best engines to use for mini bike/go kart?

[Np02]

I am sure that this has been discussed before but posting a new thread will probably get some new responses. I sadly had sold my kart back in November and am now left with my mini bike. It has the good ol' harbor freight 212 and of course it is a little screwy at times. I want to pump a few dollars into it to get it going reliably to the point where I can ride it a good distance without fear of walking it back home. I've tried to do some research but most results are from biased people or sites that are most likely getting a kickback to give the product a good review. This has brought me here to once again ask what the best small engine is that I can put on my bike. It doesn't necessarily need to be as torquey as the 212 and it does not need to have ultra high speed, I'm just hoping to find something that I can trust will work and not crap the bed six miles into a ride.

 

[landuse]

The HF 212 would be ideal. What's wrong with yours?

 

[Np02]

has been having some issues with the carburetor which would cause the bike to shutdown if I let off the gas, as well as the engine backfiring (or something) which would engage the recoil starting cord (which you are pulling) and make it go the opposite direction which not only leaves a pleasant feeling in your fingers and wrist for days, but also has made me replace the starter twice.

 

[frostyflammable]

The kickback could be valve leash that needs to be adjusted. Take the valve cover off, find TDC and use feeler gauges to adjust to spec. I don’t recall the gap off the top of my head but I’m sure someone will chime in.

The non idling (letting off gas shutdown) could be a dirty idle jet (the one below the idle adjustment) and the carb probably just needs a good cleaning too.

I have plenty of 212s on my toys and even operating them outside their designed parameters they seems good to me.

—Dan

 

[tgus3]

I believe the valve lash for both intake and exhaust is .003

 

[JTSpeedDemon]

Yeah, carburetors seem to be the part that's most liable to break down on any small engine. On my small engine projects, the carb seems to be the cause of most problems. Never heard about the starter problem though.

 

[Np02]

what was weird is this started towards the end of last season, maybe two ago, so I purchased a new carb but didn't install it because of the temps outside. The next spring it ran fine and worked mostly all summer until its now acting up again.

 

[J.S.@SMS]

Proper stock valve lash is .006 intake .008 exhaust.

 

[Panhead5496]

I agree with Dan. I have 2 predators; one with the stage one kit and torque converter on a 2 seater yerfdog pushing the large buggy and 2 adults (the engine sits several weeks [occasionally months] with no use at a lakehouse and always cranks in a few pulls) and one on a Baja Warrior with a almost 200lb man riding it all the time and both have no issues at all.

I've had chains break, tires go flat, and occasionally run out of gas, but the engines always fire right up and run strong with no issues. If you have a used predator then maybe the previous owner messed it up somehow. As far as reliability goes, I never worry about the engine messing up on long rides and having to walk home.