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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Mkay I got the kill switch (didn't take a photo) and I got the CDI today View attachment 49881
Wayy lighter than I thought which is nice.


Did you ask what the max rpm was for the unit? I know thw earlier versions we could not turn up to 18,000 rpm and higher in the boats. We even dealt with C&H Ignitions on this too They made us a custom one that would but would take a bit too get. Plus you had to run it on 12 volts. Did they how high this ignition would go to?
 
Did you ask what the max rpm was for the unit? I know thw earlier versions we could not turn up to 18,000 rpm and higher in the boats. We even dealt with C&H Ignitions on this too They made us a custom one that would but would take a bit too get. Plus you had to run it on 12 volts. Did they how high this ignition would go to?
Asked rcexl and they said its not limited at all. Even if it's limited to 18k, I really doubt my engine will spin more than 17k cuz the alx 71 spins 16500.
 
When we were experimenting with off the shelf electronic ignitions. We found on the dyno that when we changed timing on top end it would run faster. Same with leaning it down more. So I made an adjustable igniton plate to go on our engine. I would set the high and the timing to what worked best on the dyno. Than mounted a servo with a cable to the high speed needle and also a servo to a movable timing plate on the ignition plate. Click the third channel rocker forward for more and backwards for less. Worked good.
Both ends were at fixed points so it would go the the limits I had set both ways. Probably over complicated things for you but I enjoyed doing it.
 
When we were experimenting with off the shelf electronic ignitions. We found on the dyno that when we changed timing on top end it would run faster. Same with leaning it down more. So I made an adjustable igniton plate to go on our engine. I would set the high and the timing to what worked best on the dyno. Than mounted a servo with a cable to the high speed needle and also a servo to a movable timing plate on the ignition plate. Click the third channel rocker forward for more and backwards for less. Worked good.
Both ends were at fixed points so it would go the the limits I had set both ways. Probably over complicated things for you but I enjoyed doing it.
Wow! Over complicated for me but interesting
 
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So the RCEXL ignition wiring diagram sucks ass so here is how its supposed to be IMG_20190301_193418.jpg
And if that isn't obvious enough
IMG_20190301_193459.jpg
IMG_20190301_193745.jpg
Also u need a specific battery just for the CDI and stuff so the battery lead off the kill switch goes to the CDI battery, the battery for the servos connects to the off on switch and that goes to the receiver as it normally does. Just thought I'd post this for future reference and if any y'all do get a RCEXL CDI, this could help.
 
so my hi flow kit has been installed. The fuel line isn't cut or routed yet because I don't know where the carb is Gunna end up but there's the basic idea. Don't pay attention to my nasty ass fuel tank, I know Its hideous.
50208
so here the plan with the rest of the build, its getting canceled. just kidding, so what I'm trying to do is, in 3 weeks some family is coming over and they know about this build and obviously want to see it run like everybody else, so I'm gonna try my best to get this whole thing finished before or when they come. I have enough money for the rest of the parts, the challenge is getting the parts in time, installing em, making sure there's no problems or potential problems ect ect ect. definitely not impossible but a challenge, and as yall probably know ( or u should know) I love a good challenge :p:devilish:
 
mmmmmmmmkkkkkkkaaayyyyyyyyyyy T - 2 weeks LOL. this week ill try to get all the custom work such as exhuast, clutch housing, intake manifold, exhuast flange, velocity stack drilled to fit the wj71 19mm carby, crankcase clearencing for the crank, gears for ignition drilled, hall sensor mount cut out, flywheel counter sunk, exhuast brackets cut out, i think thats all. its alot but its not too hard. this is gunna be more of a challenge than i originally thought lol. 2 questions, first what types of shops would do this type of stuff? second would countersinking this part of the crank screwup the balance?? i want to drill the top part of the hole wider (only the top part not all the way thru the hole) to allow the flywheel nut to screw on to the crank. i do not believeit will mess it up cuz its directly in the middle but i could be wrong. 50357
the red part i wanna drill slightly wider ( not all the way to the magnets which aare those little circles) and slightly deaper to allow the nut to thread onto the crank
 
mmmmmmmmkkkkkkkaaayyyyyyyyyyy T - 2 weeks LOL. this week ill try to get all the custom work such as exhuast, clutch housing, intake manifold, exhuast flange, velocity stack drilled to fit the wj71 19mm carby, crankcase clearencing for the crank, gears for ignition drilled, hall sensor mount cut out, flywheel counter sunk, exhuast brackets cut out, i think thats all. its alot but its not too hard. this is gunna be more of a challenge than i originally thought lol. 2 questions, first what types of shops would do this type of stuff? second would countersinking this part of the crank screwup the balance?? i want to drill the top part of the hole wider (only the top part not all the way thru the hole) to allow the flywheel nut to screw on to the crank. i do not believeit will mess it up cuz its directly in the middle but i could be wrong. View attachment 50357
the red part i wanna drill slightly wider ( not all the way to the magnets which aare those little circles) and slightly deaper to allow the nut to thread onto the crank

YOu need to take that stuff to a local machine shop . As for the fly wheel the red area should be ok balance wise so long as the machine shop keeps everything centered .
 
I think I'll bring the exhuast to sum cheap ass exhuast shop to get welded and they might do it for free. I honestly don't care how nasty looking the welds are because it's a temporary exhuast, as long as it don't leak or break, it'd fine
 
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