Duromax 440 build-reving it up!

[Notsoezgo]

I'm going to modify this engine in order to run at higher rpm's safely. This will of course void my warranty, but no worries 👍.

[Notsoezgo]

Unlike my other duromax 440 this one only has a 7 bolt main cover like most gx390 clones such as lifan 420 and predator 420.

[Notsoezgo]

Here are the specs from the owners manual

[slonomo]

I would think that engine with a rev kit and cam would run really nicely. Watch your rpm if you don't use the billet con rod. The smaller carbs on these usually run lean around 4500 or so, so watch that.

[Notsoezgo]

Originally Posted by slonomo

I would think that engine with a rev kit and cam would run really nicely. Watch your rpm if you don't use the billet con rod. The smaller carbs on these usually run lean around 4500 or so, so watch that.

The billet rod has been ordered, still not certain on carb but have adjustable main on order too

[slonomo]

Originally Posted by Notsoezgo

The billet rod has been ordered, still not certain on carb but have adjustable main on order too

My favorite carb for my VC440 was the 28mm Mikuni style carb. If I did it all over again I'd get a VM28 Genuine Mikuni and a mount from EC. The level of adjustability and tunability is excellent on those carbs. And most can be had for around $100, well worth the $ IMO. The stock clone carbs just are not really designed for a golf cart where you are varying the throttle constantly, even the adjustable ones are not that great. You can get them to run decent though.

[Notsoezgo]

The tear down begins, removal of air box muffler governor arm carb linkage springs rocker cover

[Notsoezgo]

Removal of side cover, governor components and oil sensor

[Notsoezgo]

Governor and oil sensor removed

[Notsoezgo]

Originally Posted by slonomo

My favorite carb for my VC440 was the 28mm Mikuni style carb. If I did it all over again I'd get a VM28 Genuine Mikuni and a mount from EC. The level of adjustability and tunability is excellent on those carbs. And most can be had for around $100, well worth the $ IMO. The stock clone carbs just are not really designed for a golf cart where you are varying the throttle constantly, even the adjustable ones are not that great. You can get them to run decent though.

I ordered a genuine honda carb from ARC that raydhd suggested, it has limited idle jet that can be bypassed easily. I'll keep your suggestion for the 28mm mikuni if the honda carb doesn't pan out.