Hey, new guy here. Planning builds for 8 bikes on MTB frames. Recommend some parts?

Discussion in 'Motorized Bicycle General Discussion' started by Dirtynails, Jan 7, 2015.

  1. Dirtynails

    Dirtynails New Member

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    So, long story short I am planning on building 8 bikes for everyone in my family. We would mostly be using these to just tool around on 99.99% but to be totally transparent I'm building them as a last ditch "get out of dodge" transportation system juuuuuust in case **** ever hits the fan and the roads are clogged. I only mention this because I want you to understand why I want to build the most durable bikes I can. They need to survive a 90 mile trip 2/3s of which is a windy mountain highway. My family already knows I'm crazy and I don't mind if you guys think that too as long as you will still give me advice on the builds :)

    I can't go with dirt bikes because they are too hard for everyone in my family to learn how to ride (older folks).

    I can't go with bicycles because not everyone in my family has the level of fitness required (heavier folks).

    I can't go with mopeds because they are vintage and aren't reliable enough (been down that road).

    So that leaves motorized bicycles. Worst case if one breaks down it can still be effectively pedaled by one of the younger fitter members. Ok, phew now that we got all of the crazy tin foil hat **** out of the way lets get our hands dirty and talk builds. FYI I have limited experience with bicycles but I have a ton of experience with vintage mopeds and scooters. Please feel to chime in with suggestions on sources, models, company etc. I plan on building every bike as close to a clone as possible for part redundancy.

    Bike: 2014 Diamondback Overdrive Sport 29'er
    Solid company, mechanical disk brakes, decent gears and derailers etc, front suspension, hard tail rear, wide tires, good bang for the buck. I want to buy new and there are a lot of places with last years model still on sale.

    Motor: flying horse 66/80cc kit
    It's my understanding that these aren't actually 80cc right? It seems like all the companies out there are just selling the same Chinese motor under different names. Is that correct or is there one that's better than the others in terms of build quality?

    Exhaust: SBP expansion or custom
    It seems like people are pretty happy with the SBP kit. I have made custom expansion exhausts in the past and its a pain in the ass. I especially don't want to do it 8 times if I don't have to. I am looking for torque to carry people plus gear and a single wheel trailer up hills not looking for top speed performance.

    Carb: how is the carb that comes with the kit? It looks like a dellorto knock off. Decent? Do most people just throw on a high flow k&n knock off and rejet? Anyone ever bore them out or step it up a mm or two? Are there larger intakes available in that bolt pattern or do you have to get creative?

    Ignition: Are the stock CDI's reliable? Are any of the performance ignition upgrades more reliable? It's a fairly cheap part to replace but I would rather avoid replacing them if I can just buy a better one.


    Other random aspects of the build

    Heat/head:
    Anyone here live in a hot state and taken their bike for a long ride in the summer? Assuming you were properly jetted have you ever had overheating issues? If so do you know of any other 50cc heads with larger fins that line up to the bolt pattern of the cylinder? I have a few moped heads laying around but would prefer to be able to just buy 8 pocket bike heads or something.

    Mounting:
    The stock mounting system most people use seems kind of wonky. Unfortunately these bikes are aluminum and I can't weld that but I could outsource it. Is it worth welding engine mounts to the frame or are custom brackets and a nice thick bushing good enough for an abusive ride.

    Chain:
    It seems some people go with a 415 HD chain and I would like to as well but won't you get lateral slop on the gears doing that? Less chain breakages are great but I don't want to get that at the expense of a wrecked gear. Are there other options for durability?

    Case matching:
    I assume the 66/80cc kit is just slapped on. Is there enough material in the case to dremel it out and match the ports on the cylinder? If so have you done it and is it worth it?

    Seat:
    Minor issue but has anyone switched to something more comfortable when under power? I realize bicycle seats are designed for pedaling but hopefully thats not often :p something padded and long.

    Tank:
    I know there's a 4L version for sale for cheap but to be honest I hate the look lol. Anyone found a good source for a long (plastic maybe) tank in the 1-1.5gallon range?

    Well I'm sure there's more that I'm not thinking of right now but that's the big chunk of it. Have two bikes and two engines arriving Monday. Going to build two all the way up. Break in the motors and then do a test ride fully loaded with my brother in law. Can't wait to get my nails dirty again!
     
