Engine Mount and Frame

[Small Engine Technician]

Hi,
My name is Dylan and I am looking for some help info after doing some research of my own, and still feeling as though things just didn't quite make sense. So...

#1) I need some advice on the design of my frame (Fitting the engine, dimensions, etc.)
#2) Can I use a lawn mower engine 3.5HP and is it a good idea? If I can, how do i mount it to the engine mount? If I cant, what is a good CHEAP alternative.

I would really appreciate some responses,
Thanks Again,
-Dylan

 

[Russ2251]

Horizontal shaft should be #1 on your list.

 

[robbie]

I agree. As a beginner, you'd be better off learning basic bike design first, rather than trying to rework a lawnmower engine, which would require a weird motor mount, a new oil dipper, and a refitting of the carburetor.

Look on craigslist for old tillers, edgers, etc. A lot of them will have 3.5 to 5 hp engines. Even if you find one that doesn't run, it will be easier to make it run and fit it to a bike, than to make a lawnmower engine work.

 

[Russ2251]

I would really appreciate some responses

Your turn...

 

[Small Engine Technician]

Sorry, for the late response, i had some difficulty logging in. I really appreciate the energy and efficiency you guys put into the responses. I think i will take the advice on not using a lawn mower engine, and using a horizontal shaft. I was also wondering whether you guys could give me some sort of idea on how to build my frame, or atleast point me in the right direction. I am a very visual learner, so images and videos work the best. I saw the one on this website (the example one) and was just hoping for something with more exact dimensions. Thanks Again, Dylan

 

[souperman000]

Just scrounge around on the forums. Use the search function and stuff. There are a ton of designs scattered throughout posts on this site.

 

[kaymo]

dude, its YOUR frame. we have no idea how you should build it because you havent told anyone what you want!

do you want a mini chopper? a mini crotch rocket? what sort of general look do you want?

can you weld? do you have a welder?

is this your first project? if so, maybe its best if you find something to fix before you go building full custom. it will give you more experience for building new stuff to have fixed broken old stuff. i am not trying to discourage you, but if you are looking for that much general advice, maybe you need to start with a more specific project to tackle first.

i wish i had taken on less of a project my first few times. i tried starting from nothing and basically got nowhere. after so many projects, you learn a lot more about choosing projects and goals and getting them more realistic. remember the more projects you complete, the more you can begin!

 

[Small Engine Technician]

Kaymo,
I want to thank you for the help. Being REALLY new, this response was extremely helpful. I do have a welder, its a Mig and Flux welder, I am looking to build a mini chopper style. I see where you are coming from about fixing broken projects before going full custom. If this is the case, do you have any recommendations on something less than going full custom. This is my first project, and i want to thank everybody for all their patience with me. Thank you all so much, -Dylan

 

[Doc Sprocket]

Why not take a cruise through your local CL, buy and sells, or whatever- see if there's a bike out there that needs work. Or maybe just has a frame you like that you can rework to suit your tastes. Either way, you could find a deal on a "good start" that can get you going without being overwhelmed.

 

[robbie]

If you're looking for general knowledge of how a mini bike is put together, look here: http://www.diygokarts.com/bike-plans/mini-bike-overview.html

Or here:

http://www.sfu.ca/~jst4/plans/docs/bikes/Wren Mini Bike Plans.pdf


Somebody already mentioned welding. To weld or not to weld is a really huge question. An equally important question is bending. If you don't have a tubing bender you'll need to either make everything with mitered corners or find raw materials with bends. I just finished converting an electric pocket bike into a 49cc mini by using an old lawnmower handle. It was cool because the handle was pre-bent, so all I did was cut and weld to produce a nicely bent frame. For future projects I really want to get a bender, but you can build some really nice stuff out of pre-bent junk.

 

[kaymo]

robbie makes an excellent point. i do not have a bender, but i am constantly doing projects that have bends in them by cutting up old bends, whether its exhaust work or cage work, i weld everything

listen to toystory, search craigslist extensively. use searchtempest.com to widen your search. look for the term "project" because it means someone else has already spent time/money/blood/sweat/tears doing something and still hasnt finished it, or simply couldn't. find a project with lots of extra parts. find one that someone doesnt have ANY intention of getting back to. if you call and they say they will just keep it if they dont get enough, ignore it because they arent looking to sell!

in this economy people need cash and it gives us builders a lot of things to play with. make sure you have 100 dollars in your pocket when you go looking and lowball anyone and everyone. tell them you only have 80. or 60. ask them questions... maybe you will discover why they are selling it, or why they need money, or maybe you will discover that you have something they want and can trade!

i think there needs to be a "beginners project guide" and "project buying guide" to help people pick things and help them buy them too. as long as you arent in my craigslist area

 

[Doc Sprocket]

LOL- I do stuff like that too- If the asking price is $100, I will put $80 in my wallet and tuck the remaining $20 in another pocket. Time comes, I open my wallet- and sure enough- I only have $80!

And if they are REALLY firm, and I REALLY want the item, I can "unveil" the extra $20...

 

[kaymo]

i take a friend and hand him everything i dont want to spend. then when it comes time i tell the guy that ill have to beg to borrom money from my friend. if i really dont want to spend more i will come back and say well he didnt let me borrow any... sometimes that works, but if i really want it and he doesnt go for it i will "borrow" it. keeps you from looking like a jerk when you "find" that extra 20 lol.

ok and im going to stop sharing my bartering tricks now before it gets used against me lol. i learned from my mother at a very young age. i remember them buying a NICE pop up camper for like 1200 bucks... my mom offered like 1100, guy said 1500 was the BEST he could do. my mom was like "i have 1200." he kept trying to 475, 450, and my mom just said twice ALL I HAVE IS 1200 and walked away. he went in his office and came out and chased us out to the parking lot and said "ok 1200!" so we went back in and he says "ok plus tax comes to..." mom came back with, "i told you, I ONLY HAVE 1200" so he ended up having to give it to her less than 1100, which she offered in the first place. we left and she told me "i had 1500 to buy a camper with" it was funny as hell.