Yes , it is less than a minute from a Metro station(on the opposite side of the road) , but I forgot the name of that station since Didi have funny names for Metro stations now(I think it is the - Master'Da Surjya Sen Station - Bansdroni) . It is in Bansdroni supermarket , inside a wide side lane two or three shops away . Quite very easy to find. You should phone Guddu'jee himself for clear directions , he is a very friendly & helpful guy . The shop is genuine & well stocked , you'll be happy to visit .

Urgent help required !!!!

I took my uncle's HH passion 2001 having 40,000 kms on the odo to service it because it was idle for last 8 months.(Uncle is NRI)
I cleaned the air-filter,carburetor,petrol tank,chain.
I replaced all oil seals,rocker cover gasket and magneto oil seal ,shock-absorber oil and oil-seal,engine oil.
Replaced the spark plug and gaped it to 0.9mm.
(I got the above work done by a mechanic under my supervision)
The bike was used without battery last year so I got a new battery.

The problem- Severe misfiring at more than ~3500 RPM.
At more than half throttle it make a loud phat sound and flame also comes out of silencer.
When speed is more than 30kmph bike is misfiring and jerks can be felt easily and jerks just like there is no petrol.
At low rpm everything is fine and engine is also smooth,idles good.

No chance of adulterated fuel or bad fuel because I drained and cleaned the tank also and I got the Carburetor cleaned.

My mechanic is not well and he will come after two three days after recovering.
I described him the problem over phone and he told me to check the strengh of spark,pickup coil ,timing mark on sprocket etc but I could not find any fault.
I got a new pickup coil also but it did not solve the problem so I returned it back to the retailer

I did not check cdi and igniton coil (which is under the tank) because it was dark outside.
So,I took the bike to another mechanic and he told me to get the ignition power coil checked by a motorcycle electrician tomorrow.

Everything is fine except misfiring.

What could be the problem ?
Sibun I wanted to call you but then I did not want to disturb you.

@Shoeb-since you have mentioned that you have cleaned the carb and tank then it is not related to fuelling. change the plug gap to 0.6-0.7 mm and post the result. i think your problem will be solved. if it doesn't get solved then let the plug gap remain at 0.7 mm. no need to go to any parts shop. you have a splendor and both splendor and passion share same cdi. transfer the cdi from your splendor to passion and check. since you have mentioned that the bike was used without battery i suspect a damaged cdi. also check the charging coil of cdi in the magnet. it will also cause misfire and in hero honda bikes pickup coil doesn't gets damaged. only the cdi charging coil needs to be changed. but first check the cdi as it is plug and play and require hardly 5 minutes. just open the right side cover and swap. timing mis match will cause different problem. just swap from your splendor and check and reduce the plug gap to 0.7 mm. also remove the plug cap and connect the wire directly to plug. sometimes the plug cap also gets sort and cause problem. but your description of fire through silencer indicates cdi problem.

Yes , check and clean all electrical joints and contacts , inside the switches, fuse-box and the CDI, induction-coil, plug-wire, cap etc . Also check the rubber tube thing that passes air from air-filter box to the carb for cracks and mis-seals . The usual things that goes bad with long storage . Try filling with IOCL extra-premium for a few tanks . Generally running the bike for sometime shall clear it up very much , too .

experts need one help
will changing the viscocity of engine oil affect the mileage of the bike?;; the recommended grade of engine oil in my yamaha fazer 125 cc 2004 model is 20 w 40,,can i use 20w 50,for better protection?

Do not call us as experts. We are only trying to help fellow bikers. Usually you can go for 20W 50 as the base grade is same and no problem. Since your bike is old and there will be more clearance in engine parts so 20W 50 creates no problem. Instead of 20W 50 go for 15W 50 from motul and it is an excellent oil.
Regarding mileage it will not affect but in my extreme when i went to 20W 40 from 10W 30 mileage decreased by 7-8 kpl and immediately i shifted to 10W 30 and mileage came back. But here the difference is in lower grade i.e 20W is twice thicker than 10W. But the higher grade do not matter.

