big bore jetting issues

[BigBore24]

I have a 2000 400ex, and i put a big bore 440 kit in it a couple months ago including new sleeve, it also has a hotcams cam but im not sure which stage. I have always read on forums like this that you should bump your main jet up to around 170 or so and take your pilot up around 50 or so. but with my main jet at 152 and pilot at 42 mine appears to be running rich. It doesnt smoke hardly at all and runs strong all the way through the throttle but when i pull the spark plug it is as black as coal. I dont see any signs of it burning oil considering it doesnt smoke much and it doesnt use oil but i cant imagine im running rich with those jet sizes. Is it possible that something else is going on in the carb letting it overfuel? I have also read you shouldnt use a hotcam with the big bore, is this a possibility? any input would be appreciated. thanx

[davetheslave]

What brand jets are you running? Because if its a Dyno jet 152, thats equivalent to 170-180 in the keihn sizes. So it is possible that you may have to drop jet sizes still

[brokenmike]

thats odd, because I got a 440,11.1,stage 2 hot cam,uni filter,no lid and I was at a 170 dynojet jet, untill I got a 450r carb

[davetheslave]

I agree, I'm running that too. But I have 12.5:1 and a bunch off other mods. He may only have a stage 1 cam, and still have the airbox lid, stock pipe, stock carb etc.... . Its hard to say. Elevation makes a difference also. needle jet could have some issues as well....

[BigBore24]

I assume the jets are keihn because I got them from the honda dealer. I have a DG slip on with K&N and prefilter and no lid. I recently did away with the airbox all together but havent ridden it since to check. If I were burning a bit of oil would the plug be black and dry or would it tend to be wet with oil deposits? I dont know my elevation but im sure it is near sea level in Indiana bout 20 miles from indy. I dont notice any backfiring or bogging down but I would hate to find out i am too lean and that something else is causing the black plug

[BigBore24]

also my comp ratio is 12.5:1 could it be that I have been running it on premium instead of race fuel with the high comp? got some race fuel but havent used it yet either

[davetheslave]

You should definatly be running race gas with that kind of compression. You should try riding it now that you pulled the airbox, and switch that fuel out.