Ideas to fix a lack of "back pressure" I know I know. - Suzuki GSXS1000 Forum
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post #1 of 18 Old 09-22-2019, 09:00 PM Thread Starter
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People are going to come and say "back pressure is evil". Let me tell you, my previous GSXR's with baffle out, it was louder, but it lacked some downlow oomph, put baffle in and it got it back. I recently did a few things to my motorcycle, I finally decatted, and muffler box deleted. I have been procrastinating for a year. I did it, had it refreshed by dano did the fueling adjustments and got it back.

Immediately after decat, I got the little lump idle noise I kept hearing rapido talk about. I sent it out to be reflash, he added the fuel and did the adjustments, I also deleted o2 sensor why I was at it. Received it, and it still does the lump. I am using the stock end can, and its basically a straight through design. No baffling.

I read about people using aftermarket exhaust and since they have baffles it toned the bike up! I don't have that option and I have been thinking. Here I am thinking about how to get the low end fixed up, it has that 1000-1000-1000-1150-1000-1000-1000-1150 idle and at any real speeds doesn't matter, but at like 5-10mph that is 10% of the rpms and I can slightly feel it, that's why I sent for the reflash.

Anyway!. when I was sitting at home, I was bored and thinking of ways to prove its back pressure, I got a sock, and shoved it up to the exhaust while idling, blocking some of the airflow, and wallah the bike stayed idling 1k purrrrring. I taped that **** sock to my muffler blocking some of the opening, and went around for like 5 minutes around the block and ****. it seriously fixed it. Now, im not going to ride around with a sock in my exhaust that's stupid but it proved a point. BACKPRESSURE IS NEEDED for me at least.

I ordered a stupid little dirt bike looking baffle, called and arrestor, it arrives tomorrow. It doesn't look like much, but I ran across it while searching for baffles on revzilla, it appears to be the exact same diameter as the stock end can opening. so, in theory. Im gonna put it in, and if it needs it, maybe a few drops of sealant to tac it in the hole. It looks like a wire mesh net thing, and to me that should reduce the free flowing tip somewhat. If it doesn't reduce it enough, I can put some sealant on some of the net and block holes, and if it is too much reduction, (doubt it) I can drill a few small holes in it.

I finally set my TPS, well I checked it. It was 1.099-1.100 so I left it, I guess I really did have perfect spec from factory. scored the oem Suzuki harness for 18 bucks so figured id check. I read that the multimeter (10 dollar DMM) could even be off a little and could be between the 1.10-1.14 more so. Decided not to mess with it.


oh. I don't know my login, and fetching password doesn't work. so im back. Do you think the little arrestor(baffle looking thing) is going to create any resistance exiting the exhaust? I didnt lose any $ with the little baffle, it was supposed to be here Thursday *gauranteed 2 day delivery*, called them and asked why it was pushed to Monday, their inventory was inaccurate and actually did not have it. So they gave me $20 bucks back, so I paid like 8 dollars for the piece.

Not too mad, just anxious for tomorrows tweaking/testing.
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Last edited by PengWinnin; 09-22-2019 at 09:09 PM.
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post #2 of 18 Old 09-22-2019, 09:26 PM
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Good for you Penn!! You are trying and I applaud you! The sock idea was brilliant!

I sincerely doubt that the little screen thing will provide enough back pressure to quell the pulsating idle. What cured it for me was not just Dano raising the idle rpm, but I also sent the ECU back again and he added 3% more fuel across the range, as well as now I am running a longer muffler. My idle is back to quasi normal, and the bike runs even better. You might have to bite the bullet and order an aftermarket longer muffler. There are some brands out there that are not expensive, Delkevic, Lextek, etc.

Keep us posted!
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post #3 of 18 Old 09-22-2019, 09:31 PM Thread Starter
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I mean, if it isn’t enough, I have a mesh net, I can fill or take as little out as I need to restrict or let flow.

