Hot stalling / some starting issues

Hi folks, I've recently moved over from 12 years of R1150GS ownership and have a 2008 GSA with a stock setup (exhaust, cat, etc.).

It's a 34k bike in great condition, and one of the first things I did was give it to Steptoe for a once over (passed with flying colours).

Since then some strange things have developed. When I get stuck into slow traffic (central London) and the bike is hotter than it would normally run, it's started stalling when off the throttle and pulling up at lights. I can just about manage it by bringing clutch in earlier than I would, but it's totally different from how the bike behaves normally - only when it's hot. It's then sluggish to start again - making me think it was the battery at first but even with a strong charge and after an hour of motorway is still does it so I think the 'struggles' come from elsewhere.

A few times I've also had strange behaviour when starting from cold. Once I pressed the button and nothing happened at all. Yesterday, I started it, and then it cut out soon after. I had to get on and ride immediately and it was fine. I suspect the two things are linked but not certain.

Any thoughts? Stick coils? TPS?

Unless you know that the battery is recent and in good order then that's where to start. The batteries on the earlier 1200s (I can't remember when they changed) were undersized. Later bikes got batteries with more capacity which seem to last better. You'll get all sorts of advice regarding what battery to buy: if you're using the bike every day then go to Halfords for a Yuasa as it's a decent brand and if it dies early then it's relatively easy to exchange it. There's all sorts on eBay and the like, some of which need wiring mods to make them fit.

I had the stalling when coming to a halt. I forget whether that was on my '07 or '09 bike. The cause was a failed Lambda sensor and shortly after that, the other one failed as well.

Starter motor,

I had similar symptoms


My fix consisted of


New ( recon ) starter

New mottobatt battery

Double leading the battery, (brand new additional cables from the battery to starter)

fill up with super unleaded 99 at esso….

don't put e10 anywhere near it

Sounds like it's running too lean when hot - I'm thinking fuel pump pressure, an air leak, or lambdas. Have you checked for codes?

Why not take the bike to Steptoe as you are nearby.

I have an ‘08 GSA. With the stock exhaust I had very similar stalling problems. Same when I put a Remus and Akro end can on only worse. Problem was completely cured with a remap - no problems since then. Of course, that might not be your problem but they do run lean Sir as standard.

Sounds like main coil(s) are the problem. Disconnect the connection on both lower coils and see how the engine runs using just the main coils, it may run on one side only, or run rough if one or both coils are intermittently breaking down.

Thanks chaps. 7 replies and 7 different suggestions!

Battery is always my first thought as it always caused issues on the 1150, but it seems fine overall. Also the hot stalling issues both happened after an hour of motorway riding so when the battery is at its peak (and I’ve checked it’s getting a good charge from the alternator). I will probably replace it anyway just to be certain.

Lambda and fuel pressures are interesting ideas. Haven’t checked for codes but if it happens again I will nip over to Neil.

I did wonder about the starter but it doesn’t explain the stalling itself.

As for petrol and mapping i always use 99 and it runs absolutely beautifully 90% of the time. Smoother than my friend’s GSA. It’s only in heavy traffic when the temp is a few bars higher it struggles for some reason.

Thanks for the coil tip Neil. I’ll give that a go. I have heard they can play up when very hot.

Just reviving this as I've finally had some time to try and investigate this further (and obviously I haven't run it hot much).

I've replaced the starter which I believe was the cause of the hot starting issues. Haven't taken apart the old one to check but suspect it's at least a bit gummed up. Surprised there's no actual covers for these on the bike!

Steptoe said:

Sounds like main coil(s) are the problem. Disconnect the connection on both lower coils and see how the engine runs using just the main coils, it may run on one side only, or run rough if one or both coils are intermittently breaking down.

Click to expand...

I did a set of tests pulling different coils and seeing the effects:

Running on main coils only: Wants to stall at low revs but otherwise runs OK
Running on lower coils only: Better low down but no power accelerating in 4th
Main left and lower right coil: As above, no power in 4th
Main right and lower left coil: Stalled at low revs but ran OK-ish under load

The issue is definitely just with the idle. Even with the bike on 4 bars just now the idle was poor and it seemed like it wanted to cut out. Any thoughts before I just go and buy 4 (or 2) coils out of desperation?

Won't fix you stalling issues, but I run 10w 50 oil. I find no matter how hot the air temp is (especially in Morocco) it stays on 4 bars. Miller oils do 5 ltrs for about £55

Best of luck with the fix.