Suzuki GSX650F Forum - www.GSX650F.biz

With the Yoshi pipe I'm getting some mild backfire or popping on de-acceleration. I've been told a power commander will eliminate that, but the sound doesn't bother me so I wasn't planning on adding that. Question is will the backfire eventually cause any engine damage?

Thanks,
BobSled

no, the popping will not damage the engine or anything else.

the bike was actually doing it before you put the yoshi on. you just never heard it due to the efficiency (in deadening the sound) of the standard muffler.

Yes, a PC ($300+) can reduce (not eliminate altogether) the tendency for the popping to occur.
Plugging the PAIR hose just above the #4 spark plug (~$1) or removing the PAIR system altogether and putting on a set of PAIR removal plates (~$30) will do the same

Yes, but there is a post on here by a Suzuki mechanic highly recommending that you NOT disable the PAIR system. I'm not sure about the Yoshi's but I know that the backfiring with the 2 Bros exhaust will cause you to have to repack the muffler more frequently. But, I'm with you, I love the way it sounds.

After a little digging here is the post...

Mine backfires like crazy with my M4 exhaust, I love it! Gets me a lot of attention from the ladies while driving by the beach

I don't know how injecting a tiny amount of air in the exhaust and causing the excess fuel to burn off would cool the exhaust. No insult intended to the guy who posted that info but i'd take that word with a grain of salt.

I've met and worked with many "dealer" mechanics who don't know crap.

I for one know this little bit of information is wrong.

*PAIR is not an EGR valve. They do 2 different things and have 2 different purposes
*Removing it (or plugging it) will eliminate the popping sound on decel - I might not have made that so clear in my earlier post
*by leaving the PAIR fitted exhaust temps may be slightly lower and exhaust valve life may be increased slightly. IMO negligable. I have a 4 cyl car that the air injection system was stripped off almost 200000 kms ago and it's still going strong.
*take it off (or plug it) or don't, your bike your choice. Arguments for and against I guess

Not wanting to get too far off the subject but on the GSXF you can get a custom fuel map for your bike for far less than a Power Commander. My tuner plugs into the ECU and alters the OEM map. Do your mods, slip-on, K&N, PAIR Removal exc. Then find a dyno tuner in your area and get a map that was made for your bike

The laptop on the stool is plugged into the ECU, the map is tweaked after each dyno pull

You won't get a good DYNO and top speed with him on it ,he's sitting to up right and the wind is hitting him in the chest

I'm guna guess that the gear your tuner is using like this one (if not being this one).
Yes this can and does alter the OEM map to give better performance and does cost you less than a PC depending on how much he charges for his services and dyno time.
it does what it does without preventing the ECU doing everything suzuki designed it to do including fuel trim adjustment on the run via the O2 sensor amongst others.
It should be mentioned tho, that it is not as "adjustable" as the PC and is limited to adding or removing fuel in certain throttle opening ranges (eg: add 5% more fuel to the standard fuel map when the throttle is between 51 and 75% open).
This can make it a better tool than a PC in some circumstances and in others a not as good one. (I personally prefer it to the PC but that's me. But I'm also working on reflashing a ECU like they do with Busa's so I'm hoping to get beyond this tool sooner or later)

Your suzuki dealer and other bike mechanics that work on suzukis may also have access to what is commonly called a yoshie box which can do the same kinda things

If your a tweaker then yeah, a PC would be fun. But knowledge and tuning experience is far more important than any extra range the PC might offer. The OEM ECU has all the range a slightly modified or stock GSXF needs to gain HP and torque across the power band. Besides...my Butt Dyno hasn't been calibrated in decades

Its a shame nobody uses a full standalone ECU like used in highly tuned cars. Like AEM, Autronic, Megasquirt or Motec. Yes it costs heaps more then a piggyback like the PC or Rapidbike, but also has more controllable options and IMO the ultimate part to get the most out of your bike.

By nobody I dont mean GSXF owners but more like the 1000CC superbike owners.

EDIT

It is used on motorcycles I found out. But mostly on drag Turbo Busa's Go figure!

Any chance the biketech EFI tuner could bypass the restricted model's fuel map?

Blocking off the PAIR will absolutely eliminate the popping- as long as the blocking plates seal off the pair sockets on the valve cover. It will not burn your valves. On my SV1000, they have been blocked off for at least 18,000 miles with blocking plates (entire system removal kit): totally 100% cured the popping from less-restrictive pipes, lost a few pounds, and made for easier access to the spark plugs. I had to go back and seal the plates with gasket seal, even though the kit instructions never mentioned it. Will do this to my 650F soon.