wish me luck! - now runs sweeeeet!

[RedexRobB]

should take my own advice and read the manual. Ok, the main jets are in the needle jet holder so i know what they are and the other thing i screwed out was the pilot jet. Still non the wiser on emulsion tubes tho.

[RedexRobB]

2 and 3 will have slightly bigger jets as it helps keep the pistons cooler instead of running lean. 1 and 4 run cooler anyway being on the outside of the engine.

when zimm pulled mine apart (when he had it) it was the same but now has 105 in all 4, runs plenty rich as it is so no need to up the middle two as it stands.

I suspected ther may be a reason beind it, thats obviously it then.

[zimm]

rover220's spot on ..

staggerred jetting is quite common in zxr's .. although manly in stock bike that have been dynoe'd .. racers seem to go for all 4 being identical ..

the emulsion tubes are the long brass bits with the 8mm nut on the end that the main jet screws into.

they are cross drilled and are responsible for accurate atomisation of the fuel as its drawn through the main jet..

the cross drilled holes are tiny and get blocked.

N77 0 are stock import L needles its what was in the L4 i had, they are now in the ZX4 .. (along with the rest of the L4 carbs)

interestingly, i have discovered recently that some L's have smaller carbs .. my (rover220's) L4 certainly did as ive still got the carbs and measured them 2 days ago whilst rebuilding Emma's bike .. the throats measure ~30.5 mm where my H carbs measure 32mm and are visibly larger.. the L carbs are infact the same size as those fitted to the V early ZX4.. so all i've gained by swapping them is carb heaters that i've never plumbed in lol

so it may be worth measuring your carbs up and getting some true 32mm one's if you dont already have some.

are your jets dynojet or keihin RobB ?

keihin ones are quite short, dynojet are longer and have smooth sides ..

i ask because dynojet jets flow more fuel for a given size than keihin, so a #100 dynojet = a #102 keihin (ish)

and because #88/#90/#90/#88 is what i've seen on several stock bike that have been set up on a dyno, stock engine, stock exhaust, stock air-filter..

i forget whether you have a KnN, but with your beet system, i'd be chucking all the mains in the bin and fitting #100/#102 (keihin) jets across the board as a starting point, even a micron will want #100's and we all know the beet is better, (my H is running #102's and feels a bit weak, but thats a different airbox)

[RedexRobB]

aha, now wiser as to what the emulsion tubes are!

They are Keihin jets mate. I know what you mean with the beet system tho, it runs absolutely spot on considering. and the plugs have always been a nice and crisp brown colour so it defo running good. No K&N on it.

Im not planning to do any work on the engine at the moment, going to get the thing running and painted then will sart to think about some tuning. Plan is to get it blueprinted and dyno'd and will probably leave it at that.

[zimm]

They are Keihin jets mate. I know what you mean with the beet system tho, it runs absolutely spot on considering. and the plugs have always been a nice and crisp brown colour so it defo running good. No K&N on it.

if its lean at the topend, it'll still pull cleanly, just lack punch.. for the sake of a tenner i'd chuck some bigger jets at it while its apart.

[RedexRobB]

I just might you know, now you put it like that. So you reckon #102's for the main jets?

[zimm]

with a stock airbox, #100's or #102's at a guess.

obviously a dyno will get it spot on .. but its what i'd do if it was mine .. as it is, its def too leanly jetted for a beet system and straight through can.

[steve87]

my h1 had a similar prolem, particularly when ticking over and especially when warm. what i did was, get some ear sticks, dip them in petrol, the take the air box off ( i am about to get well technial!!!) and where there is the big hole with the sliders in, there are three little holes below, which have brass/ gold coloured things in the bottom of them.....
I then put the ear stick down and swizzeled it round, and loads of gunk came out.
bik seems to be spot on now!
steve


PS if you can explian this using really names not "holes" and "brass/gold things" would be appreciated

[zimm]

you cleaned the airjets

[steve87]

yes ..... like i think you told me to ....... we make a great team?

[Xphyral]

i think i mentioned in another post somewhere about zxr's and lousy tickover, if carbs seem fiine make sure your inlet manifold rubbers are well sealed and there's no air being sucked through. if these are leaking the bike will feel fine at higher rpm but will idle like toad regardless of carb setup. good way to check is using your brake cleaner give each rubber a squirt around the outside in turn, if you hear the revs rise then that rubber is sucking air, either through it or from either of the clamped ends.

[RedexRobB]

cheers ill give that all a go when i go home next. Its a right git with the bike being in one place and me in another! Whats even worse is i work every other day so getting a decent amount of time off of work is a pain in the butt!

[RedexRobB]

Well today i had to go to a funeral and left for home yesterday. As advised my Zimm i soaked the jets in brake cleaner overnight and also left the very shagged battery on charge in hope that it might give some life in the morning.

Well, this morning, went outside and blasted the jets with some compressed air to clear them and reinstalled everything inside the carbs. Whacked the carbs on, connected a fuel supply and gave the starter a push. Practiacally feck all fromt he battery so borrowed my mums boyfriends car battery, turned and turned and turned and eventually some life. Unfortunately still the same old problem; runs like a bag of pig shite upto about 3k revs and then the needle flies up the rev counter. Managed to get the bike to idle at about 2.5k just to listen and every now and then the revs would settle and run smoothly for a second and then run crap till it randomly smoothed out again.

eliminated the jets since they were well clean and next suspected the spark plugs. Call to my local bike shop (Bowen Moto) 'have you and CR9EK's in stock' - Yes no problem. Got there only to find they only had 1!

Fear not as they had a delivery coming in just a few hours with 10 of em, meantime i attended the funeral and not long after they called me to say they were in. New plugs were lovely and shiny and brand new. Set the gaps, whacked em in, it started and was a bit funny then stopped. Started it again and it was silky smooth!!!

Now a very happy chappy!

Got a list of bits i need to buy such as the odd screw i managed to round off on the float bowls and carb caps etc. Gave the carb outers a clean with a brush and the left over brake cleaner which brought them up lovely.

[RedexRobB]

A video of how it was running a few weeks back

http://www.youtube.com/watch?v=nVx0JZS1Keg

As i said it would struggle upto about 2 or 3k and then clean out. All the symptoms screamed of blocked jets especially as it had been standing for the best part of a year, but turned out to be the plugs!

[parby81]

funny, cos thats a bit how how mine sounds!! beginning to supsect the plugs and ht leads now, rather than anything fueling