I've been inactive for awhile, here's my current project! 79cc Predator

Discussion in 'Photos & Bicycle Builds' started by Donavan321, Jan 22, 2014.

  1. Donavan321

    Donavan321 Member

    I'm building a predator bike, I've done LOTS of research before starting. I will be running a jackshaft from AGK to drive the rear wheel(unless you can provide me a way/list of parts to make one FOR a lot less that doesn't require welding) This bike original had straight handlebars, I did away with those INSTANTLY...and added my own cruiser bars. I also plan on adding a cruiser seat as well. I will be re rerouting m exhaust so it's under the seat tube, not that it's in the way right now anyway. This huffy has a badge on it that says "HUFFY USA and the american flag above) Everything is STEEL and the welds are BEYOND solid. It's better quality than I've ever seen on a huffy. I cleaned it up after buying it on Craigslist. I mounted it all up and put a new brake cable on and neatly capped the end of the cable. Everything is CLEAN and solid! It really is a beauty. I can't wait to get rid of the ants in my pants building this. I can NOT wait until it is finished! I made MY OWN throttle linkage for the stock carb. I cut a spoke out of an unused VERY shot bicycle wheel. The wheel was black(that's why the linkage is black). So, I cut the spoke out using my angle grinder, bent the ends to the needed shape with some pliers and snapped it all together. EVERYTHING works beyond butter smooth and the throttle response is BEYOND perfect. I plan on only going 35 MAX, this will not be used to HAUL ***, I'm not interested in using it for that purpose. I will be using it to take relaxing cruises with some fellow 2 stroker guys. So anyway that's that. Here are pictures!
     

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  2. butterbean

    butterbean Well-Known Member

    You will need to come up with some kind of 3rd motor mount. The plate alone will not hold the motor under vibration. It will wobble back and forth.
     
  3. Donavan321

    Donavan321 Member

    That's alot more secure and solid than it looks. Many people have built the predator builds with just a single plate such as this, this engine is not that big/powerful and doesn't cause a lot of vibration. I've had it running for several minutes of the frame after mounting even at WOT for a few seconds and it was fine.
     
  4. butterbean

    butterbean Well-Known Member

    Ok if you say so. Big difference between a few minutes and driving down the road. I have a 98cc flathead engine in a schwinn, and there is no way I could mount it securely without a 3rd motor mount.
     
  5. Donavan321

    Donavan321 Member

    Well, as I mentioned before, it's physically larger than a 66cc china girl but puts out about the same power..maybe a little more and hardly vibrates at all. I've been talking to several people on the other forums who have built several predator builds. I'll only be geared to go 35 MAX, I'm not the type of person that likes being loud and fast. It's a valid concern, but it really doesn't vibrate AT ALL. It's a really smooth and quiet running machine. That's why a lot people who do non-kit builds choose these engines to do it with. They could very well be turned into kits down the road, definitely have a chance. I've built, ridden, and have owned several HT motors. They're getting really popular in my area, I haven't seen a SINGLE 4 stroke setup, not even the 49cc Grubees! I'm aiming towards being "that different guy" It should turn out to be nice. I do also, like the china girls, but I'm moving on to something new. I will more likely than not, build more 2-stroke builds down the road.
     
  6. butterbean

    butterbean Well-Known Member

    My bike is custom as well. I'm geared to redline at 32. Stock, my engine puts out 2.5 hp. With the gov removed (got mine with it already removed), it might be 3.5. I still couldn't mount it without a 3rd motor mount. This engine spins at probably 5.2k max and is geared at 12.44:1 with an agk jackshaft. It's a flathead (side-valved) engine, maybe it vibrates a little more than an ohv. Either way, good luck with your bike, bro.
     
  7. Donavan321

    Donavan321 Member

    Have any pictures? And OHV engines vibrate very little(at least mine anyway). I'm hoping the bike works out good, so far everything fits good, I have really good bolts going into my mount plate and it's all solid. A buddy of mine did a harbor freight build before he moved away. I haven't seen anyone use a third mount on any kind of engine especially with all of these Predators. Everyone mounts like me lol. What kind of frame did you use?
     
  8. butterbean

    butterbean Well-Known Member

    I used a repop schwinn frame. Buddy of mine has a 99cc predator (supposedly identical to 79cc in every way except displacement) and he couldn't go without a 3rd motor mount either. He has his #matic bolted to his frame as a 3rd mount. I used an ht motor mount bracket and bolted that to the two holes on the engine where the governor was attached. Maybe it's the frame tube size (skinny frame, my buddy has the same frame I do, in fact I bought mine from him).
     
