[Gautam_707]

Originally Posted by SatheeshBHP

I think it is due to Engine temperature. Hotter the engine, difficult to start. I also noticed engine tends to stall randomly when idling at hot temperatures. Once on a very hot day, after heavy traffic, engine failed to start for more than 10 mins, So I poured 1 little cold water on the engine and it immediately started in single crank.

But wouldn't pouring cold water be a drastic temperature change on such a hot temperature for the engine block? I have only had the starting issue, no turning off at hot temperatures or anything. It stalls sometimes due to random hiccups but it's very rare.

[SatheeshBHP]

Originally Posted by Gautam_707

But wouldn't pouring cold water be a drastic temperature change on such a hot temperature for the engine block? I have only had the starting issue, no turning off at hot temperatures or anything. It stalls sometimes due to random hiccups but it's very rare.

Yes, Sharp temp change is not good for engine. But after 10 mins, I thought temperature would have dropped enough to not to cause issues. I was thinking that hot engine should not be affected by splashing cold water (may be like a puddle water splashing?). Honestly I was in a hurry so didn't think much about consequences at that time.

For me also stalling is very rare but happens only in hot engine.

May be we should try with non ethanol petrol (power/premium petrol?) and check if we still have the problem.

I'm now afraid to turn off the engine in signals because it might not again for some time

[Gautam_707]

Originally Posted by SatheeshBHP

May be we should try with non ethanol petrol (power/premium petrol?) and check if we still have the problem.

I'm now afraid to turn off the engine in signals because it might not again for some time

Not really sure if the higher octane fuel or premium petrol would make such a big difference, especially since our engine is pretty low in compression. It's one of the many, many reasons I picked the fzs25 too, because that just means better reliability. I sometimes worry at the signals as well but since it doesn't take more than 2 minutes at most, it usually starts up fine. The coin rattling sound drastically gets louder when the engine is hot though.

[Ibanez_70]

Originally Posted by SkylineGTR

I have a Yamaha FZ25 BS6 model, bought 8 months ago. I have a rather strange issue with the bike: it will randomly fail to start on some occasions, behaving as if it has run out of fuel. I will have to crank it 4 to 5 times in order to start the engine, sometimes by giving it some throttle (which is bad for FI vehicles).

I own a 2019 FZ25 BS4 and I have been facing the same issue since day1. However, your injector theory seems true and it seems this is by design and not a bug. The reason I say so is because of a video I watched of YouTuber Life of Pal where he claims a Yamaha service advisor / mechanic said this to him. Sharing the link here. Worth taking a look.

https://youtu.be/N-synYK-j4M?si=6aszF447uliAVOx3