Motorized Bicycle Engine Kit Forum  

Sponsors



Go Back   Motorized Bicycle Engine Kit Forum > Motorized Bicycle > Motorized Mountain Bikes and Road Bikes

Motorized Mountain Bikes and Road Bikes Motorize a full suspension mountain bike to get a smother ride or for a little more speed try motorized road bicycles. This section is for sharing ideas on motorizing your mountain and road bikes.

Reply
 
Thread Tools Display Modes
  #11  
Old 09-03-2016, 05:46 PM
2Slow4U 2Slow4U is offline
Motorized Bicycle Member
 
Join Date: Aug 2016
Location: St.Louis
Posts: 22
Default Re: Redbox Racer post build build thread

Haha the logic with the gas tank is perfect. I only wish it was my biggest problem.

I don't think you should worry much about doing a bad port job, all I did was "clean" it up and take all the rough stuff out. I think as long as you don't push down too hard it will be fine. That's coming from me who had all the grace of Operation Dumbo Drop I didn't do a good job and it still seems to be ok.

The tachometer is a ebay special I got for 10 dollars shipped that's been rebranded by a bunch of companies. I got my money back within like an hour of when I requested it from the seller so that was cool. I'm debating getting another one of the same or getting an "expensive" one. I think it broke because there was just too much raw power going to it and it couldn't handle it. Haha I just chock it up to the high quality Chinese quality control. It only lasted about 2 rides before pooping out. It's still displaying the same thing it did from when I last posted, surprised the battery hasn't died yet.
Reply With Quote
  #12  
Old 09-03-2016, 06:40 PM
2Slow4U 2Slow4U is offline
Motorized Bicycle Member
 
Join Date: Aug 2016
Location: St.Louis
Posts: 22
Default Re: Redbox Racer post build build thread

So I tried to fix the striped out head studs with Helicoil.

The bike is sitting in the garage with parts laying all over the ground.

I got it all drilled and tapped with the Helicoil installed just fine except for the fact that I put in 2 of the 4 in way crooked. I used the philosophy of measure 0 times and cut 8 times.

When I drilled out the original threads the bit went right through it, but when I tried to drill through the Helicoil to fix it.. well it didn't happen. It's much much stronger. I ended up snapping the end of one of the drill bits and cutting out a chunk of the cylinder. It's pretty much borked.

So I guess now I have to get a new crank case body. On the bright side I still have 5 Hexicoil inserts that I can put on the new one and they will probably be the strongest part of the engine and it's one less thing to worry about.

I can also replace the bearings and do whatever when I have the engine apart.
Reply With Quote
  #13  
Old 09-04-2016, 03:58 AM
ZipTie's Avatar
ZipTie ZipTie is offline
Motorized Bicycle Elite Member
 
Join Date: Jan 2016
Location: Mpls Mn
Posts: 503
Default Re: Redbox Racer post build build thread

Your killing me with your ups and downs and your cool attitude toward total don't give up and fix fails. Remember you brought this whole problem on yourself by venturing into uncharted territory of Chinese cast aluminum. I think your tach just committed suicide if you want my opinion, id get another of the same but with a better attitude.

