Spark Plugs all die after one use!

[andass]

Riding SYM GTS 200, and in the past few days, the spark plugs all died after one use. After the spark plug die, no matter how hard i try, cannot start engine again, until i change to new spark plug, then can start engine again and ride for the next journey. But that new spark plug will die after that journey.

 

Can anyone advice what is possibly wrong?

 

Thanks

[IvikaRazI]

Could it be the wrong spark plug heat rating?

 

Could you describe the outlook of the spark plugs when you take them out? It could shed some lights why.

[andass]

Hi IviKaRizI,

 

Thanks for the advice.

 

The electrode area of the spark plug seems to be very oily with black engine oil, but the physical outlook of the spark plug looks perfectly normal with no symptoms of any adnormalities.

 

I am not sure if i used the wrong spark plug rating, but it was changed by the technician when it first spoil. How do i know what rating i should use?

 

Could it be the wrong spark plug heat rating?

 

Could you describe the outlook of the spark plugs when you take them out? It could shed some lights why.

[Marcheline]

Yes, fouling of your plugs could indicate a plug heat range that is too cold. Check your bike manual for the plug type to use. Google's your friend in this case.

 

Another thing, you could be running too rich, thereby the air-fuel mixture is not combusting properly and fouling up the plugs. But that should occur over time. If it is over just one ride, then the best bet is the wrong type of spark plug being used.

 

http://www.spark-plugs.co.uk/graphics/tech/plugconditions/dryandwet.jpg

[andass]

Yes, fouling of your plugs could indicate a plug heat range that is too cold. Check your bike manual for the plug type to use. Google's your friend in this case.

 

Another thing, you could be running too rich, thereby the air-fuel mixture is not combusting properly and fouling up the plugs. But that should occur over time. If it is over just one ride, then the best bet is the wrong type of spark plug being used.

 

http://www.spark-plugs.co.uk/graphics/tech/plugconditions/dryandwet.jpg

 

Ic, Thanks Marcheline.

 

I checked the website, the recommended model to use is NGK CR 8E. However, the one i used was NGK CPR6EA-9. Did a fast search but wasnt able to determine the exact temperature range of both spark plugs. But what the hack, i should just go and try to find the exact same spark plug as the spec sheet bah.

 

I also just did a fast experiment. I used a brand new spark plug and connect it to the cable (without screwing it into the cylinder, so the electrode end is exposed). Then tried starting the engine, but there is no spark. Isnt there supposed to be sparks at the spark plug to ignite the mixture? Is the voltage wrong?

[raven77]

if too oily. meaning too rich. go service your carburetor first. normally, it the carburetor that make the plug faulty if still cant resolve. it may be yrs engine.

[ben1112]

Ic, Thanks Marcheline.

 

I checked the website, the recommended model to use is NGK CR 8E. However, the one i used was NGK CPR6EA-9. Did a fast search but wasnt able to determine the exact temperature range of both spark plugs. But what the hack, i should just go and try to find the exact same spark plug as the spec sheet bah.

 

I also just did a fast experiment. I used a brand new spark plug and connect it to the cable (without screwing it into the cylinder, so the electrode end is exposed). Then tried starting the engine, but there is no spark. Isnt there supposed to be sparks at the spark plug to ignite the mixture? Is the voltage wrong?

 

Silly goose. Ground it! Touch the spark against the engine.

[Paladin]

Ic, Thanks Marcheline.

 

I checked the website, the recommended model to use is NGK CR 8E. However, the one i used was NGK CPR6EA-9. Did a fast search but wasnt able to determine the exact temperature range of both spark plugs. But what the hack, i should just go and try to find the exact same spark plug as the spec sheet bah.

 

I also just did a fast experiment. I used a brand new spark plug and connect it to the cable (without screwing it into the cylinder, so the electrode end is exposed). Then tried starting the engine, but there is no spark. Isnt there supposed to be sparks at the spark plug to ignite the mixture? Is the voltage wrong?

 

Ur plug thread did not touch the screw thread on the engine. thats why no spark. must close the circuit mah... make contact with frame or engine should see sparks then.

[andass]

Ur plug thread did not touch the screw thread on the engine. thats why no spark. must close the circuit mah... make contact with frame or engine should see sparks then.

 

Alright, got it.

 

Will check and clean the carburetor then change the spark plug to a more suitable model.

 

Thanks for the advices.

[Raptor]

Oily??

 

Is this a 2 stroke bike?? If it is... it could be too much 2T going in. Sometimes the 2T pump cable.. which is linked to the throttle cable is pulled out accidently...during fuel tank installation which result in excess 2T being pumped into the carb.

 

If it is a 4 stroker... did you just do an oil change? Could be overfilled or the oil rings of the piston is screwed.

