backfire when starting

[Valkcurious]

First time ever--this morning went to start as normal.....choked fully. Backfired then started. Should I be concerned? Recently changed to regular from super--but thats been a couple of months. Bike seems to accelerate smoother and better with regular gas. Other thing is I always shut off the gas valve at after riding. Twist it on in the morning. Fully choke and hit the start button. Never twist the gas on the handle.... normal to backfire? Didnt happen again after riding and warmup.

[Skinhead]

A lot of weird things happen on cold engines, I wouldn't worry unless it happens regularly.  I'd also switch back to regular.  Unless you have an advanced trigger wheel or the ESC mod you don't need it.

[Valkcurious]

Oh---had a mental moment---meant to say I switched from super to regular....Bike really runs much better on reg!

[John Schmidt]

What is the temp. when you're first starting it? Most of the time it doesn't need a choke(especially full choke) unless the temps are in the 40's or below. I don't need it even in the 40's on mine. And you're correct....no twisting of the throttle, mostly because it doesn't do anything for you when starting. These carbs don't have accelerator pumps so twisting the throttle accomplishes zero.

[Valkcurious]

Here in California it's been in the 40's and hi 30s lately. Been riding a lot-- and never had a backfire when starting...

[Rio Wil]

I am wondering if you just escaped the dreaded hydrolock......sounds like a cylinder had raw fuel and if it was beginning an exhaust stroke it squirted raw fuel into the exhaust pipe and it lit up when the engine fired up.  I would be on the alert when firing it up for the thunk!

Not trying to be the bearer of bad news, it is just if this engine has never behaved like this, then something changed......and I would be cautious.

[Bighead]

Good point.

[Valkcurious]

The thunk? So if I hear "thunk" what do I do?

[Bighead]

Tear the engine down and replace the starter gears that just broke

[Rio Wil]

The thunk? So if I hear "thunk" what do I do?

Don't hit the start button any more until pulling all 6 plugs.  Stand back from the possible fuel coming out of a cylinder and hit the start button again.  If it is hydrolock, you will know which carb is at fault and maybe you will be lucky and not break any gear teeth. Some folks make it a habit of hitting the start button for just a little blip before a long crank.....

Not trying to be pessimistic,  just be cautious for a while to see if anything more is going to develop.

[gordonv]

and do it outside away from anything you don't want gasoline to spray onto.

1 quick Thunk may be fine, but DO NOT hit the starter again until you verify that the engine is not bound up.

[salty1]

and do it outside away from anything you don't want gasoline to spray onto.

1 quick Thunk may be fine, but DO NOT hit the starter again until you verify that the engine is not bound up.

Absolutely!   

[Ricky-D]

Holy cow,

a single backfire on a cold start

and they will be having you

rebuild the motor.

***

[Bighead]

Nope Ricky just lookin at the possibilities . I took it as if he heard a clunk don't crank it over again but hey that's just the way I read it.

[Rio Wil]

Started my bike 17,342 times in all kind of weather and not a single backfire....if it did it now, I would be a little curious and cautious.....that's all......