TOPIC:

Hi everyone,

I have a 1975 Kawasaki kz400. I have built the carbs which are the original ones (Keihin) and yesterday I decided to do the ultrasonic cleaning carb. After doing that, I found that my right carb has some issues. One of them is the rubber passage plug is broken and the holes are damage. Please refer to the attached images for more details. The good news is that the bike is running very well except it cut it out 1 or 2 times.

Please could you give me any advice how to fix those issues? Which spare part should I buy to replace the rubber passage plug? How to fix the broken hole and the o-ring?

Many thanks

Doan

For stuff like this, the first thing I do is check the diagrams & cross-reference at Partzilla, then search the full part numbers on eebbaayy & go from there. NOS pics are handy. There are several rubber plugs on EB, but they are expensive. You might be able to find a generic plug but it would need to be fuel resistant.

I assume the o-ring is for the float valve seat >> the Kaw dealer & Partzilla etc have it. You didn't say you needed it, but there are several of the float valve seat assys on EB and two are NOS & pretty cheap.

Also, Z1Enterprises.com may have some items for your motorcycle & they usually have o-rings.
A metric nitrile o-ring kit may have the correct size or a size that's close enough.
....

Hi

The bike is running not well now. It cuts out several times. when it is in idle at 1st gear, I release the clutch then it cuts out. I am thinking about swap to mikuni vm30 but I want to try to fix it first. Is there any way to fix the broken metal? Do you think broken metal is the reason makes bike to be cut out?

Thanks

One of the photos shows a plugged jet. Hope you removed all the jets since those photos were taken and checked/cleaned each one by holding them up to a light, particularly the tiny pilot jets. And it should go without saying that all the various O-rings should be renewed, and the rubber plugs are required. Mikuni used rubber plugs as well so there is a good chance that you can find some generic ones at a source like Z1. Call them if necessary.

Hey I hope you got your issue fixed! I'm having some carb problems with my 1975 Kz400 as well. A friend cleaned mine and now it won't start up and idle in neutral anymore. I took it apart and found that my pilot jets are slightly different lengths and I'm thinking that's causing uneven gas flow between the two sides. I tried to take the pilot jets out to inspect them but found that they wouldn't budge even after I removed the screws that hold them down. I'm wondering if a previous owner of the bike either epoxied or JB Welded the jets in place. I'm also confused because my friend says he never did anything to the jets, so they've been different lengths since I bought the bike and it had been running decently before all this. Both jets have the same serial number and match in every way except for a few millimetres of length

Thanks,
Jay