Custom 70cc engine build

Is it worth it or stupid?

  • YES

    Votes: 20 62.5%

  • Hell no

    Votes: 2 6.3%

  • Kinda

    Votes: 4 12.5%

  • YES

    Votes: 3 9.4%

  • Nah I'll pass

    Votes: 3 9.4%
  • Total voters
    32
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Seandonato73 said:
Just a base line for compression as you don't know the ratio. I know I can run high test and not have an issue at 195psi. If its higher i normally jump up to race gas. The e85 should be fine for a bit more compression. Kinda hoping @lorraine or @Polar_Bus to jump in here with some ideas. Short vid possible ?
Click to expand...
Not sure if running 91 would be a good idea, cuz it may start pinging cuz of the low octane when blipping the throttle. Not sure tho. Tomorrow when I go out to play with it some more I will record a vid (too late, cops will probably get called if it does fire)
 
Z.hb71 said:
Not sure if running 91 would be a good idea, cuz it may start pinging cuz of the low octane when blipping the throttle. Not sure tho. Tomorrow when I go out to play with it some more I will record a vid (too late, cops will probably get called if it does fire)
Click to expand...

That would be a good sound!.....Sirens an cop tells you to freeze ,put the remote down!....LOL
 
Z.hb71 said:
We're not that cool round here ? nothing over 91 lol. I wish I had access to 110 race gas honestly, so I wouldn't be stuck with e85.
Click to expand...

Back in the 80's ,some of my friends use to race 250 Yamaha flat tracks ,they use to mix aviation fuel in with their gas ,would
not recommend it ,because I have no clue what their mix was ,you might can try some type of racing fuel ,Sean has a damn good
point on the octane though!....(y)(y)
 
Z.hb71 said:
Can't adjust idle timing, it's always 5 degrees before tdc. The timing I can adjust is top of the rpm range I believe, and it starts at 5deg and advances up that way. And it's not backfiring, it's popping like if I had the choke on, just for a shorter duration
Click to expand...
Ahhh sorry don't know much about these rc gasser engines lol
cbaker65 said:
Back in the 80's ,some of my friends use to race 250 Yamaha flat tracks ,they use to mix aviation fuel in with their gas ,would
not recommend it ,because I have no clue what their mix was ,you might can try some type of racing fuel ,Sean has a damn good
point on the octane though!....(y)(y)
Click to expand...
Used to run some av-gas in my dirt bike, was a 4 stroke though definitely was the good stuff, and nice not having to get octane booster.
 
D3MON said:
Ahhh sorry don't know much about these rc gasser engines lol

Used to run some av-gas in my dirt bike, was a 4 stroke though definitely was the good stuff, and nice not having to get octane booster.
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Wonder how av gas would fair in my engine, I hear it's a clean fuel and runs good ? That is if I could get some.
 
dougstar said:
Hey z you did all thatquietly ? nice 1 m8?
Id have to say id start with your cdi battery?
Make sure you have a good seal on your carb and manifold?
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Yeah didn't want to say anything or make any predictions of anything cuz I probably would have fekd myself lol. I'll start there at the basics and if it's not started then dive deeper
 
Z.hb71 said:
Yeah didn't want to say anything or make any predictions of anything cuz I probably would have fekd myself lol. I'll start there at the basics and if it's not started then dive deeper
Click to expand...
Good thinking coz i would have been on your case????
Just now few day back i changed my air filter on my reed block ? and the carb bolts were a bit short only 3mm thread to lock it down?.......i guessed it and went to the bolt shop asked for 5mm longer? turns out was to long coz the manifold vstack carb were not sealing 100%?? any way put a washer bot a seal . But waht iwant to say my motor doing the same pop pop little rev die ......pop pop rev die make sure u you got that good seal?
 
looks like if you got juice to carb and trying to fire up on e85 you might not have enough heat in stove. flip rig upside down with plug out and pull over a bunch of times to clear slug hole and lower crankcase, put plug back in and give it a few slow pulls to recharge fuel pot in carb. NOW open throttle wide open and spray in 18:1 mix of gas and oil , Don't flood but a nice spray. The e85 is in carb now ready to take over for the gas start. The rich oil mix in gas start spray will knock the ping out on startup. I always start my corn juice drinkers on gas first . Cold corn juice motors need a really fast start rpm and with a recoil its tough to do. start on gas run on the juice..... 110 octane is not your friend ! remember the higher the octane # the slower it burns! . Only use enough octane to get the knock controled, No more. using ultra high octane fuel in a motor that does not need it , You get lower power ....NO JOKE.. If it still does not start you might of left the bong water in pipe!
 
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corn juice said:
looks like if you got juice to carb and trying to fire up on e85 you might not have enough heat in stove. flip rig upside down with plug out and pull over a bunch of times to clear slug hole and lower crankcase, put plug back in and give it a few slow pulls to recharge fuel pot in carb. NOW open throttle wide open and spray in 18:1 mix of gas and oil , Don't flood but a nice spray. The e85 is in carb now ready to take over for the gas start. The rich oil mix in gas start spray will knock the ping on startup. I always start my corn juice drinkers on gas first . Cold corn juice motors need a really fast start rpm and with a recoil its tough to do. start on gas run on the juice..... 110 octane is not your friend ! remember the higher the octane # the slower it burns! . Only use enough octane to get the knock controled, No more. using ultra high octane fuel in a motor that does not need it , You get lower power ....NO JOKE.. If it still does not start you might of left the bong water in pipe!
Click to expand...
Thanks I'll try that aswell.
 
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