  9. Donavan321

    Donavan321 Member

    Like I said, if I ABSOLUTELY need the mount I can make one, but I haven't heard of anyone ever needing one for the 79 or 99cc predator. Maybe it depends on the frame you use, plus space inside. I won't be using the matic drive right away, I will be running a jack shaft assembly(not to be confused with the jackshaft for the HT kits that hook up to the pedals) My engine sits VERY securely on the frame, it's ROCK solid.
     
  10. butterbean

    butterbean Well-Known Member

    Yeah, I know what a jackshaft is. I'm using the same one you'll be using, the agk one. Which btw is a great choice, runs very smoothly and no noise, at least not that I noticed. I've only been using it for a few months. Prior to that was using a custom made one similar to the agk one. If you want to gear at 12.44:1 (pretty much optimal gearing for these type of engines), you can run a 22t on the jackshaft input (stock) with a 56t on the rear, or a 28t on the input and a 44t on the rear. I'm running 28 and 44. Also currently running a manic adapter, but thinking about a shift kit and internally geared hub. Not sure about that yet though, as I don't have the cash for it right now.
     
  11. Donavan321

    Donavan321 Member

    Yeah, I'm tight in the wallet too lol. I'm not really even in a position to get the AGK jackshaft, I thought about making my own homemade kind of rig. I can't weld though and don't have access to a welder. So it would be a bit challenging. I think I'll probably just go with the AGK shaft, I really want a Q-matic, but I can't take that kind of beating. I'm only putting in about $50 max every two months INTO my project. I should be getting some more money soon, but I'm really taking my time with this one.
     
  12. butterbean

    butterbean Well-Known Member

    I took my time with my custom project as well, started in December and didn't finish till march or April. It was a little nerve racking, having to wait, but worth it. I built my bike from the bare frame up, installed the bottom bracket and headset myself. Added suzuki hydraulic forks for comfort. Hand picked every single part. Nothing compares to the satisfaction of building from the bare frame up, especially when you don't use a kit.
     
  13. Donavan321

    Donavan321 Member

    I've built a couple of bikes bare frame up myself. Waiting is difficult, I have no patience, I can't even wait a week for a HT kit to come to my doorstep let alone, several months building up my machine. I started my project last month and from the pictures you've seen.....not a lot going on yet. I fixed up my brakes and what not with parts I've kept for years from previous bike builds. I always save parts off of dead HT(only killed a few) and save the gaskets, bolts,washers, nuts, intake manifolds, heads, covers, strip them of good usable parts and then just trash the blocks. I'm hoping to be up and riding by april or may.
     
  14. butterbean

    butterbean Well-Known Member

    Waiting sucks, but for the right bike it's worth it. Compared to a 2 stroke, the preddy isn't going to "blow your skirt up" in terms of performance, unless you gear it super high or add a shift kit of some sort. But the 4 strokes seem to run and ride much smoother and you can't beat the reliability. It will be a bike you will enjoy riding mostly for its differences between the 2 stroke (at least it has been that way for me). After building my 4 stroke, I have no more interest in 2 strokes at all and wouldn't sell it for less than twice what I put in it (have actually already had several offers and one guy offered to pay me whatever I wanted for it). I love this bike that much, I don't really want to sell it at all and probably wouldn't unless I were desperate for cash, which I'm not.
     
  15. ez dave

    ez dave New Member

    79cc predator

    hey man, im new to the forum but not to motored bikes, not to be cynical but while the motor looks great my concern is the frame(mild steel) and the brakes, your concept is great but again the chassis is straight scary even at only 35 mph. you can usually find good cromo frames at pawn shops, garage sales even thrift stores. i found a spcialized stump jumper rolling chassis at a thrift store once for 5 bucks. also your wheels will probably not hold true at the speeds your talking and i know the bearings will disintegrate. i see it all the time on wal mart bikes, any way just some advice, definitely not a dig. later
     
  16. Donavan321

    Donavan321 Member

    Right? See that's what my problem was with the 2 stroke bikes. I've only had one perfect one that was a smooth ride out of all builds and it was 49cc flying horse kit from bikeberry. But anyway, I always say to myself...."I'm GOING to keep THIS bike FOR SURE THIS TIME...and then I ALWAYS end up selling it, I don't WANT to sell it, but I do thinking I won't miss it and I keep finding myself selling whatever I spent the money from the sale of the bike on....and building another bike. I love the sound of the 4 strokes and no one else in my area has a 4 stroke bike that I've seen. I know it will get lots of attention once I start riding it around. I'd like to be able to pedal it too, I'll have to get that wider crank. I don't dare ask a bike shop...People say that's illegal blah blah, dangerous, blah blah. You know how that whole story goes lol. I really can't wait at all.
     
