Custom 70cc engine build

Is it worth it or stupid?

  • YES

    Votes: 19 63.3%
  • Hell no

    Votes: 2 6.7%
  • Kinda

    Votes: 4 13.3%
  • YES

    Votes: 3 10.0%
  • Nah I'll pass

    Votes: 2 6.7%

  • Total voters
    30

Z.hb71

Well-Known Member
Messages
5,784
Hi, if you follow BOTAJELL (shout out to him) and activly read his comments you'd probably know that I've been chatting with him about this build for the last 4+ months but if you haven't here's some back story, 6 months ago my 30.5cc rovan engine blew up from manufacturer error (not enough base gaskets on cylinder head) and I really really really wanted a big bore like a 46 or a 71cc rcmax or alx but I couldn't justify spending the $1600 to $2400 bucks for one and it would take forever to save up for one so I decided I wanted to build one. So now that your up to date let's get back to present day, I've currently got almost all the parts (missing intake, exhust) so I decided to start the thread alittle early to show you what I'm doing. The parts Im using are the Athena HPR cylinder kit (for piaggio), alx crankcase, Zenoah g26pum flywheel, vforce Reed, polini 6202 c4 bearings, wj 71 carb ( eventually will be switched out to a wb3a 25mm carb because that's what Athena recommends to get the full 18 (once done I'll test it on a Dyno to see the real life power) horsepower, black Bone gears 28 46 ratio, moto force head studs, bzm cranksahft, and top racing connecting rod. The motor will be running Klotz super techniplate after break in I want to switch to Amsoil dominator and maybe try Motul 800. This is by no means a totorial it's just to show my work and my goal is not to take anything away from ALX or RCMAX and I don't want people doing this I want people to actually support ALX and RCMAX, I'm just doing this for a experiment type thing. Also don't get the impression that I think I know everything or I'm trying to sound like it because I'm certainly not trying to be a know it all or trying to sound like I know everything, your still with me right?
 

Attachments

Last edited:

dougstar

Well-Known Member
Messages
4,578
Location
KZN South Africa
+1 on how much?
but the whole drive train will have to be beefed up....don't think the standard 1/5 scale car was designed to handle 71cc
so what other upgrades did you go for?
 

Z.hb71

Well-Known Member
Messages
5,784
Curious to know about what you've spent to this point?
1200+ maybe. Probably couldve done it cheaper but I wanted to use the high performance parts and try to match the performance of alx so that's why.
 

Z.hb71

Well-Known Member
Messages
5,784
+1 on how much?
but the whole drive train will have to be beefed up....don't think the standard 1/5 scale car was designed to handle 71cc
so what other upgrades did you go for?
Soon Black Bone Trannny gears, black Bone pinion and spur, and flm super duty cups and dog bones, not sure how the super duty cups will hold but if they break I'll buy Phat dad, bought these because the phatdad ones were out of stock at the time
 

Z.hb71

Well-Known Member
Messages
5,784
1000 on motor still 1400 less than rcmax and alxo_O:eek::unsure:
i spent $300 on a motor
Yeah I planned on spending "only" 550-600 but I wanted to go all out so that's what I get. Also I was over a 4 months period.
 

Z.hb71

Well-Known Member
Messages
5,784
nah thats sweet wish i could spend that but sadly not going to happen:cautious:
i have watched loads of BOTAJELL vids like his way about things ....what a legend (y)
very keen to see your results
Yup he's very helpful and awesome! Maybe one-day you will be able to! I can't wait till it's finish!
 

racerx167

New Member
Messages
2
Hey Z, just wanted to say that I am totally into what you have going on here!!! I give you a ton of credit for taking the extra time(I think you mentioned 4 months) to source out the parts yourself and move forward with such a task. It will be a feather in your cap once completed and is something off the beatin' path. Very impressed all the way around. Have you built any other engines before? Not necessarily only RC, just wondering how you acquired all of your know how for this particular project? I grew up riding and racing two-stroke dirt bikes and am just in love with the simplicity of a two-stroke engine. I was wondering if you could please email me a close-up of your parts pile(having a difficult time with seeing everything that is there). I won't be copying just want to admire your handy work and dedication. I will be following this closely and couldn't be happier for you undertaking and eventually completing your dream engine build!!!
 

Z.hb71

Well-Known Member
Messages
5,784
Hey Z, just wanted to say that I am totally into what you have going on here!!! I give you a ton of credit for taking the extra time(I think you mentioned 4 months) to source out the parts yourself and move forward with such a task. It will be a feather in your cap once completed and is something off the beatin' path. Very impressed all the way around. Have you built any other engines before? Not necessarily only RC, just wondering how you acquired all of your know how for this particular project? I grew up riding and racing two-stroke dirt bikes and am just in love with the simplicity of a two-stroke engine. I was wondering if you could please email me a close-up of your parts pile(having a difficult time with seeing everything that is there). I won't be copying just want to admire your handy work and dedication. I will be following this closely and couldn't be happier for you undertaking and eventually completing your dream engine build!!!
Thanks alot! This is my first engine build and so far ive learned a ton from this! Here's a a photo
 

Attachments

Z.hb71

Well-Known Member
Messages
5,784
Hey Z, just wanted to say that I am totally into what you have going on here!!! I give you a ton of credit for taking the extra time(I think you mentioned 4 months) to source out the parts yourself and move forward with such a task. It will be a feather in your cap once completed and is something off the beatin' path. Very impressed all the way around. Have you built any other engines before? Not necessarily only RC, just wondering how you acquired all of your know how for this particular project? I grew up riding and racing two-stroke dirt bikes and am just in love with the simplicity of a two-stroke engine. I was wondering if you could please email me a close-up of your parts pile(having a difficult time with seeing everything that is there). I won't be copying just want to admire your handy work and dedication. I will be following this closely and couldn't be happier for you undertaking and eventually completing your dream engine build!!!
Hers more
 

Attachments

racerx167

New Member
Messages
2
Hers more
Thank you so much for the close-ups!!! I know that was a bit time consuming but be thankful every picture clearly demonstrates the quality of the parts going into this build. So stoked for you trying to tackle this project YOURSELF!!! I hope others take note of what you are accomplishing here and decide to get creative themselves. To be continued...….
 

Z.hb71

Well-Known Member
Messages
5,784
Thank you so much for the close-ups!!! I know that was a bit time consuming but be thankful every picture clearly demonstrates the quality of the parts going into this build. So stoked for you trying to tackle this project YOURSELF!!! I hope others take note of what you are accomplishing here and decide to get creative themselves. To be continued...….
Thanks for the kind words!!! No problem with the photos! I'm glad I went the extra mile with the parts!
 
Top