highoctane
New member
Hey guys looking for some assistance on a very annoying engine out of 40+ I've built
******EDIT FIXED**** blown head gasket issue resolved
motor specs:
212cc hemi
stock valve
11.5:1 compression
black mamba 275 cam
arc 32* flywheel
forged rod
26lb springs chromoly pushrods etc
mikuni 22mm
So whats the issue?
I started with a 130 main and 12.5 pilot and the motor ran strong with a couple hiccups towards top end. after 3 minutes of riding I noticed the engine extremely hot so I cut it and pulled the plug. super lean. I adjusted the needle clip in the richest setting still lean. I then turned the air screw multiple times trying to richen it up still lean.
I then went up to a 15 pilot with some hiccups on low end if I gave it full throttle. went to a 17.5 pilot even worse. both pilot changes included needle clip adj as well as air screw. motor still was extremely hot with worse hiccups on high and low end with larger pilots.
I bumped up to a 135 main which is strange since some of my big valve .310 lift motors run fine on 130 according to my golden brown plug and butt dyno.
I set everything to stock needle clip in middle and air screw 2.5 turns out. still no luck motor was extremely hot. I moved needle screw to richest position on the 135 /12.5 still no luck motor runs worse (more bogging and hiccups) than with the 130 main. I turned the air screw in half increments richer with still no luck and a baked engine after 3 min.
Could this be a timing issue? I have done exact setups with 32* of timing running great on the 130/12.5-15 setting???
below are pictures of my plug after no idle time and 3 wot pulls cutting motor after on the 135/12.5 setting with needle screw and air screw in richest positions.
I have checked for vacuum leaks, used a degree wheel for timing
motor ran best with the 130/12.5 combo but would cutout at about 7k and just hiccups and fall back.
Mainly im curious about why its still lean and or hot af! I have never seen a 140 main needed on this mild combo.
thanks for the help!
******EDIT FIXED**** blown head gasket issue resolved
motor specs:
212cc hemi
stock valve
11.5:1 compression
black mamba 275 cam
arc 32* flywheel
forged rod
26lb springs chromoly pushrods etc
mikuni 22mm
So whats the issue?
I started with a 130 main and 12.5 pilot and the motor ran strong with a couple hiccups towards top end. after 3 minutes of riding I noticed the engine extremely hot so I cut it and pulled the plug. super lean. I adjusted the needle clip in the richest setting still lean. I then turned the air screw multiple times trying to richen it up still lean.
I then went up to a 15 pilot with some hiccups on low end if I gave it full throttle. went to a 17.5 pilot even worse. both pilot changes included needle clip adj as well as air screw. motor still was extremely hot with worse hiccups on high and low end with larger pilots.
I bumped up to a 135 main which is strange since some of my big valve .310 lift motors run fine on 130 according to my golden brown plug and butt dyno.
I set everything to stock needle clip in middle and air screw 2.5 turns out. still no luck motor was extremely hot. I moved needle screw to richest position on the 135 /12.5 still no luck motor runs worse (more bogging and hiccups) than with the 130 main. I turned the air screw in half increments richer with still no luck and a baked engine after 3 min.
Could this be a timing issue? I have done exact setups with 32* of timing running great on the 130/12.5-15 setting???
below are pictures of my plug after no idle time and 3 wot pulls cutting motor after on the 135/12.5 setting with needle screw and air screw in richest positions.
I have checked for vacuum leaks, used a degree wheel for timing
motor ran best with the 130/12.5 combo but would cutout at about 7k and just hiccups and fall back.
Mainly im curious about why its still lean and or hot af! I have never seen a 140 main needed on this mild combo.
thanks for the help!
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