Query Moved and Approved.

i guess both are right..... ur mechanic and service center guys. see if you put a free flow type of air filter on your bike like K&N, it increases the air flow to engine. when this happens engine gets more air so the combustion of fuel is complete. this increases power and mileage little bit. engine sound is also better little bit. but remember only air intake of engine is increased and not the fuel, fuel intake is same as before, so the engine is running on lean mixture. this makes the engine hot. so engine is heating up more. so your mechanic is right. now what happens when engine is overheated--- all sorts of problem arise, engine may start eating lot of oil, excess heat may cause oil seals to burst, excess overheating may damage spark plugs, it may ruin valves, valves bend due to overheating and in worst case ur engine may seize. now these are all the possible problems that may arise out of overheating. now which part gets ruined depend on the condition of your bike i.e. which part is weakest. the weakest part will be spoiled first. so in your case it might be possible that ur valves are ruined. i think now u got an idea of what happened to your bike. the remedy of engine overheating due to lean mixture is to change the jet in your carbureter to a bigger one so that fuel intake of ur bike also increases to balance the increased air intake.

since i had the old spark plug with me, i showed the plugs to Mr. Sherry ( an old and very reliable mechanic from pune.. and i guess he is related to aspi of bike india )

the comments that i got was that the plug is pitch black and this could me bcos of
1) a rich mixture.
2) a very badly maintained engine
3) cos of improper fuel

since, in my case, the mixture is expected to be very lean, he told me that since i regularly go on long trips ( 250 kms+ per day ) it might be possible that its just the regular wear and tear of the engine. i asked him to inspect the cyl head and he has given me an appointment of tomorrow. i.e tuesday..

by the way since u mentioned that the seals get burst, i do have this problem on my bike...

to be very specific, i wash my bike personally every sunday and that in cludes the engine exterior and so i get a good estimate as to when the seals have completely failed..

i got the bike on 7th may 2008.. and it had a bit of oil near the head cover..

the coming sunday, i washed the head clean of the oil....
for the next 7-8 months i did not have to clean the head cos of no leakage..

then in march 2009, i noticed some oil residue on the head but i did not deliberatly clean it so that i could pin point the source of leakage...
in april 2009, my bike had completed the 15000 kms so i showed the head to my frnd ( who is a very good mechanic ) and he replaced the o ring for the head cover bolt...

the next 2 months were fine but then the head gasket was blown in july. i got the gasket replaced..

then i had to replace the gasket and oil seals again in sept, dec so as to keep the leakage in controll.

till jan, my bike was stock and had no mods whatsoever and was returning 50-55 kmpl in highway condns..

then on jann 22 2010, i got the k&n fitted without rejetting, and since then hell broke loose on my bike... the oil leakage stopped but then the bike needed choke to start in mornings.. twice, engine just did not start.. so my mech got the spark plug cleaned and then the biek worked like normal for 2 weeks after which it lay idle from feb 27 to march 22 and then again the same problem re surfaced and the bike stopped running in the middle of the nh4 betn panvel and lonavala. so i got a new plug fitted
( for 350 bucks that too pulser's plug) and rode the bike slowly to pune.. the performance of teh bike had improved drastically by the new plug..
so i guessed that the old plug was the culprit however, on 3 the of april. i.e on saturday, the bike again stopped and this time i decided its time for a proper check for over heating...

now since u are saying that the seals blow faster on a hot engine, i am starting to worry cos for since the last dec, the seals are working fine.. this probably means that the engine is not over heating.. also the carbon on the old plugs says that the mixture was too rich..

now these are exactly contradicting situations and thats why i am wanting a very reliable method of determining if my engine is over heated or not...

and really thanks for the last info

can anyone plz tell me the method of reliably checking if my engine is over heating????

or the symptoms of an overheated engine???
or the symptoms of an lean mixture?

Is anyone there??

is anyone there who can throw some light on this topic?

Now this is something that even I am looking to have an answer on.

And please, dont give us the answer like, try touching the chamber with naked hands, if the hands get burnt, it is ok, but if the flesh goes off, your engine is over heating!!!

Lean Mixture = Decreased top end.

--more (replies from other members) to come---

1. try redlining the bike in initial gears - if the RPM hicks up after 6 to 7k rpm to reach red line then you are running lean.

You see with K&N & stock jets if you run your bike near to redline for long period of time this is bound to happen from what I have heard of & I have seen people using K&N for as long as 40k kms with stock settings without any problem also, but then they do not rev the nuts & bolts of the bike all the time.

Even I have K&N with stock settings for almost 10k kms now & I know my bike is running lean but then I do not redline all the time & I use W50 grade engine oil ( OEM grade is W40 ) & it is semi synthetic which helps me overcome a bit in the Heating problem

Just my 2 cents.

@abhilashabhi12,
thanks for the info dude.

I generally dont rev my engine till the redline but after reading this, i took the bike for a spin and tried to take it to the top speed.. at arroung 75-80 kmph, ( rpm was 6000-6800 ) my bike gave a sudden loss of power momentarily.. but then started accelerating again..

the loss of power was for arround 5-10 seconds.. seemed as if the engine had switched off....

now i dont know if this is what u mean by hicks???

by the way I have managed to get hold of a old "RTD" ( resistance thermocouple) from a laboratory... and am trying to get it somehow fitted on the fins of the cylinder block to check the actual temerature....

i will have the guage by tuesday, cos the guage needs to be recalibrated..

let me see as to what are the readings of the guage..

by the way can anyone tell whats the general range for the block surface temperatures so that i can have a referance..

i tried googling on this topic and found that it should generally be 200-300 deg celcius...

can anyone plz confirm this????

Best way to check for overheating is by measuring the temperature. You can also feel it on your legs. Burnt smell also points to the same. Also thinner engine oils will mean more valve clatter than usual.

Carrying on with the discussion on HOT Engines. With the summers coming to their peak, what are the best unorthodox ways to keep engine temperatures in check?

what exactly do you mean by valve clatter ??

^^The same metallic sound that the engine makes when the tappets are loose.

And one more thing, the spark plugs will be whiter and have a glazed look.

Yup, the clatter would be more like as if something is loose inside. However, the most prominent would be oil burning smell and in some cases one would also notice lack of power. The engine would feel reluctant to pull.