GSXR 400

BoaC · Derestricted Danger Joined: 27 Aug 2012 Karma :

Hi

I decided to do a bit of work on my GK71F, partly to act as a learning process and also as I was not sure when the basic stuff had last been done.

All was going well, I changed the oil and filter, removed and sprayed the header pipes and changed the exhaust gaskets (what a nightmare to get back on with those half moon colletts!), changed the coolant.

I was feeling rather chuffed with myself and had learnt loads.

Then I decided to change the spark plugs (replaced with NGK - C7HSA) and have a look at the carbs.

Well the plug change was fine, but decided not to mess with the carbs just yet, just took the top off and had a look and reinstalled the diagphram as I found it as didn't fancy pulling it all apart. Now it will not start!

I have checked the spark plugs are sparking and they are. Bike sounds like it wants to start but not firing. Battery is fully charged.

Any help would be appreciated, I have read putting a few drops of gas in the spark plug holes then trying to start may be an idea to check fuel is getting through? Cannot see why it wouldn't be though as it was before.

I had turned the idle speed knob in the centre of the carbs (they are the sort where the 4 carbs are split in two and 2 carbs share a diagphram and float - not sure what they are called). I turned it only slightly, but when would not start I tried turning it tighter to the right.

I am so sick of messing and checking then having to put fuel tank and air filter on I have rigged up a little auxillary tank hanging from a beam in the garage and am leaving the air filter off when trying to start.

Nope. · World Chat Champion Joined: 16 Feb 2011 Karma :

Have you primed the carbs? Mine doesn't have Prime on the fuel tap so I have to manually prime the carbs.

If I were you I'd spray some easy start down the air intakes and see if it will start then (You'll need to open the throttle to let it down).

If you've moved the idle screw just wind it up a bit and see if it will start, obviously kill it if it starts revving its nuts off.

When you removed the slides and diaphragms did you make sure the needles went back into the emulsion tubes?

What spark plugs did you use? I'd put the old ones back in and see if that makes any difference.
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Former: Derbi GP1 50, Sachs XTC 125, Suzuki GSXR 400 GK73A, Kawasaki ZX7R, Suzuki DR250, Yamaha RD350
Current: 2011 Yamaha XT660Z Ténéré, 2003 Yamaha YZR-R1 5PW (In Build), 2009 Kawasaki ZZR1400

BoaC · Derestricted Danger Joined: 27 Aug 2012 Karma :

How do you prime the carbs?

The needles are definetely in. So to use the easy start I lift the bits with the needles in up and then spray into where the little butterfly things that lift when you turn the throttle?

Nope. · World Chat Champion Joined: 16 Feb 2011 Karma :

BoaC · Derestricted Danger Joined: 27 Aug 2012 Karma :

Thanks all fixed now. On closer inspection I found that the fuel tap does not have a prime setting, you just push it in to prime the carbs. There is nothing on it to say you should do this to prime, found it out by mistake.

The bike would not start without the air filter on, so guess there was too much air getting in. This had me stumped as I assumed it would start, it just wouldn't run well.

Fiddled with the idle knob and all is good, bit of a pain as you have to remove the air box to get at it and it is a bit of a pig to get on tight over the carb intake.

thanks for your help.