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Do I need to tune after replacing a slip in exhaust?

2109 Views 12 Replies 6 Participants Last post by  BillV
I’m about to swap slip on exhausts. Bike came with a two bros exhaust with the cat deleted. It has a PCIII. I’m new to super sports so I’m not sure if it was custom mapped or what. It seems to run fine , maybe a bit of puttering at low rpms but I think that’s mainly because it’s just begging to have the throttle twisted at all times.

But now with a replacement to a scorpion exhaust, should I be getting this thing professionally tuned? Is a PCIII still functional in 2022? What do you recommend? Limited budget.
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if you want it optimal bring it in to a dyno tuner.. or download the map

determine if your ECU has been zeroed out, and if the map is a zero map, match maps accordingly, if they still use zero maps in 22?
if you want it optimal bring it in to a dyno tuner.. or download the map

determine if your ECU has been zeroed out, and if the map is a zero map, match maps accordingly, if they still use zero maps in 22?
How do I confirm if my ECU has been zeroed out? What does that mean?
The Yoshimura slip-ons for the K7 1000 also involved removing the cat and they didn't recommend remapping so I'd expect your 750 to be the same. For such bikes the PCIII is an independent add-on. As far as I can tell, you can get it mapped for higher performance (at the expense of gas mileage) or leave it alone. Does the Scorpion exhaust require removal of the cat?

The slip-on exhausts from Two Bros and Yoshimura that involved removing the cat nearly bankrupted both companies after the EPA sued them for violating the Clean Air Act. They've since listed those systems as race-only and I think require you to sign something to that effect. I don't know how uptight Canada is about all this but there might be complications with whoever does your tuning.
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But now with a replacement to a scorpion exhaust, should I be getting this thing professionally tuned?
You got a PC3 on it, might as well take the most advantage of it, get a custom tune

First of all:
No 2 bikes are the same, so if you want the best power out of your bike, what works for your neighbor's K7 might not work for yours


And dicking around with an online map that was originally for a 'similar' bike that had maybe less than 1k miles before dynojet made a map for it, while you're bike has seen 15 years wear and tear
will only magnify that difference


The good knews is that you have an O2 sensor standard, and this makes the ECU is capable of compensating the A/F somewhat by itself
You could simply disconnect the PC and leave it like that


Is a PCIII still functional in 2022?
Yup, especially at 1/3rd the price of a PCV

Limited budget.
Then I guess it's too late to tell you you took up the wrong hobby if you wanted to save money 😜
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Does the Scorpion exhaust require removal of the cat?
It's a K7
The Yoshimura slip-ons for the K7 1000 also involved removing the cat and they didn't recommend remapping so I'd expect your 750 to be the same. For such bikes the PCIII is an independent add-on. As far as I can tell, you can get it mapped for higher performance (at the expense of gas mileage) or leave it alone. Does the Scorpion exhaust require removal of the cat?

The slip-on exhausts from Two Bros and Yoshimura that involved removing the cat nearly bankrupted both companies after the EPA sued them for violating the Clean Air Act. They've since listed those systems as race-only and I think require you to sign something to that effect. I don't know how uptight Canada is about all this but there might be complications with whoever does your tuning.
Ya there is no cat anymore. The scorpion comes with the canister and a mid pipe. It would require removal if it was stock. Interesting about the tuning. I will check in on that. Or maybe my bike IS just a track bike if they ask... shhhh. ;)
You got a PC3 on it, might as well take the most advantage of it, get a custom tune

First of all:
No 2 bikes are the same, so if you want the best power out of your bike, what works for your neighbor's K7 might not work for yours


And dicking around with an online map that was originally for a 'similar' bike that had maybe less than 1k miles before dynojet made a map for it, while you're bike has seen 15 years wear and tear
will only magnify that difference


The good knews is that you have an O2 sensor standard, and this makes the ECU is capable of compensating the A/F somewhat by itself
You could simply disconnect the PC and leave it like that




Yup, especially at 1/3rd the price of a PCV



Then I guess it's too late to tell you you took up the wrong hobby if you wanted to save money 😜
Thanks, Nightbat. I may as well get a custom map. I have assumed it's set up properly for the two bros and cat delete, but something is telling me it was probably just a downloaded user map. lot's of popping. like a drive by is occurring every time I'm engine braking in town. people love it, I'm sure.

Lol... you're right. I've already spent more than expected on this bike. only 20k kms for a k7 though.. I hope it lasts a few years for me. Got a custom seat coming in too. My wife is going to roll her eyes when she sees it but I'll lie about how much it costs :)
Got a custom seat coming in too. My wife is going to roll her eyes when she sees it but I'll lie about how much it costs :)

Luckily, I don't have a wife, because how in the hell would I explain my set of Marchesini's coming in the mail

"Jeez honey, settle down, I got this from Alibaba for not even 50 bucks!"
tuner can let you know what you have or suzuki shop
Some guys run a slip on and don't bother tuning their bikes and say they run fine. Could be true since all bikes are different. I personally put a Scorpion slip-on on my older K6 1000 and it would barely even idle until I took it to the dynoman and had him map the PC5 to the slipon. I suggest dyno tuning if you can afford it just to ensure you're getting maximum performance out of any mods you do to the bike.
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I run a yoshi r-11 slip on, on my 2019 750. No tune or anything, I haven’t noticed any difference in how it rides or feels. Just the noise is a little nicer and looks better. You could swap it and see how it runs for a short while? If it’s noticeably different then a tune is probably needed.
Suppose if it’s already had a tune a for decat, swapping the muffler won’t affect it too much. If your track riding though and want top performance then a tune is a must.
I had a KR Tuned slip-on on my K6 1000 and it ran fine from the git-go. Didn't notice any difference in how it ran. Later switched to a Yoshimura R77 slip-on and again saw no change. There was a sneaking suspicion that the gas mileage might be a tad better with the KR but I've never gone to the trouble to check.
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