4hp Engine Tweaking

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PlyFly#14
Posts: 35
Joined: Fri Aug 21, 2015 8:25 pm
Location: New Jersey
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4hp Engine Tweaking

Post by PlyFly#14 » Mon Sep 28, 2015 6:39 pm

Hey guys,

Has anyone started to make any adjustments to their engines? At WOT I get a hesitation, which I assume is lack of gas. I also assume this means I either have a clogged needle or need one with a larger bore.

1 - Have any of you done this before
2- Any idea where to get a new needle jet with larger holes
3 - Any other ideas?

Found a great newly paved private street near me and took the kart out for a spin using TrackAddict app (recommended by Dave) and had a blast. I can see in the data where my hesitation is. @30 and again @37. And yes, that's MPH, so The Flatworks claim of a 25MPH roadster is VERY understated! Enjoy and be safe!
Plyfly#14
I need a bigger garage

Dave
Posts: 33
Joined: Mon Aug 24, 2015 1:52 pm
Location: Middletown, RI
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Re: 4hp Engine Tweaking

Post by Dave » Mon Sep 28, 2015 8:58 pm

Wow! 37MPH?! Did you adjust/remove the governor or anything? We never got over 29 with any of ours. I haven't done any playing around with the 4HP engine performance-wise, but parts should be very similar to a Honda, so I'd start there. I'm not sure if the carburetors are made by the same manufacturer on a Honda as the Lifan, so I don't know about part interchangeability, but the entire carburetor should be interchangeable (I'll see if I can confirm that with some technical drawings) and I know you can get different sized jets for Hondas (the 6.5HP Honda is what I used to use on my racing karts).

If it helps at all, 37 MPH should be 5200 RPM, and 30 MPH is around 4200 RPM with the 12" tires.
Dave
Flatworks Engineer

PlyFly#14
Posts: 35
Joined: Fri Aug 21, 2015 8:25 pm
Location: New Jersey
Contact:

Re: 4hp Engine Tweaking

Post by PlyFly#14 » Tue Sep 29, 2015 1:06 pm

The only thing I've done is adjust the screw that is threaded through the spring (which I do depending on who is driving). I've read up on opening up the case to remove the governor but I'm not gonna do that!
Plyfly#14
I need a bigger garage

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