TOPIC:

A back fire and fire in the hole. On start up two weeks ago I had a back fire and ended with a fire in the air box and yes burned the filter. I got it out with out any thing melting also pulled the filter out while it was on fire. Its toasted but got a new the other day. The point of this post to to tell you if this ever happens to you and you think you get every thing cleaned up don't restart the bike. For the last week I been fighting a no restart after the bike starts the first time so to day I pulled the carbs off to have a look see. I was amazed at the shit that was sucked into my carbs so I doing a complete tear down of carbs and cleaning, no telling where all this black stuff got too in them. Also noticed that my out side right carb was flooding a bit. Also noticed that float was not adjusted in the same place as it was when I rebuild them last year. My advice to all of you is if this ever happens to you pull the air box all the way down for cleaning and figure on doing the carbs too while your at it just to be on the safe side of thing.

My one question on this is can a hard back fire like this cause the timeing to move?

wrgoo56 wrote: My one question on this is can a hard back fire like this cause the timeing to move?

No but the backfire could have been caused by the timing having moved.
Make sure it is set correctly and keep an eye on it for the next little while.

Sounds like you were lucky there !!

This is only the 2nd time I have ever heard of this happening on a 1300.

The part that you need to really look into is that there was obviously enough petrol lying in your whole intake system & air filter to allow it to burn.

This is probably due to the awful design of our Mikuni carbs (as usual), as unlike other carbs these DO NOT have an over-flow pipe or system. This means when there is a problem inside them & they fill up with petrol too much, it spills out back into the air box & forward into the engine itself.

As you have found the float settings to be incorrect, this could be part of the issue, but also check the o rings on your float valves & the float valves & brass seats themselves as these are often the culprit too.

Finally, do you leave your fuel tap on when the bike is NOT running ? It maybe leaking past in the OFF position & causing the over-flow..........another common fault on the 1300.

Pete F
UK

No I shut the fuel off learned that early on. The other thing I am looking at is the day I did this the bike was damp you could see water drops on the frame. I do not keep my shop heated all the time. I have a feeling my 34 year old coils and wires was damp and crossed fire one with an open cly. That is on my to do list this spring is the coils and wires. As for got lucky you got that right cause I pulled the air filter out of box on fire. Carbs a part way tore down and I order two gunson color tune plugs from the UK today. Going to wait till every thing is here to put it back together and set it all back up.