Parts laying all around the floor... since when does that happen when working on a motorized bike. I have parts plus tools... rags, paint cans, flashlights, drills so you triple the mess here. Ha. Takes me longer to pick the stuff up all over the floor than actually doing the work I set out to do. I just installed a throttle on a new build I am working on and I counted some 38 tools on the floor mixed together with metal shavings after I was done, darn big mess every time. BUT...nothing is worse than a crooked helicoil when one goes for a straight one. Never used one here and doubt Ill ever get the pleasure of messing one up, cause I know i would mess up ahead of time and just have the whole engine taken to a scrap yard in hopes of saving valuable time and my pride, a mans got to know his limits when it comes to Chinese 2 stroke engines, and I know mine...clutches, carbs, grease, cables, air cleaners, Heads are fine along with sprockets and chains and that is it. I wont touch engine bearings, pistons, ports or I would need a bigger swear jar installed in my garage. I would buy a 79.00 engine faster than you could say Helicoil 3 times and save the borked engine for spare parts or a conversation piece. As far as Measuring 0 and cutting 8 times, I just do every operation twice cause I always screw up every install once no matter how simple it seemed at first. Although I am getting better and have first time successes now and then nowadays on these motorized bikes. They are the definition of finicky in not too tight not to loose. Anyhow your posts are like therapy to me and no doubt many others in the future that we and our bikes combined with our incredible mechanical skills are subject to many fails and some wins. Just remember 2slow4u...that it is all ok as long as your gas tank isn't upside down more than once a day and only in 10 second increments while driving down the road. Now that is some serious Motorized Bike philosophy right there.
__________________
"One pull and It's on, one snip and its off"
“Lets not get too technical”
Reply With Quote
  #14  
Old 09-04-2016, 09:22 PM
2Slow4U 2Slow4U is offline
Motorized Bicycle Member
 
Join Date: Aug 2016
Location: St.Louis
Posts: 22
Default Re: Redbox Racer post build build thread

One of the reasons I like the bike so much is that there is always something I can work on to improve it and I can do "mods" based on my current ability. Even though I'm not where I want to be i'ts fun looking back and seeing how much more I know compared to when I started.

These engines are nice because they aren't some $10,000 race engine and it's cheap to work on/learn. Although I've probably already spent more on repairs than a new engine would cost haha. These are good because I like fixing stuff, although it would nice be to able to ride every once in a while.

Maybe I can say if the gas tank is upside down or not to describe how good the repairs went heh.

Last edited by 2Slow4U; 09-04-2016 at 09:37 PM.
Reply With Quote
  #15  
Old 09-05-2016, 02:47 PM
ZipTie's Avatar
ZipTie ZipTie is offline
Motorized Bicycle Elite Member
 
Join Date: Jan 2016
Location: Mpls Mn
Posts: 503
Default Re: Redbox Racer post build build thread

Precisely why especially these engines are so refreshing to play with and work on as a hobby. The simplicity and the cheap cost of parts and or entire engines combined make for no problem scenarios for experimentation, customizing, fixing, and self inflicted destruction.
Plus upside down gas tanks are a totally free bonus.
My sons parasitic gas tank flipped the other day and he blamed it on me because...before I installed it on his bike I put a piece of duct tape under it to keep his paint from getting scratched up. (Good intention here) Then I accidentally tipped his bike over one day to his dismay but we saw no damage. However such jarring action caused a tiny tiny , gas leak at the stud and the gas turned the tape adhesive into a new top secret lubricant. When his tank flipped upside down suddenly while riding...he immediately remembered all the dumb things I did and connected all the dots and rightfully blamed me for it. I denied it all with a crooked smile and then burst out laughing and said I meant well as he glared at me and proceeded to grab my spare gas tank hanging on the wall and in his words, install it the right way. So he is, as you are, an official member of the upside down gas tank club. New members...Please sign up below...

I am an official member of the upside down gas tank club.


--------------- -------
Forum name. Date.
__________________
"One pull and It's on, one snip and its off"
“Lets not get too technical”

Last edited by ZipTie; 09-05-2016 at 02:55 PM.
Reply With Quote
  #16  
Old 09-05-2016, 03:16 PM
mogollonmonster's Avatar
mogollonmonster mogollonmonster is offline
Motorized Bicycle Elite Member
 
Join Date: Aug 2015
Location: Overgaard AZ
Posts: 468
Default Re: Redbox Racer post build build thread

High performance parts are a must! I see your bike also drips with them. I recently had to make a set of high performance bushings for my motor mount.

