R1150gs mid range rpm running problem

[west coast traveller]

Good morning to you all. Hoping for a bit of advice re my 2003 twinspark.
Bike starts and idles fine from cold. Runs fine throughout rev range until showing 3-4 bars on oil temp gauge. It then develops hesitation at 3500-4000 revs (won't increase revs when holding throttle steady and refuses to accelerate pat 4000 rpm in 6th gear). Feels like a combination of "hunting" and using choke on a hot carbed engine. Intermittent problem which comes and goes every few miles on a ride. Idles perfectly when hot.
TPS and TBs checked, cables fine (see my previous faux-pas!) and coils swapped. Fuel tank breather fine. Serviced regularly.
I'm thinking possibly sensor issues (oil/lambda etc) but not sure this marries up with the intermittent nature of the fault.
I would be grateful for any advice from forum members. Thanks in advance.

 

[Roger 04 RT]

At 3-4 bars on the RID, your Motronic stops it's warm-up fuel enrichment and starts referencing the O2 sensor. The rough running at 3500 RPM sounds like your engine is simply lean but the lack of acceleration above 4000 in 6th sounds like fuel starvation.

Let your bike idle with it rigged so that the return line from the fuel distributor is routed to a collection tank. Let your bike idle for 60 seconds. You should collect 2 liters of fuel. This means the pump, hoses and filter in the tank are good. If not you may have a split in-tank hose.

http://bmwsporttouring.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=838620#Post838620

 

[west coast traveller]

Many thanks for the reply. I will have a check later today and see what happens.

 

[Roger 04 RT]

If that's not it, since it's a twin spark, steptoe would probably say to pull and ground the secondary plugs and see if it will run only on the stick coils.

 

[west coast traveller]

Just sent off for a spare female connector so should have the answer one way or another in a couple of days.

 

[west coast traveller]

At 3-4 bars on the RID, your Motronic stops it's warm-up fuel enrichment and starts referencing the O2 sensor. The rough running at 3500 RPM sounds like your engine is simply lean but the lack of acceleration above 4000 in 6th sounds like fuel starvation.

Let your bike idle with it rigged so that the return line from the fuel distributor is routed to a collection tank. Let your bike idle for 60 seconds. You should collect 2 liters of fuel. This means the pump, hoses and filter in the tank are good. If not you may have a split in-tank hose.

http://bmwsporttouring.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=838620#Post838620

Return flow rate checked at 2ltrs in just under 60 seconds so all seems in order there. Changed injectors for a refurbished set I have. Just done a short run with engine up to temperature and roll on acceleration progressive. Will give it a longer run tomorrow as this should show whether the problem solved. If not, further checks with stick coils as per advice.

 

[stolzy]

If that's not it, since it's a twin spark, steptoe would probably say to pull and ground the secondary plugs and see if it will run only on the stick coils.

Its the stick coils, its always the stick coils.

 

[west coast traveller]

Its the stick coils, its always the stick coils.

A brilliant marketing ploy by WMB.....I've replaced so many over the past 11 years I should have bloody shares in the company!

 

[chilipepper]

West coast, was it the stick coils? I have exactly the same problem on my 2005 1150, de cat and remus straight through. Power commanders are no longer available for this model so i might have to revert to standard

 

[west coast traveller]

West coast, was it the stick coils? I have exactly the same problem on my 2005 1150, de cat and remus straight through. Power commanders are no longer available for this model so i might have to revert to standard

Still a work in progress though nearing the end (I hope!). I've changed injectors and replaced TPS with a spare. I've noticed quite an improvement but still intermittent problem as first described usually starting after brisk running for 10 miles + ( previously problem showing as soon as 3-4 bars showing on oil temp). As per the advice on this thread I've checked coils and replaced one with spare after I did the TPS and swap. I've ordered new set of coils as I suspect at least one is starting to break down.These should arrive this week so I will let you know how things pan out.

 

[Massive Lee]

A test that will cost nothing requires to let the engine idle, and then disconnect the plug at the stickcoil (don't pull the stock coil, just the connector). If idle goes down, then the stick plug is working. If idle stays the same, then the stock coil is dead. Repeat for the other cylinder.

When I purchased my GSA, it had the same symptoms as mentionned on top. I did the test and then bought two stick coils. When fitted, idle speed got raised by close to 500RPM. Had to readjust.

 

[chilipepper]

West Coast and Lee

Thanks for the information, I'll try the stick coils first and work my way from there. Does anyone know the best place to purchase stick coils?

Thanks again

 

[west coast traveller]

West Coast and Lee

Thanks for the information, I'll try the stick coils first and work my way from there. Does anyone know the best place to purchase stick coils?

Thanks again

BMW dealer ( though I've always had to order as they haven't had them in stock), James Sherlock (usually next day delivery even where I live!!), Motorworks- always helpful, or eBay for Beru coils. Hope this helps.

 

[chilipepper]

Well the bike is now flying!!

I started with a talk with Geoff at Hilltop, I replaced the stick coils which improved the bike but there was still a flat spot and reluctance to rev out.

I took it in to Hilltop and ran it on the rolling road, the fuelling was all over the place, with a surprising over-fuelling where the flat spot was. Geoff remapped it and hey presto with the correct fuelling it ran much better and gained 20ft/lb of torque where the flat spot had been. In between run's he rebalanced the throttle bodies while also working on a BSB Kawasaki (which the dealer couldn't get to fuel right, Geoff fixed the Kawasaki there and then (secondary butterflies weren't functioning properly, with them removed the bike ran much better)

We then ran my bike again and after Geoff told me he'd worked out what was wrong with mine - "39,000 miles and the valves need reshimming, their not closing properly.

I took bike to BMW and the checked and in deed they had stretched and needed shimming! After this was done the bike now absolutely flies, Geoff has a wealth of knowledge and directed me in the right direction for which I am eternally grateful! I intend to revisit in the New Year and re run the bike on his dyno to see how much better it has got.

The only down side is the bike has stopped back firing and popping on the over run