oil on spark plug threads !!

[V!RU$]

Guyz I own a pulsar 150UG4.5 , for a past few months I've noticed a strange problem of oil on my spark plug threads...
whenever I take spark plugs out for cleaning there is oil on the spark plug threads
I tried cleaning the oil both from the spark plug as well as from the engine but it appears everytime
There are certain observations i would like to describe..
The engine is sounding normal and doesnot feel stressed at any rpm
No black/white smoke from the exhaust at any rpm
Level of oil drop is noticeable but not alarmingly fast
I am currently using bajaj dtsi oil and i keep the drain interval to 3-4k
The bike has done 17k on the odo with regular servicing
I would like to mention that there has been no engine decarbonizing done so far
There is no loss in mileage or power so far...
I tried changing the spark plugs but no use and oil is there on both left and right spark plugs
I googled it and it seems there is a valve seat leak i don't know what it means .

I would like to know is this a serious problem...
And what be the approximate expenditure
If there is anyone who has faced similar problem then I would appreciate his help
Thanks in advance

[antz.bin]

Thread Approved

[paul.1911]

As what you have mentioned i'm sure that your valve oil seals have gone, that needs replacement. Its not valve seat leak, its actually valve oil seals which prevents the oil from getting into the combustion chamber though valves way. So thats needs replacement, its not stopping the oil, therefore its getting into the combustion chamber and then to the spark plug thread.
The bike is really smoking, but its very less therefore its not visible. If u drag your finger in exhaust tip, you will see wet type black soot. Thats indicates smoke. If no smoke it'll be dry.
So all you need to do is...replace valve oil seals, along with new head packing and new head o-ring, and your problem will solve.

[muztariq]

I would use test some other brands of 20w50 grade oils and see if the problem persists and then go for the work as informed by paul. DTSi oil does contain some additives, also Bajaj SVCs add some nulon additive which may be causing such appearance of the S.Plug.

Use any SS/Mineral oil for only 3k kms max.

[V!RU$]

@paul - thanks for the valuable information bro, you cleared all my doubts
Any estimate on the total expenditure ...?

@muztariq- okay bro I'll try switching the oil brand this time
The problem is that in Lucknow it's difficult to get 20w50 in synthetic
No motul dealers also ... I'll try reverting to mineral or semi synthetic this time

[V!RU$]

I took the carburetor out for cleaning today due to unstable idling and the engine was stalling excessively when cold..
These are the photos i took after removing the carburetor from the engine
Is the amount of oil deposited inside normal ??

[Prith]

I took the carburetor out for cleaning today due to unstable idling and the engine was stalling excessively when cold..
These are the photos i took after removing the carburetor from the engine
Is the amount of oil deposited inside normal ??

I can see sludge on the valve rim...If you have a carb cleaner, just spray that on the valve and try idling for few minutes. Effectively, after spraying the sludge will dissolve to some extent and burnt in the chamber, and idling will allow it to be pushed out.

How is the pick up? Do you see any marked change?

[V!RU$]

@prith I have never used a carb cleaner before and I highly doubt it will be available in my area..
Can any household item can be used on the sludge ??like kerosene or paint thinner ??

After cleaning the carb idling and cold starts have improved a lot..
Can't feel a huge difference in acceleration..but throttle response has impoved.

[paul.1911]

@paul - thanks for the valuable information bro, you cleared all my doubts
Any estimate on the total expenditure ...?

sorry dont know the expenditure, but i'll be less and affordable. Estimate as 500

The amount of oil which u have seen inside on the valves, have come from the valves way. i.e., the valve oil seals have not stopped the oil.
Even if u change the oil viscosity the problem will not solve, even if it luckily solve, then it will not be a permanent solution. When engine becomes hot, the oil becomes lighter and then again it can find its way through valves.
So the permanent solution is to get the valve oil seals change.
And then when u'll remove carburettor, u'll see no more oil in that area. and it'll look dry.

Edit:
What happens here is, at intake stroke when piston goes down the intake valve opens so along with air fuel mixture that oil is also getting into combustion chamber. So at compression stoke when piston compress the air fuel mixture the oil went to the spark plug threads.
You can also see, when u rotate your crank counter-clock and u'll see that valve open. Don't use self, as crank will have many rotations and your piston will suck dust inside.
While cleaning carb, always use clean soft cloth to cover (push inside) the intake manifold to prevent dust from getting inside.
You can also have Cyclo Carb Cleaner thats a very best product to clean carburetors which remove carbon from any area very easily. Can also be spray on combustion chamber. its highly inflammable. cost 220. Works perfect. Its like carbon killer!

This shows what happens when valve oil seals get worn. The oil gets though valve stem.

[Prith]

@prith I have never used a carb cleaner before and I highly doubt it will be available in my area..
Can any household item can be used on the sludge ??like kerosene or paint thinner ??

After cleaning the carb idling and cold starts have improved a lot..
Can't feel a huge difference in acceleration..but throttle response has impoved.

Dont worry, you are on right track. Are you using fuel from reliable bunks. Try Shell or HP for next tank fills and see how the response is. Also do try running your bike in constant RPM for long duration to see if this cause any smoke to build up. Don't go for any local fuel system cleaning products, you can try STP/Valvoline complete fuel system cleaning product to remove that gunk and sludge. Check Ebay, simplest way to get them shipped to your location.

[Arpansikdar]

Re: oil on spark plug threads !!

Plz help!!!!
i owned a hero Xtreme 2014 model,,it has completed 20000 kms,,some days ago a mechanic adjusted tappet because there was a tik tik noise from the engine,,,after that i saw slightly littlebit oily black carbon deposit on spark plug thread where the bend type rod starts there,,not on tip,,tip is clear..but no white smokes i cant see from silencer pipe at normal speed(40/50 km)and not in idle aslo,,i used motul 10w30 mineral engine oil,,is that a sirious problem,,help me out,,what i have to do,,a cylinder piston cant damage in 20000 km,,,as i dont misbehaving with my bike,,never crossed 60km/h speed,,and engine oil dropped at every 1500 km..

plz help me guys