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Discussion Starter · #1 ·
Hi all. I'm having an issue with a K7 track bike I bought recently on a budget.
I've tried a few things but I'm running out of ideas and I don't have the cash to take it to a shop at the moment and run up a bill for troubleshooting this type of stuff.
On my first track day, it ran great for the first few sessions but then didn't seem to want to rev past 11k RPM and it got worse in the next session so I just decided to call it a day in case I caused any further damage.

As I didn't have chance to give the bike a thorough inspection before the TD, I stripped it down and checked a bunch of stuff.
First issue I found was the #1 coil connector was damaged where it grips the spark plug and it was very loose so I ordered a new one and thought I'd found the most likely cause....well I didn't. I took it for a quick ride and it was now even worse. The bike won't take full throttle at all without bogging down and it has roughly the same power as a 250cc. I can even hear the issue now with the bike idling in the garage, it sounds like it's not running on all 4 cylinders but it is. Putting back in the old coil also didn't make any difference.

Since then I've done the following:

  • checked valve clearances. All within spec.
  • Checked coil resistances against manual. All OK.
  • Checked compression. A bit lower than I'd like but all just about in spec so probably the cause of this issue.
  • Checked fuel pump flow rate against manual. All OK.
  • Completely bypased the Bazzaz FI, TC and QS unit by removing the Bazzaz harness and going back to stock. I also checked the colour coding of the wires in the manual to make sure the primary and secondary injectors and the coils were connected to the correct cylinders. The bike still idled and revved crap.
  • Put the bike in dealer mode and checked for codes. I have the "SD" fault code all the time as the damper was replaced with an Ohlins unit but I'm not getting any other code. I actually temporarily installed a resistor to clear the code and the FI light went out.
  • Removed the fuel pump and disassembled it to access the strainer/filter. The filter looked pretty bad so I removed it and reinstalled the pump so see if it make any difference. (I know I need a new one before using the bike but I'm in Ireland and it will probably take me a week or two to get a replacement). I fired the engine up and it sounded perfect, seemed to rev nice and quick/smooth too. I put the bike back together, including all the bazzaz loom, to go for a test run and make sure it was OK but I didn't even get out the garage door and I knew it wasn't running right again馃槶. I don't have the proper equipment to carry out a fuel pressure test with the bike running but I did connect the pump up to a gauge after this and primed with fuel, I was getting approx 40psi. The manual states 43psi. My gauge is for 0-300psi so I couldn't get a more accurate reading but I think it's OK.
Is there anything else I'm missing here? Could it be the ignition or maybe the injectors themselves?

The only other thing I noticed worth mentioning is the quick release connector for the fuel line to the tank - on the occasion where it ran well after removing the gauze, I got a little squirt of fuel when disconnecting the line. I took note of this as further proof I'd finally found the problem as there never seemed to be any pressure in the lines the 10x times I had removed it before or since (often within seconds of running the engine). When I hooked up the pressure gauge for the test using an old piece of fuel hose, there was a significant amount of pressure remaining in the line afterwards too. This has me thinking, do those connectors go bad or why would there not be pressure in the hose after running the engine?

Any suggestions would be much appreciated!
 

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Bogging down is normally a clogged main filter, not the strainer. What flow rate did you get? The SD code might put it in limp home mode, hence the limited ability to rev. The pump motor has a check valve to keep the fuel line pressurized after the prime stops. That may be what the squirting is about.
 

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Discussion Starter · #3 ·
Bogging down is normally a clogged main filter, not the strainer. What flow rate did you get? The SD code might put it in limp home mode, hence the limited ability to rev. The pump motor has a check valve to keep the fuel line pressurized after the prime stops. That may be what the squirting is about.
Thanks Bill.
I can't remember the flow rate now as that's the first thing I tried a couple of weeks ago but it did meet the spec in the manual. I may need to repeat the test now after removing the strainer.

