Just finished my mk indy with zzr 1100 d engine, i have the full power carb tops so is running around 150bhp, i have a pipercross panel air filter and standard jets in at the moment which are 155 on outside carbs and 160 on inside carbs, its coughing and farting above 7000rpm, i know i need different size jets but can any1 tell me what size they used e.g mr guiness or anyone else who has the same engine. many thanks

It may not be the jetting.
As it left the factory, your ZZR1100 would have had ram air which incorporated a feed to the float chambers to balance the pressure inside the carb venturis to the same as the float chambers.
I have personal experience of someone who neglected to fit this pipe on his single seater powered by a ZZR1100 motor.
Without this knowledge, they could only get the engine to pull strongly was to physically choke the inlet.
The simple act of connecting all the air pipes correctly uncorked the engine and it flew after that.

I would seriously consider this avenue first.

hi thanks for that i have heard before that when u take the ram air pipes off they run rough but how do i sort it out because they original air box doesnt fit under my bonnet, thnks again

the ram air pipe is on and getting loads of air through it

Standard jetting in the bike is 155 mains. I messed around with fitting bigger and bigger mains, until I spoke to a guy who ran a ZZR engine in a Jedi (and won the hillclimb championship in it).

He recommended 200 mains (that's 2.0mm) so I got the drill out and opened up a spare set. It runs rich lower down, but doesn't run lean, bog down under transition and seems to pull strongly from 1500 rpm to the red line.

There is no point in going larger than 2.0mm as that is the size of the hole into the carb casing! If you get the float valves set up right it should be OK and fit a dyno jet needle kit, to give better control when it goes from part throttle to full. Can't remember where the clips are on my needles, but the difference between the factory needle and the dyno jet ones is significant.

I think the original bike silencers were pretty restrictive and as mine has pretty much a straight through exhaust, the extra fuel seemed to work.

One other thing that I found made a huge difference to the running of mine was going back to the original copper stranded ignition leads, rather than car type silcone / carbon ones.

Usual internet disclaimer applies, any advice is just my insane ramblings, worked for me, your own circumstances may require different solutions etc etc.

hi guinness thanks for your help, i driled out a spare set of mains last night to 2.0mm gonna fit them today and see how it runs i will keep u posted thanks again

engine runs mint now ive put 2.0mm mains in, just bogs down abit when i first put my foot down but the carbs need balancing so i think when they are done it will cure it, car hits redline in every gear now at 11500rmp, and is doing 130mph in top ger, the car hits 11500pm in top gear aswel, the car flys now and pulls lke a train in everygear, thanks guys

[Edited on 31/5/11 by vananddan09]

guinness are going to elvington on june 11th it would be good to see your car and have a look as a fellow mk zzr1100 owner, im going in mine

Hi all,
I've come across this thread while trying to find a solution to my ZZR1100 Locost not being able to rev to any more than 6000 rpm. I read the information in the thread and used it to find a slightly more hi tec fix, and I felt that I should join the forum to share this knowledge. So here goes:

I live in the UK and built my Locost between 1996 and 2001 based on the very first incarnation of Ron Champion's Build a Sports Car for under £250, but strayed from the plans a little, and used Ford Capri 3 litre V6 Essex engine, gearbox and rear axle.
I rebuilt the car in 2009/2010 using a Kawasaki ZZR1100 D1 engine and Quaife reversing gearbox. The engine is stock, and I use a pair of ITG foam air filters slipped over the stock Kawasaki plastic trumpets, and homemade 4 into 2 into 1 headers with a massive Cheeseman stainless steel silencer from a Caterham, to keep the noise down.
I use the car only on the public roads, and over the last 2 years has proved very reliable, but only capable of reaching around 6000 rpm in any of its 6 gears. It was also bogging down while blipping the throttle when stationary. I'm also running Dynatek Dyna 2000 ignition and Dyna coils and thought my problems may have been faulty ignition parts.

In the UK the ZZR1100 was restricted in the early 90s due to an agreement between the big 4 Jap bike manufacturers to keep the power down as it was getting a bit out of hand. This lasted for 2 or 3 years until Triumph ignored the gentlemans agreement, and the rest followed suit. The ZZR1100 in the UK was restricted by extra moulding in the plastic carb tops which stopped the slides moving any more than 2/3 open. To check this, stick your finger inside the carb and push the slide up, it should go all the way up and flush with the top of the carb bore. If it doesn't you are restricted to 125hp. Change the plastic carb tops for the later model ones and release the full 140 odd hp. Simple as that.
If you have ditched the original airbox arrangement, and/or modified the exhaust - stock ZZR1100 is a 4 into 2 system, but looks like a 4 into 1 into 2 ( it isn't as the part that looks like 1 pipe is actually 2 D shaped pipes back to back) then you will definitely need to rejet the carbs.
Being an ex biker I have heard many times of guys fitting Dynajet kits, so after reading this thread went in search of one. The current cost in the UK is around £120. Yes I know they can be had cheaper if you look around, but it's still a high price to pay if it doesn't cure the problem.
Looking on ebay I found a solution for a reasonable sum from the USA.
Have a look at http://www.6sigmajetkit.com/
I bought mine from ebay and it arrived in just over a week. I spent 4 hours last sunday afternoon pulling off my carbs and fitting the kit, with great results. The package comprised of 1 set of 175 jets, 1 set of 185 jets, some spacer washers to lift the needles, a drill bit for drilling extra holes in the slider pistons (for improving throttle response), another drill bit for removing the blanking plug to get at screws that need adjusting ( not applicable on UK machines) and some comprehensive instructions/explanations (cheaply photocopied, but very helpful).
*Please note: There are 2 options for improving throttle response. One is to drill the hole in the slider, and the other is to chop coils off the springs. I read this as one or the other. NOT BOTH. Therefore I did NOT chop any coils from my springs, as they cannot be put back on. A hole in the slider can be re-filled with e-metal resin though. And this worked well for me.

Testing the car afterwards was a revelation. I was grinning from ear to ear. It felt like the car now had double the power!! Of course this is probably because previously it only had half the power it should have had. Throttle response is now instant, with absolutely no hesitation. And it revs way up past that 6000 rpm and would probably hit double that if I was brave enough. It also seems to run cooler.

Many thanks to the guys before me on this thread, who directed me to what the problem might be, and I recommend doing what I have done rather than just drilling out the jets to 2mm. I used the 185 jets that came in the kit,and the standard ones on my bike were 158 and 160. (The middle carbs have different sized jets to the outer 2 from the factory, due to the temperature they run at on the bike.)

Different parts of the carb affect different throttle positions, so just altering one item will leave the engine running poorly at different throttle positions.
I also recommend getting a Haynes manual as it gives better pictures of the carbs than the instructions with the Sigma kit.

Please post any feedback on this subject as it helps others as it's hopefully helped you.