Slight hesitation/misfire at 5000 rpm

[windychris]

Any ideas?

Going through the revs it seems to just hesitate as it passes through 5000 rpm, clears its throat and then it's fine.

This has been apparent since I took it on a trackday - I had thought it was just a plug dead/on its way out (it's a twinspark) but my recent full service hasn't cured it.

HT lead to the bottom plug? Lambda sensor? Coil on one of the top plugS?

[Jason M]

Chris - could be any of those I reckon. When I read the GS boards (before I developed GSTDS - GS tosser disinterest syndrome) they seemed to have problems with the coils on the plugs of the twin sparks. My GS is fu*kin about again misfiring and stuttering and I reckon (hope!) it's the plug leads but this sort of thing is a flippin nightmare

Good luck!

Jason

[Steptoe]

Simple to check the main plug coil caps. Which is a fairly comon problem

Pull the lower spark plug caps off, and see if it runs on the main plugs.

If it only fires on one side or misses on one side, re-attach the lower plug cap and see if it then runs normally . If so you've found the faulty main coil cap .

You can swop the main plug caps over just to double check .

They've recently made a change on the main coil caps, the internal material is a different colour , whether its made from a different material i don't know, but perhaps BM have realised at last there is a problem with them .

[FalcoDog]

I'm not sure how relevant this is but my R1200S will hesitate at around 5000 rpm if I put lower octane fuel in it. It doesn't misfire but rather bogs a little, as if it's trying to figure out what to do. Maybe this is caused by the knock sensor? It never happens with high octane.

[windychris]

Thanks lads, traced to a dicky top plug cap/coil.

Tried the pulling the bottom leads off method to isolate which side.