I've been trying to sort out a minor but annoying problem with my 1150 for two years now, and finally appear to have cracked it thanks to Steptoe.
It's a bit of a long story, but bear with me:
This is my second GS, both were from new, the first one which I had for three years was completely standard.
The latest one had a Y-piece fitted from new, and while I was in a spend-happy mode I asked my dealer to fit a K&N air filter, but kept the stock exhaust as I like my neighbours and prefer my speeding to be stealthy.
It never felt right at low revs. The best way I can describe it (and this is what I told my dealer) is that the throttle response was "fluffy". For example when blipping it between down changes the engine always felt like it was lagging a split second behind the twistgrip movement. If you blipped fast enough the engine would actually 'bog down' as if the mixture was too rich.
Sometimes, usually after a spot of high-revs action, the engine would simply cut as I shut the throttle and pulled the clutch in when coming to a stop.
And it felt weird on the overrun, like the fuel supply was being cut off as the bike rolled down through 2500-3000 rpm, forcing me to declutch much earlier than I should have to.
I knew this wasn't just subjective, because my first bike didn't exhibit any of these faults. I also knew it must be down to a combination of the Y-piece and freer-flowing air filter, but I didn't want to change it back to stock because (i) I'd thrown the cat away and (ii) I really liked the extra mid-range oomph that this set-up produced.
The service manager (who's an ace bloke and reads this forum) was sympathetic and helpful but couldn't really see what it was that I didn't like, other than the engine cutting out. I had the throttles synched several times under warranty, but the BMW diagnostic stuff couldn't spot anything wrong.
So for 16,000 miles I've been riding around the problems, accepting them as the price I had to pay for the performance. I read stuff on here about cat-code plugs and noticed that my bike didn't have one. I think the dealer removed it when he fitted the Y-piece.
I tried putting the standard one back in but it made no difference so I assumed that the cat code plug was not related to my problems.
Then last month the bike's warranty ran out and I thought about maybe fitting a power chip to see if that would help matters, however at £270 a go I thought I'd read up on them first.
A web search turned up a fair bit of stuff on chip makers BB-Power, including the fact that in conjunction with their chip they used different combinations of wire jumpers to connect the cat-code terminals to each other (I then realised that in effect that's all the cat-code plug is - a fancy connector between terminals in its socket).
The eight different set-ups go from stock bike (cat, can, K&N air filter) right up to having high-lift cams fitted. The second stage was for my set-up, Y-piece, K&N with standard can.
Then I did a search on this forum and discovered that Steptoe had used the same jumper connections, but with the standard BMW engine chip.
"What the heck, I may as well try it," I thought. And so I did just this morning.
BLOODY HELL WHAT A DIFFERENCE!
The bike has been transformed for the cost of three inches of wire and two spade terminals.
The low-rev behaviour is completely different, it's now like my first GS - but I've still got the extra mid-range punch from losing the cat.
I suspect those who have written on the forum about the Motronic system going into a kind of generalised safety mode when the code plug is absent may be right.
It certainly seems that the dealers don't know everything about the subject.
Sorry the posting is so long, but I thought it was important to give you plenty of detail.
And Steptoe, if we ever meet the drinks are on me!
It's a bit of a long story, but bear with me:
This is my second GS, both were from new, the first one which I had for three years was completely standard.
The latest one had a Y-piece fitted from new, and while I was in a spend-happy mode I asked my dealer to fit a K&N air filter, but kept the stock exhaust as I like my neighbours and prefer my speeding to be stealthy.
It never felt right at low revs. The best way I can describe it (and this is what I told my dealer) is that the throttle response was "fluffy". For example when blipping it between down changes the engine always felt like it was lagging a split second behind the twistgrip movement. If you blipped fast enough the engine would actually 'bog down' as if the mixture was too rich.
Sometimes, usually after a spot of high-revs action, the engine would simply cut as I shut the throttle and pulled the clutch in when coming to a stop.
And it felt weird on the overrun, like the fuel supply was being cut off as the bike rolled down through 2500-3000 rpm, forcing me to declutch much earlier than I should have to.
I knew this wasn't just subjective, because my first bike didn't exhibit any of these faults. I also knew it must be down to a combination of the Y-piece and freer-flowing air filter, but I didn't want to change it back to stock because (i) I'd thrown the cat away and (ii) I really liked the extra mid-range oomph that this set-up produced.
The service manager (who's an ace bloke and reads this forum) was sympathetic and helpful but couldn't really see what it was that I didn't like, other than the engine cutting out. I had the throttles synched several times under warranty, but the BMW diagnostic stuff couldn't spot anything wrong.
So for 16,000 miles I've been riding around the problems, accepting them as the price I had to pay for the performance. I read stuff on here about cat-code plugs and noticed that my bike didn't have one. I think the dealer removed it when he fitted the Y-piece.
I tried putting the standard one back in but it made no difference so I assumed that the cat code plug was not related to my problems.
Then last month the bike's warranty ran out and I thought about maybe fitting a power chip to see if that would help matters, however at £270 a go I thought I'd read up on them first.
A web search turned up a fair bit of stuff on chip makers BB-Power, including the fact that in conjunction with their chip they used different combinations of wire jumpers to connect the cat-code terminals to each other (I then realised that in effect that's all the cat-code plug is - a fancy connector between terminals in its socket).
The eight different set-ups go from stock bike (cat, can, K&N air filter) right up to having high-lift cams fitted. The second stage was for my set-up, Y-piece, K&N with standard can.
Then I did a search on this forum and discovered that Steptoe had used the same jumper connections, but with the standard BMW engine chip.
"What the heck, I may as well try it," I thought. And so I did just this morning.
BLOODY HELL WHAT A DIFFERENCE!
The bike has been transformed for the cost of three inches of wire and two spade terminals.
The low-rev behaviour is completely different, it's now like my first GS - but I've still got the extra mid-range punch from losing the cat.
I suspect those who have written on the forum about the Motronic system going into a kind of generalised safety mode when the code plug is absent may be right.
It certainly seems that the dealers don't know everything about the subject.
Sorry the posting is so long, but I thought it was important to give you plenty of detail.
And Steptoe, if we ever meet the drinks are on me!
