Board logo

Silver top zx6r carbs on three cylinders ??
dan8400 - 7/5/14 at 08:09 PM

Hi everyone

On Saturday morning my Tiger went down to three cylinders. Was only popping out so came home and got the tin top. I have since changed the plugs and leads (gapped plugs etc).

The car seems to tick over on four and rev on four but when under acceleration (especially mid to high revs) it drops to three. Is this an ignition problem? Ie coil pack going down? Or a fuelling issue. I am not sure what to try next

Any suggestions welcome

Thanks
Dan

avagolen - 7/5/14 at 08:33 PM

I would have a look at an air leak around the offending carb or a blocked jet.

You could try spraying WD40 around the inlet manifold and see if the revs change.
If not then I would give the carb a deep clean with some carb cleaner.

What are you using to connect the carbs to the manifold, are all connections still secure?

Just my random thoughts.

dan8400 - 7/5/14 at 08:36 PM

How does the wd40 help? Will it show up an air leak?

Good idea on carb cleaning. Am I best off removing them and disassembling them / cleaning them on a bench?

Thanks
Dan

dan8400 - 7/5/14 at 08:37 PM

Are there any easy ways to clear blocked jets anyone??

avagolen - 7/5/14 at 08:45 PM

From what I hear, if there is an air leak, spraying with WD40 raises the revs as it sucks in the propellant etc.

I stripped my carbs and soaked them in carb cleaner and sprayed all holes/jets/bits with it as well.
(one at a time making sure I did not get the bits confused/lost etc)

It definitely made mine run better. Make sure you check how far out the air bypass screw or what ever it is
called is before you start - screw it in gently noting the turns required until it stops.
(located at the engine end of the carb underneath)

HTH.

19sac65 - 8/5/14 at 03:52 AM

Are you using a ford coil pack
They can give that symptom

dan8400 - 8/5/14 at 04:31 AM

Yes. It's the one that came with the engine. Are they expensive? I have another old one lying around. Will try that for comparison

Thanks
Dan

davidimurray - 8/5/14 at 08:14 AM

Have you checked the balance on the carbs?

Does it only run on 3 when you are accelerating or when cruising?

dan8400 - 8/5/14 at 08:20 AM

It does it on both. Mid to high revs

mcerd1 - 8/5/14 at 09:26 AM

quote:
Originally posted by avagolen
From what I hear, if there is an air leak, spraying with WD40 raises the revs as it sucks in the propellant etc.

^^ easystart works a bit better

you just mist it around the inlet manifold etc (not into the air filter or anywhere that air is meant to get sucked in)
and if there is an air leak close to where you sprayed it will get sucked in and the engine will rev up a bit

davidimurray - 8/5/14 at 09:32 AM

quote:
Originally posted by dan8400
It does it on both. Mid to high revs


It is unlikely to be the main jets as they have quite a big opening. The pilots are tiny holes and blowing through doesn't neccesarrily clean them. I found that the best was to clean was to remove pilots and soak in carb cleaner overnight. Wouldn't hurt to do mains at thes same the and they you have a good base to look for any further issues.

dan8400 - 8/5/14 at 09:45 AM

Ok. Thanks for the replies.

This gonna make me look like a noob but how do I remove the jets?

Zx6r carbs


I am off to buy a new coil pack for the car too. Might as well eliminate everything. Already changed plugs and leads
Thanks
Dan

davidimurray - 8/5/14 at 07:09 PM

quote:
Originally posted by dan8400
Ok. Thanks for the replies.

This gonna make me look like a noob but how do I remove the jets?

Zx6r carbs


I am off to buy a new coil pack for the car too. Might as well eliminate everything. Already changed plugs and leads
Thanks
Dan


No worries, done mine loads of times now and I can do them blindfold

Step 1 - Put some rubber tube over the float bowl drain into a jar, then undo the screw and drain the fuel out of the carb. Do this for all 4. After this do not turn the ignition on or you will fill them back up! Don't forget to close the drain screws

Step 2 - Remove the float bowl. There are 3 screws, 2 at the engine side and 1 in the middle at the air filter side. With the carbs on the carb the screws will be facing upwards. If you have the original kwak screws I strongly suggest you change them for some cap heads as the originals are made of soft cheese!

Step 3 - Carefully remove the float bowl, there may still be a little bit of fuel in there so be careful.

Step 4 - If the carbs are still on the car you will now be working upside down. But if you use a little mirror you should see this -

Get a flat bladed screwdriver, make sure it is a good fit in the slot and un screw the main jet and pilot jet. The pilot will be like a long tube full of holes, the main will just be a short stub, there is no need to remove the main jet holder.

Step 6 - Remove all 4, fill a glass (don't use anything plastic) and chuck all the jets in there for 24 hours. While they are in there give a spray up the jet passages.

Step 7 - as the Haynes manual says, reassembly is the reverse!

[Edited on 8/5/14 by davidimurray]

dan8400 - 8/5/14 at 07:33 PM

Thank you for that description David. Excellent advice and a brilliant step by step.

I feel confident to have a go at this now

Thanks
Dan

Btw my new coilpack arrives tomorrow so that is another thing eliminated

[Edited on 8/5/14 by dan8400]

Paul W - 5/4/15 at 09:12 PM

Dan did you fix this problem?