400ex carb? or other?

[sixer3]

I've got an 05 with the "velocity" intake tube (ebay) wth a k and n filter and outer wear, hmf slip on,

and im a pretty experienced "jetter" imo

im running a 170 kehin jet, seems rich but its acually a perfect plug color....problem is i have good plug color all around with a 42 pilot and stock needle, but I have these problems

1. continuous crack on the throttle from no throttle to WOT it dies in 4-5 cracks...only under load

2. it idles but the rps seem to be pulsating, un-like any other 400 i own.... 1of 3 ...

3.if i pulse the throttle from no throttle to about 1/4 throttle then let off quickly as the engine decels it nearly dies then comes back up to idle

I've tried leaning and richening my air/fuel screw, richening and leaning my pilot jet, and checking for intake and exhaust leaks, and im at a dead-end....soon to be a 450r carb anways, just has me puzzled....

im also getting a spark knock(i think) at high rpms cold or warm motor, seems to possibly be a low octane ping.knock? on a stock bore??...........thanks for any help one may provide...

CHRIS

[2004exrider]

170 seems a little bit rich to me, try taking your airbox lid off or putting in a 165 and see if it helps. You shouldnt need that big of a main if all that you have is a slip on and a K&N filter. Your getting spark knock and have stock compression? What octane are you running. There's also a possibility of having a lot of carbon build up that is making it 'ping' (though very doubtful).

Jimmy

[sixer3]

i have the velocity intake tube basically an aluminum pipe that eliminates the stock air-box, snorkel, and boot assebly just the filter connected to the pipe, which means lots of air, but im guessing still too rich also, my plug must be lying :)...i guess that could cause a weird spark knock...since i could be flooding it out?