I buy Webra "bully" 35cc engines and rebuild them for the Rcexl ignition modules. I have reworked 5 of them now and bench run everyone of them before offering for sale. The rework consists of throwing the Delorto carb to the side and installing a Walbro WT-540 carb. This is a bolt on replacement but does require relocatioin of the threaded bolt holes that secure the carb to the phenolic insulator ring and paying attention as to not blocking the diaphram pulse port that drives the pump in the WT-540 carb.

I also machine a mounting ring that fits over the strengthening webs on the front of the case where the front bearing race is located. I made my own hub puller for this procedure since the rear hub needs to be removed to install the machined sensor mount. Some have been know to remove the webs to install the sensor mounting ring but I am against it because this weakens the front case and bearing support. The new sensor mounting rig also gives a solid mounting platform for the sensor and keeps your engine in perfect timing at all times. Set it and forget it! I also make a timing ring and press a 1/8' diameter by 3/32" long neodyum magnet in the ring and leave it a sliding fit over the rear hub so I can set the timing with a degree wheel. Once the timing is set with a timing "beeper" at 28 degrees BTDC I then secure the ring into position with a film of JB weld and let cure for 24 hours before running the engine.

I use a Bennet muffler for the Zenoah G-38 and it is a perfect fit. I also make an adaptor plug for the head to accomodate a NGK CMR7H plug that locates the electrode into the combustion chamber at the correct depth for maximum spark and power. My converted "Bully" engines will turn a 3W 19x7 @ 8200 rpm and will idle consistently below 1000 rpm without missing a pop.

I run 92 octane pump gas with Stihl HP Ultra mixed at 40:1 but will soon be testing all my gassers on 100/130 AVGAS.

Here are some pictures of my conversions.

Speedy Gonzales