Pattern fuel pump problem

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Joined: Wed Aug 14, 2019 8:01 pm
My Bike: ZXR400 L9

Pattern fuel pump problem

Post by Pops » Sun Dec 08, 2019 4:28 pm

I’ve been chasing a problem with my ZXR400 L9 low speed running for months. It was running very rich up to 4000 rpm, starting without choke etc. No problems t all at higher refs and above 1/4 throttle.

Changed float valve seats and needles, re-set float levels, ultrasonic cleaned carbs, checked diaphragms and needles etc. The situation improved but the problem was still there.

Then I got suspicious about the pattern fuel pump which had been fitted by the previous owner shortly before I bought the bike -( it’s the typical e-bay product at about £25) - the output looked VERY high and the connections were 10mm rather than 8mm.

So got hold of second hand standard pump and fitted it. The difference in the speed that the pump operated at and the output was obvious immediately

All rich running problems now sorted 👍

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