TOPIC:

Hi guys! My first question is about the well known difficulties to tune CV carburetor without airbox.
My bike is a z350 (the same z400 with a smaller cylinder bore) with a keihin cv32 carburetor and short mufflers, you can see a picture in my "new member topic" here: 

www.kzrider.com/forum/forum-index/10-new.../620127-hi-everybody

the keihin original set up is pilot jet 35, main jet (primary) 70, main jet (secondary) 95, needle 03301
at the moment i only raised 1mm the needle and i regulated float height at 22mm but i didn't change any jet. the bike runs but it can't reach max rpm.

ignition timing is set correctly and the spark plugs are ngk b8es

i read this guide:
www.kzrider.com/forum/3-carburetor/48466...d-exhaust-re-jetting
but i don't know exactly what to do with main jets. Should i increase both primary and secondary by the same size?
for example 70->75 and 95->100 (5 points increase both) or i have to increase just one??
is there anybody who found a good set up with this carburetor and pod filters??

Thanks for any advice and sorry if it's always the same question but i'm a beginner with this carburetor

Sorry if i’m asking again, i finally found a couple of secondary main jets to try. I found a 100 and a 105, i think the good one is between these two if the guide is correct… (stock is 95 now). Unfortunately i can’t find the primary main my only option is to drill it but i will do it only if i’m sure… is there someone with experience with this carburetor that has already done this before?? Should i leave it as original (now is 70) and try only changing the secondary? Or i have to drill it to 75 or maybe to 80???

Hi Mak21

Sorry I cant help with jetting advice but here are some thoughts until the 400/440 guys get here.

Do your current pods have a lip on the inside that can block or partially block the various openings in the intake side of your carbs ?  It happens and no jetting will fix

If you have difficulty finding Keihin jets in Europe then you could try Z1 Enterprises in the US . Click on the Z1Enterprises box above. Enter "keihin" in the search box and hit enter. They have a large selection of main jets priced about 2euros each. You may have to buy a few different sizes and experiment with them.  Also, they ship internationally by US Mail.

A few KZR members have come up with creative airbox/pod solution. See  kzrider.com/forum/3-carburetor/599569-cu...ox-for-kz440?start=0   There are others and a bit of searching should  work.

Hope this helps


 

Thanks for the reply JR, i have already removed that lip on the inside i think it’s ok but maybe i will take a look if i can make more improvement.
i was thinking too about an homemade airbox but it has to be aestetically well designed because i have all that part of the frame completely visible so this will be my last option, i prefer to do the best that i can with pods!! 
maybe this week i will try changing the secondary main and leaving the primary original to see what happens, then if i need to buy something i will think about to order from the US…

Not all pod filters are created equal. Some do have a lip that can effect how air gets to the air jets in the carb. Some do not flow any better than a stock air box/filter do, or worse flow less air.

It appears that the bike runs but not able to reach max rpm, Not able to pull to red line can be caused by either too rich or too lean mix. You need to figure out which it is. I might suggest using the chock system to see. Can you obtain a higher rpm with part choke than with out it. If you can then the mix is lean as your carbs do have a choke and not an enricher system so when used it is blocking air intake and not added fuel via the enricher system.