MOTOR - SPARK PLUG QUESTION HELP.

HERO MAJESTIC PANTHER- HAD SINCE NEW AND MY PROBLEM IS MY SPARK PLUG WHITE PORSALIN IS ALWAYS SUPER WHITE. IVE TRIED A COLDER PLUG AND STILL THE SAME. IM RUNNING REG GAS AND IVE TRIED SUPER UNLEADED BUT STILL THE SAME. I ALSO USE 4 OZ . OF OIL PER GAL . B/J AT HANDY BIKES TOLD ME TOO. IM WONDERING IF I NEED TO USE A LARGER MAIN JET ????????????? TO ME ITS RUNNING LEAN FROM THE LOOKS OF THE PLUG . ANYONE HAVE ANY THOUGHTS TO THIS PROBLEM. ?????? ( 1700 MILES ON MOTOR NOW) THE JET IN IT NOW THAT CAME WITH MOPED IS A # 51. ALSO IVE ALWAYS HAD SPARK KNOCK AFTER 25 MPH. SINCE MOPED WAS NEW. IVE TRIED TO MESS WITH TIMEING BUT STILL THE SAME. THANKS GUYS, DOUG IN TEXAS.

Re: MOTOR - SPARK PLUG QUESTION HELP.

There's nothing wrong with a white insulator..

The indications of a dangerously too-lean mixture is that a top-speed plug chop on a brand new spark plug shows efinite signs of overheating.. The porcelain insulator will be pitted, grey or spotted with bits of aluminum.. or it's electrodes will show melting at their sharp edges under magnification.. And look down deep inside the insulator. If, after the plug chop, you see any black soot deep down in the bottom it's from unburned fuel, and the mixture is not too lean.

First check and see if the combustion chamber has a lot of carbon collected inside. This carbon build-up reduces the combustion chamber volume and it raises your compression ratio. A compression ratio that's high causes the fuel mix to burn hotter and faster.. if there's a thick layer of carbon, carefully chip and clean it away..

Even a small piece of carbon in the chamber that remains red hot can cause preignition .. no spark is needed since it's red hot and ignites the fuel mixture.

Another thing that happens is people use the wrong spark plugs.. if it's too long the edge of a thread of the spark plug protrudes into the combustion chamber and gets red hot.

Or, any sharp bit of protruding metal in the chamber can get red hot and stay hot.. and it ignites the mix before the spark does.

Assuming the combustion chamber is clean, the cures for pre-ignition vary .. you could drown the engine in fuel with a bigger main jet but that will kill power output. .. You could cut back on oil a bit to richen the mixture..

Or you could retard the ignition timing a bit .. OR you could use a higher octane fuel. ..Or you could lower the compression ratio with a thicker head gasket.

I know you've already tried some of these solutions.. and it's very hard to believe that an unmodified, completely stock, brand new bike would have a preignition problem at +25mph.

If there's more to the story of the history of the bike, say so.. like if someone shaved the head.. or "forgot" to reinstall a cylinder base gasket .. or messed with something else..

Re: MOTOR - SPARK PLUG QUESTION HELP.

ive tried super unleaded- no one has touched my moped but me. my motor is 100% stock. ive cleaned the head and the piston top exhaust system.ive messed with the timeing. still the same. handy bikes told me to break my motor in for the first 300 miles with 5 oz. of oil to a gallon of gas - after that they said to stay at 4 oz. of oil to a gal of gas. reason they say that is because you need plenty of oil to lube the internal bearings in the motor. i use a NGK -BR5HS. BEFORE I HAD A HOTTER PLUG , THE PLUGS IVE TRIED ARE THE PLUGS THEY SAID I COULD USE. THE ORHER PLUGS WERE LONGER . THE BR5HS IS SHORTER I LIVE IN A VERY HOT CLIMATE AREA. IM 10 MILES FROM REYNOSA MEXICO. WERE IN THE UPPER 90S AND 100+ TEMPS. ** YOU THINK I SHOULD DROP A 1/2 OZ OF OIL TO SEE WHAT THAT DOES ** THANKS DOUG

Re: MOTOR - SPARK PLUG QUESTION HELP.

i guess the question is whether or not there's a problem in the first place .. This bike is still fairly new to you.. are you actually hearing the ping of preignition or is what you hear normal? The idea that a stock bike would suffer preignition is pretty odd.

Nothing you've tried so far got rid of the "ping" which suggests that whatever you hear is not preignition... you may be hearing piston slap, exhaust, gear noise .. or who knows what.

An old spark plug doesn't present an accurate picture of the current condition of the engine. So, to find out wht's happening right now you'd do a top-speed plug chop with a brand new plug. If the plug comes out still looking brand new, it is of the correct heat range, it's gap is correct and the air:fuel mix is correct.. and chances are ignition timing is very close to ideal..

But if, after a plug chop, the new plug comes out with definate indications of overheating, something needs fixing... otherwise you're ok.

:

As far as break-in, the rings must be forced very hard against the cylinder wall so they wear down against the new cylinder cross-hatching.. The ring shape will then match the shape of the hot cylinder. The cross hatching doesn't last long and after a few miles of hard running break-in may be over.

But a proper, fast break-in procedure requires care .. as you mentioned it needs extra lubrication .. and a close eye must be kept on heat buildup.. galling of the rings.. glazing of the cylinder wall and other problems.

