The Hodaka Club Forum

Is there a Resonator Revisited article on how to drill the case on a Model 03 if you’re going to premix?

Also, if both premix and oil injection enter at the same point, thru the carb intake, why does it make a difference whether the oil is mixed into the fuel before it enters the intake air stream or during the process? Just curious. I’m going to be starting my 03 motor rebuild and want to know the “How’s & Why’s” of this issue. Thanks! Victor

viclioce wrote: ↑Mon Dec 14, 2020 7:45 am Also, if both premix and oil injection enter at the same point, thru the carb intake, why does it make a difference whether the oil is mixed into the fuel before it enters the intake air stream or during the process?

Compare the pump in the schematic to a Road Toad. Note that the 03 has two outlet lines rather than a single. Premix will never make it to the left crank bearing without the modification.

OK, Dale. It’s not that I doubt. So what’s the case drilling to be done? Is there some specific directions somewhere? Was there a Resonator Revisited article, or is it just something which has been passed by word of mouth? Victor

viclioce wrote: ↑Mon Dec 14, 2020 12:01 pm OK, Dale. It’s not that I doubt. So what’s the case drilling to be done? Is there some specific directions somewhere? Was there a Resonator Revisited article, or is it just something which has been passed by word of mouth? Victor

The 03 Wombat was designed to get lubrication from the injector pump rather than from premix spray in the crankcase cavity. If you want to run the 03 Wombat with pre-mix and without the injection pump then the left case must be modified to have a lubrication path that all of the other models have.

I don't know of any instructions so can't help there. I do find several posts here on the forum that discuss the modification. It looks like the common recommendation was to send it to a Hodaka machinist to do the drilling. Ron Liddle, Rich Gagnon, Danny Cooke were all mentioned.

I would look at any hodaka engine that isn't running a injector pump and you will see how it is done?? Ace 90, 100, 125 that are not using a injector pump. --------- Clarence

Thanks. I’ll contact Danny Cooke.... Victor

Got it! I understand what to do! Danny told me what to do & I now know how to switch back & forth between oil pump & premix! Victor

viclioce wrote: ↑Mon Dec 14, 2020 6:23 pm Got it! I understand what to do! Danny told me what to do & I now know how to switch back & forth between oil pump & premix! Victor

Good for you

victor how about sharing that info. sounds like something i need to know about.......albert

As sorta explained above, the older Hodakas have an opening in the top of the left crank bearing boss. This allows for lubrications to penetrate the bearing boss & lubricate the left crank bearing. So a hole must be drilled there to allow for premix to lube the bearing.

I don’t know the size of the hole. So what I would do is fit a drill bit into an older Wombat case which has the the hole and find a dril bit which goes in snugly.

Danny said after drilling, if you’re still using the oil pump but need to switch over to premix, disconnect the oil pump cable from the throttle and tie it off to the bars. Then add premix to the tank and the oil pump will stay at idle speed so it doesn’t push too much oil from the tank into the carb. And carry a spare spark plug just in case the plug fouls.

You can switch back and forth as needed, as long as you’ve drilled the top of the left crank bearing boss. Victor