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Is there a difference between the cats on the BCR and the other ‘S’ machines? Also how many variations are there on O2 sensors? (For single spark, twin spark and BCR perhaps?). Please help - seems a bit of a minefield.....!

There are 2 cats for the 1100s
18 12 7 687 567 - 01 is for the twin spark (fitted to my BCR)
18 12 -1 341 033 for single spark
The 2 O2 sensors are different part numbers
I have a single spark cat for sale in very good condition (minus 02 sensor) if anyone is interested

Thanks, Dave, but surely if the BCR has a Laser exhaust as standard, it would need a ‘freer’ cat than the other models?
Just want to be clear that there are only two types of exhaust and Lambda sensors, not an extra set purely for the BCR?

I’ve never heard of any difference. Not that it means anything worthwhile!
Get your local dealer to bring up the relevant pages or look yourself www.realoem.com.
Can I ask why you want to run with a cat? I thought the popular mod is to remove it?

As Dave says, the engines fitted to the 1100 were either single or twin spark with negligible performance difference between them. The only difference between the S, Ssport or BCR were rear wheel size, suspension and pretty paint. When I got my Ssport it had a Laser system fitted and dealer said it came with decat pipe and cans,and an ECU chip, but not sure about chip. it had also had a Lennies induct pipe and K&N filter fitted to get more air through the engine.
Hundreds of posts on here over the years about this and ways to gain a few extra BHP, bedtime reading for weeks!!!

Al.

Thanks All, will have a think.....

Just an FYI to say that there are 2 part numbers each for the cat and Lambda sensor, but these are dependant on the date of manufacture of the bike and not whether it is twin or single spark ⚡️.
MotoWorks very helpful with this and sell Lambda sensors for almost half the price charged by a certain BMW main stealer....
Reason for putting cat back in is to get the bike back to standard. My theory is that the fuelling and exhaust system are set up and designed as a complete system. Just increasing gas flow through and out of the engine is likely to make for poor fuelling except at high throttle openings when the map would allow significantly more fuel in and perhaps keep up with all that extra air.
The map isn’t otherwise going to compensate as it doesn’t have enough feedback. I would also guess that the extra air flow would cause unburnt fuel to pass through the exhaust - the Lambda sensor would then see too much O2 and actually lean off the fuelling??
I have had all sorts of tedious random starting issues and a general feeling of reluctance to pull unless you wrenched open the throttle, when it actually felt surprisingly quick.
Rode today for first time as standard - started properly and much more tractable at low and medium speed and throttle openings. Had no issues with overtaking. Will see what it has done to fuel consumption...(I had to adjust the throttle bodies and idle quite a bit after fitting the cat - idle was up around 2000 rpm! Shows that the extra back pressure has allowed much more efficient burning of the idle mixture??).

Karl1000 wrote:and a general feeling of reluctance to pull unless you wrenched open the throttle, when it actually felt surprisingly quick.
.

What set up did you have before you returned to standard? The above symptoms sound a bit like a failing ( slow switching) lambda sensor., Afaik above 60% throttle opening the lambda is ignored plus there are various other throttle , rpm scenarios where the bike goes open loop also.

Interesting, could also be that. I fitted a new lambda sensor as well, so lots of changes at once!