  2. Greg58

    Greg58 Well-Known Member

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    Re: Hey, new guy here. Planning builds for 8 bikes on MTB frames. Recommend some pa

    Welcome to the forum, it sounds like you have a solid plan. You will get many ideas from a lot of members here that really help. I run the #41 chain on both of my bikes, it has run flawless for almost four years on my first bike. Its a little wide for the sprockets but I've had zero problems.
     
  3. Dirtynails

    Dirtynails New Member

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    Re: Hey, new guy here. Planning builds for 8 bikes on MTB frames. Recommend some pa

    Awesome, thx for the tip on the chain.
     
  4. Davezilla

    Davezilla New Member

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    Re: Hey, new guy here. Planning builds for 8 bikes on MTB frames. Recommend some pa

    Definitely got a solid plan for your builds... i know mountainbikes do have their challenges with space limitations and all (I learned this one first hand) but not too bad once you get one done and can repeat what you did on the others to get things to fit.

    For your questions... Here's my thoughts and answers...

    Bike... Your choice sounds good as long as the frame is 20" or more, anything smaller and you'll need to pull the engine to change a spark plug like me. Carb clearance is an issue on mine too.

    Motor... You're right again, they're really 66 or 70cc depending on wich crank they come with, they're marked and sold as 80cc because these manufacturers count the combustion chamber volume along with the bore and stroke so yes, 80cc, but really 66 to 70cc when you measure with conventional ways. There are a few of these engines that are noticeably better than the rest... Dax engines are really good quality with 1 piece cranks, 40mm stroke, upgraded bearings and run very smoothly, whether or not they're balanced I'm not sure what they do but they do run very smooth compared to others. Neil (MotorBicycleRacing in this forum) also sells a Very good engine that has all the goodies mentioned about Dax's as well as very smooth running. Both excellent engines to start with, especially if you plan on adding more power to them.

    Exhaust... The SBP pipe is one of the best, but definitely the easiest to tune and they make excellent power, arrow's Snake pipe is also very powerful. Other than modified dirtbike pipes, the SBP or Snake pipe is best.

    Carb... the stock NT carb will do just fine and I got one pushing mine up to 40mph easily, unless you plan on laying down some money for a Mikuni vm18 or Dellorto phbg 19mm + manifolds, the stock NT will do very well. another really good carb is the dellorto Sha 14-14 carb and it's clone the RT carb sold on Dax's site... The RT is a bit more responsive than the NT and easy to tune, they're priced very nicely too.

    Head... The Fred head, the Diamond head, or a Hi Hi head from a 70cc Puch all work great for better compression, performance, and keep the engine nice and cool, even after a hard run. Stock heads are ok for stock engines but with low compression and they tend to get too hot too fast.

    Mounting, you definitely want to upgrade here, the stock mounts aren't very rigid to the frame so lots of vibrations are transferred into the frame and handlebars. using solid billet mounts or welding brackets to solid mount the engine to the frame will give the smoothest ride. For the rear mount I used 2 rear mount blocks and did away with the mount strap, made things way more solid and rigid. The rule of thumb for mounting is that the engine should not move if you push it hard by hand, it should be as rigid to the frame as possible.

    Chain... The 415HD chain will do well if you get a good namebrand chain or the 41 chain will also work really well. try to get good quality chains if you can.

    Case matching... If you can do it I'd recommend it, it's pretty sloppy fit and not hard to clean up, there's also a nasty casting ridge at the top of the transfer openings, just cleaning up this ridge and smoothing it will make a noticeable difference, also cutting 5mm off the bottom of the piston skirt on the intake side will help with more port duration and better port timing, going past 5mm can make the engines boggy at low speed so don't go past 5mm here... There's a lot of porting how to's in the high performance section here if you want to go further than just the matching, cleanup, and piston cutting and ramping, but just by matching the transfers, cleaning up that casting ridge, chamferring the ports, and ramping the piston 1mm down at the transfer openings and exhaust port with the 5mm cut on the intake side of the skirt will give you much better performance without sacrificing low speed performance.

