Good evening to everybody i wonder if any of you can help me ?

My yzf is playing up,its running really rich,so rich that's its of the scale at a dyno tuners, I've replaced the jets with new ones two size's lower,its better but that still hasn't fixed it.

The bike is hard to start up when cold and seems to run on 3 cylinders but after its warmed up it runs fine in fact sweet as a nut.

The bike has had no mods to it what so ever it is totally standard,and the exup is set correctly,I've stripped the carbs and there all ok with all the diaphragms in good condition and the needles are in the correct sequence,there's also new plugs and filters on it.

Also the choke doesn't work correctly.

I'm stumped can anybody help me please????

The bike is a 1996 model, 4HD5 engine.

hi ya,couple of things you can try mate

for one get the choke sorted that won't help and

have you had the carbs balanced lately because that

would cause it to run rough on tick over!!

mine runs really rick as well but i have a

full system on it and have no exup valve!!

cheers

I have already checked the carb ballancing and that's ok also the choke movement on all the cables is fine so in theory the bike should run fine,got any more ideas.

I would check from basics onwards even down to valve clearances!!

could even be a coil or lead..

One thing i did find when workin on mine is if you look at a workshop

manual and look where the main air jet and pilot air goes its

the oppisite way round done ask why cause its made some headaces

with me and some yamaha techicians i know..

One thing i'd say as well and i dont mean to tell you how to suck

eggs is get the carbs set up on sum good dyno and carb balances

one main prob i had with mine was cheap ones

dave

are your floats set to the right height ?

I believe they are but i have to buy the correct tool for the job (a bit of plastic tube doesn't really give you the best check in the world)unless anybody knows the measurement from the bottom of the carbs to the top of the float

Sounds like its going to be one of them annoying ones, jsut need to start checking from the most basic bits onwards. BUT get that choke sorted first

Sounds like its going to be one of them annoying ones, jsut need to start checking from the most basic bits onwards. BUT get that choke sorted first

I had a very similar problem with my YZF. Seemed to be a carberation problem but was infact an ignition prob. Hair line crack in a plug cap was creating an intermitent misfire. New plug cap and HT leads completely sorted it

And the annoying thing is its always the last place you look