Kz 400 ltd non starter

Hi everyone hope someone can help me I put pods and shortened exhaust on bike lifted the needle with a shim changed prime jet to a 80 and main jet to 90 got spark but bike still will not start, spark is good when plugs are out but when they are in and I put spare plug in cap spark is, nt good, please any ideas it's doing my head in thanks in advance

It sounds like your battery may be marginal.

With the plugs out, the starter does not need to fight against compression so it isn't working as hard and there is more power left to run the ignition. With the plugs in, the load is increased so any weakness in the battery will be more evident. I thought I had a known-good battery (~1 year old) in my KZ400; it had some starting issues that went away with a new battery.

That should help your ignition. The mods you have made to the (presumably) stock carbs are another topic - one which has been discussed on this forum many times. The short answer is that CV carbs do not respond well to pods: recommend you re-install the stock airbox or switch to Mikuni carbs.

Has the bike ever run with the current carb setup?

Hi thanks for the reply car battery used with jump cables bike still being worked on but got spark carbs taking petrol only thing I can think of is starter clutch makes odd sound turning over under compression could that be a factor but it have started in past and valves been altered to spec, I have a 454 ltd also kept it spec airborne and full exhaust runs lovely and was going to put pods on, no way now trouble I have had cheers