TOPIC:

I just finished the putting new pipes on my 440 and on the first test ride it backfires every time I let off the throttle. It didn't do this with the megaphones. Any advise would be appreciated.

A backfire on deceleration or a hanging idle usually indicates a lean condition.
You need to richen up your fuel mixture. Start with the idle mixture screws.
They are located under a plug on top on the engine side. Your best bet would be to
get a DynoJet jet kit for a '80/83 KZ750 LTD [KZ750H]. It has all the parts you will
need and good instructions to follow. You may wonder why this jet kit. There is no
performance parts currently available designed for the KZ400/440. Except for
having a cam reground. The KZ750 4 cylinder uses the same carb. The only
difference is the ventri size. The 440 has a 36mm throttle bore vs. the 750 34mm size.
The carb body castings and throttle butterfly valve are the only differences. They use
all the same parts including the slide and diaphragm. The DynoJet kit includes jets for
different stages of tuning/performance. It also has the hardware to remove the idle
mixture screw plug and the correct jet needles.


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I assume the megaphones had baffles in them. Do the new pipes have baffles? Ed

650ed wrote: I assume the megaphones had baffles in them. Do the new pipes have baffles? Ed

With wide open short pipes you may not be able to eliminate decel popping.

The pipes are emgo universal turnouts. They have a small baffle