Max rpm for a 79 cc 3 hp lifan motor

[Russ Mason]

I overrode the Governor and the motor reaches 5800-6000 rpm at 28-30 mph. Anyone know what the red line rpm should be? Specs for the motor simply say 3500 rpm, but I’ve no idea if 3500-4000 is max.

 

[berdomb]

For that motor.....no

But i once researched hopping up 6.5 hp motor on a go devil.
Go cart people on the go-kart forums have it down to a science. They know exactly what every part is good to for RPMs. Those little six and a half horsepower motors can make up to 14 horsepower at higher rpms.

Some of this stuff will be true for smaller motors too

I increased my governor's speed to 4200 that was the safe maximum to go to without any replacing parts.
At 4800 flywheel would self destruct
At 5xxx...needed stronger valve springs, etc

By 6000.....half the engine had to be replaced with higher quality parts....pistons, crankshaft, valve train,flywheel, etc
Harbor freight was a favorite engine because it was cheap. Blowing up Hondas would get expensive in a hurry.

Point is, the engine that's designed to run at 3,600 rpm, probably isn't going to stay together very long at much over 4, 000 without some upgrades. Flywheels coming apart can also injure you pretty badly if not kill you....so theres that to consider......especially with something that's between your legs......

 

[Will'smotobikes19]

5,000+ is a no go for cast rods they will shatter if going high rpms.
It might work fine for a while then randomly go boom. I think larger motors break the cast rods easier, But a short stocky rod vs a long rod and more HP is the breaking factor.
If it's the phatmoto type 79cc the rod could shatter cast aluminum porosity is the problem.
Smallest billet rod fits a GX120 or lifan copy unless a shop custom makes one.

Also this: the 212cc predator can get up to 70 mph and 20hp with the right mods.

 

[berdomb]

A recent post from a go-kart forum where
someone blew up a 79cc predator....... Was looking for a new flywheel and can't find one.

Affordable go karts sells a 79cc stage 1 predator for $440..... That has a billet flywheel. So it does appear that's the first step for those engines. Theres actually a little bit of discussion about those engines on go-kart forums it appears as well as some Facebook groups.

 

[sfavartist]

I overrode the Governor and the motor reaches 5800-6000 rpm at 28-30 mph. Anyone know what the red line rpm should be? Specs for the motor simply say 3500 rpm, but I’ve no idea if 3500-4000 is max.

I've been running mine up to 5300 regularly for a year . I cruise a 4800. No prob. I'm not going to tell you that taking unnecessary risk be isn't dumb but it's been fine for me I'm working on my stage 2 predator right now but this has been fine in the meantime on the 44 tooth bracket I'm able to just approach 30 32 maybe

 

[DAMIEN1307]

I've been running mine up to 5300 regularly for a year . I cruise a 4800. No prob. I'm not going to tell you that taking unnecessary risk be isn't dumb but it's been fine for me I'm working on my stage 2 predator right now but this has been fine in the meantime on the 44 tooth bracket I'm able to just approach 30 32 maybe

You won't be getting any reply from Russ Mason...If you had looked at his information at the time of replying to his last entry, you would have seen this....You can see this info by simply hovering your mouse cursor over a posters avatar.

Russ Mason​

New Member
Joined Oct 22, 2020
Last seen Nov 22, 2020

He was here for exactly one month and vanished...lol...Just like my money after my divorce...lol...DAMIEN

 

[Bullfrog]

Unless you replace the connecting rod with a billet rod, I wouldn't bypass the governor.

No clue how high you can actually run one but I had a Briggs engine on my racing kart and the rod was the weak link. The oil dipper would break off and then the rod would break shortly thereafter.

The flywheel is a safety concern but just like the rod, I have no idea what rpm it can actually handle.

 

[Chainlube]

Unless you replace the connecting rod with a billet rod, I wouldn't bypass the governor.

No clue how high you can actually run one but I had a Briggs engine on my racing kart and the rod was the weak link. The oil dipper would break off and then the rod would break shortly thereafter.

The flywheel is a safety concern but just like the rod, I have no idea what rpm it can actually handle.

I run a stock rod on my GX, it hasn't blown up yet and it turns 6700. I changed the flywheel because the lighter ones spool up faster. I see stock flywheels and rods pulling 6000 all the time and have never saw blow up.

As for the OP, probably at the max rpm now.

 

[SirLurksAlot]

I looked for 152f-3 max rpm specs ... All I found were posts in kart forums and the consensus seemed to be that 4000rpm didn't hurt them but going higher had a big impact on reliability. Valve float plus broken conrods and crankshafts were reported. No upgrade parts seem to have been made for them, either . On the other hand, folks on the phatmoto facrbook page seem to get away with it... So I just don't kno. Myself, I'll cruise mine at 4000rpm but no higher.

 

[Barnfresh]

FYI there’s a huge group of Phatmoto motorized bicycle riders that run these 152F engines hard, ungoverned, They spin up 6200-6400 RPM and will run all day long without problem. If you’re interested in the little Lifan 79cc engine check out the Phatmoto (Builds/Mods & Info) Group. They are currently working on sourcing the 3.5hp Lifan 154F 105cc engine to retrofit the bikes.