 

Is there smoke coming out of the exhaust? Black is too rich.. bluish white is oil burning.

 

Too rich could be a dirty air filter being the cause. Or are you those biker who must keep their cleaning cloth in the airbox and it has now been sucked onto the air filter restricting free flow of air to the carb??

 

For NGK plugs... the lower the number.. the hotter the plug.

 

With regards to the spark plug heat range.. the OEM recommendation is CR8 but your mech puts in a CR6 which is way too hot. Hot plugs give good idling and low speed running but then to short out during high rpm operations. When a hot plug starts to short out... firing becomes intermittent and the plug loses heat faster and it starts to collect deposits of unburnt fuel.. which makes it black and oily too.

 

Get the correct heat range of plugs fitted first before you try anything else.

Edited August 31, 2009 by Raptor

[andass]

Hi Raptor,

 

Thanks for the lesson, it is very beneficial enlightening.

 

I just wanna update the progress and think everyone for their advices.

 

I sent the bike to a garage specailised in scooters (Fxxxxx Sxxxxxxxxx in Kallang area) and the mechanic also not sure what to do. Ultimately he charged me $35 for and washed the carburator and changed the spark plug. I ride back and halfway performance really dropped badly, and by then, it was night time, and i slowly ride it to LAB. The technical salesman at LAB started the bike and saw a lot of white smoke when i start the bike and say most probably need top overhaul. I then left the bike with the technician Jack, who will inspect the bike and advice accordingly. Its a 3 yr old bike, and ex owner change the engine oil regiously every 3K, not sure why piston are leak so early.

 

Oily??

 

Is this a 2 stroke bike?? If it is... it could be too much 2T going in. Sometimes the 2T pump cable.. which is linked to the throttle cable is pulled out accidently...during fuel tank installation which result in excess 2T being pumped into the carb.

 

If it is a 4 stroker... did you just do an oil change? Could be overfilled or the oil rings of the piston is screwed.

 

Is there smoke coming out of the exhaust? Black is too rich.. bluish white is oil burning.

 

Too rich could be a dirty air filter being the cause. Or are you those biker who must keep their cleaning cloth in the airbox and it has now been sucked onto the air filter restricting free flow of air to the carb??

 

For NGK plugs... the lower the number.. the hotter the plug.

 

With regards to the spark plug heat range.. the OEM recommendation is CR8 but your mech puts in a CR6 which is way too hot. Hot plugs give good idling and low speed running but then to short out during high rpm operations. When a hot plug starts to short out... firing becomes intermittent and the plug loses heat faster and it starts to collect deposits of unburnt fuel.. which makes it black and oily too.

 

Get the correct heat range of plugs fitted first before you try anything else.

[testamant]

Hi Raptor,

 

Thanks for the lesson, it is very beneficial enlightening.

 

I just wanna update the progress and think everyone for their advices.

 

I sent the bike to a garage specailised in scooters (Fxxxxx Sxxxxxxxxx in Kallang area) and the mechanic also not sure what to do. Ultimately he charged me $35 for and washed the carburator and changed the spark plug. I ride back and halfway performance really dropped badly, and by then, it was night time, and i slowly ride it to LAB. The technical salesman at LAB started the bike and saw a lot of white smoke when i start the bike and say most probably need top overhaul. I then left the bike with the technician Jack, who will inspect the bike and advice accordingly. Its a 3 yr old bike, and ex owner change the engine oil regiously every 3K, not sure why piston are leak so early.

 

Hmmm Black oil?piston leak?,i tink you need to let a fren or a close fren of yours to have a look at ur bike before asking them to overhaul,i had mine fair of share too but i'm riding a 2stroke bike,running rich on fuel and 2t,can also cause to clog up ur sparks and have oil smearing out from ur engine blocks,aniwae a 3 years old bike should be still in a good condition to ride on.but do take note,piston can't leak,they can just get punched through!!!! and you can get that if you are using a different spark plug,if you say it is leaking,i presume the gasket to the blocks,where the pistons are,tat need overhauling !!!,all the forumers here gave you options is so that you can isolate and point out to the mechs to cut down wastage of money,but all of that is in your hands,so cheers bro,may you get to rectify ur bike problem as cheapand as soon as possible.

[4th_Espada]

Learn alot from this thread too...keep it coming guys...

[hamsterwhale]

Riding SYM GTS 200, and in the past few days, the spark plugs all died after one use. After the spark plug die, no matter how hard i try, cannot start engine again, until i change to new spark plug, then can start engine again and ride for the next journey. But that new spark plug will die after that journey.

 

Can anyone advice what is possibly wrong?

