carb woes!

[jake]

ive just recently bought a shed of a L zxr, to use the frame and engine as spares etc, so i took the carbs off and noticed they are smaller than the H ones. 30 or 31mm, is this the same for all the L models, or just the imports maybee? strange as i thought it was the early H model that had the smaller carbs...

secondly, especially for the H owners(L bellmouth material seem less likelly to shrink), next time you have your airbox off, check them rubber bellmouths for size!... Mine have shrunk down to about 25mm!! they should be 32mm, thats why my bike was lacking power/running rich on the dyno last week i thinks

[RedexRobB]

could be that someone has swaped the originals?

[zimm]

well, bugger me ..

after you mentioned the weirdy 31mm carbs on your L4 it's been playing on my mind a bit, so much so that while changing the camchain on the ZX4 today i got the verniers out and measured the carbs .. and lo and behold .. 31 mm !!

(they are off my old L4 import, but have heaters, ZX4 carbs are smaller again ..)

which i guess explains why its never really pulled cleanly through the rev range no matter what i did to the needle's/jets/airbox, cos ive been trying to replicate known setups from bike with 32mm carbs .. DOH !

thing is its been running crap for so long now (and i hardly ever ride it) that i cant remember what jets are in there, or work out if its rich/lean .. i do know they need balancing though, the vibes are just nasty.

[jake]

strange. now, the h1 and h2 i have deffo have 32mm ones...but they could of been swapped out? who knows.
with your l4 import having the 31mm aswell, maybee all the L imports have 31mm? or maybee its just as random as the slipper clutches seem to be...

[Scott221]

I've been hearing alot about these trumpets. My zxr runs absolutely terrible if im honest. The revs constantly 'stick' and does anyting but rev cleanly. When cold, if I open the throttle full it will cut out (running rich?) The bike is a giraffe to start when cold, it will run find for maybe 5 seconds, then drop right down to 2-500 rpm and die. I have to hold the throttle open. Saying that it runs ok when im riding it, just pops alot when i get out of the throttle and theres a nasty flat spot at 4 thou.

Need to get it back on the dyno.

[zimm]

strange. now, the h1 and h2 i have deffo have 32mm ones...but they could of been swapped out? who knows.
with your l4 import having the 31mm aswell, maybee all the L imports have 31mm? or maybee its just as random as the slipper clutches seem to be...

well, my H carbs are coming off in a bit so i'll see what size they are, wish i'd measured the uk carbs i put on the L4 now..

[masterofinsanity]

well according to the specs on the main site both H & L models have 32mm carbs just checked the manuals also they both state 32mm.

[zimm]

weird isnt it ..

however the manuals also say the cams are all the same, and the camchain tensioners and they arent.

[zimm]

ok, have now measured all my sets of carbs ..

ZX4-G = 30.5
H1 = 32mm
L4 import = 30.5

so yep, def 2 sizes of carbs in use across the range.

[masterofinsanity]

are you measuring these yourself zimm or is it stamped up on the carbs?

[zimm]

measured with verniers mate ..

carbs are marked the same .. just cvkd.

its the wall thickness thats the biggest visible difference.

and possibly why L's stock main jets are #95, whilst H's are #98.. or that could just be the airbox design ..

really wish i'd measured the carbs i put on my L.. it def ran better, but i put it down to them being well balanced/setup and having dynojet needles.

they were supposed to be off a UK spec 1997 L5, and "should" have been 32mm.

[rover220]

measured with verniers mate ..

carbs are marked the same .. just cvkd.

its the wall thickness thats the biggest visible difference.

and possibly why L's stock main jets are #95, whilst H's are #98.. or that could just be the airbox design ..

really wish i'd measured the carbs i put on my L.. it def ran better, but i put it down to them being well balanced/setup and having dynojet needles.

they were supposed to be off a UK spec 1997 L5, and "should" have been 32mm.

tell em where to measure and ill do it, plan on doing carb rubbers while im waiting on sorting the puncture

[zimm]

tell me where to measure and ill do it, plan on doing carb rubbers while im waiting on sorting the puncture

internal diameter, inner (engine) end.

[jake]

the L4 ive got with the 31mm carbs, also had smaller diameter bellmouths too. might be worth checkin whilst you have tape measure in hand

[jake]

are you measuring these yourself zimm or is it stamped up on the carbs?

Aye,as zimm sez, they are quite visibly different in the thickness of the wall to the engine side of the carb mouths. almost as if they are the same as the 32mm's, but havent been bored out as much.

they do however, have different numbers printed on the carbs. i have 4 sets all different. H1, H1sp, H2.(all 32mm) and the L(31mm).
this may just be different numbers for batch etc.... so maybee means nowt