AMA - 3000-A-AF - Dual-Engine FJ1200

[FreakhouseCustoms]

Video #2:

Front-engine driving the drivetrain.
Rear-engine in Neutral.

If you watch this video, you'll see why I won't be trying to get both engines to sling the chain at the same time.

[Doc B.]

Man, you're moving at light speed. I've been stuck for a week just trying to get an oil cooler to fit. Meantime Fran adds a second motor, wires the whole bike, rebuilds the carbs, tests the thing twice and plans to build the second version of his drivetrain.

[FreakhouseCustoms]

Man, you're moving at light speed. I've been stuck for a week just trying to get an oil cooler to fit. Meantime Fran adds a second motor, wires the whole bike, rebuilds the carbs, tests the thing twice and plans to build the second version of his drivetrain.

Small bites.  Goal is to get one thing accomplished every day.  It all adds up at the end of the week.
 

If it makes you feel any better, the plan is to build THREE versions of the drivetrain.  One more version out of the salvage steel I got in a dumpster dive, then I'll order some new/clean plate steel.   We all know it'll more likely be four versions when all is said and done.
 

Also, it looks like the "good" carbs aren't firing on the #3 cylinder... and maybe have never been!?!  The rebuilt set are running great, so I guess it's time to service the "good" set.
 

[Stan Back]

Ever thought of wearing a helmut -- or are you just so wonderful nothing could happen to you.  Especially on well-constructed, proven motorcycles.

[FreakhouseCustoms]

Yessir. I always wear a helmet when I'm going further than around the block.

In all of these videos, I don't get over (a GPS recorded) 25mph... I have gone faster down that hill on my bicycle.
 

To be very clear, I am not wonderful.  I'm not special.  I'm mediocre at best.
I'm not breaking any new ground here.  I'm not doing anything different than much better men than me have been doing for decades before me. I hold no illusions that I'll even reach my goal.

But what I will be, is the guy having the MOST fun trying.
 

[Stan Back]

Freaky --

I was having a terrible day and unwisely decided to take it out on you.  Bad decision.  I was a terrible motorcycle rider, which, I see, is nothing like you.  I fell over a couple of times but with a much lighter bike.  And I never fell over in my roadster, but did a few figure skating moves a time or two.  But yesterday I was only trying to encourage you to be a little safer.  You certainly are showing your chops thru your build and I'm impressed.  Best of luck, and my apologies again, too.

Stan

[FreakhouseCustoms]

Stan!

Please do not apologize for anything!  I took absolutely ZERO offense to your post.
 

What I said is the actual truth of how I feel about myself and my racing.  I am in this because it's FUN!  I don't pretend to myself that I'm any more than I am:  Just a regular Joe.  I never want anyone to think any more of me than what I am.  All the groundwork has been laid out and documented, I'm just copying what's come before me. What do they say? 

"There is nothing new under the sun"   

As a testament to me being "nuthin' special" - check out my latest video.
I break down and (try to) explain the easiest way possible to build a dual-engine motorcycle.  Anyone with a welder, a grinder and a couple levels can do it.  It takes absolutely no special training, everyone and anyone can do it.




Let's bring back the Dual-Engine Motorcycle!!!
 

[stay`tee]

enjoying your build  ,,

 I notice that the connecting chain is slack in the picture that one clicks on to activate the video,, however in the video it's under tenshion,, how do you adjust this chain ??

[FreakhouseCustoms]

enjoying your build  ,,

 I notice that the connecting chain is slack in the picture that one clicks on to activate the video,, however in the video it's under tenshion,, how do you adjust this chain ??

Whoops!  You're right - I still have a piece to figure out how to install.  At this exact moment, when both sprockets are actually affixed to the transmissions, there is very little slack in the chain.  What you're seeing in that picture is the front sprocket off and that's why the chain is slack.

Now - my plan is to use a primary chain tensioner from a Harley, because that's what I just happened to have sitting on my shelf.  Don't ask me why I even have this part, as I've never even owned a Harley, but it's a nice piece that fits the bill.  Please note that what you're looking at are 630 chain and sprockets - again what I had laying about - the real engine coupler will use 530 chain and sprockets.



Once it's all said and done, I'll have a slot cut into the back plate where the tensioner can slide up and down to remove the slack - and I want to build a chain guide that the top of the chain will glide on simply to stop the chain from whipping up and down as well.

