Need some help

[Jeannot]

Just picked up the bike from 36,000 service. It was great, never been like that before. Decided to take it to work tonight to give it a bit of a run. 8/9 miles down the motorway, I was doing about 75m/hr, pushed it a bit more to 85m/hr and the engine started to struggle (hard to explain). Anyway could not go any faster than 70m/hr. The bike feels like it is running on 1 cylinder. I called my mechanic but could not help over the phone (I am taking it back tomorrow morning). I am going back tonight and was wondereing if there are a few things that i could check. Another funny thing was I had about 4 bars on the petrol gauge, and within a few miles it went to empty. I put some petrol in and kept an eye on it but it has moved down so far.
If anyone can help before I make my way back (or call the breakdown service in case it can't make it) it would be very much appreciated.
JC

 

[Steptoe]

Simple thing first.

Is it a twin spark ?. if so could a coil cap have failed.

 

[Jeannot]

Simple thing first.

Is it a twin spark ?. if so could a coil cap have failed.

Any way I can check that? Thanks Steptoe

 

[elevensies]

yes

what year bike is it you have, does it have 2 spark plugs in each head, one large one one small, does it say ''twin spark''on the rocker covers

lots and lots of info to give it away mate..

and

who did the service?

bollox just seen you have an 850, so its a single spark

 

[Jeannot]

Thanks elevensies for the reply. It is strange because at one stage it picked up again, just suddenly like that, and then towards the end of my journey it started to go bad again (though not as bad as when I was on the motorway). Just hope that I can make it home tonight, it's only 37 miles, if not will have to call the breakdown people. Just thought someone may have had the same problem in the past and know about it.
JC

 

[big albig]

Water in your tank possibly, did they change you fuel filter, you may have had low fuel in you tank and its drawing in water and some fuel. possibly.
good luck anyway.

 

[elevensies]

did it start ok, or was it a pain?

could be water?

 

[JoeC]

No real answer but just thinking out loud :

trapped fuel lines under tank
is there a smell of fuel? If so check for leaks on right hand side of bike
loose spark plugs
loose spark plug caps

 

[Jeannot]

Bike came out from the 36,000 miles service this afternoon (Lou Crump did it) and the bike was a joy, hence decided to use it to go to work as it was bringing up a smile to my face. It just started when I opened up from about 75 to 85/90miles/per hour.
Water could be possible but shouldn't have done it from the start?. If it was a trapped tube it would have done it from the start maybe, no?. I rode the bike from Lou to my place and this was about 7 miles, and he rode it too without problem.JC

 

[elevensies]

my guess then is possible loose relay

steptoe is your man from here im afraid, if it had been bad from start up then us mere mortals could possibly help

something is breaking down under load i think

 

[Jeannot]

Just made it home. Bike was really running crap and then suddenly it started to run more smoothly. Will let you know what my mechanic think it is
JC

 

[raginmund]

My bike ran on one cyclinder on my way to RGM a few weeks ago. Turns out I'd dislodged the throttle connector thingy when I'd put the tank back on

 

[Jeannot]

Took the bike back to Lou this morning. He ran his diagnostic tool on it and came back with an error (he is not sure that it is the problem at this stage - the bike was fine this morning ). The fault has to do with the CAT system, there is a short circuit, he replaced the thingy connector/wire going from the CAT to the next connector, but the fault was still there, he also checked some of the wiring. SO instead to go replacing the whole electric loop (apparently it is a huge job), he will bypass the CAT system with a potentiometer (not sure about the spelling) and this will hopefully override the reading and fix the fault, this is what run on his 1100. We will have to take it from there and see what happens. Lou also check the fuel filter. WIll let you know how it goes, may help somebody else in the future.
JC

 

[elevensies]

mm, that sounds a bit drastic, if the ECU is playing up, as daft as it sounds it could be a loose wire somewhere.

 

[Jeannot]

mm, that sounds a bit drastic, if the ECU is playing up, as daft as it sounds it could be a loose wire somewhere.

Like I have said, Lou told me that to replace the electric loop (??) would be a major job as he has to remove quite a lot from the bike. The other solution is pretty easy and should work according to him. I am going to have to trust him on that one, I have already spend a fair bit on the service, + back bearings and other bits, so money is getting tight. When I bought the bike, it came with a third party exhaust and it was not right (bike was backfiring a lot). I had the original exhaust put back in but since was never 100% right. Yesterday when I picked it up, it was like having a new bike until it went wrong on the motorway. What I don't understand (nor does Lou) is that the bike was fine this morning. He only saw the fault because it tested it with his diagnostic computer/tool thingy (he tested it about 6/7 times). The fault showing is 2344 and according to BMW it is a Oxygen sensor shorted to ground. Lou checked some of the wiring, even replaced the wiring loop going from Exhaust to next connector but the fault was still showing. Next step would be to replace the next loop and this is the one that involve a lot of work.
JC

 

[Stewart H]

May be worth trying another Lambda sensor before diving into a wiring loom replacement, especially knowing that yours has been disturbed recently, it does not need to be genuine BMW, the change from Lambda sensor to CO pot that your man suggests is certainly a possible solution for my old 1100 but I dont know about your newer twinspark.

Stewart

 

[Jeannot]

May be worth trying another Lambda sensor before diving into a wiring loom replacement, especially knowing that yours has been disturbed recently, it does not need to be genuine BMW, the change from Lambda sensor to CO pot that your man suggests is certainly a possible solution for my old 1100 but I dont know about your newer twinspark.

Stewart

Hi Stewart, Lou replaced the Lambda sensor but the fault was still showing hence the next step is a wiring loom replacement. I have a 850GS, it is not a twinspark as far as I know, it is why Lou is suggesting this option.
JC

 

[Jeannot]

Got the bike back this morning. Lou did a great job overall fitting the potentionmeter, the bike runs very nice. Would definitely recommend Lou to anyone.
JC