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zx9r running problems, help please.
roadrunner - 12/8/07 at 01:41 PM

Hi all, brief background.
Fitted my engine, everything worked ok, except for flet spot at 4500-5000 revs, and bogging down when seeting off with full throttle, so i stripped down the carbs to give them a clean, put everything back, and hey presto, no power on top revs, it would thust manage 60mph, took it to Boggs for rollingroad set up, turned out it had been dyno jetted, so Dave removed main air jet plugs and rejetted to 150, tried it out, he cured the flat spot and the bogging down in first, and gave me some more power back, but not all, it still wont rev to its max, he said it had an air leak at the inlet amd that would have to be sorted first, that has now been delt with, but problem is still there.
Any ideas fellas, i'm at a loss.
Brad


marco - 12/8/07 at 01:57 PM

Funny that, i took mine to Dave to get it checked out as the carbs were standard and had no jetting work done since been put in the car.The car did run fine though it was just a concern that if it was lean i may have problems down the line.

It was running lean at the top end when he checked it out. The main jets were changed and i trailered it home. First trip out after that and it would cough and splutter at lower revs, so i took it back and he said it was too rich at the mid range/bottom end and he basically started again with it.
It runs pretty well now although i have a flat spot around the same revs as yours and it does a little cough if a i give it the full pedal from low revs, i guess i need to drive it more like a bike and drop it down to get into the power band rather than like my old pinto which had loads of bottom end torque..

ps.. i had same air intake leak he fixed it there with some gasket seal the bottom of the carb rubbers and he also blocked the middle intake air screw thingy's before he started tuning it..


ReMan - 12/8/07 at 02:30 PM

Are you running with an airbox, tried mine yeterday without airbox, wouldnt rev abouve 6k, back on , full revs.
Apparantly theylike stationary air at he carbs


roadrunner - 12/8/07 at 02:35 PM

Seems strange that he blocked your main air jets, and unblocked mine.


roadrunner - 12/8/07 at 02:41 PM

Running with a suasage filter, but the back plate needs replacing, too many holes, but there was no problems before.


roadrunner - 12/8/07 at 06:48 PM

Could it be that ,when i put the carbs back on after the clean, then went out for a spin, i realised that i had'nt connected the throttle position sensor wiring to the loom, it's just that i've read that it could cause problems if its been interupted.


roadrunner - 12/8/07 at 07:46 PM

Right , i've tried another rectifier, blocking some of the holes in my back plate, and i've temporarily blocked the main air jets again, but that seems to make it a tad worse, and nothing has worked.


marco - 13/8/07 at 05:42 PM

If you had too many holes in your back plate that were giving more air intake then why remove the air jet plugs?

If only there was a rolling road locally that also knew alot about bike engines?

You have got me wondering about the throttle position sensor but I thought it only mattered if it was altered at the bolts rather
than only disconnecting the connector..

Which day did you go as Dave did tell me that a guy was in just before me with air intake leaks around the base of his carbs where the rubber o rings are.


roadrunner - 13/8/07 at 06:01 PM

Hi marco, i was there on the thursday before you, Dave rang to tell me he had just had someone in with the same problems as me, this was monday, i had just arrived in Zante for a short holiday.
Rang Dave today, he is sending me some bigger jets to try, 175, he put 200 in yours.
I will just have to see if they work.
Brad.


marco - 13/8/07 at 07:10 PM

Looks like my fuel bill going up then

Let me know how you get on with the 175's it might be the 200's are a little too big.
Do you think the cough around 5k is when the main jets come into full play?


roadrunner - 13/8/07 at 08:35 PM

It could be , but i'm not that clever with the technical bits of an engine, hense the visit to Boggs.


roadrunner - 13/8/07 at 08:38 PM

Forgot to mension marco, he told me today ,that he took your air plugs back out, and you could always try and put some smaller fuel jets in yourself, its not difficult.


roadrunner - 17/8/07 at 07:54 PM

Still no bloody luck, received 180 jets from Dave at Boggs, fitted them , tried it, still the same, took advice from local garage to go back to standard jets, still no good, decided to lift the dynojet needles two notches, still no good, is there something else that could cause this problem, i'm getting to my witts end.


roadrunner - 23/8/07 at 08:01 PM

Right, i've changed the carbs for standard set up, been out and it's running better now, just a miss fire to sort out to get full power.
Also i have decided to fit the air box like Andy W.


mistergrumpy - 23/8/07 at 10:04 PM

Keep it coming mate.I'm very interested in what you come up with. By standard set up are we talking as per the bike?you've now unblocked the air jets?I wish you luck mate.


roadrunner - 26/8/07 at 07:53 PM

Thanks for that.
Balanced the carbs up, seem to sort out the missfire, went for a spin, still no top end power, but i do seem to have an intermitent missfire.


cossiebri - 26/8/07 at 08:54 PM

might be worth having a word with joelP ?
Don't know what he done to mine,but just done a 1,100 mile round trip to the nurburgring. Only problem i had was when leaving portsmouth to drive to dover (1:00 am !) it was around 8 degree's and found the carbs would ice up. apparantly kawasaki's are known for this?sorry to hear about the probs mate, keep at it your get there in the end