Join Date: Nov 2010
Location: Mulberry, FL. USA
The Zephyr's are not "oil and air cooled"..the engine is only air cooled. The oil cooler only helps with the extra heat picked up by the wet clutch, which is cooled by the oil, hence the term 'wet'.
...I presume the bike has original air box, and stock exhaust,. if it does not, then it is extremmely hard making it run smoothly...very, very hard......obviously; it does not have the stock needles, but could you verify the pilot jet, and main Jet sizes??
In the US the outboard cylinders 1, and 4, main jets have #88, and the two center ones 2 and 3, have #90 jets. And these are very conservative figures to satisfy extremelly stringent pollution regulations with everything stock.
The pilot jets are #35 in all fours, I personally run #38.. The needles are also different; N52A on #1 and #4, and N52N in #2 and #3. The theory is the the carb runners being straight shorter in the two center cylinders provide more air than the two outboard ones, with longer runners.
The Kehin CVK 32 where used in a variety of engines, including off road 4-wheeler, thus, the jets and needles are very different depending on every applications. Even the last KZ750 in the US, the '90s ZR-7 in North America had same CVK 32s, but very different jets and needles from the Zephyr 750, only because it had a 4 into 1 exhaust.
Last edited by Hugojose; 08-15-2019 at 06:38 PM.