. Got the coolant topped up at 13,700Kms to just above the maximum line. .

My odo is currently 14,100Kms. I got the the pump seals changed around 13,300Kms. The coolant was also topped up at 13.3K Kms. Coolant dropped till just above minimum line after riding about 400Kms. Got the coolant topped up at 13,700Kms to just above the maximum line. After riding some 400Kms it's in between minimum and maximum now.

Visited service center today and he told it's common in 390 and during summer, for coolant to drop such levels I have explained above. He told it's just about 20 to 30 ml coolant drop per 400-500Kms and totally fine. Engine oil was changed at 13,300Kms as well. The sight glass is clear, oil looks dark Reddish, no milkiness, no bubbles, nothing. The current coolant level was marked, and trip was set to 0. He told to track the coolant drop and Kms ridden this time and only if it is by a huge margin, to replace head gasket. They were clearly hesitant to replace it now and advised not to simply get the engine removed as this very normal and not an issue.

Would this be OK? Is there anything I have to worry about? Or should I insist them to replace the gasket now? Is 20 to 30 ml of drop during summer is real?

Also, I dropped the idea of performance head gasket as it will increase already high compression engine to a full point.

Got NGK Laser LKAR8AI-9 from NGK dealer. Surprisingly was only ₹280.00.

Instant feedback after install was knocking and vibes used to be in idle and mid range mostly disappeared. Now have to see speedo to know its past 80

The mechanic seems to have give you sensible advice. Keep an eye on the coolant level and the oil color for the next few 100km.
Usually during a drain and refill, the coolant doesn't get filled up to capacity and after a few km its normal to see a drop and requires a top up.. this top up routine might be required around twice (on a new or a bike that had coolant drained and refilled). But after that you will most probably only be seeing a fluctuation in the level (goes down and up by a little) and that is normal. If you see it only going down, then there is an issue... which could be due to the water pump seals or the head gasket.
Do you notice any white smoke from exhaust ?
Before you touch the head gasket, double check that it's not the water pump seals (which are cheaper and easier to replace).. there is no guarantee that the previous repair job held up.

I saw that it was available on amazon for a similar price a few days ago, but now it's vanished.. and am not able to buy it locally.
Let me wait a few days and see if i can source one locally, or I am going to request you to send me one over and i'll pay for it
Just itching to experiment.

My odo is currently 14,100Kms. I got the the pump seals changed around 13,300Kms. The coolant was also topped up at 13.3K Kms. Coolant dropped till just above minimum line after riding about 400Kms. Got the coolant topped up at 13,700Kms to just above the maximum line. After riding some 400Kms it's in between minimum and maximum now.

Visited service center today and he told it's common in 390 and during summer, for coolant to drop such levels I have explained above. He told it's just about 20 to 30 ml coolant drop per 400-500Kms and totally fine. Engine oil was changed at 13,300Kms as well. The sight glass is clear, oil looks dark Reddish, no milkiness, no bubbles, nothing. The current coolant level was marked, and trip was set to 0. He told to track the coolant drop and Kms ridden this time and only if it is by a huge margin, to replace head gasket. They were clearly hesitant to replace it now and advised not to simply get the engine removed as this very normal and not an issue.

Would this be OK? Is there anything I have to worry about? Or should I insist them to replace the gasket now? Is 20 to 30 ml of drop during summer is real?

Also, I dropped the idea of performance head gasket as it will increase already high compression engine to a full point.

I got it from flybhp website https://www.flybhp.com/ngk-laser-iri...oaApgqEALw_wcB

thank you for the link, i did come across this site earlier but wasn't sure if it was reliable.
and i still am wondering how this ngk ir plug is so cheap, usually the ngk ir plugs cost around Rs.660 for almost every other model. could this be a fake
the same plug is available in the us/uk for around 15$ .
anyway let me buy it and check it out.

Hello friends.

I have decided to buy duke 390 couple of days back & seen some bikes.
I have 2 good bike in my eye now. 1 with slipper clutch model & the other w/o (old version)

Both have come to same final price.

The 2017 duke 200 has softer front suspension, is it possible to fit the 200's fork springs on the 390?