So, to avoid trouble with people who might not know what they're doing, they will tell everyone to drive slow for 300 miles. This eliminates the posibility that a new owner will screw up and seize the piston or similar and need service. However this low speed, low stress running makes the rings wear to the shape of the cylinder at low speed and low stresses. At high speed in a hot cylinder those rings may not seal as well as they could.

For example, I have a bottle of Red Line (synthetic) racing oil here.. on the side it says:

"To break in new rings, a petroleum lubricant should be used at normal loads for 15 minutes, or Red Line Racing Oil may be used if engine is operated at 80% load for 15 minutes immediately after initial start up."

Re: MOTOR - SPARK PLUG QUESTION HELP.

thanks for the information and your time . im just going to run this motor and if she blows i have a brand new engine ready to install that i just got from handy bikes. the noise i get is like small stones hitting on tin after 25 mph. after 25 i can hit spots where the engine is quiet .99% of the time i stay at 25mph. when i have traffic behind me i run faster and move to the right and let them go by me. i checked my plug the NGK BR5HS AND I LIKE HOW IT LOOKS IT HAS A SLIGHT BROWN CAST TO IT. ive had that plug in for awhile now. its the colder plug. thanks again DOUG

Re: MOTOR - SPARK PLUG QUESTION HELP.

i guess you know that a BR5HS is hotter than a BP6HS .. higher numbers are cooler.

A heat range is available because a plug's insulator nose must stay just hot enough to burn away all combustion residues so it doesn't foul .. around 1000 F or so. A cold plug will eventually foul or cause occasional misfires.

But a "cooler" plug doesn't remove any appreciable amount of heat from an engine. The plug itself just runs cooler.

A cooler plug alone won't help cool an overheating engine except in one instance... when the too-hot heat range plug itself is causing pre-ignition.

A nose of a plug who's heat range is too 'hot' will get too damn hot.. maybe 1,200 F or higher. And so the plug itself ignites the mixture before the spark occurs (pre-ignition). This is where a cooler plug is called for. find one that's hot enough to stay clean but not hot enough to cause pre-ignition.

Some tan color is normal on older plugs, but on a brand new plug / plug chop, a clean, white insulator nose indicates you've chosen the proper heat range. That is how you determine heat range.. just pick a plug heat range that stays clean.

Changed weather conditions, different fuel/oil batches, engine modifications or normal engine wear and lots of other things can demand a cooler or hotter plug... so do the normal tuneup maintainance checks, including a plug chop whenever something related to combustion temperatures changes.

Re: MOTOR - SPARK PLUG QUESTION HELP.

all the plugs ive used are what handy bikes have said to use. i also used the plug that came with the bike and it had a bosh # on it , i took it to an auto parts store and the cross referenced that plug. i know theres many factors involved with an engine. with the ngk BR5HS im now getting a a slight brownish color on the white tip. on the others it always stayed super white. FROM 4OZ. OF OIL PER GAL DO YOU THINK I SHOULD DROP TO 3 1/2 OZ. ????????. I HAVE 2 KINETICS NEVER RUN - BRAND NEW AND TOM I GUESS HES THE OWNER SAID TO USE IN THESE BIKES 3 1/2 OZ. OIL PER GAL. THE BOOK SAYS 4 OZ. PER GAL. MY BROTHER HAS A 2003 KINETIC AND HE RUNS 4 OZ. OIL PER GAL. I SEE HE SMOKES QUITE A BIT WHEN HE TAKES OFF FROM A STOP. THANKS DOUG IN TX.

Re: MOTOR - SPARK PLUG QUESTION HELP.

When asked to both cross over to another plug manufacturer and change heat range, the guys behind the parts counter have been known to cross reference plugs to NKG and get the wrong heat range. Most brands don;t use the lower-number = cooler range. But the important thing is not the number or brand name... it's how the plug works in your engine.

I use 4oz/gallon.. a 32:1 mix. When i disassemble the engine there's a nice coating of oil on all parts.. i get no exhaust smoke after the engine is warmed up .. no oil ever drips from the tail pipe... so i'm happy.

The consequences of running with not enough oil are pretty bad and i have no interest in cutting back on oil for no good reason.

Just like with the plug heat range, type and gap, the fuel:oil ratio is not written in stone. .. milage, wear, riding habits, terrain, state of tune, etc., can all make a difference and may indicate something other than what is generally recommended is needed.

Nobody knows what a particular bike needs better than the knowledgable, informed bike owner who determines things for himself.

oops

oops.

_Most brands don;t use the lower-number = cooler range_

scratch that..

Some brands do use the lower-number = cooler range .. but not NKG. Some parts guys make the error... so double check to make sure your Bosch plug crossed over correctly.

Re: oops

ALL THE PARTS STORES HERE HAD NO CROSS REF FOR NGK PLUGS. I FOUND OUT THE CORRECT PLUG NGK FROM HANDY BIKES. AND FOR KINETIC I CALLED COSMO AND TOM TOLD ME WHAT NGK TO USE. SAME ONE HANDY BIKES SAYS TO USE IN PANTHER. THANKS DOUG

Re: sorry for jumping in so late here

doug, try to richen up the mixture. that's what stopped the spark knock noise in mine. also happening after about 25mph.

as u know i'm also using the ngk b5hs plug in mine.

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