Suzuki GSX-R Motorcycle Forums Gixxer.com banner

1 - 10 of 10 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter #1
Hi, I've recently bought a 2015 GSXR 750. I believe this is the L5 model?

It's the MOTO GP edition and has a Yoshimura exhaust as standard. The previous owner has had the cat removed. From what I've read, this could reduce back pressure and possibly cause the bike to run lean? Do I need to install a power commander and get this bike dyno tuned or is it ok to run it as it is?

My main concern is that the popping under deceleration could cause damage to the bike somehow. My secondary concern is that the bike is not running optimally as there would be less back pressure than it's designed for, therefore it'd need a tune. Any info would be appreciated as I don't know a lot about this, thanks.
 

·
Registered
Joined
·
35 Posts
Look up the PAIR valve mod/block off to possibly get it to stop popping on decell. You might have the A/F checked on a dyno to see if it running too lean?
 

·
Registered
Joined
·
4 Posts
Discussion Starter #5
Tons of threads on what? The PAIR valve? Or the cat removal?

I did a Google search before I joined the site, and spent the afternoon looking for answers. That's what prompted me to join the forum to post my own thread, was hoping to get some detailed technical info from a mechanic or engineer.

I understand the concept of blocking the valve off, as it'd stop air getting into the exhaust and stop the fuel igniting. But my question was more related to whether or not it's doing damage to the bike, and whether I need to get the bike tuned since the cat has been removed. Don't know whether it's worth buying a power commander or not. Bike seems to go ok but temps are 80-90 degrees C.
 

·
Registered
Joined
·
4 Posts
Discussion Starter #7
Have you even read those threads? One is asking for a map to make his exhaust pop more! Then someone claims that you can't tune for that(you can it's called a pop map). Some threads are saying it's too rich, others are saying it's too lean, some are telling other people to use the search function, without reading their quesiton properly. None answer my question - does it cause damage, and do I need to tune it. Don't really want to buy a power commander and dyno tune unless I have to as it costs hundreds.

I thought this was a forum where I could post a question, and maybe even talk to people with engineering knowledge. Hopefully get a detailed response. Instead I get someone telling me to "search google"... wow, if only I'd thought of that. Like I said I've been reading opinions plastered across forums for hours, but no actual information. Can anyone tell me what removing the cat will do? Will it make the bike run hot? What's the normal operating temperature for a 2015 750? Will it cause damage to the engine at all? Any other effects(apart from the obvious increase in emissions)?

Simply shoving a marble into a tube isn't really what I'm looking for. I'd rather treat the cause than the symptom, and wanted to know details. Didn't think I'd cause offense by posting a thread about a GSXR on a GSXR forum.
 

·
Administrator
Joined
·
15,295 Posts
Have you even read those threads? One is asking for a map to make his exhaust pop more! Then someone claims that you can't tune for that(you can it's called a pop map). Some threads are saying it's too rich, others are saying it's too lean, some are telling other people to use the search function, without reading their quesiton properly. None answer my question - does it cause damage, and do I need to tune it. Don't really want to buy a power commander and dyno tune unless I have to as it costs hundreds.

I thought this was a forum where I could post a question, and maybe even talk to people with engineering knowledge. Hopefully get a detailed response. Instead I get someone telling me to "search google"... wow, if only I'd thought of that. Like I said I've been reading opinions plastered across forums for hours, but no actual information. Can anyone tell me what removing the cat will do? Will it make the bike run hot? What's the normal operating temperature for a 2015 750? Will it cause damage to the engine at all? Any other effects(apart from the obvious increase in emissions)?

Simply shoving a marble into a tube isn't really what I'm looking for. I'd rather treat the cause than the symptom, and wanted to know details. Didn't think I'd cause offense by posting a thread about a GSXR on a GSXR forum.
I answered already. Get it turned and be done with it. It's running lean. I have never heard of anyone damaging their bike. I mean how much more in depth do you need to go? There are hundreds of threads on this and the common denominator is tuning it.
 

·
Administrator
Joined
·
15,295 Posts
And why do you think you caused offense? I kindly welcomed you and told you to search the site because there are hundreds of threads on this. It's been discussed, in depth for years. And you think you offended someone? C'mon man. Don't start that bullshit.
 

·
Registered
Joined
·
296 Posts
Popping on deccel is normal, a/f is too lean to burn in the cylinders and instead ignites on the exhaust, that's when it will pop. PAIR just injects air to allow that to happen as it is better to burn it in the exhaust than expelling raw fuel to the atmosphere, blocking/removing PAIR will just reduce the frequency but it will still happen (no extra air from PAIR, richer a/f in the exhaust, it doesn't ignite). Tuning it to completely remove it will just add even more fuel on deccel. As a matter of fact, the popping is there with the stock exhaust, it just does a very good job reducing the noise.
 
1 - 10 of 10 Posts
Top