had a reference number to NGK BP7HS. I have successfully used NGK BPR7HS and an Autolite 4123. Great Plugs. Does anyone know how long a plug should last (in general)? I've been running the Autolite 4123 for almost a year and it hardly has any erosion on the center electrode.
 
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