Custom 70cc engine build

Is it worth it or stupid?

  • YES

    Votes: 21 63.6%

  • Hell no

    Votes: 2 6.1%

  • Kinda

    Votes: 4 12.1%

  • YES

    Votes: 3 9.1%

  • Nah I'll pass

    Votes: 3 9.1%
  • Total voters
    33
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Z.hb71 said:
Can't find 110 or 100 octane which is what they run.
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It should and will run on 95 and up even less I've forget what manufacturers say lol as long as you have compression spark and enough oil to lubricate the engine it really should run

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Teejay112 said:
It should and will run on 95 and up even less I've forget what manufacturers say lol as long as you have compression spark and enough oil to lubricate the engine it really should run

Sent from my SM-N960F using Tapatalk
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Yes it will run but at high rpm it will ping and eventually melt a hole in my piston due to the lack of Octane and high compression. ALX has retarded the ignition to a point we're it will run on 95+ for the end users convineince. I do not want to retard that much because you can possibly loose power. If I wanted to do that, i wouldn't be working on ignition at this point.
mark35 said:
I think it's the same thing mate,, Ron = Research octane number
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Ohh thought it was different.
 
Z.hb71 said:
Yes it will run but at high rpm it will ping and eventually melt a hole in my piston due to the lack of Octane and high compression. ALX has retarded the ignition to a point we're it will run on 95+ for the end users convineince. I do not want to retard that much because you can possibly loose power. If I wanted to do that, i wouldn't be working on ignition at this point.

Ohh thought it was different.
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I hear that

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Z.hb71 said:
Yes it will run but at high rpm it will ping and eventually melt a hole in my piston due to the lack of Octane and high compression. ALX has retarded the ignition to a point we're it will run on 95+ for the end users convineince. I do not want to retard that much because you can possibly loose power. If I wanted to do that, i wouldn't be working on ignition at this point.

Ohh thought it was different.
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Have you checked your compression yet? It didn't look like your squish was going to be very tight from the pic in your other thread, I could be completely wrong though..lol
 
Ok watched the vid. Hes just finding tdc sticking a degree wheel on it and setting up the cdi trigger and pick up. That's straight forward enough. So this unit is designed to advance 25*. 5*base +25* advance= 30* total timing. So you can pick any where you want to set it you just have to remember it advances 25* more. 5* advance isnt much. So just by running this cdi box may eliminate the ping issue. If it pings just move your sensor to retard the timing a bit more. Retard = closer to tdc. So if it pings set it to 29* now your base timing will be 4*. Or at least that's about how I understand how this system is set up.
The guy off ebay got back to me as well. He doesn't sell fixed timing cdi. But he said something off a moped may work.
 
Seandonato73 said:
Ok watched the vid. Hes just finding tdc sticking a degree wheel on it and setting up the cdi trigger and pick up. That's straight forward enough. So this unit is designed to advance 25*. 5*base +25* advance= 30* total timing. So you can pick any where you want to set it you just have to remember it advances 25* more. 5* advance isnt much. So just by running this cdi box may eliminate the ping issue. If it pings just move your sensor to retard the timing a bit more. Retard = closer to tdc. So if it pings set it to 29* now your base timing will be 4*. Or at least that's about how I understand how this system is set up.
The guy off ebay got back to me as well. He doesn't sell fixed timing cdi. But he said something off a moped may work.
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Mmmm ok. Yes a moped one would work just would need a different pick up, here's a question, most moped cdi's only have one adjustment for the whole powerband, if I were to get one, would this be ok? Or should I invest in one that has a high speed timing adjustment and low speed adjustment?
 
You may loose a bit in the bottom but I don't think it would hurt anything, as your more worried about top end performance. Now my 3 biggest saws I use a lot (70,89,118cc) all have fixed timing. 20* for the 70cc and 23* for the 89 and 118cc saws. All 3 start and run great. (With a compression release)
 
Seandonato73 said:
You may loose a bit in the bottom but I don't think it would hurt anything, as your more worried about top end performance. Now my 3 biggest saws I use a lot (70,89,118cc) all have fixed timing. 20* for the 70cc and 23* for the 89 and 118cc saws. All 3 start and run great. (With a compression release)
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Hmmmmmm. What ever ignition I go with what do u suggest to start out timing wise? Keep in mind I'm using E85 Wich I heard will need more advance. Also I'll have plenty of bottom endso even if I loose alittle, I won't notice. So I guess pretty much my only choices are the RCXL cdi or a moped one, there are much better options like the Malossi ignitions and what not but I'm not tryna be broke B4 I'm done with the ignition being those systems are expensive as hell.
 
I (personally) would go with the RCEXL system. 19 to 20* has always been a mainstay of where to start out for timing on static ignitions. With the advance and where you start out I don't think it will be an issue running e85. Remember these systems are favored by flight guys. A lot of them run a gas/ glow fuel mix. Glow fuel= alcohol +nitro+oil. About close to what your gonna have with the e85 eith ot the 20% nitro. I think the system is priced fairly and rather easy to set up. If the hardest thing you have to do is chuck a degree wheel on when you want to play with timing then that's not bad. Actually I'd just come up with a way to in grave a few degrees either way so you only have to degree it once.
 
Seandonato73 said:
I (personally) would go with the RCEXL system. 19 to 20* has always been a mainstay of where to start out for timing on static ignitions. With the advance and where you start out I don't think it will be an issue running e85. Remember these systems are favored by flight guys. A lot of them run a gas/ glow fuel mix. Glow fuel= alcohol +nitro+oil. About close to what your gonna have with the e85 eith ot the 20% nitro. I think the system is priced fairly and rather easy to set up. If the hardest thing you have to do is chuck a degree wheel on when you want to play with timing then that's not bad. Actually I'd just come up with a way to in grave a few degrees either way so you only have to degree it once.
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Awesome, I guess it's better to start alittle retarded instead of advanced so it doesn't ping. I guess the RCXL system has more adjustability being you can put it were ever the heck u want on the flywheel instead of it being limited by a screw like a moped one. I think the RCXL system is probably best for me being I'm not very inclined to wiring. Thanks
 
The hall sensor is the pickup. You need to place a magnet in/on the flywheel for the hall sensor to pick it up. But you cant have any other magnets on it or it will mess with the signal. That's why the vid showed the aluminum ring with the magnet in it. Does your flywheel have magnets built in ?
 
Seandonato73 said:
The hall sensor is the pickup. You need to place a magnet in/on the flywheel for the hall sensor to pick it up. But you cant have any other magnets on it or it will mess with the signal. That's why the vid showed the aluminum ring with the magnet in it. Does your flywheel have magnets built in ?
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Yup it does, wondering if my magnets on my flywheel would work with they're system? If not I'll find something else or make something else
 
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