ngk c7hsa equivalent with longer thread reach

[chamjisky]

hi
i had stripped the spark plug threads and installed a bushing .
now the issue is that he spark plug is recessed ..



the electrode is hardly protruding into the combustion chamber.
though the bike is runnig but its not running optimal ..

so is there any ngk non irridim or expensiv for that mtter plug with deeper reach ?
it should be at least 3mm more deep then the stock one .

 

[my67xr]

what sort of bush did you use?
can you post up any pictures of it or a link to a site that sells them ?
it is strange that the plug wont reach the combustion chamber.


NGK has a listing for Racing Spark Plug range,
they have 3 with a 19mm long thread (3/4"), and about 6 different 19mm long threaded Irridium spark plugs available
you would want to talk to a NGK rep before you bought them though, just to double check they'd fit/work.

the longer reach spark plugs are a lot more expensive than the standard plugs.

hottest heat range, cost $40ea delivered- (if bought in a pack of 4 spark plugs)-
http://www.ebay.com.au/itm/NGK-RACI..._Parts_Accessories&hash=item19dd0c6622&_uhb=1

mid heat range, $36 each delivered-
http://www.ebay.com.au/itm/NGK-Spar..._Parts_Accessories&hash=item5af2e46d69&_uhb=1

coldest range, $52 each delivered-
http://www.ebay.com.au/itm/NGK-RACI...hicles_CarParts_SM&hash=item3a4d0ddc83&_uhb=1





for the $40 odd dollars you would be spending on a spark plug, it may be cheaper to buy another head and fit that?
depending on what you have now ?

 

[zwebx]

unless you want to drill the spark plug hole a bit larger then helicoil it i would post a wtb up in miniclassifieds

 

[motodevo]

Drill it out and retap it to 12mm, you can get the same plug spec in 12mm, or as said helicoil it

 

[rotn50]

We have 125 zongshen horizontals at work with D8EA ngks in them, the D8EA is what the vertical motors mainly run.

 

[my67xr]

i have an old Ducar 125 head that has the D8ea too.

 

[rotn50]

There ya go lol. The good ole Ducar has a special place in my heart, there a real goer. All our brand new 125 zongshen buggies have them, every other horizontal is 16mm but the bloody D8s are 18mm lol.

 

[chamjisky]

this is how the ngk c7hsa plug is sitting in its hole when fully threaded..

btw will it work in the current setup ? where the plug is recessed in its hole .. ? does it matters ?
i will be giving ngk c7e/cr7eb/c7e a try if i find them locally ..

or i will try c8e series (Resisted or non reisted) .. if neither works i will replace the head as thats cheap

 

[chamjisky]

i am finding ngk cr8egp platinium plug .. with one copper washer inserted it is physically perfect and sits flush with the head ..

but should the different heat range be of concern ?
the bike is 88cc.. making 9.5:1 CR

 

[my67xr]

the repair looks like someone has bashed a Flange Headed Nut, backwards into the spark plug hole ?
or pulled the nut into the head by having a bolt on the chamber/valve side of the head.
it has damaged all around the thead in the chamber, and possibly damaged the valve seats too ?

i would just look for another head

 

[chamjisky]

no the valve seats are ok .. it just appear sso in pics because its not cleaned ..

the bush is typicall in this part of the world ..

most machinists install it and say it doesnt matter if the plug seating flush with chamber or not ..

anyohw ..

now my question is will the differnt heat range matter and how ?

like originally it had c7hsa .. now i will be using cr7egp .. (

 

[my67xr]

with the CR8EGP,
running a colder spark plug, it would be more prone to foul up and turn black with carbon.
this makes it harder for the spark to jump, and it will get worse till it wont run.
it will need to be run at higher rpms/temps to keep it clean too, or it will drop off in performance reasonably quick

the CR7EGP,
is the same heat range as a standard plug, so it should be fine
and being a Platinum Alloy fine tip plug, that is a bit better too than the stock plug.

 

[chamjisky]

with the CR8EGP,
running a colder spark plug, it would be more prone to foul up and turn black with carbon.
this makes it harder for the spark to jump, and it will get worse till it wont run.
it will need to be run at higher rpms/temps to keep it clean too, or it will drop off in performance reasonably quick

the CR7EGP,
is the same heat range as a standard plug, so it should be fine
and being a Platinum Alloy fine tip plug, that is a bit better too than the stock plug.

hmm thanks thats some realy info ..

i will be replacing the head ..