 

Thanks

 

from what u gave the description on ur spark plug, its a wrong heat rating, stock is 8 u use 9, the diff of temp in the tip of the spark plug is 100c, for every diff in 1 level of corresponding level, unless ur riding ur bike very hard, having a cooler plug would only foul it up, having a too hot tip would result in the spark plug disintegrating, so i suggest u use back 8 if prob persist or poor FC or throttle response is noted, change it to 7....hope this helps....

 

Cheers!

[zyrofillica]

hmmm so could using a wrong rated plug cause the gaskets to leak? why is there so much white smoke (means your engine is burning engine oil)?

[jonathanlim]

Mayb you like to try the 'real' scooter specialist located at 494 Mcperson Road.

 

You can contact him at 8415 1724, his is botak.

 

The best guy for scooter that me know.

 

Hopes this helps.

[Raptor]

from what u gave the description on ur spark plug, its a wrong heat rating, stock is 8 u use 9, the diff of temp in the tip of the spark plug is 100c, for every diff in 1 level of corresponding level, unless ur riding ur bike very hard, having a cooler plug would only foul it up, having a too hot tip would result in the spark plug disintegrating, so i suggest u use back 8 if prob persist or poor FC or throttle response is noted, change it to 7....hope this helps....

 

Cheers!

 

Read again one his replies.

 

He went from an 8 to a 6.

[Marcheline]

I wouldn't really trust the LAB mechanic. For a piston ring to wear out in less than 3 years, you must be riding hundreds of kilometres every single day.

 

I guess you've exhausted all possibilities, including carburettors, air filter, spark plugs, electronics (if any). Do update us on whether the top overhaul helps. The symptom you quote does look like engine oil is getting into your combustion chamber.

[zyrofillica]

hmm maybe engine wasn't properly run in when new. hence piston ring up lorry fast.

[testamant]

hmmm so could using a wrong rated plug cause the gaskets to leak? why is there so much white smoke (means your engine is burning engine oil)?

 

2 Things due to white smoke,too much 2t mixe unless he using premix or u are running lean my dear fren........

[andass]

Thanks everyone for helping to brain storm the possible cause. All the inputs have helped me and possibly many others get a lot of insights into the mechanics of the bike. I had just gotten back the bike last night and this is the detail:

 

Jack, the macho big sized LAB mechanic was my mechanic and he was very honest with me. He could had lied to me that my piston jam or some major thing was spoilt, but he didnt. He said it was due to the leak in the gasket, where the coolant entered the piston (or combustion) chamber. Since water vapor looks like white smoke, we had initially thought it was engine oil that got in. He changed two gaskets, one of which he mentioned was out of stock, so he had to customized/cut for me. From the look of it, seems like an aluminium material, but i cant be sure, as i only see the side. He also changed the piston oil seal and helped me top up my coolant and of course, engine oil.

 

It was the Chief Mechanic who decide on the cost. He charged me $370, but i told him its very much, so he reduced to $350. I understand there are a lot of work involved, but i really not sure if it deserves this kind of charges... But bike was already fixed, what can i say. . .

 

But the good thing is, he said if the engine got problem within these few days can send it in again, and asked me to get freebie from ah boy. Ah boy was also very nice, and he gave me a KISS helmet.

 

Till now, I still dont know what was the real root of the problem. The previous owner is my friend, and he took care of it very well, and i just got it from him 4 mths ago, and i did my fair share of maintainance till now. The only mistake i made was not checking the spark plug model and engine oil model. BTW, this is not considered an overheal right?

 

 

I wouldn't really trust the LAB mechanic. For a piston ring to wear out in less than 3 years, you must be riding hundreds of kilometres every single day.

 

I guess you've exhausted all possibilities, including carburettors, air filter, spark plugs, electronics (if any). Do update us on whether the top overhaul helps. The symptom you quote does look like engine oil is getting into your combustion chamber.

[zyrofillica]

2 Things due to white smoke,too much 2t mixe unless he using premix or u are running lean my dear fren........

 

his isnt 2 stroke bike. so might be running lean? maybe wrong spark plug caused lean conditions resulting in higher operating temp which dmg the gaskets resulting in coolant leak? He did take a look at the piston and piston right right? No damage? Btw for info purposes, what is your current mileage (kms travelled)

[andass]

his isnt 2 stroke bike. so might be running lean? maybe wrong spark plug caused lean conditions resulting in higher operating temp which dmg the gaskets resulting in coolant leak? He did take a look at the piston and piston right right? No damage? Btw for info purposes, what is your current mileage (kms travelled)

 

Hi Zyro,

 

Yap, the Pistons were checked and they were fine. The current mileage is close to 63,000Km. The previous owner is my close friend, who took care of the bike religiously and did a proper run-in when he first got the bike.

[Hydher]

$350 seems steep for a gasket change but since its rectified and you got freebies, let the matter rest and thanks for sharing.

[zyrofillica]

oh mine is still at 20k km only. long way to go. hope its problem free~