UK Monster Owners Club Forum » .: Technical :. » Mods & How To's » Flat spot 5k after fitting db killers

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Old 06-12-2018, 03:43 PM   #1
jerry
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Flat spot 5k after fitting db killers

Had to fit very short 48mm db killers to my termis on the S4 in Thailand to get them down to the 95db that local fuzz are targeting ,,

Bike has PC3 , termis ,, airbox mods and my special map Mark 4low and was running perfectly without the db killers ,,

with them its still silky smooth and fine up to 4500rpm then it hits a flat spot until 6000rpm
and then it runs fine up to redline

i can start off the line and blast through the flat spot with full throttle all the way to red line ,no problem , but in high gears at constant throttle say 4000rpm ,, opening throttle the flat spot is a hesitation blip ,,

so time to re- write my PC3 map was thinking just lean it out a tad between 4500k and 6000k so less fuel is flowing due to the db killers ,, and see if that fixes it as the map used to have quite a fuelling jump at that point ,, tonight I have written Map5low

will see tommorow if im successful or have to tweak it more ,,


at least the cops are off my back ha ha
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Old 08-12-2018, 11:38 AM   #2
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oops this is weird , went for a ride and the bike is all wrong the map i loaded did not load , when I checked my PC3 it did not have my Map in it and when i reloaded it it defaulted to an unknown map ,, seems this unknown map has been in my bike for a couple of years ??? and is probably the reason for very high fuel consumption ,, Its not the map I loaded on 2/Feb/2010 .. its not a map I wrote and its not a Power commaneder library map .. its weird it was uploaded in November 2016 thats all i know ,,but at the time the bike was in my spare room and my wife and I were in UK house was closed up so ??

Im gonna try and reset the PC3 and flush out this weird unknown map ??


anyone ever seen this problem ,, no one has had access to my bike so Im a bit confused
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Old 10-12-2018, 03:33 PM   #3
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ok reset and purged the PC3 got the right map in now its better but still not perfect ,, needs more tweaking between 4k and 6k on 30% throttle also not so smooth on transitions and a bit rough at 2-3.5k in traffic

work in progress but having the db killers is a blessing ,, no fuzz hassles ,


another odd fault oday on test run about 30 miles up the road bike appeared to run out of fuel ,, so i checked and its still had fuel so i pulled the filter out the tank and the roadside ,, it was ok but the fault was that hose from pump had detached as jubullee clip had vibrated loose,, after 2 hours faffing around in hot sun and fuel it was fixed and ended up doing another 50 miles

,, writing some map upgrades tonight ,, but its tropical rain tommorow so may not get to ride it
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Old 10-12-2018, 05:59 PM   #4
stopintime
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I was told by my engine builder that I 'need' a db-killer-map. I'm not going to change maps back and forth and 'never' need to use the db-killers. Had one track day with them in and had that flat spot.

Q:
Does your Monster run 'closed loop'? If so, won't you have a flat spot and/or other rubbish in the lower rev areas regardless of PCIII?
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Old 11-12-2018, 03:26 PM   #5
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S4 does not have O2 sensor its a primitive IAW59 ecu but with power commander some very smooth free running maps can be made ,, it was perfect with my custom maps before I put the db killers in ,, just got to tweak it to get back to smooth low speed running and fat midrange , will take a few attempts ..
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Old 14-12-2018, 03:08 AM   #6
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its proving more difficult , the DB killers add a lot of back pressure ,, I can get it nice at certain throttle % conditions ,, but in other place its too lean at some revs then at same place just right ,,might have to get on a dyno but nearest one is a long way away

so may cops with db meters now , 95db is limit , otherwise i would remove db killers and put old free revving with smooth transitions and nice low down running map in
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Old 14-12-2018, 07:19 AM   #7
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There are cops with dB meters?
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Old 14-12-2018, 11:28 AM   #8
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Quote:
Originally Posted by Billbo View Post
There are cops with dB meters?
Yep ,, fascist aint it

good news drilled 3 each db killer 6mm holes in the outer rim to reduce back pressure ,, worked well bike is more responsive , and smoother already ,, and still under the noise threshhold at 91 db at 1 metre from silencer ,,


hoping fuel consumption improves too as its currently only 30mpg and should be 45mpg or better if ridden gently ,, the fuel consumption problem is classic TOO MUCH BACK PRESSURE SYMPTOM..

have further adjusted fueling map but wont make any more adjustments until i see how far a tank of fuel takes me I want 140-150 plus miles to a tank not 100.
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Old 14-12-2018, 12:45 PM   #9
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I have found that my 1200s runs better with the baffle in, when it was out it was louder but every now and again there would be a loud backfire (probably) as fuel was burnt in the pipe. Bike is smoother now so I will keep an eye on consumption next.
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