DD350E-6c Debaffle Advise Please

Hi Guys,

Just got a Laro Prostreet 350 (DD350E-6C) some may know them as Hunter Daytona 350 or Regal Raptor Daytona 350 and I think even another brand or 2 use them. All the same bike just different badge.

I've been hearing mixed stuff on Debaffling the exhausts. Some say you can just do it fine with no dramas. I did see one of these models with the exhaust cut off neatly just past the baffle and the guys said it runs fine on Youtube.

The main problem I have is some people mention that debaffling etc can mean you need to adjust the air intake on the bike as well or you may get backfires etc..

I'm no mechanic but was wondering if anyone has debaffled this model and has advice, know how etc

Also the speedo bounces around like hell. gets worse the faster I get. Bounces with a difference of about 10km's either side. Is this easily fixed?

Lastly the fuel tank shows as empty with half a tank. Again easily fixed?

Specs according to Laro Site: http://www.laro.com.au/prostreet-350-2/

Thanks Guys.

With carb bikes, then it should be fairly easy to do something like cut off or de-baffle a muffler. However with EFI bikes I really urge caution. I'm no engineer or mechanic, but I have experimented with mufflers, carbs and air filters on a few previous bikes so take my opinion any way you like.

Basically if you make a bike breathe out more easily it then needs to breathe in more easily and burn more fuel. Back when most things had carbs, that was easy, put on a hi-flo air filter, then put a bigger jet in the carb/carbs and change the needle height. These days you need to re-map your ECU to balance out the fuel, however you need a new muffler and fuel map with ECU re-program to achieve this or do it with a dyno.

You'll hear people shouting from the rooftops that their bike with some straight-thru muffler or semi restricted muffler is now super-duper, safer, lighter, and their bike is more powerful too. They won't hear that this may not be the case or even be damaging their bike, it might make them even get angry or annoyed to hear it or even regard it as a personal attack, and will try to convince you to do the same as they have. This is because with all the extra noise, throbbing and excitement the bike seems to have improved at least psychologically. The thing is; if straight-thru pipes are better it can be easily proven on a dyno. You can even gain Kw but lose Nm, although nothing is certain as some ECUs can deal with big changes in fuelling and others can't. You see if the air is coming out of the bike faster this will probably create a lean condition, the backfiring coming from unburnt fuel getting into the pipes. With those straight-thru pipes you have no back-pressure and then the torque will be massively down when tested. Have a dig around on youtube there are some videos showing what happens when you put straight thru pipes on a Harley vs stock. Sure, stock pipes are heavy boring and quiet, but the bike is way down on torque with straight-thru mufflers.

IMO don't de-baffle but find a better muffler that is designed specifically for your bike. You could try one designed for a very similar bike, but that would be partially guesswork, but better than having a straight-thru muffler.

Speedo, maybe a loose cable, or cable is too stretched or snagged.

Fuel tank, maybe float mechanism is poorly adjusted.

Hope this helps.

Thanks for the advice. Will look further into what you are talking about and read up on it a bit.

Headlight was out when I left work tonight.. Pulled into servo and fiddled around to fix it. That was a worry riding in pitch black along the shoulder of a 90km/h zone to a service station. Don't know if the cable 'unsnagged' or something but it was a lot less bouncy than before. :icon10:

OK so had a look around and I see what your talking about now. Located the ECU on my bike and found out it is a 'Delphi Sec'.

From all the articles I could find you are right. EFI bikes need ECU remap or an ECU Controller attached. ECU modules on their own can make minor adjustments to fuel usage etc. Some can adjust a little easier on their own than others to small changes. Even drilling holes on some occasions can be to much for the ECU.

From what I read anything from debaffle to new pipes will require ECU remap or Controller attached.

Thanks for the great advice. Saved me from a possible costly mistake.

There is a former professional mechanic teaching people how to de-baffle/de CAT their stock Harley pipes and putting a stubby muffler on an Aprilia Mille. No ECU mods, no dyno, no air-box mods. 'Because bikes will look sound and better and be a few kg lighter'.

So this myth clearly extends from senior mechanics right down to the massive majority of owners who must believe that their ECU can cope not only with the lean condition caused but with potentially huge drops in torque.

Maybe the designers and engineers don't want to spoil peoples fun by telling them the truth or maybe the information isn't as disseminated as it should be. I know most performance bike owners wouldn't touch a muffler without doing an ECU remap, but I think this logic has not reached the minds of people modding older/commuter/cruiser bikes.