Hi Samir,

Regarding carbs on leopard engines, we’ve never in our testing seen carbs matched better to specific engines. We test all our carbs and if we change the engine we keep our fastest carb on always.   The fastest carb from our experience is the fastest carb.

We race tag senior so I can’t speak to the jr. stuff but I imagine the same principle would apply. However I would also imagine a junior carb is set up different than a senior carb. Couldn’t tell you for sure.

On rebuilds, it also seems to matter how high you are revving your engine. If you are revving it consistently higher you might not get the 8-10 hour life but if lower you may actually get longer.  We’ve had a couple engines go on us around 7 hours and it has been the thrust washer not the piston.

These are my non engine builder prospectives.  Hope this helps.

The motor builders will set the carbuerator for the fuel delivery curve that is right for the way the set up their motors. For driveability and maximum power the carb needs to be rich on the bottom and lean-out as the RPMs rise.

So a motor builder will set the pop-off pressure, fulcrum height and suggest needle settings according to experience or on the dyno.

Certain carbs will just flow more air and therfore they make more power but all can be made to run well. Some motor builders will set/adjust the throttle stop position for WOT at the point where the air flow is at its maximum.

I find that regular maintenance like daily disassembly and cleaning keeps it running good and reliably. Also I recommend a good fuel filter as debris really screws with the operation of a pumper style carbuerator

I will agree with above, your fastest carb will always be your fastest. Test different ones cherish the best.

As for rebuilds, when the bottom lets go you loose the whole motor. So be careful only worrying about compression.

Hey Samir,

I couldn’t tell you those off the top of my head but I believe the pop off on most of our carbs are around 10.  We don’t really mess with the settings at all, just test them one after the other and watch the stop watch.

– Dave