I’m gonna Put it in, do several runs, I can use some tape covering some holes if I want to try to add or remove pressure. Eh. Worth a shot. Once I find out what it needs I can use sealant or maybe drop some solder into the holes to close em.

I just like the look of stock exhaust, and I will be honest, it sounds purty. Isn’t loud at cruise, or just riding around, but when you give it that hard throttle, it roarssss way deeper than it was before.

Used oli decat pipe. Was a fun little project. Now to remedy the backpressure.

lol I did the decat with pipe on bike with a little oscillating cutter and carbide blade I paid $10 for the blade and cut straight thru. Had to take a few breaks, the poor little battery oscillating cutter tool was over heating.

Pretty strong metal, but yeah. Cake. Took about an hour all said done. The decat part took a little bit but no biggie w a drill.

Last edited by PengWinnin; 09-22-2019 at 09:34 PM.
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post #4 of 18 Old 09-23-2019, 12:27 AM
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Before my tune I had the rough idle. The woolich Dyno tune fixed that and more. You can tune your afr etc to suit your hardware, or keep experimenting with hardware to suit your tune. Even though that last one seems a little crazy to me there are many on here who have achieved a good result. I'm spoilt. Not everyone has access to a woolich performance centre or has the $770 for the service. I wish you luck.

When life throws you curves, lean into them.
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post #5 of 18 Old 09-23-2019, 02:30 AM
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Welcome PW,
I can relate the back pressure effect/ I had a Honda CBR929 or 954 (can't remember which one I did it too) where the stock can had a perforated sieve visible where the pipe bolted on to the can.
I cut it out, and it ran weaker. So much effort and no gain.

That sock made me think about Harley Davidson.
Their 'potato potato' sound could be be inspired by a real potato or two in the can then as a sock works well as you say.

Rob.
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post #6 of 18 Old 09-23-2019, 01:55 PM Thread Starter
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I’ve been doing several test with different amounts blocked. Here’s my final one so far.

Video of idle difference (using duct tape just to add and remove easily to see how effects bike)

Question, should I block the bottom up? Or should I block by the ring back?

Does it matter? I figure baffles in bikes are usually sealed off on bottom, and the flow goes up around it and through holes

Sealed part of it and retesting, can always add sealant to more holes, but not so easy to remove.

https://youtu.be/SgYUVxnCNAI
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Last edited by PengWinnin; 09-23-2019 at 02:15 PM.
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post #7 of 18 Old 09-23-2019, 03:43 PM
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It's really all about exhaust velocity but the term back pressure is used interchangeably. Either way, I'm with you on it and agree that some is needed.

You can maybe try something like this link?

https://www.wish.com/product/57c5478...SABEgIs__D_BwE
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2018 Suzuki GSX-S1000

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post #8 of 18 Old 09-23-2019, 04:27 PM Thread Starter
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Well I wish I saw that before this.

Ordered a 45mm by 8cm one anyway. It’s 6 bucks and if it works awesome.

But I’m getting close. I have it **** near idling perfect, but it’s getting blown out while riding and I don’t want to affix it til it’s perfect

May wait til that arrives but yeah, idles and sounds better with a baffle

Only downfall, I lose some of the sound.
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post #9 of 18 Old 09-23-2019, 04:50 PM Thread Starter
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I give up, it keeps blowing out. I got it’s idle perfect but no good it won’t stay in, and I won’t lie

Don’t like the tone as much as no baffle. Lol
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post #10 of 18 Old 09-23-2019, 05:32 PM
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That was the problem when I put the baffle in the Yoshi.

Smoothed the idle right out, but lost some oomph and sounded almost stock.

So I pulled the baffle out and tried Rapido's trick and sent the ECU to Dano for a bandaid (Dano's words) which raised the idle and added fuel. Still wasn't right so sent it to 2WDW and now it idles down to smooth (most of the time) and gained quite a bit of torque down low. Not sure what they did different, but the bike runs like a scalded cat!

2016 GSXS1000F
2017 GSXR1000
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