Burger 400

[2wheelover51]

Not sure if it's just my old (2012) Burger 400, but do all 400s make a popping/misfiring noise on turning off? Mines alsays done it, whither I use the key or the cutout switch it doesn't turn off with a nice quiet or regular silence, it always makes a pop or misfire type noise. maybe they run a bit weak for environmental reasons?

[Data]

No they shouldn't do that! You should just hear the decompression cam slap back & forth as the motor stops & sometimes the camchain tensioner. It makes a dead stop clunking noise. That's quite normal. Wondering if your decompression cam is sticking. Does it start in a nice lively way?

[2wheelover51]

Hi Data.
Yes it starts normally, easily and fires right up. There are no misfires when it's running and fuel economy etc. is all good.
It's just when I turn off (it has, on the odd occasion not done it!) it usually gives this last little pop, like it wants to run for another stroke before it turns off. I hear very little mechanical noise from it, it's a nice quiet motor, it's strange.

[Data]

Ok, this just might be a minor fuelling issue. If you start the bike from cold & run it for just a couple of minutes, does it still make the popping noise when you turn off? In other words does it pop even when the motor isn't warmed up?

[2wheelover51]

Hi Data.
I can't say I've noticed it. I've thought it might be a bit of carbon build up which is igniting any left over vapour, but as you say a minor fuelling issue is probably more likely.

[Data]

There is one other thing it could be. Have the valves been checked for their clearances lately? Exhaust valves nearly always get tighter as time & miles go by. They can cause this sort of issue on some engines when they are just a little too tight. Also your engine can run completely normally in the early stages of the valves becoming too tight. Worth checking if they haven't been done lately. They are bucket & shim but I've found them tight on several customers bikes in the past, some with very low miles! It doesn't take long to check them. But it's a bit more work to adjust as you may know.

[2wheelover51]

Hi Data. Yes, a good idea! I generally check everything when I get my vehicles, and usually find I've dismantled them for nothing and everything is fine and feel I'm being "anal" as they say these days, but no, I've not checked for a tight valve. I have to fit some new tyres for the MOT in March, but will get my feeler gauges out and have a look at those clearances!
Not a long winded job on the user-friendly Burgman.
Cheers, I will let you know what I find.

[Data]

Yes, let us know.

[2wheelover51]

Hi Data. I eventually got around to checking them, and found yes, one of the exhaust valves is heading towards being tight. I can get a 0.2mm feeler gauge into the gap, but not the 0.25, so it's between those two figures. The others are all well within spec. so I'm going to have to strip it again pretty soon and replace a shim. I've done it before but not on a Burgman. Things are a little bit tight in there. 10 years ago it would have been an easy job, but these days I get a bit achey being bent over a bike for a couple of hours. I'll wait until things warm up a bit! Thanks for the advice!
Oh, and I only had to replace the front tyre and it sailed through the MOT.

[Data]

Hi ya, that's definitely the cause I'd say. Well done for finding it. Plus1 on the aching back! We're getting old now!