    Seat... The Cloud 9 seats are very nice and comfortable, a layback seat post really helps if you're taller. There's a member in here that makes layback seat posts out of solid bar stock and they're very nice, no flexing or bending, they also help absorb any remaining vibration keeping it off the seat area. You can also fill your bars with lead shot if they feel buzzy from engine vibes, possibly not necessary if you got good well balanced engines, but that's a fix if there is vibration discomfort at the seat or bars.

    Tank... The 2L tanks will provide plenty of ride time per tank since these things get very good milage, if you still need more fuel, used moped tanks or replica moped tanks can be found on ebay, you can also mount one of those Honda CRF50 clone tanks if you like the plastic rugged dirtbike look... There are also a few who make custom tanks, but they can get pricy. One cool looking one is the behind the seat mounted mini keg tanks, they hold at least 2L and mount to the seat post out of the way and look great.

    Others will have similar or different opinions about all this, but most of them will be good suggestions and opinions, a lot of it is about how you want them to run and how you want the bikes to look. For the engines and performance, I just mentioned the basics, but a few others and myself can help you build something really fast if interested, there's a lot of talent in here so enjoy...

    Hope some of this helps and enjoy the builds...
     
  5. maniac57

    maniac57 Old, Fat, and still faster than you

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    Re: Hey, new guy here. Planning builds for 8 bikes on MTB frames. Recommend some pa

    Davezilla covered it well.
    About all I would add is you might want to rethink using aluminum frame bikes since they are harder to get the engine solidly mounted and securing the chain tensioner properly is also much harder. With a steel frame, you can easily tack the tensioner for total reliability.
    I prefer the ride as well, but most people will never notice any difference. Engine vibration can cause serious failures with no warning on Aluminum frames too.
    I'd look for a steel frame mountain bike with a normal diamond frame layout and level top tube for ease of building, proper engine mount fit, and best level of hardware for the money. Look for at least good Vbrakes and components.
    Be aware most 29'ers will be a pain to mount a stock ragjoint rear sprocket, and might require a sprocket adapter. The kit sprocket is designed for 36 spoke wheels, and most 29's are different.
     
  6. Dirtynails

    Dirtynails New Member

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    Re: Hey, new guy here. Planning builds for 8 bikes on MTB frames. Recommend some pa

    Thanks for the heads up on the wheels. I really would prefer to go with a 29er if possible. Got a good source for the sprocket adapters?

    About the steel frame. I would have loved to go with a steel frame but I dont know much about bicycles and in my searching all I saw was crap mtb bikes or really high end mtb bikes that used steel. Any recommendations?
     
  7. Dirtynails

    Dirtynails New Member

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    Re: Hey, new guy here. Planning builds for 8 bikes on MTB frames. Recommend some pa

    DUDE. Quality response!
     
  8. mapbike

    mapbike Active Member

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    Re: Hey, new guy here. Planning builds for 8 bikes on MTB frames. Recommend some pa

    A couple things I'd like to add here is, whatever engine kit you decide on you will be well served to chunk the supplied mounting hardware studs and replace them with some quality hardware like the kit that Sick bike parts sells, its a well spent $9.95 for sure.

    http://www.sickbikeparts.com/catalog/product_info.php?cPath=22&products_id=43

    SBP, has a few other things that can make installing the engine easier also, I dont want to give all the credit to just one vendor here because we have several that are very good and I have had great experiences with, spend a good bit of time on the forum here reading and use the search feature to find specifics on what you have questions about, yeah there is a lot of hooplah..... in some of the threads but most have some valuable nuggets strung through them also, and several of us guys on here are normally quick to try our best to point someone in the right direction with info that is usually based on our own experiences with technique and different parts and ways to make the parts work as good as they can.

    Ok enough of that, now for a couple more of my Texas country fella long winded opinions and thoughts....LOL!

    Also I recommend using some Blue thread locker/loctite on all the fasteners and I personally use nyloc nuts on the mounting studs and also double nut them, I have had to many issues with loosing nuts that vibrated off or lose and using crappy kit hardware can get you in a bind as well, I have had a couple rear mounting studs break when trying to get by with the soft kit supplied stuff, the loctite allows you to get the nuts and studs tight and secure without having to over tighten them and stress them to the point that vibration takes a toll on them and they eventually snap.

    These things are just good insurance in my opinion and add to overall reliability.

