Maintenance & Technical > KX500 Original
Shortened Silencer
Motoroost1:
Stock and worn out . The Suzuki only had 150psi of compression and the TTR230 is brand new :) That was like salt in the wound for the TTR boys :) They were doing some seious trash talking for weeks prior to the race :) Not any more .
Polar-Bus:
--- Quote from: Motoroost1 on May 01, 2012, 11:44:46 PM ---So , what's the theory behind silencers ? If I compare the standard PC 304 unit on my 2007 KX250 to the PC R-304 race unit , the R-304 is much shorter . So , logically , I would assume that less core size would mean less back pressure and potentially greater flow at high rpm . Right ?
If that's the case , why do most people say that the shorter silencer is stronger in the mid rpm range ? In theory , does this mean that it is actually weaker at higher rpm compared to the longer silencer ?
I hate to sound stunned , but , I am new to 2 strokes and I want to make sense of this as best as I can . If the shorter silencer makes more power , why isn't everyone using it ? In my experiment , the shorter silencer was stronger in the mid range for sure . But , I've only done very limited testing so far under one basic riding condition ( service road ) .
--- End quote ---
Personally I think the custom shorty silencer and more power thing is a bit too bold of a claim for a KX500. I'll bet all's your hearing is elevated noise rather than actual power gains.... my favorite bolt on performance comment "It's far easier to loose 4hp than gain 2"...
Motoroost1:
Now that I've had an opportunity to ride the bike on decent length trail rides ( 30 miles ) with both silencers , my original feeling stands . The engine is slightly stronger in the mid rpm range with the shorty . It's is slightly louder , but minimally . The difference in sound is very small . Does it make more or less top end power ? Who knows ? The mid range is where I spend the vast majority of my riding time , and here , the shorty feels better to me . The great part is that I have 3 different silencers on the shelf . The shorty , a Power Core and a Turbine Core . So , in minutes , I can change at any time if I decide to . I am not trying to convince myself or justify a performance improvement in the shorty simply because I made it and it HAS to be better . Personally , I couldn't care less which one is on the bike . Performance is all that matters and at this stage of the tuning , under the trail conditions that I have ridden , the shorty works better . Not sure why . Perhaps it's just the interelationship of some of the key components ( air filter , Rad valve , Gnarly pipe , jetting , riding style etc ) that favors one silencer over the other . But , no matter how you slice it , like it or lump it , there is a performance difference between the 3 silencers.
I am certainly not suggesting that everyone go out and chop 4" off their Power Core expecting miracles . Until I get develop a better understanding as to why the shorty seems to work ( on my bike ) , it is nothing more than an oddity . But , an interesting one ( to me at least ) . Everyone has an opinion and I respect that , but , unless it's based upon personal hands on exhaust system development experience , saying it doesn't work , means next to nothing . How would anyone know , unless they've actually done it ? So , here's an opportunity for those with hands on knowledge , to step up and provide real data to explain why things should and shouldn't work . This way we all can learn so our bikes get better and that's what this is really all about . Right :)
turdle:
if you had access to a dyno you could find out the difference between all 3 silencers. i am going to cut and weld a sparky on mine. and i should have access to a dyno this summer. if i get on the dyno i will post up my results.
Motoroost1:
Unfortunately , I don't . One of the local motocycle shops do have an in house dyno , but , it is reserved exclusively for the street bike guys and they have been unwilling to put an off road bike on it . (???) So , at this point , it's not much of an option unless something there changes .
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version