Suzuki GSX-R Motorcycle Forums Gixxer.com banner

1 - 20 of 31 Posts

·
Registered
Joined
·
13 Posts
Discussion Starter #1
Hey guys, first post from me.

I just bought 750 06 ridden on the track. Spent all of my money on a bike that feels slower than my old cbr 600 f4i?!
When you are in any gear at any rpm if you open the throttle all the way it bogs and then accelerates slowly. I can readline it, so i think its not the fuel pump. Also, I don't see any change in rpm/noise when I open the throttle, so I would assume it's not the clutch (it has a new clutch, I looked at the plates and they seem fine). If you baby the throttle and open it slowly it runs, but then again - it accelerates slowly. I got it on GPS to around 152 mph, it took ages!
Runs 15w50 yaccoo oil.

What would you suggest?
 

·
Hand-Eye Coordinator
Joined
·
6,529 Posts
To add to what kinzell said- does it have a fuel controller? Does it have a full exhaust and "race" filter?
 

·
Registered
Joined
·
13 Posts
Discussion Starter #5
To add to what kinzell said- does it have a fuel controller? Does it have a full exhaust and "race" filter?
Will get her to a shop and check the flow of the fuel pump.
Yes, she does have a PC but it is disconnected right now. She has an Arrow slip-on, the valve in the exhaust (STVA?) is removed.
The power commander is mostly used for a quick shifter, it set off the FI light, so the seller disconnected it for now and called the shop to check the wirings.
She also has a race ( k&n ) air filter, the filter is clean and oiled.

What should I ask them to check other than the fuel pump and probably injectors?
 

·
Dreaming of buttsecks for years...
Joined
·
13,422 Posts
When you are in any gear at any rpm if you open the throttle all the way it bogs and then accelerates slowly. I can readline it, so i think its not the fuel pump.
That's the first thing you should check. Why would you not think it was fuel starvation?
 

·
I know things... A lot of things.
Joined
·
3,152 Posts
+1 to what TheGeek said. The following is also a hint of fuel starvation:

If you baby the throttle and open it slowly it runs, but then again - it accelerates slowly. I got it on GPS to around 152 mph, it took ages!
On the other hand though, it is a bit odd that the fuel system can deliver the fuel to reach such a high speed, while at the same time failing to allow accelerations comparable to a 600F4i. It might also be a good idea to have a look at the spark plugs and replace them if necessary.
 

·
Registered
Joined
·
106 Posts
ran into the same issues when I first got my 600, it was the strainer in the fuel pump for me. Do a fuel flow test. Look up the test on youtube very simple todo.
 

·
Registered
Joined
·
13 Posts
Discussion Starter #9
That's the first thing you should check. Why would you not think it was fuel starvation?
The old spark plugs are burn/dark so I would assume it runs rich, rather than lean.
Also she can readline. A friend got a bad fuel pump on his cbr 600rr and it would not go above 10k with the bad pump.

The plugs are new (less than 3k km). Maybe there may be an electrical problem?

Can it be related to some of the maps in the ECU ? Is there a way to connect to the ECU without some dealer cable ?
 

·
Hand-Eye Coordinator
Joined
·
6,529 Posts
Will get her to a shop and check the flow of the fuel pump.
Yes, she does have a PC but it is disconnected right now. She has an Arrow slip-on, the valve in the exhaust (STVA?) is removed.
The power commander is mostly used for a quick shifter, it set off the FI light, so the seller disconnected it for now and called the shop to check the wirings.
She also has a race ( k&n ) air filter, the filter is clean and oiled.

What should I ask them to check other than the fuel pump and probably injectors?
Boom.

I bet that you have slower than spec fuel flow because of the fuel filter, resulting in a lean condition.

That lean condition is compounded by the fact that you have a "race" filter and you took off the cat, which results in more airflow over stock. Low fuel flow plus more airflow means super lean AFR.

Put the PC back on. So what if the quickshift triggers the FI? You can adjust the kill times on the QS to shorter durations, if you really wanna get worried about it. Basically, any kill time longer than 0.050 will set off the light or you really start hammering through the gears successively.
 

·
I know things... A lot of things.
Joined
·
3,152 Posts
Another thing to test, given the condition of the plugs, the power delivery problems at high loads and the history of the bike, would be compression. You mention that the plugs were sooty; were they in more or less the same condition for all cylinders, or did some stand out?
 

·
Registered
Joined
·
13 Posts
Discussion Starter #13
Another thing to test, given the condition of the plugs, the power deliver problems at high loads and the history of the bike, would be compression. You mention that the plugs were sooty; were they in more or less the same condition for all cylinders, or did some stand out?
I saw only 3 of them and they all were in the same condition. I hope the compression is fine, otherwise, I have just bought the biggest lemon ever.
 

·
Registered
Joined
·
13 Posts
Discussion Starter #15
She is in the shop. I will post updates when I have more information. The fuel pump will be cleaned, the oil and filter changed and TPS rechecked and adjusted to spec. Once the PC is reconnected I will see if changing the fuel level on it will help.
 

·
Registered
Joined
·
106 Posts
She is in the shop. I will post updates when I have more information. The fuel pump will be cleaned, the oil and filter changed and TPS rechecked and adjusted to spec. Once the PC is reconnected I will see if changing the fuel level on it will help.

Best of luck man!!
 

·
You should listen to me. No, seriously, listen to
Joined
·
7,716 Posts
If you need a new main filter, and there's a good chance that you do, you'll find out why it's important to keep contaminants out of the tank. Cut rate gas can be very expensive.

Checking the flow rate and, if needed, cleaning the strainer and/or replacing the main filter isn't very complicated. Couldn't you do that yourself?
 

·
Registered
Joined
·
13 Posts
Discussion Starter #20
If you need a new main filter, and there's a good chance that you do, you'll find out why it's important to keep contaminants out of the tank. Cut rate gas can be very expensive.

Checking the flow rate and, if needed, cleaning the strainer and/or replacing the main filter isn't very complicated. Couldn't you do that yourself?
To be honest, I'm pissed by bad mechanics and shops that charge too much, but I neither have the place nor the tools to do anything more than lubing my chain. If the filter is clogged I would assume it's related to ridding on the track with only 4 liters of fuel per session and never actually filling the whole tank.
 
1 - 20 of 31 Posts
Top