Have just managed to test drive my locobeast amongst various minor rattles and vibrations which have come to light I have noticed that the engine revs to the redline very willingly in all gears, however it splutters and is all but undriveable at low engine revs. I am running a pipercross filter having modified the jetting etc in line with all the advice available on here and the Yahoo site.The straight line performance was unreal however making the problem even more frustrating. Anyone out there got any ideas as I think I have tried everything. Ps I dont think I could go everywhere flat out

Either try different needle settings with the dynojet kit - or maybe you need to get it to a rolling road.

'fraid I can't help any more than that.

Will try out your suggestion on needle positions tonight hopefully,and keep everyone posted just incase some one else is suffering the same problem

Sounds like your pilot jets are blocked/dirty. When our pilot jets were blocked it wouldn't tick over but as soon as you went above abou 3000 rpm and it was using the main jets (which is what you have replaced) it ran fine. The needles don't affect low rev running as only the pilot jets are used from no throttle up to about 1/8 throttle. Take the pilot jets out and see if you can blow through them.

Click here for jet location picy



[Edited on 19/8/03 by MK9R]

Hope your right about the pilot jets because the needle heights had little effect. However I had cleaned these previously

I have now had time to try all the possibilities with dirty jets and needle heights etc , I have even tried adjusting the fuel level in the carbs all to no avail. Just browsing and found a helpful note from ZX9r on getting his engine running properly,one point I can't quite get to grips with his mention of" blocking the main pilot air jet with a matchstick and epoxy "My workshop manual refers to nothing as the main pilot air jet ? .Not having bought a dynojet kit I have no notion of what this is perhaps someone could enlighten me. Oh by the way I have however installed the 155 mains and used the recommended 2-2.5 turns out settings, giving me an engine that revs cleanly whilst the car is stood still but on the move splutters badly in all gears at low revs.Please someone save my sanity cause next thing tried out might be a box of matches !!!!!

I don't want to muddy the water, but have you considered the ignition side of the equation? It's possible that something electrical could be the problem. Did the engine come from a crash damaged doner? could be something as simple as the throttle position sensor or similar has been disturbed.

Al.
i]Originally posted by W A M
I have now had time to try all the possibilities with dirty jets and needle heights etc , I have even tried adjusting the fuel level in the carbs all to no avail. Just browsing and found a helpful note from ZX9r on getting his engine running properly,one point I can't quite get to grips with his mention of" blocking the main pilot air jet with a matchstick and epoxy "My workshop manual refers to nothing as the main pilot air jet ? .Not having bought a dynojet kit I have no notion of what this is perhaps someone could enlighten me. Oh by the way I have however installed the 155 mains and used the recommended 2-2.5 turns out settings, giving me an engine that revs cleanly whilst the car is stood still but on the move splutters badly in all gears at low revs.Please someone save my sanity cause next thing tried out might be a box of matches !!!!!

Dont mind muddy water ! perhaps clearer than the route of this problem.Havent ruled out anything yet but not having resolved the outstanding issue of this main air inlet thingy I feel a bit reluctant to bring even more potential problems/causes to the table,YET!!!.Engine was running in lightly damaged bike prior to removal.

Hi W A M,

I've just read through your problem and no power at lower revs can be the result of an air leak which would lean out the mixture.But I see you say you have installed 155 main jets. When I fitted the dynojet kit the original jets that I removed were 155's. These were replaced with the 140's in the kit. Now as I understand this the smaller jets lean out the mixture and this is corrected by blocking the main air jets. If you run a pipercross and free exhaust on 155's this could be causing the problem. This applies to a C2 engine so the jet sizes will vary if it is different.

Now to answer the question, if you remove the filter, plate,trumpets etc. from the carbs, look down the intake and the main air jet is in line with the needle on the float side of the carb.

Steve

[Edited on 25/8/03 by highspeeddirt]

The engine is a C2 model with a very free exhaust it did have std mains@155 as suggested.However most others seem to use 155s, I think the problem is that at low revs the mix is too rich as lowering the needles seems to cure the prob but causes poor high speed performance. was advised that the mains must be OK as the engine is willing enough(MANIC) above 3000 revs

Are you saying that you fitted dynojet adjustable needles but kept the std 155's? My dynojet came with 132, 136 and 140 jets.

If you think it is too rich then blocking the main air jet will make it richer.

Steve

I presume theZX9 uses Keihn carbs similar to my ZZR1100, in which case, you will need to block off the air jet if using an aftermarket sausage air filter. Nothing to do with the main jet or exhaust.
To find the little bugger, remove the plastic carb top (4 screws) from one of the carbs, and the diaphram/slide.
Now, on the top rim of the carb, you'll see the 4 screw holes, and a further hole between the front 2 screw holes. This is where the air jet resides.
Remove the air jet, and clean the threads with some aerosol carb cleaner, and blow it out with an airline.
Next, mix up some Araldite, and dip the end of a matchstick into the glue. Jam the matchstick into the air jet hole, and let the glue dry.
When all 4 carbs are done, use a very sharp craft knife to pare the glue/matchstickss level with the top of the carb bodies.
Job done.