  17. butterbean

    butterbean Well-Known Member

    Even the wide crank might not be wide enough, in fact I'm almost positive it won't be. I had a wide one piece and I had to make it wider. You'll need a table vice (you can do it on the frame if you want, but have a replacement set of bearings ready for the bottom bracket) and a blowtorch. Get a yellow canister for the torch (mapp/pro gas) and heat it at one spot till its red hot and bend it out, then at another spot and bend it in. Let it cool at room temp so it doesn't get brittle and for the love of God don't touch the hot metal. I did and got a quarter sized blister as a reward for my stupidity.
     
  18. Donavan321

    Donavan321 Member

    Trust me I've been building MAB's for several years and have over 100 builds behind me. This is not a typical walmart huffy. I got it from a buddy who bought at a bike store. There is a USA sticker on it. It's a rare find and the frame is very sturdy and has perfect structural integrity. I've only blown 2 wheels in my whole MAB building experience. I lubricate them often and keep them in shape. The front brake is a heavy duty calliper and the pads are very thick. I will also be adding a rear brake as well. Thanks for the input!
     
  19. butterbean

    butterbean Well-Known Member

    Got to be honest, I don't even use caliper brakes anymore. Front drum and rear coaster, but rely more on the front than anything. I always wore pads out too fast, even with a 2 smoker. I recommend a better brake. If you want to stick with what you have, thats your choice. I understand that you have building experience, and I also understand that people have told you the 79cc produces little more power than a 2 smoker, but if this is your first big 4 stroke, I highly suggest you rely not only on what you have heard and what your prior experience tells you. 4 strokes are completely different from 2 strokes in a lot of ways.
     
  20. Donavan321

    Donavan321 Member

    I understand that as well, I have a lot of engine knowledge and have torn apart many 2 strokes. I have some experience with 4 strokes but still understand most of what I need to know. As far as the brake, I will be keeping the calliper FOR now, until I can get something better, I may end up running a sturmey archer front drum like I have in the past. As far as my riding habits, I don't really even use the brakes unless I have to. I'm also an elite member on motorbicycling.com lol, not that it has anything to do with anything, but I've earned that label from skills presented, advice offered, etc. I'm not too active on this forum, seems like my posts don't get a lot of attention. I'm very mechanically inclined and manage to make something work even if it's not supposed to lol. No one told me the 79cc produces a little more power, I know that from experience as well. In my case this engine is only physically larger than a chinagirl and puts out only a little more power. Hardly vibrates at all, smooth running engine, firmly fixed onto the frame. I've built several walmart and other "department store" bikes and I know the type lol. I have to say, I don't have many bad experiences to report using lower end bikes. I mostly build on steel frames, steel wheels. Although, I have done aluminum frames/aluminum wheels...again never had any issues. Never burned up a clutch, I've seized 2 engines(not because of lack of oil or utter negligence on my end, but because I tightened the studs too far and a chip of aluminum jammed the crank shaft. I don't want people thinking I'm going into this project as a complete newbie, I've interacted for several months and researched, got information, etc. If a problem arises, it can get sorted out. Also for the wide crank, my crank clears but my pedals are too short(no foot room) so I think having the wider crank WILL fix the problem, I do have a propane torch(takes longer than MAP gas) and I can bend as/if necessary. I've stripped apart pretty much every happy time engine I've owned, even fabricated my own head gaskets. I've messed with the e clips in the carbs as well, always junk any CNS carb I run into. I usually run #41 roller chain, and run a different fabricated chain tensioner, or just back the wheel up and have the chain tight enough....so I don't have to rely on a "spoke eater". I like running straight plug heads on the 2 strokes too, usually run a 44t or 36t sprocket in the rear. For brakes I use either callipers(if I have to) V-brakes(my favorite) or run a front drum/rear coaster, front drum/rear sidepull, OR front drum/rear V-brake. I'm not trying to sound like "I'm better than you blahh blah" that's not it. I've seen some of your builds and it's interesting to see how everyone has their own intriguing ways of doing things. All of my HT builds have run smooth even when not on the gas, they pull along nicely, I treat my stuff very carefully, clean the bikes after every ride until they are SPOTLESS. I like adding mirrors, performance air filters, old-school speedos, etc. Always doing something to make it unique.
     
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