Getting fed up now

Still have full throttle coughing over 7500rpm

Rolling road session was a flop. Changing jets and neadles in session to no avail. One guy I know said that these engines zzr1200 often have too tight valve clearances. This made some sense as its fine when cold. Anyway checked clearances 5 were too tight. Got the necessary shims. Clearances now ok . Still no difference....bugger
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Have thried all permutations of jets. now on 155's 150's being stock. Wide band lambda recording suitable values at Full throttle. Other that that its all as it came out the bike except for different air box and exhaust cans.

Thought I would next go to basics and get a compression test cold and hot.

Any other thoughts as I feel I am banging my head against the wall.



[Edited on 29/12/10 by Lightning]

Changing the airbox may be contributing to your symptoms. I know from having numerous bikes, the slightest filter and exhaust change has fairly large effects on the performance of the engine.

plugs? Spark leads? coil getting hot?

(working on the idea of the spark breaking down at high rpm)

You might of answered your own question,Airbox and exhaust.

My R1 powered MNR had a hesitation on the throttle and wouldnt rev out,i took it to a really good guy in Malton North Yorkshire who has a business rolling road tuning TT bikes etc and also has a rolling road for cars.

He spent 2hrs rejetting etc and couldnt get it to his liking,he pulled my carbon can off and ran it up and it 70% cured it,he told me to buy an R1 standard can and bring it back (Didnt charge me a penny at this point) bought a can off Ebay went back a week later and what a change in the engine.however he still wasnt happy and said the MNR manifold supplied was not really doing a good job and i should run a cold air feed into my ITG sausage type filter which i did. (Still didnt charge me anything and he must have spent 5 hrs collectivley over two visits) i had a new manifold made and went back,30 mins later fantastic total different car and got an extra 27 bhp from day one.
He charged me £80 and got my gear indicator tuned in on his rollers as well.

Great drive home i wouldnt go anywere else now. top bloke

I would check your air intake first and then if the gases are getting out

[Edited on 29/12/10 by sonic]

I would put in the standard air box but wont fit.
Yorkshire is too far from Devon.
I suppose I could get an air box and run it with the back clam off. would have to be off road then. ....mmmmm

I didnt have the standard airbox fitted,I had a ITG foam sausage type filter and ran a cold airfeed in from the front with ducting straight onto the filter.

Just a word of warning if you take the can off and run it up,the gasses coming out of the end get F--king hot!!! when he did mine he put a stand with a plate on between the end of the manifold and the bodywork,the plate was glowing at the end!!!

Fuel pump delivery rate ?

I'm running a zzr1100 which is nearly identical, without the airbox it pulls ok to aboult 7000rpm then it coughs and farts and spits tons of fuel out the carbs. With the airbox fitted it pulls clean as a whistle.

I tried it with filter socks - still crap.

I tried making an airbox of similar size to the original using the original air filter - still crap.

I cut a huge hole in the bonnet and used the airbox till I came up with another solution - Worked perfect

Davie

I'd put 26p on your airbox causing the problem. Bikes are very sensitive to airbox changes.

air box or over fuelling has to be one of the two.

Thanks for that guys.

With a sausage filter it runs like a bag of nails. With the home made airbox it runs much better but not great.

The problem is the rear body wold have to have a F8ck off big hole cut.

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[Edited on 29/12/10 by Lightning]

Ok , just ordered an air box. Maybe I can reverse it. Dont know till it arrives


BTW changed plugs and leads. Possibly coil packs???

What was happening on the dyno? Didn't the guy give you a clue as to what was happening to AFR or timing?

I don't understand that the lambda is fine, but there is a problem.

What I mean is how can this be?
If you had a miss-fire (i.e. ignition) then this is recorded as rich (residual fuel in exhaust)
If you had a fuel pump problem, then you would be going lean
If the carbs/airbox are unhappy then I don't understand how the mixture could remain stoichiometric.

Anyway, there goes theory again.

Are all the plugs the same colour? I had problems with leaks and sticking needles, enough to make me change to EFI.

I guess if it works with the bodywork off, and the stock airbox, then at least you know whats going on.

Matt

PDQ and BigCC are a little closer than Yorkshire....

quote:

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I don't understand that the lambda is fine, but there is a problem.

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Hi, just a point but what are other people using airbox wise on this type of car?

I don't know much about this model but i assume its not the only one built,or do they not normally have your type of engine fitted.

Only a thought,sorry if i am missing something.

Mick

from my experience I would agree with the other comments regarding airbox and cans

these modern bike engines tend to be so damned fussy, but the airbox is the main thing that upsets them

I always get full throttle set right then work back, thats how I was taught to do it and never failed me, depending on how restrictive your filter setup is, I probably would have started with bigger mains

I normally go up 10% on the mains to get started. quite often shimming up or lifting the needle a notch too, but I normally have quite free flowing exhausts on the bikes, with no worries about the SVA etc

quote:

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I probably would have started with bigger mains

I normally go up 10% on the mains to get started. quite often shimming up or lifting the needle a notch too,

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Hi Steve

I tried the original airbox on my ZZR1100 but it wouldn't fit the right way up and fouled on the engine cradle when reversed.

I've run a sausage filter for 7,500 miles (occasionally fitting a PX600 Airbox for quiet trackdays) with no real problem.

Originally it would cough and struggle at the top end, but that was cured by relocating the fuel pump closer to the tank (so it pushed rather than sucked), changing the plug leads (and relocating the coils so I could use an OE solid copper set), and fitting 200 jets and a set of Dynojet needles.

It runs rich at low revs, but on WOT pulls like a train all the way to the red line. (There was no point in going larger than 2mm with the jets as that is the size of the hole in the casting into the float chamber).

HTH

Mike