2008 GS500F + full exhaust + K&N + rejetting

[Helmet27]

Hey all, i got my Jardine today ,took half an hour to do the swap, piss easy really. It is bloody loud man!!!!! Maybe to loud...... yeah right,haha!!!!

--------Drewbytes: thats good news mate, i hope i get mine as close as yours to stock!

--------Galahs: with your Jardine K&N's and your 20,65,145 jets on your bike, do you get alot of back-firing when down changing and decelerating? I mean, almost an excesive amount of back-firing? Coz i am, any ideas?

[galahs]

Yeah you get alot of backfiring if you use very hard engine braking, especially down hills. its a problem associated with having such a free flowing intake and exhaust, causes the mixture to lean out too much when the throttle is snapped shut.

I get no backfitring at all with normal riding.

Increasing the idle speed alittle can help, as does just keeping the throttle open a slight slight touch as you deaccelerate. 

[Helmet27]

Chees Galahs, i shall put that into effect immediatly. I like the backfiring,its sounds nice but sometimes it can get to much, haha. What power do you think it makes with these mods? Not much more i'd suspect, but there does seem to be more of a hit down low. . .

[galahs]

A few horse power or so at the most. Here is a page with a few different dyno charts.
http://gstwins.com/gsboard/index.php?topic=45924.0

Also pulling in the clutch rids the backfires if you want to be real quiet in a residential area.

Depending on your bike it might be fitted with a PAIR system if so read this

Running more lean than stock (as in an air filter that flows more air) can cause some popping on deceleration. Blocking off the secondary air (PAIR on Suzukis) may help. This is a path from the airbox to the exhaust which causes unburned fuel to detonate in the exhaust rather than being dumped into the atmosphere. The popping is the fuel being ignited by the exhaust. Blocking off the secondary air prevents the fuel from getting into the exhaust.

[Helmet27]

Thanks Galahs, yeah, i'v been trying different things to try and quiet it down, although my dads sv650's staintune muffler is VERY loud, and the 06 Bonniville with straight throughs was loud aswell,so i think the neighbours should be used to it by now , Plus theres a load of dickhead 20 somethings living across the road that all drive loud assed holdens and civics 

Your bike is an '05 isn't it? If it is,does yours have the PAIR system? Cos mines an '05. . .

[galahs]

Nah mine didn't.  but I've seen another 2005 that did???

[Helmet27]

Thats a bit odd, i can't figure why that would be. Hey, i saw that you have done research on sonic springs, have you made that upgrade?

[bill14224]

Hi, Drew:

Have you found the 7-10 extra horsepower you were looking for, or did you find it's less than half as much?  You will get more midrange power though, and that's what matters on the street! 

I went back and looked at the dyno charts posted on this board with similar mods and it looks to me the differences in readings from probably different types of dynos is larger than the power increases we're getting by putting new pipes, filters, and jets on our bikes.

For instance, Anne's bike (1999) dyno'ed at 43.2.  Other bikes, newer ones with the same mods, dyno'ed at 36 and 38, but we see a stock comparison ad showing a stock GS putting out 39 next to a 500 Ninja putting out 50.  Looks to me like dynos vary more than the few ponies we're getting without head work.. and I'm talking about the bikes, not us... well.. maybe both!! 

[drewbytes]

Bill, I have no idea  It does feel stronger at full throttle and it is hard to quantify, but a hill I ride every day on my way to work it reaches a higher speed at the top of the hill than it did before the mods. Whether it's 1, 3, or 7 hp? Dunno. I don't intend to dyno it to find out, not that I have a before figure anyway.

[galahs]

Yep got 0.85kg/mm front sonic springs. Best upgrade i have ever done on the GS500.

I got them shipped direct from SonicSprings
http://www.sonicsprings.com

[bill14224]

Drew:

An uphill test may be the best thing I could think of!  Yes, hill climbing may be the best way to test the midrange of your bike.  More midrange will make hills easier to climb.  Are you climbing at 5000-7000 rpm like I would suspect?  See what I mean?  Midrange HP is what matters on the street.

Japanese engineers are pretty smart, and they design bikes to run well with near maximum mpg for their displacement.  Like everyone who upgrades learns, you have to increase flow through the engine to increase HP by upgrading every component in the system; air filter, exhaust, and jets, and porting heads if you want to take it further.  But, you pay a mpg penalty of about 20% for picking up a few HP.  That's why the Japanese engineers made the bike the way they did in the first place.  They understand that if you take the design beyond where they did, you'll pay a big price in efficiency for a little more power.

[drewbytes]

Drew:

An uphill test is the best thing I could think of!  Yes, hill climbing may be the best way to test the midrange of your bike.  More midrange will make hills easier to climb.  Are you climbing at 5000-7000 like I would suspect?  See what I mean?  Midrange HP is what matters on the street!

It's 4th gear starting from 60kph at 4000 rpm. Stock it was doing 80-90kph at the top of the hill, now it's doing 100-100 kph. So it's between 4000 - 7500rpm or so I think

[bill14224]

Drew, if you look at the stock HP dyno graphs, you'll see a dip in midrange HP in the range you're talking about, between about 4500 and 6000 rpm, meaning it's not dropping, but not climbing in a linear fashion as we would like in a perfect world.  Increasing flow through the engine improves it, but it comes at a mpg cost, which the Japanese engineers decided wasn't worth it.  It's been that way since the '70s when I got involved in motorcycles.  I understand why.  More midrange is great, but there is a significant cost.  Significantly more peak power at 9000 or more rpm costs cubic dollars, to use the words of David Johnson, the racer who posted a most interesting article on this website in the Racer's Corner.  The solution to this is 4 valve per cylinder heads.  With those engines you get the linear increase in power, but you have the added cost and complexity of a multi-valve design.  Valve jobs for your bike are cheap.  Valve jobs for a GSX-600R are not.

[allaussiegrown]

Cheers Galahs, now i gotta go out and get a set of K&N filters and the same jets as yours plus do a "fenderectomy" and get new indicators.

Check this out for some indicator ideas
http://gstwins.com/gsboard/index.php?topic=40133.0


Are you game to try this 

what screen is that? i am waiting on my Zero Gravity Touring screen to arrive, it is dark smoke. Once i have put it on ill take photos of the bike

[galahs]

Its a ZeroGravity Double Bubble light smoke