Looking for some recommendations re. spark plug types for a Dnepr MT-11. The bike has electronic ignition (if that matters). I'd like to replace mine and the spare parts box I have contains a few sets of Russian plugs. Thinking there may be some better choices out there. Please advise.
Thanks!
Doug
Full Version: Dnepr spark plug rec
Hi
NGK BP7HS is the standard that most people use. Some people have been known to run a BP8 HS as well with no issues.
Dub
NGK BP7HS is the standard that most people use. Some people have been known to run a BP8 HS as well with no issues.
Dub
NGK - BP7ES if you have the longer plugs
Thanks! I'm off to NAPA to se what they have. Any rec. as to the proper gap? Your help is much appreciated!
Doug
Doug
0,5/0,6 there about
If you are using a different coil then experiment with a lrager gap. Sat 0.8mm for a Jap coil and 1.0mm for a Hardley coil. If you have a black plastic Russian coil then try 1.0mm too.
Like Shoutou said, be aware that the heads are made in to different types, one with long and one with short plug threads!!! For long threads use BP7ES, for short threads use BP7HS.
If you use long plugs for a short thraed head, you will destroy your piston, and vice versa you can burn a hole in the piston!
If you use long plugs for a short thraed head, you will destroy your piston, and vice versa you can burn a hole in the piston!
QUOTE (DneprCossack @ Feb 15 2010, 03:46 AM) 
Like Shoutou said, be aware that the heads are made in to different types, one with long and one with short plug threads!!! For long threads use BP7ES, for short threads use BP7HS.
If you use long plugs for a short thraed head, you will destroy your piston, and vice versa you can burn a hole in the piston!
If you use long plugs for a short thraed head, you will destroy your piston, and vice versa you can burn a hole in the piston!
The short plug heads are somewhat rare this side of the pond, due to the fact that they are usually from MB 650 bikes.....HOWEVER....as heads get replaced, parts shifted around they show up here and there. The short plug type usually have a brass or bronze bushing cast into the head, it was later found to be expedient to simply cast a thicker head at the spark plug hole. The long plug will more often than not only last, for one revolution, as the contacts are grounded out, as that are pressed togather. I disagree that a short plug in a "long" hole will burn a hole in a piston, Ignition timeing and or mixture issue are the more likely culperts......
....Ken
I have worked on bikes that only had short plug heads, MT11s and MT16s. Some of the heads DID have more threads and a deeper plug hole than others but none had the full depth of a long reach plug. I fit a dummy plug and open out round the plug hole with a Dremel to un-shroud it.
QUOTE (Serious Black @ Feb 16 2010, 02:57 AM)
I have worked on bikes that only had short plug heads, MT11s and MT16s. Some of the heads DID have more threads and a deeper plug hole than others but none had the full depth of a long reach plug. I fit a dummy plug and open out round the plug hole with a Dremel to un-shroud it.
Thanks! Looks like I have the long threads. Many thanks for the advice!
Doug
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