Hey guys, I bought the easykart 125 tag engine. It will be here tomorrow. That seller was great to deal with. He sold me the package (even battery) shipped for $468.
any set up or mounting issues I should be aware of? Its gonna go on my 1986 margay expert III chassis with fwb and 40mm axle. i currently run a modded predator so I do know that I will have to run this engine outboard, i think (sprocket on outside of motor). Any help would be greatly appreciated.
I'm the other guy who didn't buy it.
Anyhow, run 8 oz. castor (Maxima 927, Burris, or similar) per gallon of gas, and you can run non-ethanol 98 octane in it too. You'll have to run it outboard, like you said, but the low-rpm engagement clutch should be pretty trouble free -- just lube the inner bearing lightly occasionally. The starter brushes on the TaG part are known to fail, so a backup starter (outboard, handheld) would be a good idea, with the proper nut to fit the PTO nut exposed outboard of the clutch. The KT-100 starters should work.
This has about 2.5x the power of your predator, so be prepared for a learning curve on setup, driving, and handling. The only drawback is the fixed jet carby. If you're just running for fun, ditch that carb (but save it) and put a standard 2 jet Tilly or 3 jet IBEA on there, somewhere around 30mm should work -- just make sure the manifold matches and the pulse hole lines up from block through gasket to carby. Check the reeds occasionally or if performance starts being flaky -- I prefer carbon fiber. Hold it up to a bright light -- if there's more than 2 pinholes, replace it. Also replace if the edges are frayed or feathered. Replacements should be available from major kart shops.
As far as carb tuning, the inner (closest to engine) needle is low speed, the outer, high speed on a tilly style carb. I start with both around 1 turn, then once engine's idling ok and warm, I go on track and tune the following way:
Adjust low speed needle OUT (unscrew) until engine stumbles. This is called 4-cycling because it sounds marginally like a 4-cycle. Then turn it back in until you get crisp accelleration with no bogging, at about 1/8 turn at a time. Then adjust HIGH needle in same way so that at upper end it's 4-cycling, then turn in until you get a clean pull all the way through the rev range. Once the HIGH is set, you may have to readjust the low slightly. When ideal, I look for a small puff of smoke from off-throttle to accellerating out of the turn. Helps to have someone looking for you. I'll link a pic below for what I look for.
NOTE: this method promotes engine longevity, but isn't the MAX performance. Once you're skilled at driving and tuning, you can then start tuning the low and high by ear. It's hard to describe, but when you're right on the edge of being too lean, the exhaust note is more "crisp" or "cracking" and that's ideal, but you're at risk of detonation or seizure if the ambient engine temp or eir temp change. Since you have an air-cooled, the engine temp WILL change as the race goes on, a phenomenon called "heat soak". You'll have to enrichen it slightly on longer runs, at the expense of performance, but to keep your engine alive. That's why liquid-cooled are faster -- they last on the peak longer. Anyhow, that should get you started. I'd replace the diaphragm in the carby -- cheap insurance -- and get some extra reeds (don't drop a screw in the bottom end of the engine) and have fun! PM me if you need more info. The best adjective to describe driving such beasts on asphalt is VIOLENT. Get a rib protector so you don't break ribs. I'm serious. You'll thank me later.
~Ted