I actually didn't know there was another filter until I read a few more threads on the topic last night. I'm hoping removing the strainer yesterday caused this filter to free up temporarily and has simply picked up the same dirt again, causing the issue to return. I will attempt to clean/flush this filter in the next day or two and check the flow rate again.

Regarding the SD code - the code was showing all along and the bike ran fine for a few sessions so it must not cause my bike to go into limp mode, although funnily enough the resistor was in place when it ran fine yesterday and removed when I attempted to take it for a test ride. I'm waiting on a set of connectors and crimpers to attach the resistor permanently so I can also rule this out later in the week also.
 

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Discussion Starter · #5 ·
Page 4-23 of the service manual says that SD will put the bike in limp home mode.
That is odd. SD has been on since I bough the bike and was running perfectly for an hour or two on track before I experienced any issues.
I'm actually using my old k5/k6 manual for reference as I don't have the k7 manual yet so the bit relating to the SD is missing.

I attempted to back flush the HP filter with throttle body cleaner earlier.
I didn't notice any dirt come out but it's hard to tell.
Anyway, I ran the bike again and still have the same issue.
Following this, I carried out another flow test and got 400ml in 10 sec so that doesn't seem to be my issue.

I think I need to remove the Bazzaz wiring harness again to be sure that wasn't causing a problem too and sort out the SD code before going any further.
I'd just install a new fuel pump to rule the issue out but even a used one costs several hundred so I'd rather not if it can be avoided!
 

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Discussion Starter · #6 ·
I did some more investigation today. Removed all the bazzaz stuff again and soldered on the resistor for the steering damper so no more SD code.
The bike still ran crap so I tried unplugging the primary injectors one by one with the engine running. Unplugging injectors 3 or 4 resulted in the engine almost dying but injectors 1 and 2 made almost no difference. I find this a bit weird as the headers for those 2 cylinders are getting hot!

I removed the throttle bodies and injectors and flushed the injectors with TB cleaner, then put them in an ultrasonic cleaner I have for a couple of minutes before reinstalling. This resulted in the bike running well...for 10 mins at least! I didn't get chance to do a full power, redline run but it was much much better than before. After a few mins of riding it slowly started to run rough again. However my new strainer still hasn't arrived so the pump is likely taking in some more contaminents and they just got blocked again.

So it's still not fixed but progress at least. I plan to remove all 8 injectors for cleaning and flush the lines when installing the new pump filter. It's probably a good idea to clean the fuel tank too. Anyone know of a good procedure to properly clean the injectors when they are out of the throttle bodies?
 

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Here's a reasonable procedure. You'll need a syringe, a connector, a pushbutton switch, and some other stuff.

Your flow rate is unexpectedly high. Any chance that a hole has been drilled through the main filter element?

Here's the K7/K8 service manual.

You should also check the condition of the injector and spark coil connectors, both at the injector & coil as well as at the ECM. Any blue-green deposits are a bad sign.
 

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Discussion Starter · #8 ·
Here's a reasonable procedure. You'll need a syringe, a connector, a pushbutton switch, and some other stuff.

Your flow rate is unexpectedly high. Any chance that a hole has been drilled through the main filter element?

Here's the K7/K8 service manual.

You should also check the condition of the injector and spark coil connectors, both at the injector & coil as well as at the ECM. Any blue-green deposits are a bad sign.
Thanks for those links Bill, much appreciated. I pulled the injectors again and there was some little white flakes in the back of the injectors. I'm not sure what it was or how it made it past the high pressure filter but I've flushed them all now anyway, along with the lines and completely emptied the tank. I checked the pump housing and from what I can tell, the filter on the outlet side is intact.
I installed the new filter mesh on the suction side and filled up with fresh fuel. I took it for a 10 or 15 min run and got well up in the rpm and it seems perfect now so happy days. I plan to do a trackday again next month so that will be the ultimate test.

Now to move on to my dodgy rear brakes 馃槀
 

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I could be totally off base but wonder if those flakes were chunks of a drilled through filter element. If so, you may end up with clogged injectors again. We'll see.
 
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