www.zxrworld.co.uk

hi guys. im new to the forum but not to bikes and mechanics. this is my first zxr400, i bought it in october last year as a non runner. ive been though the bike and with a bit of work, got it running. i rode it to its mot in december an it had some bad flat spots when cold but soon cleared and went like the pocket rocket i was hoping for but it wouldn't idle below 2000rpm when hot. i bought some generic carb balancers off ebay but i couldnt seem to get the bike to run any differently. i took some advice from a local bike tuner/garage and he sugested to buy another set of carbs. so second set of carbs fitted but the bike ran the same. This is when i joined the forum for some advice. so advice i picked up was a possible air leak. i checked the carb mounts and found one had a small split so i replaced the two worst ones and cleaned all the faces and reassembled hoping that was the fault but ran the bike today and it was fine for a good 20 mins running in the garage fan cutting in and everyhting, i turned it off put all the side panels on and seat back on and was going to take it for a ride but it just wouldn't tick over under 2000 rpm again . im giong to try and balance these carbs tomorow but i cant belive that both carbs have got the same running issues and why does it only play up after its got hot and then switched off for 10 mins!!!! any pointers with any other sugestions would help. i was thinking poss fuel pump as you can only feel it click once every 5 seconds but i dont know if this correct. cheers chris

you can test that your fuel pump is working by putting the end that joins to the carbs in a jar and pressing the starter button, you should see fuel squirt out. Other things that could be wrong is the idle screws could be set wrong, check how many turns out they are, i think it should be 2 1/2 turns out but check the manual or it could be that you inlet valves are too tight. have you also tried winding the idle adjuster out? mine was playing up and wouldnt idle under 2000rpm and it turned out to be that the pilot screws were too lean. good luck

how many miles has the bike done?

when did you last check the valve clearances?

if they are tight you will have a nightmare starting the bike, hot or cold.