Twin Engine Driveline

[KB2ROCKET]

if you frieght train the engines they are done like this
the front engine has a clutch the chain on that clutch goes back it a solid sprocket on the crank of the rear engine THEN outboard of that sprocket you mount another clutch and the chain from that goes to the rear wheel sprocket
.
this way you can start the front engine then just rev it up and its clutch will enguage and start the rear engine
.
the engines will be out of sync at first then auto sync based on clutch slipage and firing pulses
.
their are lots of ways to do it but i know for a fact this works
.
oh one more thing you will need to run one clutch with the sprocket inboard and the other clutch with the sprocket outboard
have fun

 

[loppy]

KB2ROCKET, nice input. That frieght train technique sounds interesting. You must have had a longer crank on the rear engine to mount both the solid sprocket and clutch. Who makes it? Have any pics of it?

I've been laying out the chain routing. The engines are in-line with one long chain. I made an idler plate that mounts to the rear engine case. The purpose of it is to increase the angle of the chain so more teeth on the clutch sprocket are engaged. There will be three idlers total. One on the plate as I just mentioned, one just in front of the year sprocket so the chain doesn't hit the frame cross support, and one behind the front engine on the lower return route of the chain to take-up slack and prevent the chain from slapping the engine plate.

I changed the springs in both the clutches to the stronger 3000 rpm's versions. By doing this, each engine can be started independent of each other and rev'd up without having its clutch engage. I also decided to go with the stronger clutch springs to be able to bring the rpm's up at the starting line without the clutches wanting to pull the bike forward and prevent red lighting. Also, the the motors will be closer to their powerband's off the line.

Here are some mock-up pics...

 

[KB2ROCKET]

on the rear engine make sure you machine down the sprocket hub as thin as you can get away with with out the chain rubbing anything then mount the clutch YES YOU ARE RIGHT the shaft will not go all the way flush with the outside of the clutch what you can do is cut the tip off a different crank shaft and insert it in the hole and drill out the threaded hole and use this tip as a spacer (dont forget to line up the keyway slot) then you just need to find a longer bolt
.

check out this link http://www.heartbeatracingproducts.com/RandD_pg2.html#

 

[jareeb]

hears another way this can be done

just an idea if ur plan doesnt work well with that long chain only problem with this idea is it will be wider.

 

[KB2ROCKET]

Running a jackshaft is a great way of doing it if you don't mind running the engines side by side:thumbsup:

 

[5 Horse Fan]

Yeah and you have an infinite amount of ratios to play with !!!!:thumbsup:

 

[jareeb]

Yeah and you have an infinite amount of ratios to play with !!!!:thumbsup:

yeah and it a clutch brakes then u just take the chain off and have another motor to get you where u need to go.

 

[125ccCrazy]

if you frieght train the engines they are done like this
the front engine has a clutch the chain on that clutch goes back it a solid sprocket on the crank of the rear engine THEN outboard of that sprocket you mount another clutch and the chain from that goes to the rear wheel sprocket
.
this way you can start the front engine then just rev it up and its clutch will enguage and start the rear engine
.
the engines will be out of sync at first then auto sync based on clutch slipage and firing pulses
.
their are lots of ways to do it but i know for a fact this works
.
oh one more thing you will need to run one clutch with the sprocket inboard and the other clutch with the sprocket outboard
have fun

'



what happens if your speeding along and the rear engine dies or worse yet locks up? the front engine will try to keep it turning over.... If the front engine dies or locked up there wouldn't be an issue since the clutch drum would free wheel but the other way around could be a big problem..

I still think a double gear rear clutch and single front would work great and if either engine died or locked up you will keep going...

when you take the slop out of the chain will the top and bottom rub together?

 

[5 Horse Fan]

'

I still think a double gear rear clutch and single front would work great and if either engine died or locked up you will keep going...

Engine dies................Engine locks-up................are we planning some kind of coast to coast road trip?????.................I'm In !!!!!!:thumbsup:

 

[125ccCrazy]

Engine dies................Engine locks-up................are we planning some kind of coast to coast road trip?????.................I'm In !!!!!!:thumbsup:

I don't know about coast to coast but you will be able to ride it home and not have to push it with that other set up.