Sorry, only just mangaed to get back on here to read this, but anything i could have added has already been said

I'm not sure what size jets we have replaced the originals with, they just came with the TTS filter kit along with the instructions to block off the air jet.

WAM, Have you found the main air jet?

Thanks for keeping the thoughts coming guys! MUCH appreciated.I have now located the main air jet thanks to Highspeeddirt(filter end of carb right above the removable bowl in line with the needle).The carbs came with the adjustable needles and 155 mains not that I bought the dynojet kit Too easy,(expensive).I assume that Rorty is refering to what Kawasaki call the air leak valves.If so these are currently open!possible cause?.Should the main air intake and these air leak valves both be blocked or am I mixing up too much info.ps I think this one topic may get me Senior builder status SOON!.Hopefully the whole problem will bottom out soon! ie avoid buying the dynojet kit.

If you have adjustable needles, then a previous owner has already fitted a dynojet kit for you (standard kawi needles are non adjustable). If you take off the air filter and back plate the air corrector jets are on the face of each carb, yours should be blocked off with a brass screw (part of dynojet kit).
155 mains sound a bit big, but i doubt that thats whats causing the misfire at low revs.

Al.

If by air leak valves you mean the four holes below the intakes on the engine where you connect up the carb balance pipes then these have to be blocked. Mine had two blocked and two with open connectors. If these are open they would give the air leak that I said about to give no low end power. I would block these first because they will let in more air than the main air jets.

I still think 155's are too big and when you block the main air jets it will be too rich.

Steve

We had a Dynojet kit on our car with a C1 ZX9, and it made 110 BHP at the wheels, 100 BHP with standard needles. On the dyno it was fine, but on the road it had a virtually undriveable flat spot at 5000rpm, so we reverted back to the standard needles. We haven't blocked any air channels and the car seems to pull relatively cleanly through the rev range.

BTW - the Dynojet needles were on the 'highest' setting, i.e. the adjustable washer was right at the top of the needle. We were also running with a Pipercross 'sausage' filter.

Are your carb's properly balanced?

Steve.

Thanks again guys have not had much time lately but will try a few more things today.Potentially I have an other idea,someone else suggested previously to look at the ignition side of things. Have done this ;and the throttle position sensor is not giving readings in the correct range.Keep you all posted later!



Cheers Andy!

Guys just managed to get a definate answer to my fuel problem. My local rolling road center has some experience of becs to this end he advised that this was a problem called fuel stand off, an exhaust or inlet manifold tuned length problem. Just managed to borrow an exhaust from one of the grass tracking boys to try and prove the theory. Guess what, he was right. This is a 4-2-1 and not the 4-1 type which I had made. Can anyone shed light on the art of exhaust manufacture as I copied the original kawa downpipe lengths and this obviously didnt work. Again some advice or just your opinions would be great as I would like to make the right thing this time!.

The systems on the bikes are optimised for the bike/rider weight to power out put. A 4-1 system is ideal for high RPM and good power high up.
Put the engine in a car, and there's more weight to lug around, therefore more torque is required to move it at low RPMs. A 4-2-1 system will provide more torque lower down the rev range without compromising the horse power.
Larger diameter headers will also improve torque, and vice versa for high revs.
There's a page on my site about building a 4-2-1 system if you're interested.
Reading back through your posts, I wonder if you're expecting too much of your engine, if you're driving it like a regular car.
Even with a good 4-2-1 system, you still need to keep the bike engine within the power band. It won't happily chug along in 3rd gear in heavy traffic like your mum's old Morris.

Thanks for the info RORTY much appreciated . I must admit that I also had concerns over my expectations of the engine, but after driving the car with the revised exhaust I now know that all that remains is to build a decent system for my self. I have just visited your web site for all the reqd info,GREAT SITE !!!!! thanks again.



Cheers - Andy

Crikey, just how bad was your original exhaust sytem, to create such problems.
do you have a picture?
Mines a homebrew job, made with absolutely no recourse to exhaust theory,scientific calculation, or anything technical. The car pulls like a train in all gears, (to the redline), tootles along in traffic with the merest whiff of throttle, and sounds blimming gorgeous.
Although to be fair it is 4-2-1, and i did have a long chat at some crossroads with a chap about exhaust theory, before i built the thing

Al.
Originally posted by W A M
Thanks for the info RORTY much appreciated . I must admit that I also had concerns over my expectations of the engine, but after driving the car with the revised exhaust I now know that all that remains is to build a decent system for my self. I have just visited your web site for all the reqd info,GREAT SITE !!!!! thanks again.



Cheers - Andy

4-1 exhaust shouldn't be too bad - all Stuart Taylors standard BEC exhausts, like the one I have, are 4-1, and the majority of BEC's run 4-1 without a problem.