Help needed with an experiment please

[Russ]

Coming home today i noticed something about the power delivery on my 12. I can't say i noticed it before, but having changed the exhaust and whilst enjoying its 'tunes' i have noticed something rather odd.

There seems to be a minor lull in the power delivery somewhere around 4.5K rpm then at about 5.3K rpm it gets a second wind and takes off, but the lull is very subtle.

I noticed it by putting the bike into 6th on an empty stretch of motorway doing about 65-70mph, opened the throttle to the stop. The bike builds up speed and the rate of acceleration increases, but then when it passes 80mph there is a definte lull in the rate of acceleration (almost as if its running out of puff) then once round to 90 the rate of acceleration increases again, and by 100+ its keeps pulling harder and harder.

Can anyone with a remus can and someone with a standard can please try and see if they get the same result?
I am wondering whether this is a common issue and that the race can is liberating more ponies thus exacerbating the step in power or whether the can has modified the fuelling parameters, and this is indicative of a problem.

Does anyone know if the second set of plugs kick in when under full load above 5K rpm? If i were to guess, thats what i'd say was happening.

 

[smartrider]

I dont know, but I suspect.
There is a slight dip in the power at about 5 thousand rpm , and its to do with the regulations that the bike has to pass i.e noise and emissions. they make the bike do the right emissions and noise at the right time.

Changing the can or y peice will not change that, its all to do with the "map" on the ECU.

Just my thoughts, could be total b###s##t

 

[NakedRider]

I noticed the same thing. Funny thing is it was there before the Remus also. I looked at www.sjbmw.com at some dyno charts and it clearly shows a torque dip at that RPM. I have install a full Remus and the dip, to me, seems less than when it was stock. It's just that thats a terrific place to start your roll ons so you notice it more.

 

[Clive]

I have the same "dip" around 5K on standard exhaust. - I only seem to notice it on Motorways

 

[Dave Price]

When Dynajet offer their Power Commander, it should be possible to rectify this dip in torque/power.

 

[Russ]

I'm pleased its not just me then

DP, you are right, *if* dynojet can make a Powercommander for the 12 then it should be possible to tune this out.

I found another 'empty' stretch of motorway this morning to repeat the exercise but was able to maintain full throttle, 120 came and went, 130 came and went, went past my previous 'best speed' of 132, 135 came and went, and it still had shedloads of go, it would have hit 140 and probably gone off the clock!

This Scorpion can has certainly liberated a few more ponies

 

[Bert]

I noticed the same thing. Funny thing is it was there before the Remus also. I looked at www.sjbmw.com at some dyno charts and it clearly shows a torque dip at that RPM. I have install a full Remus and the dip, to me, seems less than when it was stock. It's just that thats a terrific place to start your roll ons so you notice it more.

Agree with Cadave- ditto- Remus Revolution fitted.
Ban those 'cats'

 

[Dave Price]

I'm pleased its not just me then

DP, you are right, *if* dynojet can make a Powercommander for the 12 then it should be possible to tune this out.

I found another 'empty' stretch of motorway this morning to repeat the exercise but was able to maintain full throttle, 120 came and went, 130 came and went, went past my previous 'best speed' of 132, 135 came and went, and it still had shedloads of go, it would have hit 140 and probably gone off the clock!

This Scorpion can has certainly liberated a few more ponies

Mine actually revs quite easily to the limiter in top.

 

[ChrisK]

No flat spots on mine, remus system sounds love leeeeeeeeeeee, louds of grunt

 

[GSmonkey]

I've got a Remus and I wouldn't say there's a dip, more a step. I think it was there before the Remus, but can't say for sure.