    Also make sure you have a small propane torch and a small roll of fine wire solder, when you go to tune the carbs that always come with main jets that are to big you will want to save some money and trouble in my opinion by just soldering and re-drilling out the main jet to get the engines purring like a kitten instead of blabbering down the road spitting way to much pre mix and running like your dragging an 80lb bag of cement mix...

    You'll need some wire gauge drill bits for this task and it is a very simple thing to do.

    Here is where I get my bits and the small bit vise to do the job, cheap tools and a simple job to do.

    https://www.widgetsupply.com/product/WB05.html

    http://www.widgetsupply.com/product/SHG3-840.html

    As Dave mentioned it always a good deal to clean the burs up in the intake and exhaust ports, below is another leak to an inexpensive set of drum sanders that will help you get that done with use in a dremel type rotary tool.

    http://www.widgetsupply.com/product/SGR6-1412S.html

    Use good thorn resistant tubes in the tire, grease the bearings in the hubs of the wheels with a good quality grease such as Lucas High Tack Red.

    If you want to make a single speed cruiser bike much easier to peddle I like to replace the sprocket of the cranks with a smaller 36T rather than the big 44T and on the coster brake wheels I will even replace the sprocket on the wheel and move it up a few teeth to a 23 or 24T, this makes the bike way easier to peddle and makes it more like a multi speed bike that is in a very comfortable gear.

    http://www.ebay.com/itm/Bicycle-Low..._Chainrings_BMX_Sprockets&hash=item3a7ac9a6dc

    http://www.ebay.com/itm/like/181623018226?item=181623018226&vectorid=229466&rmvSB=true

    Hope some of this ifo and the parts links will help you out a bit.

    Map
    .duh.
     
  9. KCvale

    KCvale Well-Known Member

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    Re: Hey, new guy here. Planning builds for 8 bikes on MTB frames. Recommend some pa

    If you want something simple to operate and maintain that will run all day long (you mention 90 miles) with a pull start and automatic clutch 49cc 4-stroke.

    It runs on regular gas and reliable.

    Figure about 28MPH direct drive for the less speedy family members, and make a couple of jackshafted 3-speed shifters for those that need more versatility (climb hills, haul ass, or tow another bike).

    That's what I would so if was a worrier like you ;-}
     
  10. mapbike

    mapbike Active Member

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    Re: Hey, new guy here. Planning builds for 8 bikes on MTB frames. Recommend some pa

    I agree KC,

    If he has the funds to invest the most reliable option is gonna be the 4 Stroke set up.

    I don't use them so it never even crossed my mind, I always have the 2 smokers on my mind.

    another advantage like you mentioned KC is the part of being able to run straight gasoline and not needing to worry about 2 cycle oil, in a survival type situation that could be a deal breaker if you could find any oil.

    If at least regular motor oil could be found you could premix with it and get by, but the enemy would see and smell you coming from a long way off...LOL...!!! Sorry DirtyNails I couldn't help putting this in here..

    dnut
     
  11. Dirtynails

    Dirtynails New Member

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    Re: Hey, new guy here. Planning builds for 8 bikes on MTB frames. Recommend some pa


    LOL! Well dont worry I am not one of those zombie apocalypse dudes. We have vehicles at the cabin that would be much better than motorized bicycles. I just want to be able to get us there through clogged streets.

    I totally hear you on the 4 stroke thing and its something i really thought hard about. My problem with it is they are more expensive which on one bike isnt a big deal but on 8 it adds up and I can work on a two stroke with a blindfold and 1 arm tied behind my back. Am I just being stubborn? I know there isnt a huge difference between them i just grew up working on the stinky dirty guys and I love them.


    Edit: If you were going to pick a 4 stroke kit which one would you pick? I dont know much about them.
     
    #11 Dirtynails, Jan 8, 2015
    Last edited: Jan 8, 2015
  12. mapbike

    mapbike Active Member

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    Re: Hey, new guy here. Planning builds for 8 bikes on MTB frames. Recommend some pa

    Ive worked on both throughout my life, and hands down these little 2 smokers are one of the simplest engines I have ever fooled with, super simple and with a few mods like we have mentioned thay can be very reliable, I have several thousand miles on my bike combined and most of what I do to them is just tinkering, I have run a couple like i was trying to hurt them and I did, I have run a couple like I wanted to kill them and I cant...LOL!

    getting a good engine that has good internals and fairly good balance is an important thing, the foundation has to be good or all the rest dont matter much just like anything else in life.

