Running way too lean with a 185 main

[3x440ex]

Hey guys,I was wondering if anyone could help me out here. I went riding today to break in a new motor and it was running LEAN and HOT. We up on the jet from a 170 to a 185 and that was still too lean:huh I'm running with no airbox lid, W/B air filter, a full race port head with three angle valve job, full W/B exhaust. I'm checking for air leaks tomorrow. Any help would be appreciated alot. Thanks

[Leo]

did you check out the rubber boot between the carb + motor carefully for cracks? sounds like your sucking air somewhere to me..!

Leo

[CBRSLIDER]

I second what Leo posted. I was going thru the same problem with mine. I checked the boot and sure enough it was cracked ever so slightly. I also checked around the airbox/air boot junction and found the sealer was cracked and mostly gone, so I resealed it up.

Ray

[Rip_Tear]

I expect its what Leo said... Yay Leo! You are the man!;) :D

[3x440ex]

fixed it!!! no leaks, i had to go up to a 200 main.

thanks for the help.

[Colby@C&DRacing]

I do not believe that the 200 main fixed your problem it just masked it by adding enough fuel to compensate for an air leak. I have never see a 400 that needed a 200 main jet. You might look around for a leak like everyone said.

Colby at C&D Racing

[3x440ex]

that was the first thing i did, i sprayed starting flued on the rubber boot between the carb and head and got nothing, besides it's a new boot. then i sprayed it on the boot that goes into the carb and still nothing. where else should i check. the motor was just put together a few days ago with all new gaskits.

i have a hard time beliving it needs a 200 main myself but lets look at the airflow......it comes in a W/B filter no airbox lid, into the carb with no choke, thru a full race port head, and out a full exhaust system. that's alot of air moving thru the motor and doesn't more air mean more fuel? plus it's been in the 30's and 40's here in Virginia.

[DBL-D49]

I had to replace the intake manifold on my 400 also(rubber boot between carb and engine). I landed from a jump and the rubber separated from the aluminum of the manifold. When i got a new one, it looked slightly different than my busted one, maybe it's something Honda updated. Something else, it could be cracked, and as you ride, the jarring and vibration could allow it to move enough to pull air that might not be noticable during idle. A 200 main jet sounds way big!

[3x440ex]

it has a new boot on it but it sat in the shop for like 8 months ( don't ask) they did update the boot some from what the guy at the dealer told me..maybe when the guy did the head work he forgot to use sealer around the new boot.

O.k. would the wiring harness where it goes into the cdi box, if it's not making a good conection, cause it to retard the timing and in return make it run lean:confused: