www.zxrworld.co.uk

Hi,

Don't know if you know but I currently have a ZX400 G engine in my L2, I know fek all about it as they are not really exact to the later models. The clutches are box standard (feel the power when shifting or what!) and the tensioners on them are skunk.

Anyway, I either heard or read somewere that ZX400 engines have a smaller inlet than the Hs and Ls? I currently have the L carbs on it at the mo and seems to be really poo under 4000rpm. Top end pulls really hard, all the way up to 142mph @ ~13900 no problem, the bike also can reach rev limiter at 15000rpm in lower gears no sweat so I'm guessing the main jet is spot on. Mid range is ok I guess but I have set the needle to the leanest option with the slides drilled. Mixtures are on 2 1/4 and float heights at 11mm.

I have a strange feeling that the float heights could be wrong? Anyone have any idea if the float heights are different on the ZX400 G carbs?

Regards

Rich

zx4 carbs are smaller than the unrestricted zxr's 32mm carbs ... but the same size as the ~30mm carbs found on the restricted (import) L models, just without the "carb heater" gubbins...

they have different needles and emulsion tubes to match the zx4 airbox and exhaust.. afaik spec float heights are same across all zx4/zxr4 carbs ..

oh, they arent interchangeable.. the cable bracket gubbins are different ..

anyway, its probably/possibly the cams.. as mentioned in the other thread.. but ..

I normally end up with the float heights at 12-13mm to clean up the midrange, and ..

what needles are you running ? dynojet ? you could try the stock ones, if that gives cleaner/more consistent fuelling upto 10k its a step forwards, but you may need to alter the main jet to get the topend back (up a size or two)

Hi,

Thanks for the info very handy! So my engine has them SP cams which aren't adjustable right?
I've got the dynojet needles yes, I changed the float heights again today up by 1mm and it seems to be getting better and better. They are now currently set to 12mm, but if I boot it at low rpm it still stutters abit so I think I'll raise it again by 1 more mm and see what happens. I'll try some stock needles indeed, never thought of that thanks!

I'll let you know on the outcome.

Regards

Rich