    The engines thatsdax sells are very good ones, good cranks, good bearings and good gaskets other than the intake gasket which I always make my own.

    I know there are other engine sellers out there that may have engines that are very good platforms also, but lately the dax engines have ben the overall best I have had.

    Map
     
  13. Dirtynails

    Dirtynails New Member

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    Re: Hey, new guy here. Planning builds for 8 bikes on MTB frames. Recommend some pa


    Ok thanks,

    yeah i have two motors coming from amazon right now. They are flying horse 66/80cc from bikeberry. Would you recommend canceling those and ordering from dax then?
     
  14. mapbike

    mapbike Active Member

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    Re: Hey, new guy here. Planning builds for 8 bikes on MTB frames. Recommend some pa

    That would be your call brother, but I honestly doubt that the engines you ordered will be as good as the dax engines.

    Its possible that they may work out ok, I haven't had one myself but i'm honestly not a big fan of bikeberry based on experiences some on here have had with them, but other have said they've had good service so... who knows.

    I do know for a fact that Pablo at SBP and Duane at thatsdax are top notch vendors that I have bought serval engines parts and pieces from since 2009 and I have always had perfectly excellent service and not a single complaint or problem with anything I have bought from them, dax does charge a bit more for his engines but they're proven winners and he provides excellent service after the sale and to me that is added value I dont mind paying a little extra for.
     
  15. Dirtynails

    Dirtynails New Member

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    Re: Hey, new guy here. Planning builds for 8 bikes on MTB frames. Recommend some pa

    Yeah was just checking out his site and he says 5 day lead time cause he builds to order and tests the engine. More than happy to pay 50$ extra for that. I wasnt able to cancel both amazon engines but I got one cancelled. I guess I will take a look at the motor when it gets here and if its not bad ill just keep it for spare parts and order from dax. I called and left duane a message.
     
  16. KCvale

    KCvale Well-Known Member

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    Re: Hey, new guy here. Planning builds for 8 bikes on MTB frames. Recommend some pa

    So long as all 8 people can pedal start a 2-stroke and work a clutch you save about $20 each bike going 2-stroke since 4-stroke 7G kits are only $200.
     
  17. mapbike

    mapbike Active Member

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    Re: Hey, new guy here. Planning builds for 8 bikes on MTB frames. Recommend some pa

    Sounds like you have a good plan.

    welcome to this great adventure....!
     
  18. Davezilla

    Davezilla New Member

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    Re: Hey, new guy here. Planning builds for 8 bikes on MTB frames. Recommend some pa

    So with the $20 they save on the kits they can buy pull starters for $15.. Still $5 ahead.... Then another $20 to 25 for a cantrifugal clutch and no more pedaling or popping the clutch...

    Most 2 stroke kits cost around $139 (give or take a few either way)
    Add 15 for pull start... $154
    Add 30 for centrfugal clutch... $184

    Still cheaper,faster, and louder going 2 smoke... :p

    Sorry but I had to... I've spent a lot more than 200 on mine... and most of that's in the engine... Add another $60 for the fred head, $30 or so on copper gaskets, $15 for a pull starter, $25 for a centrifugal clutch, $35 for a KTM pipe, just to tear up and weld back so it fits, and $Who knows how much on other carbs, reed valves, and let's not even mention the extra tools I bought just for this hobby...
    Ok, I guess I see your point now...

    I just prefer 2 smokers myself... scratg
     
  19. mapbike

    mapbike Active Member

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    Re: Hey, new guy here. Planning builds for 8 bikes on MTB frames. Recommend some pa

    Dave with exception to just a couple of things here you told my story......LOL!

    I just wonder how much I eally have spent since fall of 2009 when I built my first one with a BGF Red BAT engine kit I paid $113.00 shipped to my door for, and wouldn't ya know it that sucker is still running though... only about 1,400 miles on it but they have been hard miles or rough dusty roads mainly, but let me tell ya it's a bone shaker and will get retired this summer.

    I'm a 2 smoker on these bikes myself, but I do have two 196cc GX200 clones in the shop and two HF 79cc still new in the box I'm gonna do something with some day.

    something about the 2 strokes having so much power in such a small compact package and so cheap to have and work on.

    Map
     

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