Flatspot at 4000rpm...

[GS7A]

Hi all, went up to Scotland weekend before last and noticed a flatspot between 4000and 5000rpm, but then pulls ok above 5000rpm. Any ideas what the problem could be? My bike's a 2003 R1150GS Twin Spark.

Still managed 1100 awsome miles in 3 days

 

[ELIMINATOR]

coilpack on its way out?

 

[mandon]

happened to me.......check tps

 

[Bikerbrady]

similar started with me and it turned out to be coils

Biker

 

[GS7A]

Hi Mandon, TPS... Do you mean tappets?

Guys, I guess the only way to prove if it is the coil packs failing is to change them; is this correct or is there some way of testing them?

Cheers

Phil

 

[GS7A]

TPS... Throttle Position Sender... Doh

 

[ELIMINATOR]

http://www.ukgser.com/forums/showthread.php?t=91406&highlight=coilpack

try here.


http://www.ukgser.com/forums/showthread.php?t=134525&highlight=coilpack

 

[davegs]

Flat spot

Put it on E-bay quick!
dave gs.

 

[GS7A]

Many thanks for your help guys. I'll try and diagnose the problem as suggested by “Eliminator” this weekend and post a progress update. That is if SWMBO gives me time off from decorating… Payback for the Scotland trip with the lads

 

[Steptoe]

I guess the only way to prove if it is the coil packs failing is to change them; is this correct or is there some way of testing them?

Cheers

Phil

Pull the lower secondry plugs off and see if it starts and ildes on just the main plugs.
If it fires on one side then it's obviously the side it isn't firing on

 

[GS7A]

Hi Steptoe, it runs fine at idle and tick over, the problem only shows itself between 4000 and 5000rpm. Over 5000 is also okay

 

[Steptoe]

Hi Steptoe, it runs fine at idle and tick over, the problem only shows itself between 4000 and 5000rpm. Over 5000 is also okay

Oh dear oh dear.
It's how you check the main cap coils, it doesn't really matter what it's doing at idle or tick over.

It's something you check then you can move on to check something else in the chain. One thing at a time.

So if someone were to suggest it could be your cap coils you can reply, "i've checked those, thanks", and then they can offer another suggestion.

 

[GS7A]

Hi Steptoe, now I feel very small… Thanks for the lesson in diagnostics; I’ll give this a try tomorrow and see how I go.

 

[GS7A]

Okay, I have only just been able to do anything with the bike as I had bi-carpal tunnel relief surgery done two weeks ago and have been resting my hands.

Diagnostics performed this morning:-

Removed both secondary plug leads and tried to start the bike on just the mains; bike won’t start. Put the secondary’s back on and it starts first time.
Changed both master plugs for new ones, same problem. With the secondary’s disconnected the bike won’t start. Secondary’s back on and it starts first time.

I guess that both ‘stick coils’ could have gone, but I would have though it more likely that the main coil has packed up as it is common to both. (This assumes that the secondary plugs are fed by their own coil?) The manual that I have doesn’t show the twin spark ignition, and I haven’t had the tank off to this point.

Any thoughts guys?

 

[ianboydsnr]

Okay, I have only just been able to do anything with the bike as I had bi-carpal tunnel relief surgery done two weeks ago and have been resting my hands.

Diagnostics performed this morning:-

Removed both secondary plug leads and tried to start the bike on just the mains; bike won’t start. Put the secondary’s back on and it starts first time.
Changed both master plugs for new ones, same problem. With the secondary’s disconnected the bike won’t start. Secondary’s back on and it starts first time.

I guess that both ‘stick coils’ could have gone, but I would have though it more likely that the main coil has packed up as it is common to both. (This assumes that the secondary plugs are fed by their own coil?) The manual that I have doesn’t show the twin spark ignition, and I haven’t had the tank off to this point.

Any thoughts guys?

the main coils are the stick that goes over the sparkplugs, thats why there called stick coils so each one is a separate coil

 

[GS7A]

Did wonder about that. I had the same problem with my Audi TT and had to change all four. Before I shell out for new stick ciols is there anything else that is common to both that I can check?

 

[ianboydsnr]

You can sort of check them, by pulling them off the sparkplug slightly, the spark should jump the gap between the cap and the plug, and make a ticking sound, its not infallable though, one of mine went down, giving the same symptoms, increased the amount of fuel used, i just replaced both.