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Review of L2 GSX-R750 and a potentially complex issue

3436 Views 53 Replies 7 Participants Last post by  craigfer63
Hi everyone. As you all know I'm new to the forum and I would like to post a little review of the limited time I've had with the bike so far.

A little about me. I've been riding for about 15 years now. But haven't been to the racetrack yet (planning on that within the next 6 months). I also haven't owned many bikes but I started off on a Kawasaki ZZR250, then upgraded to a 1999 Yamaha R6, then a 2013 ZX6R (new) and now a 2012 GSX-R 750. I've had small rides on a 2013 Triumph Daytona 675, 2015 Yamaha MT-09 and a 2018 Honda CBR1000RR. Again, I've mostly ridden street but I am fairly confident in handling the bikes at high speed and through corners (as far as street riding goes). I also like working on my own motorcycles because I just don't trust the dealers unless I can't fix something due to lack of resources.

With that out of the way let's move on to my small review. Five days ago I went for an inspection of the bike it looked clean and seemed well taken care of, hence I purchased it. It has the following mods on there:
-Full Yoshimura R77 (??) exhaust
-ECU and dyno tune (130hp apparently)
-Aftermarket grips
-Bonamici Racing brake and clutch levers
-Clutch switch mod for clutchless start (throws an FI light but more on this later)
-Techspec tank pads
-Fender eliminator

I've since ridden the gixxer 750 only 3 times since then, including riding it home from the inspection. Today I went for the longest ride (about 40 minutes) with my wife on the back. It feels great to ride and it's not an overly aggressive body position. I can actually flat foot the bike which is neat. I've changed the shift pattern to GP shift as that is what I had on the ZX6R, which helped solve an issue I had with the gear lever placement as I was riding today. It goes well but I find the power is lacking which must be due to the clutch switch issue I've been reading about on this forum. Brakes feel good for the street and stop really well. Handles corners well enough but I think after changing to new tyres, it might be better at this. Overall a great bike and not many complaints.

Now comes the issue I'm having. From what I understand, removing the clutch switch forces the bike to use a neutral map and therefore it loses power. According to the guy I bought it from it has been tuned, but the throttle still feels choppy, almost the same as if it was from the factory. Because of the aftermarket levers, there doesn't seem to be a mounting point on the bike for the clutch switch. But it has been zip tied to a harness with 2 wires connecting to it (see picture)

Automotive tire Automotive wheel system Gas Auto part Pipe


I want to fix this up and put the clutch switch back where it belongs so that the bike can run as it was intended. I really don't care that I have to pull in the clutch to start the bike. That FI light annoys me (I don't have the dealer switch to pull the code) and I feel the lack of power is due to this issue. So the problem for me is two fold. 1. improve the bikes performance and 2. get rid of the FI light. The issue I'm having is where can I mount the switch and which wires do I connect to the switch?

Now to be clear, the bike runs smoothly and without issue despite the FI light coming on. I could leave it as is but I feel like I'd be gaining so much more if I could resolve this issue.

Any help would be greatly appreciated. Thanks for reading :)
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I'd get the stock perch and run the aftermarket levers if you like them, that will give you the clutch sensor back... perch shouldn't be too much and those levers should plug right in, should but if they are chinese knocks offs who knows? good levers aren't that expensive to get and the stock perches are plenty good..

get that clutch sensor going then ride it and get back to us if its still off, does it have a power commander or anything like that? there is a chance the ECU was zeroed out for a PC or something and previous owner removed the PC before sale leaving the ECU with a zero map?
They are Bonamici Racing levers. Italian brand and very good quality so they're not chinese knock offs. I will definitely be sourcing the stock perch from somewhere, but we're all locked down here in Sydney so I'll have to wait until we can go out again 😔

I haven't been able to have a look under the seat yet (been busy with work and family) but when I get the time I'll have a look under there and see. I don't think it has a PC, as I believe the previous owner would have told me. I'll provide an update when I get the chance.
can you just tape the switch closed till then? be careful it might start in gear
I don’t think that’s necessary. I did a little bit of testing yesterday. If I hold the switch in (clutch engaged) the bike won’t start. But once I release the switch (clutch disengaged) the bike starts up.

I can still use the current switch but I’ll have to figure out how to mount it to the bar/lever and I also have to find a small metal piece to glue onto the lever to activate the switch. Hope that makes sense.

Again there isn’t anything wrong per se as it is currently. It’s just that I don’t want the bike throwing an FI light. Seems like an easy fix though.
I found another issue with the bike. The shift light doesn't work. When I turn the ignition on, the shift lights activate along with everything else on the dash, so they have the potential to work. But I have tried many times to try and set the shift lights but never had any success.

Today, I took the bike in 1st right up to the rev limit and no shift light came on. Orange lights did not come one and the white light did not come on either. I'm thinking it might be due to the FI light because of the clutch switch "fix". I ordered a new clutch perch switch which will take about 4 weeks. I'm hoping that will fix all the issues I'm having. Admittedly, the issues are very minor and doesn't actually affect the running of the bike. But I want to track this bike in the near future and I would like everything working with no FI light.

