Backfiring and hicupping

[mcjaeger]

During rapid deceleration and acceleration, when pushing along some tight stuff, my GS seems to hicup and back fire. I have not noticed any specific surging that seems to be evident on an out of tune / out of synch bike.

Power is certainly evident, just the back firing during rapid deceleration.

As I have just purchased the bike, I have not removed the Spark Plugs. I asume from the documentation that was presented to me with the bike they are only new as they had been replaced on the 40 000KM service.

If anyone on the list can offer some advice please do.


P.S. What is better than the Wallabies kicking the All BLacks Ass in Rugby?

Our Cricketeers Kicking the South Africans Ass at home, in front of the South African's.

 

[mcjaeger]

I am also running Hi-Octane (Premiun) Unleaded Fuel as suggested in the hand book.

I does not seem to matter if the bike is hot or cold, it still gives a pop and seems to die.

 

[BIG GORDY]

PREMIUM FUEL

IS YOUR PREMIUM FUEL THE SAME AS OURS???????

THE STUFF THEY RECCOMEND IS 95 RON IN OUR COUNTRY (MINIMUM OCTANE LEVEL). WHAT THAT MEANS IN AUSTRALIA I DONT KNOW. DOES THE 85 MON ALSO MENTIONED IN THE BOOK MEAN ANYTHING TO YOU?????????

BIG GORDY

 

[mcjaeger]

95 Octane

Gordy,

Our "Premium Unleaded" is 95 Octane. I plan to try some new plugs. See if that works.

Thanks for the reply mate.

 

[bashplate]

I can make my 1150 (with a y pipe and race can) pop and bang on decelleration by rolling off the throttle at 3Krpm in second gear.
It's been suggested that this occurs when the sensor in the cat (or my case y pipe) isn't airtight.
I find this adds to the character of the bike so haven't tried to fix it, but you might want to check this.

Phil

 

[mcjaeger]

Thanks Phil,

I will have a look at the sensor and security of the pipe in general.

 

[Mick Fagan]

Hi! The 1100GS's imported into Australia didn't have Cat's fitted, therefore they don't have an oxygen sensor which helps the computer make finer adjustments.

My own 1100GS backfires like a rocket on heat when pushed to the limit on tight and twisty stuff. Also it burbles when coming down the gears and the revs are dropping close to the injectors switching on again, which they do at or near idle speed.

Basically, the injectors shut off when the throttle is shut off and they come back on again at about 2,250 rpm or thereabouts, as there is no oxygen sensor, the exact amount of go juice isn't given as accurately as it could, therefore a backfire occurs due to either under or over metering of the petrol required.

Another reason for backfireing is leakage in the exhaust system, I run a Staintune low pipe which allows me to run 2 full aluminium panniers, this pipe isn't the greatest in the non leaking of air department, therefore it burbles and occassionaly scares the bugs right off the bike following me when it lets rip!

By the way Shell Optimax is 98 Octane and will, after about 3 tankfuls, give you a range of 425 Kilometres solo, not pushing it that is.

I have a 41 litre Touratech tank and I've actually gotten 760 Klm's out of one tank and it was still running. Useable from this tank is about 36 - 36.5 litres of juice. But two up with big aluminium panniers and running the bike at it's GVM I get 600 Kliks to a tank safely, just.

 

[mcjaeger]

Mick

Sounds like my problem to a "T". I am running "Optimax" now, second tank. I had Woolworths Premium unleaded prior to that.

I am going to Wodonga for 2 Months work next weekend. I would like to catch up for a chat whilst I am down your way. I am taking the GS with me. Drop me a message and I will see what I can do and how we could catch up.

Michael Jaeger

 

[Mick Fagan]

mcjeager, on May the 5th the BMW MCC of Vic is having a ride that starts in Albury and ends Corryong. It starts from Online Motorcycles at departure time of 0900. Coffe and biscuits before the start.

You could be interested in that. I won't be there as it would mean a 750 Klm day and I run my own business and I have to work bright and early on Monday.

Mick.

 

[mcjaeger]

Mick,
I hope I am free over that weekend. I look forward to it. I fell in love with the K100 at Online, but purchased an 86 Motorsport from Seaside in Ballina, a long time ago now.