OT

You can try 20w50 or 15w50 for one fill and see for yourself the difference , there is no harm in it . Motul 5100 15w50 semi-synthetic or Motul 3100 gold 20w50 technosynthetic are good oils to try in this grade .
But 20w40 oil is sufficient for Fazer's engine , and you won't need any extra protection, unless you have some special riding conditions to deal with ... try a bottle of Motul 3000 4T plus 20w40 , cheap and very very good .

Thanks sibunjee and Pinaki jee

Thank You for quick response Sibun and Pinaki ji,

I was suspecting a faulty CDI (because the bike was used without battery for very long time) but I couldn't not swap it with my splendor's cdi because my uncle needed the bike urgently so I told him not to cross 30 kmph in any gear,also I did not have my digital meter with me then so told him to give me the bike later.

I have done whatever you guys suggested before posting my problem here,I had checked all the possible faults except cdi,ignition coil,cdi power coil.
I even checked spark strength,plug cap,wire, pickup-coil,timing,tappets etc as I was doing a complete service of the bike and replaced all possible parts as a precautionary measure.

I will get back the bike tomorrow from my uncle and will update it here so that everyone can know the cause for severe misfiring.
I have all the necessary service specifications of cdi,ign.coil.
Please give me some time and I will post everything.

(I have also experienced minor misfiring in my passion but that would occur occasionally and was solved by replacing ignition coil and spark-plug wire which had rusted severely.)

Actually it is the higher number that matters! The lower number (20W) denotes the viscosity, hence easy circulation, at cold conditions or when the engine is cold. The higher number is the viscosity of the oil at operating temperatures of the engine.

The oil remains at the lower viscosity for very little time, and quickly attains the higher number as the engine heats up.

Your point is correct but practically it is different. a 10 w 30 oil has a base oil viscosity of 10 but a 20 w 40 oil has a viscosity of 20. so practically a 20 w 40 is twice thicker than 10 w 30. now lets look at the upper grade. a oil doesn't posseses multigrade properties but the additive makes it. the higher grade is denoted at 100 degrees. so at 100 degrees your engine will not feel different at different viscosity. but the thing is that a 20 w 50 doesn't posses much difference than 20 w 40 as a 10 w 30 does. believe me i have tried 20 w 50 in my joy in summers and bike didn't feel different than 20 w 40. but when i used 20 w 40 in my extreme instead of 10 w 30 then mileage decreased by 7-8 kpl and bike felt sluggish. immediately i changed to 10 w 30 and it feels better and mileage again returned to normal. in my joy i use 10 w 40 and it feels more free to rev than 20 w 40 both when cold and hot. try comparing oil side by side using filter paper and you will get a clear picture. although in theory upper grade matters but actually the lower grade matters more.

From your description it seems that the bike is misfiring when going into advance mode. check the cdi as lack of battery would have damaged it.

I too feel that spark is not advanced at high engine speed and that is causing sever backfire as the un-burnt air-fuel mixture is getting ignited by the hot silencer and feels like silencer will burst any moment.

I will report the result after swapping the cdi tomorrow.

Thanks Pinaki jee for the in detail direction and picture too....got the clear idea.

Thanks for the picture

The problem was found to be a faulty ignition coil,replaced it with Power ignition coil,Cost Rs.185.

Looks like hero Honda has got fail-proof CDI and power coil .
HH uses 1.Denso or 2.esiu (something like that)

As I mentioned sometime ago that my 2005 passion also misfired due to a faulty ignition coil but it was not that severe.
So from my previous experience I checked it first and it was the culprit.

CDI does not go bad if battery is not used as ignition is completely on AC.
(From my experience)

Pinaki ji,
I got AP-2 Veedol lithium grease made specially for bearings.(50gm for Rs.20)
I like lithium based grease because it does not eat rubber.

I found this at my oil shop-(Picture only for reference)
Now reliance also makes oil,LOL.