Twin 66cc 2 Stroke Build Thread

[frank66]

Thanks for all the helpful advice, I've been a bit worried about the timing myself so now I think I'm going to go fit a timing chain between the two engines on the right side so that both clutches are still used with one big chain on the left as I'm not sure how well one clutch would take the extra power.

i realize now the cranks must be fixed together! not the output sprocket or the clutch.


so stack the engines like you have done allready and weld a sprocket to each small bevel gear. thus a chain to connect the two added counter shaft sprockets locking it at 180 degrees.

like this a single carb will be excellent.

 

[frank66]

i suppose just one clutch then.... if timed at 180 degrees means the torque wont be doubled up but rather more often... deleting one engines complete clutch and sprocket would be wise as its not needed!

with only one output now/ a single chain to the rear wheel.

 

[frank66]

an extra stock chain and one or two extra stock countershaft sprockets will work great if you cut the front half of the clutch covers away. thats all you need to complete.

 

[irishpowerjunkie]

what about 2 jackshafts running 1 from each engine linked with a bmx type freewheel on 1 and regular keyed sprocket with 2 and have with different ratio a direct connection through second set of cogs to main jackshaft, i don't if anyone would be able to follow my thinking on it but if you can make sense of way i mean, why not try it?

 

[Dom]

Thanks for all the more comments/advice, me being my usual self have managed to come up with something that will work well out of bits I had lying about similar to what I had originally planned timing wise as I didn't really want to run a jackshaft.

I've welded 4 M4 threaded rods to the flywheel/drive wheel and then using nuts and washers either side I was able to adjust the standard 44t sprocket to make it run straight and true, as said earlier I'm still going to run two chains as I don't think the rods would hold up under a lot of stress. Now to make the other one up!

 

[frank66]

im listening but im concerned the drive ratio used to be 4 to 1. all you needed to do was match the crankshafts up to a single output clutch.... i will leave you to it and pop in later to see your progress. twin jackshafts or whatever does nothing but over complicate a simple proceedure. requiring two 2 stock items. good luck with whatever you choose. i realize this is your dream so good luck again.
frank

 

[joey1320]

Thanks for all the more comments/advice, me being my usual self have managed to come up with something that will work well out of bits I had lying about similar to what I had originally planned timing wise as I didn't really want to run a jackshaft.

I've welded 4 M4 threaded rods to the flywheel/drive wheel and then using nuts and washers either side I was able to adjust the standard 44t sprocket to make it run straight and true, as said earlier I'm still going to run two chains as I don't think the rods would hold up under a lot of stress. Now to make the other one up!

I'm trying but failing to understand your objective here. What now? You welded the studs and added the 44t sprocket, but you are kind of in the same place you were before, just with a bigger output sprocket.

[scratch head]

 

[Dom]

There's a sprocket on each engine in the same place and they will be linked by a chain this will be keep the engines perfectly timed, then there will be another big chain in the usual side around both engines driving the wheel, hope this makes sense?

 

[boxcar]

It's going to fly apart.
I'm not trying to flame you or be mean.
Think balance.... The 44 tooth sprocket mounted the way you did has very little.
I understand what you are trying to do.
But , welding studs to the clutch basket gear is a bad idea. Its a fairly delicate part to begin with.
If you want to link the two engines at the output shafts you will need to do it at the primary sprockets.
It's going to require a machine shop.
You will need to extend the output shafts on both motors for chain clearance.
Fabricate a dual sprocket for the lower engine and then add outrigger bearings to hold the extended shafts on each engine.
By doing this you will be able to link the two engines with a short chain then drive the rear wheel from the second sprocket ( duel sprocket) of the lower engine.
Realize that I'm spit balling here. I have done no calculations , and am not claiming to have done any proper engineering on this idea. ( disclaimer )

 

[Dom]

I guess we'll wait and see what happens, you never know until you give it a go. Like I say I've balanced them as best you can it's just whether it's enough / the threaded bar holds up.

Today I got the timing chai fitted, was a bit of a pita to get on but got there in the end! Bit annoying how they've started greasing the chains from factory now it gets everywhere. haha

 

[YesImLDS]

I gotcha that makes sense. As long as the welds hold I don't see what the problem would be except that giant spinning death machine next to your leg. I'd think about getting some smaller sprockets as well as some sort of a shroud to keep yourself from being a new amputee.

 

[cannonball2]

So what happens when the clutches slip?

 

[curtisfox]

Getting interesting got to watch this closer,see what the out come is..............Curt

 

[Dom]

So what happens when the clutches slip?

There will be another chain on the other side around both engines for the drive which should keep most the stress off the timing chain.

Yeah I'm going to make a cover for it don't worry. haha

 

[Yume]

Is this project still active? I'm interested in following the progress!

 

[GoreWound]

I just took a look through the thread...
I think his bike ate him.

Just came to life, screamed "you made me unwhole!" and consumed him in it's roller-chain jaws.
*takes off hat*
Let us have a moment of silence for our fallen brother, may his entrails evermore lubericate the drivechains of the Afterlife.
*21 backfiring straight pipe salute*

 

[Dom]

^ hahah that made laugh way too much. Yes it is still going just progress has been a bit slow as I'm building a Turbo MX5 (Miata to you) and blew my first engine up so that is taking my time and interest!

 

[GoreWound]

^ hahah that made laugh way too much. Yes it is still going just progress has been a bit slow as I'm building a Turbo MX5 (Miata to you) and blew my first engine up so that is taking my time and interest!

someone once told me that blowing up a miata engine is a right of passage for gearheads
so...
Mazheltov!

also congradulations of being alive, honestly though your bike is the kind of scary that makes me want to keep watching. good luck out there.

 

[Slogger]

That reminds me of the porto-band saw we had at work.
<shudder>
Has your wife seen this?