Making a custom bike engine

[Theon]

The barrel/s you'd want new, E bay?
Unless your just looking for reference?
The case I imagine you just want for reference?
Surely someone on here has some old bits and pieces they'd donate?

 

[Davezilla]

The cheapest I've seen are from BoyGoesFast on ebay, cylinder, piston, and rings for $25 + 10 or $15 for shipping, He might cut you a deal if you buy all of them at once. His cranks are a decent price as well.

Cylinder + Piston set...
http://www.ebay.com/itm/400589413315?_trksid=p2059210.m2749.l2649&ssPageName=STRK:MEBIDX:IT

Browse his other items for the crank, he should have them for about $25 as well, Not all 66/80cc cranks were created equally tho, some are 38mm stroke and others are 40mm, with the 40mm ones becoming more of the norm, but still worth asking before buying.

I've seen bare crank cases as cheap as $15 but can't find the link... I think the going rate for a set of bare cases is around $30 but definitely worthwhile to shop around or ask for bulk discounts etc.

can you tell I'm interested in your project as well?

 

[curtisfox]

This is interesting and I would love to see it come about.
What would be super would be if someone came up with a inline 4 like the old HENDERSON or INDIAN, I am sure there would be a market for it. LOL.........Curt

 

[Mitchg95]

I went ahead and bought a barrel and rod for the 48cc engine last night. Should be here within a week, hopefully.
I love the looks of the old Henderson inline 4's they are beautifle engines.

 

[Mitchg95]

What is the length from the bottom of the barrel to the bottom of the fins where the cylinder mates together with the case?

 

[Theon]

Bottom fin to barrel base is approx. 4mm

 

[rogergendron1]

i have been looking into to this as well ...

i am a machineist also , i work for microline pentax and manufacture medical instruments for surgery....

i was thinking about a whole new crank case with the proper case preasure around 1.3:1 and a case inducted reed valve from a high end moped, the cilynder would be ether a moped jug or a custom made aluminum one cnc manufactued on a 5 axsis but the design would be as sutch that you can bolt bolth to the case so one would have the option to run a cheap moped jug or buy the expencive cnc milled high performance one that can be modded to his or her liking this would involve making a billit case with a jug bolt patter the same as the puch moped so you could use the puch jugs and big bore kits but the option for a custom machined one would be there for those who wish it, there would be a custom head also like a fred head or diamond head..... it would run the puch moped crank and conrods in the billit case and run the puch 2 speed or one speed auto clutch.... this way the field of performance parts and upgrades is wide open for the builder !

the billit case would also have mounting points or studs and multiple stud holes so and mounting blocks, this way you could mount it offseet or on a wide tube frame or on a cruiser frame simply by changing the studs to a differanyt set of holes IE: wider pattern or thinner pattern offset or not and then space the motor off the fram by means of the differant blocks that would come with it IE: 1in block 2in block 3in block exe....exe... the blocks would be cut one one side to fit around the frame and can be had in differant frame tube sizes and thicknesses.

this is my idea ... mabey you can use it IDK share all i can man !

 

[rogergendron1]

i also though of a twin cilynder case useing two puch or a custom made crank and all puch moped parts..... the jugs would be vertical and side by side but the intake would be a 2 into 1 and it would run a large 22-26mm dellorto phbg carb for ease of tunning

the clutch would be a puch 2 speed or a belt type variator from a moped (like a cvt)

 

[Mitchg95]

I love your ideas Roger, I especially like your idea for mounting the engine, mind if I use it?
Can someone tell me how to upload a photo?

 

[Mitchg95]

What is the width if a 48cc bike engine cylinder, at the widest point?

 

[Theon]

Store your photos on photobucket,
Click on the 'Go Advanced button'
there is a small yellow icon of a picture click that and copy and paste the 'direct link' URL
click on 'manage attachments' paste here also.
I don't have a 48cc barrel but it is around 100mm wide.

 

[Mitchg95]

There is what I have so far, the first picture is all three case segments with 3/8 plates in between that I indend to have bearings to support the shaft. The second photo shows what the segments should look like
And the third shows a case segment drawing as if you were looking at the case, head on

 

[Theon]

You doin' a flat six?
That is really cool!
Now I really want one!
It'll be the 'Porche' of bikle motors.
what you going to try and squeeze that into?

 

[Davezilla]

A flat 6 would really be cool... Something like this... with 2 extra cylinders... http://dle-engines.com/dleg0222.html ... That would be a 288cc engine if you use the 48cc jugs, or a 396cc with the 66cc jugs on the typical 40mm stroke... That could Easily make about 50hp or more if designed really well...

 

[Mitchg95]

I have no clue what frame I'm going to squeeze it into, probably a cruiser but idk yet.
I love the design of the dle222 I'd love to see how they made the cases
Hopefully that 48cc fpjub and rod come in sometime in the next couple days so I can get a better drawing done. I've decided to make the crank disks 3/8" thick.what diameter should the actual shaft be? What do you think guys?

 

[Theon]

The standard China girl cranks run a 15mm main journal and 16mm big end pin.
I guess it all depends on what bearings you plan to use, what stroke you use, and how you plan to connect the 3 case's and crank sections.
Are you planning on splitting the cases verticaly or horizontaly?
Do you plan a single crank or three cranks that join?
I would be thinking splitting the cases verticaly and making the cases as 2 halves that have all three barrels each rather like a Volkswagen Case, (I use to work on VW's). These would then need to be align bored as VW cases do. I would then run loose needle rollers for main bearings, However this would require hardened split shells.
But allow you to run a larger Dia main Journal.
Also the standard rods need to be pressed between flywheel discs, I'm not sure how you plan this on a multi cylinder engine, and would require some tricky alignment.
However split big end rods such as out of a chainsaw are going to cost!
A very challenging project! Currious to see what you come up with.

 

[Mitchg95]

This part, I just designed will go I between the case segments. This part is supposed to hold bearings to support the shaft. The reason it is so long, the rounded circular parts will fit into the case, this will provide more rigidity to the engine

It will be made out of two square blocks. They will be milled to equal thicknesses of 1.5 thick and 3inches wide, then bolted together and the circular details will be turned and bored out for the shaft and bearings

 

[Mitchg95]

I'm planing to make the crankshaft out of multiple parts and press the con rod onto the pin on the crankshaft, then press the disks together, with a slightly loose fit. Maybe five thousandths of an inch on eighteen half of the rod

 

[Mitchg95]

The parts still have not arrived, they were scheduled for delivery today, but did not show up. Can someone tell me what is the measurement of the bottom of the con rod where it meets up with the crank pin? I need to know the major diameter, I think the one inch od shaft might be a little to big so I might need to change it.
Thanks
Mitch

 

[Theon]

Crank pin bearing O/D is 20mm.
I/d 16mm.
http://screamingroo.com/online-store/big-end-bearing