"Running Dangerously Lean"?

[Geordietraveller]

I was seriously thinking of replacing first the end can and then the downpipes/cat on my 12 but after reading the latest issue of Bike magazine I don't know whether to bother. Their long term test bike has been fitted with a Laser system and is now apparently running "mega lean".

I would have thought that with having a brain the size of a small planet, the GS FI would compensate for a free-flowing exhaust without having to resort to such crude implements as Power Commanders. (Honda Blackbirds seem to be able to cope fine by themselves)

Has anyone who's changed their exhaust had any problems / checked the condition of their plugs recently?

I'd hate to muller the engine for the sake of a nicer exhaust note and a couple of bhp.

Si

 

[Fanum]

My Remus and y piece were fitted by my dealer, and I've asked them to check the plus specifically twice on services, both times the plugs looked OK.

I'm not too worried though....if they supplied them, fitted them and haven't recommended either verbally or in writing that there's a potential problem, then it's down to them if my engine drops a valve.

Sightly more tenuously, but only slightly so, if you could show that any BWM dealer fits remus/y pieces but not power commanders, that would back up any claim you might have to make.

I'm not worried about it, but will probably get one of the new generation chips designed specifically for twin spark boxers when it comes out early next year.

 

[Schtum]

I would have thought that with having a brain the size of a small planet, the GS FI would compensate for a free-flowing exhaust without having to resort to such crude implements as Power Commanders.

I think you malign the Power Commander unfairly. It's possible to use one to have the fuelling for the bike to which it's fitted custom mapped very precisely.

 

[Geordietraveller]

Maybe, but I'm still suprised that the GS can't enrich the mixture enough to cope with an aftermarket exhaust when my old Blackbird could do it no problem.

I think it's a bit rough if it is the case, given the dependence on computers for the rest of the bike (brakes/knock sensors etc).

To be honest I think it SHOULD be ok but this Bike article put the willies up me a bit. The only thing is that the guy went from a full race can to road legal because it was too loud - I can understand the need for a Power Commander with a race can (just not a road legal one)

 

[Sergeant Pluck]

The on-board computer probably can compensate for free flow exhaust, but it would need to be told it has one fitted in this first place. I'm guessing that the Laser system is just a direct replacement end-can? Are the lambda's in the downpipes left in place? The 'brain' will have no way of knowing whats going on in this case. Not sure about the 1200, but the 1150 has a series of different 'cat code plugs' which can be fitted dependant on what exhaust config you have. They tell the bike's brain which fuel map to use.

pr0ne

 

[Richard Stallard]

Mmmmmmm!!!

I've got a Y piece and a Sebring race can on my 1150, runs OK but feels a bit flat sometimes at the top end, likes to be revvved out a bit more to get it to hussle through the box.

Top speed as seen on the GPS 120mph is this about right?

Sounds FKN amazing and pops back sometimes.

Which my fuel injected Harley never does.

is there a Power commander I can get? and if there is what advantage is it?

 

[schnauzer]

do a search on power commander and techlusion for the options for an 1150.

 

[Richard Stallard]

Thanks will give it a try

 

[Geordietraveller]

I'm guessing that the Laser system is just a direct replacement end-can? Are the lambda's in the downpipes left in place?

It seems that the journo replaced the whole system, losing cat on the way. Laser systems I've seen retain the lambda sensors so the bike should be getting the relevant info.

Never heard of 'cat code plugs' before - Mill told me their next demo bike would have a Remus end can fitted, I'll see if they've made any other mods.

 

[Sergeant Pluck]

Never heard of 'cat code plugs' before - Mill told me their next demo bike would have a Remus end can fitted, I'll see if they've made any other mods

The 1200's may well not have them. The 1150's certain do - that's if the owner kept them in They are literally nothing more than a jumper which tells the motronic which fuel map to use. Very low-tech and probably doesn't exist on the 12xx.

pr0ne

 

[Dinger]

I had road-legal Micron Delta+ end-cans fitted to my '03 Blackbird for about 8 months. When the 16,000 service came around the plugs ranged from pale to almost white. The guy doing the job (JAWS Motorcycles) suggested that I should either fit a Power Commander, switch the cans back over, or lose some valvegear.
I think I'll stick to the original zorst on the GS.

 

[Russ]

If the laser system was a full replacement and dropped the CAT plus all the sensors, then of course it would run dangerously lean, because the computer cannot detect the level of unburnt HC so cannot decide whether to run rich or lean...i'm surprised the thing ran at all! typical stupidity from BERKS magazine! Simple logic chucked out the window!

An end can change will be compensated for by the computer becuase it can detect the changes wrought by said can (by detecting unburnt HC etc... in the upstream and downstream areas of the CAT) and adjust fuelling accordingly, hence the sensors are there. (this a simplistic overview of a complex system, and there are variations, but it all roughly works the same way)
Changing a full system without feeding codes to the computer to trick it into thinking all is well will cause all sorts of hell...lean fuelling being one of them

In answer to Richard's question, 132mph confirmed by the GPS (the 1200 speedo is dead accurate too).

Think of it another way...the computer has to compensate for different weather conditions too (eg. Damp and cold, dry heat, humid heat etc...), it doesn't do it by magic, it uses the sensors to adjust fuelling etc... accordingly hence pulling out the other end of the pumbling will leave you with a mess and a big bill!

 

[Richard Stallard]

Thats not bad 132mph, know what you mean about the speedo, the one on my 1150's shall we say about 15kmph optomistic.

Do you think 120mph for an 1150 is about right?

thanks

 

[Russ]

Thats not bad 132mph, know what you mean about the speedo, the one on my 1150's shall we say about 15kmph optomistic.

Do you think 120mph for an 1150 is about right?

thanks

Thats pretty darn good! (I'd assumed -wrongly - you had a 1200!),

I test rode an 1150, and it struggled to get over 115mph flat out in top...a testament to its previous owner(s)