Rough running 1150 - advice please

[Bob Jeffries]

Did a 1800 mile tour of Scotland over the last 6 days and the 1150GSA was perfect until the last day - as I was accelerating hard past a row of cars after a roundabout I got to about 5500rpm in 4th and it was as if I had hit the rev limiter - a sudden loss of power and rough – I changed up and all was well.

Ever since it's been intermittently like I have a 4 cylinder that’s running on 3 but it’s not as bad as a 2 cylinder running on 1, more like 1.5.

It seems to be getting worse and seems to be at above about 2500rpm when accelerating, cruising seems OK. It may be a coincidence but I also seem to be getting a lot of "popping" on the overrun that I didn't get before.

It's 2.5 years old and has done 11800 miles so will be having its 12000 service as soon as I can get it in but I'd like to try and fix it myself first - any ideas.

 

[Steptoe]

is it a twin spark ??

If so i'd check the plug caps first .

 

[Timolgra]

This happened to my old 1150 single spark just after I sold it

It turned out to be a dodgy HT lead

 

[oblertone]

Check the widget !

Not normally unseated by riding, more often by fiddling, but it do make 'em run rough

 

[Bob Jeffries]

Yep it's a twin spark, how would I tell if it's a plug cap, or should I just change them anyway?

 

[orca the porker]

Hi Bob,
Exactly the same thing has just happened to a mate of mine on his 1150. we have spent many a happy hour cleaning electrical thingys and a last resort before dealer we changed the HT leads £75.00 , OUCH, but still no difference .
On the last test run after installation of said HT leads i suggested whilst in the petrol station and as a very last resort, why not try some injector cleaner . Well after 300 miles last, 150 today, it has not missed a beat .
In conclusion might just be a cheap mix, let me know how you get on!!!

Cheers good luck, ORCA.

 

[Bob Jeffries]

Thanks for all the suggestions, I'll try them all.

Checked the trottle cable seatings - all OK

Next will be the plug caps - just need to find a local GS'er who'll let me swap to check them out

I'll do the injector cleaner as well just to be sure

I'll report back when I'm happy the problem has been solved

 

[miconone]

Rough running

Sounds like corroded plug caps, I had the same problem.

 

[Gas'd Off]

Simple one but have you looked at your sparking plugs? Is the air filter full of shite? Exhaust sensor cable connection? Missing rubber cap on the intake manifold? Leaky fuel hose on high pressure side?
Good luck, Prolly just your imagination

 

[Arbreacames]

As Steptoe hinted, it sounds like one of your jugs is lighting on the secondary plug. Take a look at this guy's methodical analysis and resolution:
twinspark coil

 

[Bigtwin]

As Steptoe hinted, it sounds like one of your jugs is lighting on the secondary plug. Take a look at this guy's methodical analysis and resolution:
twinspark coil

Hmm - thought on the 1150 TS the bottom plug didn't do anything at tickover?