If anyone has any suggestions for the shift light issue I'm all ears :) I'm just not very good when it comes to electrical stuff :LOL:
where do you have the light set to activate? disconnect battery for 10 minutes or so, see if the system resets when you reconnect it?
WOW what the F%&#k is that ? No bare wires on your bike ! The clutch switch, like all the sensors on your bike talks to the ECM. Clutch in and out, tells the ECM your in neutral. You can take it off, but you need to press the switch to tell the ECM. Or delete it from the ECM.
Dealer Mode Switch here
Need to fix any FI codes.
Shift light setting in Owners Manual.
You need Workshop Manual.
I’ve had quite a few bikes myself. Around 800,000 miles seat time and two 750’s. 09 and 17. 17 was the best handling and second best powerful behind my 17 gsxr 1000 and 18 R. I was running a K&N Race filter, Full Yosh R77 17-46 520 sprockets. Just one tooth more on the rear. Had Danosperformance.com “Daniel” do a mail in ECU flash and that bike was quick. Bstones S21 tires are good enough on the street keeping the power down. My 1000’s the S21’s suck but on the 750 perfect. Ran his tune for a long time then got the bike dyno tuned locally and picked up 8 more HP 136 almost 137 and it felt a little slower honestly. Definitely would have Daniel flash the ECU again. Price is on point and he knows his stuff. Not a greedy prick like most places charging insane prices for stage 1 and 2 crap that doesn’t even change fuel maps. I would try my set up and go from there. Motul 7100
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WOW what the F%&#k is that ? No bare wires on your bike ! The clutch switch, like all the sensors on your bike talks to the ECM. Clutch in and out, tells the ECM your in neutral. You can take it off, but you need to press the switch to tell the ECM. Or delete it from the ECM.
Dealer Mode Switch here
Need to fix any FI codes.
Shift light setting in Owners Manual.
You need Workshop Manual.
I've ordered a new clutch switch to replace this one. It's on the way but might take up to 4 weeks. I didn't actually realise the switch was just tied on there like that. I thought it was just removed altogether. This is my first gixxer so I'm still learning how the bike works.

I've disconnected the battery for 10 minutes as suggested and the shift light still doesn't work. I'm wondering if the guys who tuned the bike had played around with it and turned it off? The tune was performed by bcperformance in Smithfield (Sydney).

Do you have the 750 manual? That link goes to the 1000 manual.
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No sorry. Search for one or buy one very important to keep your Gixxer in running condition.
Did you follow the Owners Manual when setting shift light ?

We need the FI code to proceed.
K7 750 here.
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I have the 2011+ GSXR600 manual. I assume they are almost identical in every way. I definitely take care of my bikes and know how important that is 😊

I have followed the manual regarding the shift light and still nothing. I’ll keep investigating.
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So rather than start another thread I'll post here. I don't think this is an issue but it's something I am experiencing on the bike that I have not experienced on my previous ZX6R. I often have a habit of using engine braking when slowing down and I usually do not rev match during downshifting, especially when street riding unless I'm really riding hard.

Anyways, lately I have noticed a couple of times when I had to slow down quickly, I would shift down to either 1st or 2nd gear and the rear would lose traction and fish tail slightly. Doesn't concern me as I still feel in control. I'm sure this bike has a slipper clutch so is this supposed to happen? Or am I being too aggressive with the engine braking and should start rev matching more? To be clear, there is nothing wrong with the clutch as it engages and disengages perfectly fine. As I mentioned before, I never experienced this on the ZX6R. Another possibility is it might be the tyres. I'm due to replace them by the end of the year going by how much tread is left. What does everyone think?
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Your slipper clutch is working, and gives you a smooth transition when down shifting. Rev matching protects the engine from damage. Slipper clutch is adjustable but yours sounds right. here is the L2 slipper clutch.
The adjuster bolts #22 (3), rest on the clutch driven cam #19. When down changing cams #18 and #19 lift the clutch pressure disc (plate) #15 .
You can see these adjusting bolts #22 (3), through the inspection hole in the clutch cover. OEM is 3 threads showing above the locknut.
2 1/2 threads showing gives more slip. (if you go in too far, clutch will slip under acceleration !)
3 1/2 threads showing gives less slip. Good thread here.
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That’s very informative. Thank you. I’ll have a look when I get the chance.

There’s so much to learn about this bike that I’ve never had to learn before lol. This is great.
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Was able to paperclip the bike into dealer mode today and got C65 code. It was also reading "-C00" so no issue with the TPS.

So now the issue is possibly two-fold. Firstly, an extensive search on this forum revealed that most of the C65 code issues could be resolved by reinstalling the clutch switch. I already intend to do this but the switch is coming from China and will arrive anywhere between mid-October to mid-November.

Secondly, C65 could also indicate an idle issue. Which makes sense as my bike tends to idle quite rough and bounces between 1100-1500rpm on cold start up. Though it does settle a little bit after it is warm, but it's definitely not idling at a steady rpm like it should. I think to resolve this I have to reset the ISC valve?

I finally feel like I'm getting somewhere with this FI light :LOL:
a switch from china? good luck with that, ronayers is the place
a switch from china? good luck with that, ronayers is the place
I'm in Australia. Most places are closed now due to lockdown so had to make an online order. It's just a small part so I don't really care where it comes from.

I should have done this earlier but I finally found the solution to the FI issue. I can say with absolute certainty that it is the clutch switch that is throwing the FI light and giving me the C65 code. Because the current clutch switch has been cable tied to the harness, after starting up the bike, I moved the cable tie to cover the switch mechanism (so it is always depressed). And that's all I had to do. No FI light came on during the ride today and I definitely noticed an increase in power. This I found strange as I’ve read the bike will use a neutral map if you remove the clutch switch. But because the bike was tuned I didn’t think it would affect the bike. On/off throttle also seems to be smoother now as well with less jerkiness in low gears.

Another observation is that the A and B mode indicator is not showing on the dash. But that is of no concern to me as I would just keep it in full power mode any way.

Now I just have to fix the gear shift light issue. I'm completely stuck on this one :confused:
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Clutch Switch is an on / off momentary switch. So you are saying with this switch depressed the bike works well ?
What readings are you getting when you test the Gear Position Switch, as per the workshop manual ?
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