L1 Dies when throttle, Only Idle with Choke on.

[Greekstar]

Hi guys.

I am currently restorring a Zxr400L1. I bought it cheap from a breaker, not knowing the history/condition of the bike.
I just fitted a new CDI, new spark plugs, new fuel and air filter.
Cleaned the carbs the other day.
I then mounted the carbs, pulled the choke lever to fully engaged and pushed the starter. When the carbs were filled, the enginge started instantly.
But during warm-up the engine cycles alot up and down, from 1000 to 4000rpm. It dies when i use less than 3/4 choke. When i turn the throttle it dies unless i let go of the throttle.

S0.. i am convinced the problem is relating to the carbs. But where do i start?

air screws are set to 2 1/4 and 2 3/4 from full in. Haven't touched them. Needles are standart and clean, they move freely up & down. Jets are clean.

Hope u can help...

[ross46]

Have you checked for air leaks? The rubber mounts can perish, spray some carb cleaner around them and if the revs change there's a leak, also the pilot screws sound too lean, 2 1/2 is about a turn extra than standard, you could try that aswell

[Greekstar]

So..I adjusted the swimmer hight and airscrews. Engine runs alot better now, and does not die when i turn the throttle.

But carb 1&2 leaks petrol from the overflow, could this be caused by wrong swimmer adjustment or is it a worn swimmer needle/valve?

I just ordered 4 new valves from ebay, just to be shure. Im excited to see if this cures my problem?

[ross46]

Swimmer? I'm guessing you mean float height? And yeah, check there all around 11mm