[donpearsall]

Since I have never connected two engines together I have some questions...
1. I see the two countershafts are extended to connect them. How did you extend them?
2. Will you have the two transmissions shifting at the same time so that each is in the same gear?

Keep on building!

Don

[FreakhouseCustoms]

Since I have never connected two engines together I have some questions...
1. I see the two countershafts are extended to connect them. How did you extend them?

Please feel free to ask any questions or question anything you see!
I enjoy nothing more than talking through this stuff, as I'm still learning and still figuring out how it's all going to work.

I simply used the 1.5" round tube I used for the frame and welded a sprocket on either side.  I'll get you a photo tomorrow.
This is still just a mock-up, when I do it for real I'll have booked some time with my buddy who's got a lathe & mill.  Not only will all surfaces be flat and true, but I'll also make up centering devices to locate everything and make sure that they will be welded together centered & true.

2. Will you have the two transmissions shifting at the same time so that each is in the same gear?

I will have both transmissions shifting together at the same time.  A piece of solid rod will connect both shifters and that rod will be actuated by the foot shift lever.  Now, I SAY this, because I've done it before on the last bike... but now that I'm keeping both engines on the same plane, I still have to figure out how to route this rod, if I need to build any additional levers and/or supports, etc.

(I say "etc" like I know what extra bits will be needed  )

Small bites.  One problem at a time.  One solution as they come.



Don

[thefrenchowl]

Hi, about your 630 chain tensioner... I have H-Ds so I know!!!

If you run it dry, it will jettison in next to no time.

The shape is fine but H-D runs it in an oil bath hence the nylon shoe will last, but not forever!!!.

Before H-D went really really cheap, they went really cheap then they were just goin' cheap around late 60s.

Before that, they ran a tensioner where a stellite treated steel blade was welded on to the bracket:



You should find in your stash a piece of hardened or alloy steel good enough to allow chain tension durability.

I tend to use old spanners for such hard work, they are cheap and they are indeed special alloy...

On the subject of shifting 2 gearboxes together, I seem to remember Ack Attack had loads of problems a few years back when both Yabusa engines, due to vibration or whatever, refused to shift 5th and 6th gears. 1st to 4th was OK... In the end, they just lowered drastically the final transmission ratio to get the record in 4th gear. Might be worth enquiring to see if they resolved and how that issue recently?

Best of luck from Patrick

[Stainless1]

You can do an adjustable roller as a tensioner. It could be a small sprocket on sealed bearings or a nylatron or delrin roller.  Any of the 3 will survive as a chain tensioner running dry.
Consider air shifting... while most just use it to shift up it can be set up to shift both directions.  MC2032 has his Harley set up to shift both directions... You must use the clutch for down, but you can set it up clutchless for up with motor kill. 
It might be easier to do air than routing rod linkage that is solid enough to shift both motors.... just a thought....
Keep up the good work 

[mc2032]

Yes, up and down shifts with a paint ball gun c02 bottle, 150 psi regulator, a 3" throw air cylinder, the horn button and a single pole double throw switch.  Park the switch at the center most of the time to avoid accidental contact.  I have an ancient Dynatec shift counter for engine kill.  I think this bottle has been on the bike 3-4 yrs now, just remember to shut it off after each run and open it before the next.  I even used the stock horn button wiring for most of the installation.  Stainless pointed out to me oh so many years ago, get into your tuck as soon as possible and the only thing moving is your thumb.

[FreakhouseCustoms]

Hi, about your 630 chain tensioner... I have H-Ds so I know!!!

If you run it dry, it will jettison in next to no time.

The shape is fine but H-D runs it in an oil bath hence the nylon shoe will last, but not forever!!!.

Before H-D went really really cheap, they went really cheap then they were just goin' cheap around late 60s.

Excellent!
THANK YOU!  That's good to know, because I've never been inside an HD and I had no idea what this thing was, besides that it was a "chain tensioner".
I have a few other ideas regarding materials and if I even need this style of tensioner.  I'll know more once I get the 530 chain & sprockets & the "driveshafts" all made and spinning around.

But thank you for letting me know that the HD tensioner should be in an oil bath, that is not outside the realm of what I'm willing to build.