 

[jareeb]

I don't know about coast to coast but you will be able to ride it home and not have to push it with that other set up.

yeah i going to try my idea on a go kart later down the road

 

[125ccCrazy]

yeah i going to try my idea on a go kart later down the road

that will work good on a gokart due to the width of the kart plus it will be easier to access the left engines pull start than side by side on a bike..

 

[5 Horse Fan]

My dual engine setup consisted of a belt drive between the two engines and a clutch on the rear motor. I am more concerned about the chain or belt braking between the engines.

Why can't you run two clutches and one chain???? If the engine dies or locks-up you should be good......

Minibikes, so simple yet very complicated.....:scared:

 

[jareeb]

that will work good on a gokart due to the width of the kart plus it will be easier to access the left engines pull start than side by side on a bike..

yeah it should there is a video on youtube with a kinda side by side dual motor it wheelies. but that cuz the motors are past the back wheels

 

[KB2ROCKET]

It should work just keep in mind that the idler sprocket is going to be under great stress because it's on the pull side of the chain. I just try and avoid super long chain runs
have fun

 

[Oldsalt]

My dual engine setup consisted of a belt drive between the two engines and a clutch on the rear motor. I am more concerned about the chain or belt braking between the engines.

Why can't you run two clutches and one chain???? If the engine dies or locks-up you should be good......

Minibikes, so simple yet very complicated.....:scared:

5 Horse

I guess a lot of people have built multi engined minibikes and have some really good ideas. I'm trying to keep an eye on what is going on here and learn how different people have done it because I'd like to try it some day.

You say you used a belt to tie the engines together? Can you post a picture. As I understand from past posts in various threads, by people that have built multi engine minis, that belts won't work. But I'm sure yours works. Now I'm really confused. There was a picture of a triple engine mini posted early on in this thread. But no one seemed to know or would say how the three engines were hooked together. I looked up an old picture of another mini that has three engines. Probably built much earlier. It is attached. I wonder how that one was done. I'll bet it was chain driven without belts. Does anyone know? But as I recall from posts a few years ago this guy really didn't know what he was doing.

But come to think about. If two engines are difficult to get right, and there seems to be a lot of disagreement on the best way, so it is probably a LOT more difficult to hook up three. What do ya think?

 

[5 Horse Fan]

5 Horse

I guess a lot of people have built multi engined minibikes and have some really good ideas. I'm trying to keep an eye on what is going on here and learn how different people have done it because I'd like to try it some day.

You say you used a belt to tie the engines together? Can you post a picture. As I understand from past posts in various threads, by people that have built multi engine minis, that belts won't work. But I'm sure yours works. Now I'm really confused. There was a picture of a triple engine mini posted early on in this thread. But no one seemed to know or would say how the three engines were hooked together. I looked up an old picture of another mini that has three engines. Probably built much earlier. It is attached. I wonder how that one was done. I'll bet it was chain driven without belts. Does anyone know? But as I recall from posts a few years ago this guy really didn't know what he was doing.

But come to think about. If two engines are difficult to get right, and there seems to be a lot of disagreement on the best way, so it is probably a LOT more difficult to hook up three. What do ya think?

I should have worded that better.....
I meant the dual engined minbike in my head.:laugh:

Speaking of that, I might draw some pictures on my computer and post them to my project thread.

Think about it !!!!

206cc + 206cc = 412cc or 26CI
The Torque.......The Horsepower.........makes me all giggly inside.........that's not gay is it ?????

 

[C9H13NO3]

Say Oldsalt, that picture looks familiar:laugh::laugh::laugh:

 

[125ccCrazy]

My dual engine setup consisted of a belt drive between the two engines and a clutch on the rear motor. I am more concerned about the chain or belt braking between the engines.

Why can't you run two clutches and one chain???? If the engine dies or locks-up you should be good......

Minibikes, so simple yet very complicated.....:scared:

thats not the set up I was referring to....

 

[Oldsalt]

Say Oldsalt, that picture looks familiar:laugh::laugh::laugh:

Ya. It's an old picture that was posted a long time ago and the builder, I can't recall who right at the moment, was questioned as to how the engines were hooked together and etc. His answers to the questions were highly questioned by a lot of people that had a lot more experience than him in building multi engined minibikes so I don't think he really got around to showing how he tied the engines together. In any case it is pretty sure he has nothing to offer but it still might be interesting to know how it did it so that I don't try the same thing when I learn enough to try building one myself.