engine tweeks to increase hp

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I don't know IF .075" is a good number, as each head I have done is a different measurement depending on the spark plug to piston clearance. I use a modeling clay to check the clearance.

I only noticed this, when buying multiple kits???????
 

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rainy day today so I pulled the heads off three engines. comp on 2 stock engines is 55lbs. the moded engine is 100lbs.
stock head is 12.1 and the shaved head is 5.8. I cut .075 off:eek: have over 137 miles on the engine runs great will pull the front wheel about 2 inches off the ground if the throttle is open, when first started.


nice mod,but i,d watch the bronze bushing.i moded my engine and after time the bushing compresses{soft metal}and creates a gap,after that it,s only a matter of time befor it dissintergrates.watch for a tick,tick sound that matches the rpm of the engine.
 
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I'd recommend premium fuel anyway for any performance mods. Compared to a car, the cost difference is minor to get the premium. Ever since I raised my engine RPM, I run premium now. It runs smoother and quieter with 93 octane, and doesn't ping like the 87 octane does when over the stock 3600 RPM. I'd rather pay a few more cents on good premium for a performance engine, than risk blowing the engine on cheaper gas.
 
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Hey guys.
Heres a simple mod that adds more umph. It's the bottom jug gasket. Its' thicknes as stock is around 1.50mms. I replaced it with a proper oil imperveous compressed cardboard gasket that's only .75mms thick. This not only raises compression it also alters both ports timing and increases HP and performance no end. I've been running this on a 70cc HT for 2000ks and couldn't by more happy with it. I've also done all the usual mods on exhaust and carby and juice bottle and have reached 57.4kph on a 44t sprocket.

Happy riding.
 
Hey cabinfever1977.
I also have a 48cc running on a 44t and have had it up to 62kph. Don't get me wrong, I'm not skietting but I reacon the 48t's rev a whole lot more than the 70t's, a lighter piston may be the culprit, but I've never been able to get it to go up steep hills without having to peddle. All the mods I've done on the 70ty has given me a huge increase in tourqe. There ain't been a hill I've come across yet that I can't go up at atleest 43kph, in fact the harder the hill, the harder it seems to accelerate. These little engines may at first glance appeare to be somewhat fragile and poorly finished but with the right amout of attention in the right areas offer enormous potential.

happy rides
 
Shift kit is the best mod you'll ever do for these things. Keeps you in the sweet spot of the RPM band, and is nice to cruise without screaming the engine all the time.
 
i have a gutted pipe, no head gasket, drilled holes in the plastic intake cover, needle clip on the highest notch. engine runs really well, does a little wheelie when taking off under certain conditions, top speed around 60km/h. some of these mods like the pipe and removed head gasket might reduce engine life, but the motor's are cheap and i care more about going fast than i do about going far, so its all good.
 
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