Gasket and reed surface lapping
Like I've done with my DLE 20 and RCGF 32 before, I followed Frank Bowman's advice for all Chinese-built gas engines by lapping the carburetor and reed valve mating surfaces in my DLE 30.
For the purposes of this modification I will refer to the above components jointly as the intake assembly.
Lapping is the process of smoothing a flat surface remove undulations and imperfections. According to Frank, many Chinese engines suffer from a lack of quality in this area resulting in hard starting and rough running. To the shop!
The first step is to remove the carburetor and reed valve block assembly from the rear of the crankcase. I had no trouble separating the carburetor from the reed valve cage but the heat block was stuck fast to the rear crankcase and I had to use a fair bit of force (hands only) to break it loose. The gasket didn't survive intact so I ordered a new set and moved along with the lapping.
Lapping started with the rear crankcase.
With a sheet of 320 grit sandpaper taped to my glass surface, I lapped the rear crankcase mating surface while it was still attached to the engine.
Moving along the intake assembly, the next part is the reed valve cage. Here's the reed valve mating surface before lapping...
And after lapping.
And the carburetor mating surface before...
Heat block mating surface before...
Carburetor mating surface before...
Holding the throttle closed to keep debris out.
Carburetor mating surface after.
While I had the carb off the plane I removed the cover to check the filter screen. What a mess!
New gasket set.
Putting it all back together.