Default settings on the secondary air-intake regulator

[Rune56]

@horse It could also be the mixure of fuel and air. Then I increase the throttle slowly from 2000 rpm it comes 1-2 hiccups. When I increase it really slow they disappear. I have used a dyno mapper, but it didn't give me any thing. The sparkplugs are more dark than they should (with sot in mind). The switch on the clutch handle worked before, but is now defective. I noticed no difference in the preformance of the engine. I have changed the fuel pump, filter and tested the pressure valve. The secondary throttles are calibrated for the second time. The rest I'll calibrate when I assemble it together again. It seems as if the problem gets bigger as the engine gets hot. Oil temp sensor is controlled and works as it should. I have checked all the electrical connections by using 5,5 volts using store bought batteries coupled in series. It might not be enough power to open or close the secondary throttle.

[gsxbarmy]

Could it possibly be that the injectors need to be cleaned? I've no idea whether this could cause the issue or not, but maybe a consideration?

I know you are based in Norway @Rune56 but this is one of 'our' recommended companies in the UK for doing this, I guess there must be similar local in Norway.

https://gsx1400owners.org/forum/index.php?topic=95.0

[grog]

So all you have is a stutter under acceleration? Have you, replaced spark plugs, tipped coil leads, had injectors cleaned? Clutch switch must work, if not sends a different MAP, you can here difference at idle pulling lever in/out. Cant see why youre worried about secondaries at a 2k rev problem.

[Snorre Kristoffersen]

The choke function on Suzuki FI of the time was not fully off until apx. 74deg C. In my opinion the big cooler is cooling the oil too much and I have covered the whole cooler to get temerature up. Even then I never see over 80 deg in normal riding conditions. I am on my 2.GSX1400, I had the first reg.d in Europe back in 2001. This was bored out to 1550cc with Yoshi ST1 cams/PC3/Yoshi 4-1 and 4deg advancer. Even on this one with fully covered radiator never had problem with overheating.
Sooty plugs leads me to think that the mixture is wrong.

[Horse]

@horse It could also be the mixure of fuel and air. Then I increase the throttle slowly from 2000 rpm it comes 1-2 hiccups. When I increase it really slow they disappear. I have used a dyno mapper, but it didn't give me any thing. The sparkplugs are more dark than they should (with sot in mind). The switch on the clutch handle worked before, but is now defective. I noticed no difference in the preformance of the engine. I have changed the fuel pump, filter and tested the pressure valve. The secondary throttles are calibrated for the second time. The rest I'll calibrate when I assemble it together again. It seems as if the problem gets bigger as the engine gets hot. Oil temp sensor is controlled and works as it should. I have checked all the electrical connections by using 5,5 volts using store bought batteries coupled in series. It might not be enough power to open or close the secondary throttle.

With the description you give I still feel it sounds like a miss which could be injectors but I would still tilt towards electrical , as you say if you accelerate hard it's worse that's classic electrical as the load is highest at low speed high throttle opening , besides an injector, fuel /air  starvation usually does not cause a miss more a hesitation / loss of power. Hard to diagnose over the internet, that's why the fault description is critical as we are guessing what is actually wrong , after making sure the injectors are OK I would give the electrical side another look but you are there and should have a better feel for the fault
Horse

[Snapey]

Rune56 you have a PM.

[Rune56]

I have new injectors and cluch switch. I've checked all the connections in the front light. I also have new coils, cables and plugs. I've been through different workshops in Norway without any luck.

74 degrees sounds a little cold.

I've also bought new carburetors with servo and sensors. That was not a cheap ordeal. I'll assemble it the next couple of days. I'll post a new message if that fixes things. I've almost changed every part on the bike now.

Thank you all for your suggestions and I'll soon answer PM's I've recieved too.

[Rune56]

I'VE FINALLY FIXED MY BIKE!

It took me almost three years, but now the bike runs as smooth as it should. The issue was either the clutch switch or the throttle bodies. Im not sure because I changed both of them at the same time. When I assembled the engine last night it had no delay. Now I can meet this summer head on and put this to rest.

The only warning I got was that the F1 light has turned on twice (C28 or C29, I cant remember. Both errors has to do with the secondary thottle valve servo or sensor). I've changed the throttle bodies, and the clutch switch. The rubber to the injectors are sealed tight, so no problem there. Vac lines are ok.

Thank you all for your suggestions and feedback. I'd like to thank the broader forum-community too for giving me both space and time, and not least tolerating my posts probably ridden with mistranslations and bad grammar. You guys are great.

Rune

[Eric GSX1400K3]

Glad you got it sorted mate

[Hooli]

Good result there.

[Mick_J]

Glad you got it sorted mate.