does not matter much i ran my bike on K&N without upjetting as much as 30K,only recently i was able to source a suitable size jet.

@Rocky,I have been running my bike on Motul 300V 15W50 since almost 35K+ kms,change it around 2.5K-3K(yes its overkill,but i rip my bike hard so I change around these figures)

Motul 300V 5W40 is more suitable for Zma, as it is nearer to the recommended grade.

Depends on how you think/use
15W50 is thicker(more stable at high temperatures)than 5W40,so if you use your bike on highways at highrevs especially in north indian summers,15W50 does help engine run better.

Yes,i agree with that. But some guys like to stick to the company recommended grade as much as possible, so made it clear that 300V is also available in 5W40.

I just had it for a week , then removed it. I did not upjet.

Thats what even I thought, thank u

Phew... you are lucky chap with both bikes

I have used Motul 300V 15W50 once and used it around 5k. It was good good for long runs. havent tried Motul 300V 5W40.

Aswin, fully Agree with MG and Akshay. Piston rings or the valves the cluprit. Unless you are very confident of the mechanic, do not give outside. Remember, if something goes wrong, Authorized Service Stations are accountable.

Based on what the mechanic at Millennium motors said, he seems to have diagnosed the problem well. Go ahead with the same mechanic.

Just one small thing to add .... if there is some oil visible on the cylinder head around the spark plug housing, it might be the valves. Otherwise chances are more that the piston rings need replacing !!

Smoke
Black Smoke = Excessive Fuel Burning
White Smoke(your case) = Engine oil Burning
As you already know this is supposed to be piston ring.

Jerking at high speed
This is supposed to be a Jet problem in Carburetor. There are two jets in all. The Main Jet and Pilot Jet. Pilot Jet is for ideal to 1/2 of the throttle at times where as Main Jet gets into action when the throttle is pushed harder usually at high speeds. Most probably your Main Jet has got some of its holes blocked. Get them cleaned and you will be enjoying that 90.

Also, don't forget to get your choke wire checked. It happens at times that the Choke wire gets stuck up and causes the carburetor to malfunction.

Hope it helps.
Ayush

Any one has HH email Id/contact no to complain ?

Thank man. Mine is black smoke. I had a confussion before I posted that its whike smoke, its actually black.

I hope you got your problem solved by now. In case you should know that excessive burning of fuel leads to black smoke, this adds carbon to spark plug, reduces mileage and that fuel burning smell fumes up, turning the volume screw correctly in the carburetor fixes the problem. If not changing piston rings or fixing if any leak in the joints do help.

wbr
Ayush

Ok now I have seen both smokes white and black
Got my bike serviced. Cleaned the jets and the jerking issue around 80's completely vanished. Got it tuned correctly , adjusted the tappet, changed air filter.

Bike revs up to 110 far better than how it was before. Dont feel any loss of power. I am really happy to get a good mech after a long time. He was workign in Millenium , now resigned from there and has started a new workshop a month back. Good thing is he knows the stuff and has got training on engine also.

He said will have to change the piston rings to fix the white smoke issue.
Can I change the rings alone or do we have to chang the whole bore set ?
Any one has done engine over haul for ZMA before ?

Tell me about the mechanic dude... Searching for a decent guy for a long time now. Where in Bangalore is his workshop. whats his name?

if rings are worn out no need to change piston and bore.
you can just change the rings
they used to cost around 280 bucks 2 years ago

white smoke = either valve seats are worn out or the guides are worn out or rings are gone.
1.Q. How to check valve or related spares on head?
A. if u want to check valve or valve seats or the guides then run then open the valve cover and start the engine and set the RPM @ 1500, then pour some new oil on the valve. if the smoke increases then u can go for head work if not. then prolly work is with either rings or whole block.
2.Q How to check Rings?
A. After confirming the head open the head assembly and pour some 20 ml oil on piston surface and kick the engine slowly (make sure timing chain is properly kept n should rotate while kicking) if the oil stains are not going from the cylinder bore that means rings or bore worn out or may be both.
3.Q. How to check rings or bore?
A. ask u r machinist to check the bore by using bore gauge. If the Gap or the bore is increased by some micron. Then no matter u change the ring the smoke won't stop. u will have to change the block piston set. Coz in cylinder assemply three spares are depending on each other piston, rings and cylinder bore itself. So if u change only one of the sapre soon or later same problem will pop-up. Also check the ring position. Some times only by ring position also oil starts entering in the chamber.

If the engine smoke is white with kinda steam (moisture feeling) then water is mixed with engine oil due to leakage or the crank breather is clogged. If the crank breather is choked then while high temperature. internal air gets heat up and at the time of getting cold it becomes water. So prolly chances of mixing water internally.
Above was for white smoke.
If the smoke is black then set the carb properly.
Let me know...

Chinmay Dangre, Nice inputs there. Thanks for sharing.