Dont give me one but two Mac's side by side

[mcbob]

I know that this is not a Kart related thread but it's another project to add a little interest besides not working on Mac's makes Mc Bob a dull and boring fella.

I'am in the early stages of putting together two Mac's side by side using a cut down Horstman clutch drum bolted and drilled to fit around the starter pawl legs on the flywheel of the right Mac with the left hand Mac running the clutch.

I have used a piece of 6mm aluminum plate to tie the two fuel tanks together and a lower brace too keep the back of the engines in alignment plus the handleframe so it works out to be a stiff little package.

The inner exhaust header is a very tight fit but it clears the fan housing by a couple of MM.

Hopefully i'll end up with two modified 101's in the place of the two old Macs i'm using to set things up. The balance of the two engines on the front handle feels pretty good as i've had a bar and chain on it and the balance point so far works out to be with your little finger up against the centre brace of the front handle.

Anyway fellas more info as i progress in the building of a Mc Beast.

Mc Bob.

[Mark Brubaker]

Lookin' good McBob ! Ya know they say 1 is good,, 2 is better,,, and 3 is best.... Just food for thought..

Mark

[mcbob]

G'day Mark and thanks for the PM's that some others sent .... the clutch drum is simple i reakon, i just ground down the centre spigot till it still had enough meat so it allowed the flywheel nut to remain fully engaged on it's thread then drilled two holes in the drum itself that locate over the posts that the starter pawls are normally attached too i removed the little raised starter pawl stops to let the drum seat, i can if needed drill two more holes in the drum and fit bolts to use the flywheel removal points as an extra securing point.

When i get around to dismantling the two units i'll take a pic of this rather simple procedure.
P.S I used a Horstman clutch drum. Also i suppose using this method would allow you to mount as many as a man is able to pick up together 2 or 3 or 4, heck mon i'd better start doin a little bodybuilding.

Mc Bob.

[Russ Smith]

Hey McBob,
Yeah, you better get into lifting some weights (and I'm not talking about beer mugs) if you're planning on pull starting that monster.

[mcbob]

Gday Russ i suppose starting them won't be too bad as i only have to pull start the left engine and it will start the right engine and thats fine providing the left engine is kind and looks after me.

The weight is not to bad really and the balance of the two engines in my hands is at the point of my small finger and when it's next to the centre post of the handle.

I have one 101 to use now i have to get another together to complete the kissin cousins act.
Both of the 101's will have decompressors as my middle name is not "Arnie" or "Tarzan".

Mc Bob.

[Rob Voska]

Are they going to fire together or 180 deg appart?

[mcbob]

Are they going to fire together or 180 deg appart?

I suppose that will be at random as if i lock the saws together then i don't need a clutch to couple them up so aligning timing in unisun is rather impossible.

Then i have to be able to start two engines locked together so if i use the output shaft on the right hand engine it's going to place one heck of a load on that crank.

Mc Bob.

[david martin]

mcbob you will find that the two engines will fire in a random fashion at low speeds then as you head down the straight they will auto sync. it will be like music to youre ears

[mcbob]

mcbob you will find that the two engines will fire in a random fashion at low speeds then as you head down the straight they will auto sync. it will be like music to youre ears

Well thats great to hear as i was hoping to uncover a past user of twin Mac's looks like i have.Mc Bob.

[steveohara]

David,

Please explain why you think the two motors will "auto sync" when the speed increases???
Steve O'Hara