Backfiring and cutting out at 6.5krpm

[Magoo]

Hi folks,

Having spent some time in Antarctica for work, and then getting home just in time for this poxy lockdown, my bike got it's 1st run out in months today.

It runs nicely up to just under 7k rpm, then pops a loud bang, rev counter reads at zero for a second (with total loss of power), then the bike continues running until Near 7k rpm when it does the same...every time.

I plan to have a look at my valve clearances tomorrow. Can you suggest any other constructive avenues of inquiry?

(1990 GSXR1100L)

Cheers,

Magoo.

Edited May 24, 2020 by Magoo

[wraith]

Crabs need cleaning and new fuel in, if it's been sat all winter with the same fuel.

[Captain Chaos]

38 minutes ago, Magoo said:

, then pops a loud bang, rev counter reads at zero for a second (with total loss of power)

sounds like ignition problem to me. Check all the electrical connections are clean and tight. Might be some resonation-induced vibrations at 7000 rpm causing trouble.

[Wee Man]

I'm with the Captain on this, sounds electrical, especially with the rev counter dying. 

Side stand switch still in good working order? 

[Magoo]

Thanks for your input guys, much appreciated.

Funny you should mention the sidestand switch. It's been pretty flakey for a while now. (Sometimes I have to kick the stand in hard for the bike to allow me to leave. (Was thinking to bend the tab on the stand out a bit to ensure switch depression....but I always forget when getting home)

Tomorrow I'll take it somewhere quiet so as not to irritate the neighbours and see if I can make >7krpm in neutral. (Will do a wiring check 1st)

Many thanks.

[Wee Man]

The side stand switch can be bypassed temporarily to rule it out. Some folks do away with it all together.

[Magoo]

It was the sidestand switch. Right on the money Wee Man.

Cheers, I owe you a beer.

[Gixer1460]

19 hours ago, Wee Man said:

The side stand switch can be bypassed temporarily to rule it out. Some folks do away with it all together.

You want to get a sense of humour - deleting posts tut tut tut!

[stellafella]

Had something similar with my slabby recently, similar to you, get to a certain revs and lost the  tacho and pops and farts.

traced it to the wires going to the coil pack, terminal connector had opened and it was lose on the spade on the coilpack, I just squashed it back together with pylers to get it tight again.

 

glad you got it sorted

Edited May 25, 2020 by stellafella

[Wee Man]

4 hours ago, Gixer1460 said:

You want to get a sense of humour - deleting posts tut tut tut!

Explain?