Port surgery is no big deal, although I must recommend skipping the power tools in favor of a set of needle files. You can always take more off, it's putting material back on that's hard. My next trick will be piston mods like notching and ramping.
Reply With Quote
  #17  
Old 09-05-2016, 10:46 PM
2Slow4U 2Slow4U is offline
Motorized Bicycle Member
 
Join Date: Aug 2016
Location: St.Louis
Posts: 22
Default Re: Redbox Racer post build build thread

@ZipTie That's a good story, welcome to the elite club!

@mogollonmonster yea I agree, power tools are easier but make it a lot easier to mess stuff up.

The more I read about bearings and replacing internals the more I get bogged down on info and I can see the price shoot up. I'm starting to think a new engine will be cheaper in the long run and better on my sanity.

Where's the best place to get one? The only thing I can find from the sponsored links are kits and not just the engine.

These engines pretty much the same right? just need to make sure the head bolt sizes. are the same.
__________________
http://imgur.com/a/nXkoA/layout/grid
Founding member of the Upside down gas tank club
Reply With Quote
  #18  
Old 09-06-2016, 04:32 AM
ZipTie's Avatar
ZipTie ZipTie is offline
Motorized Bicycle Elite Member
 
Join Date: Jan 2016
Location: Mpls Mn
Posts: 503
Default Re: Redbox Racer post build build thread

Hey I'm not in that darn club, but i did cause my son to join the upside down tank club, so maybe I'm a honorary member or a surrogate member.
Please know i am no engine expert, but I go for the ones with a balanced one PC crank and a 40 mm stroke. All is a bit better balanced, and the rod i believe connects to the middle of the piston too, for less funky vibration and a tad more horsepower I'm told. They go by name of PK80 or called by some sellers BK80 etc run about 140.00-150.00 with free ship in most cases. Plus has 8 mm mount studs etc. Dax engines are good but his web site confuses me a bit.
its a reasonable priced quality engine with hex bolts throughout too I've Purchased balanced engines from bekit on eBay or try speed 66.com a forum sponsor with a ad here can help you with a real good one pc crank engine with the same features I believe.
Heck i get the whole kit as the stuff with it is pretty much free to you and never hurts to have spare parts laying around (like gas tanks) cdi carbs etc. and the chain guard can make a good bread knife I hear.
or just get the cheapest engine money can buy. Kapluey...brrrrr...kaboom.
Something I haven't heard yet... Thankfully.
__________________
"One pull and It's on, one snip and its off"
“Lets not get too technical”
Reply With Quote
  #19  
Old 09-06-2016, 04:59 AM
ZipTie's Avatar
ZipTie ZipTie is offline
Motorized Bicycle Elite Member
 
Join Date: Jan 2016
Location: Mpls Mn
Posts: 503
Default Re: Redbox Racer post build build thread

Ps. 2slow4u...I looked at your pictures and a few odd things come to mind.
1 Your tach blew because you have the 5 feet of spare slack wire wound too many times around your steer tube causing a severe electromagnetic field interference thus the digital overload. Also now your bike is a giant electro magnet as it rolls down the street, it will no doubt collect every wayward nail in the gutter and street causing an increase in flat tires.
2 Wipe the bike grease off your camera lens before taking more shots.
3 Your plug, head and head gasket are hopelessly covered in a mixture of un-burned and fried fossil fuel, plus unknown black crusty stuff. Looks perfect to me. Carry on.
He hee


Zip
__________________
"One pull and It's on, one snip and its off"
“Lets not get too technical”
Reply With Quote
  #20  
Old 09-06-2016, 07:06 PM
mogollonmonster's Avatar
mogollonmonster mogollonmonster is offline
Motorized Bicycle Elite Member
 
Join Date: Aug 2015
Location: Overgaard AZ
Posts: 468
Default Re: Redbox Racer post build build thread

Call Duane at that's Dax, get an FS80, it'll run you about $150 shipped. Balanced crank, 40mm rod, grade 8 hardware throughout. Best bang for your buck.
Reply With Quote
Reply

Tags
slow

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -5. The time now is 08:58 PM.


Sponsors

Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
MotorBicycling.com