Topic: Opposed Billet Flywheel mods

[Don Gienger]

Hello Everyone.
Here is a recent E mail I sent someone about the fitting of an ARC Billet wheel off of a Intek Twin to an Opposed motor.
Here are the pictures too.
Let me know if this helps
Don

Hello,
Here are some pictures to show you what has to be done.
#1 You need to cut a new groove in the crank 90 degrees from the original spot. Placing the crank with the factory keyway facing the back of the motor or away from the intake like you see in the picture lined up with the casting on the block cut a new keyway in the direction of the Mag mounting tabs.
Now looking at my pictures you will see a TDC in black magic marking on the block on the tab the factory keyway must line up with. The 90 degrees from there you cut your new keyway in using a dremel. ON the dremel I stack 2 or 3 cutting disc on it to cut my own keyway. You can see in the picture the little lines left by doing this.
Again with the factory keyway lined up with the block casting that I have marked the keyway you will cut in 90 degrees from there will line up with the Magneto mounting area.
The ARC Billet wheel for the Intek V Twin comes with two Magneto mounting brackets and all you need is one. Tell them that when you order one. Or remember I am an ARC dealer and I can get them for you to you for cheaper then they post on their site.
#2 Now the next mod is simple. There are four bolts that hold the tin on under the flywheel. Those four bolts stick up to high and need to be turned down or replaced.
I use Panhead bolts. As you can see in the picture then need to be as low as you can go. Intek V twins have the same bolts in them for the same reason.
#3 Starter mods. As you can see in my pictures I used a Briggs High Torque starter. I took the starter apart and heated and flattend the mounting housins so I could move the starter as close to the flywheel as possible. Intek Twin wheels have the largest ring gear ARC makes but it is still smaller then the factory Oppose gear. So you need to first use the regular 12 hp starter gear and then move the starter as close as possible.
Take the stock Opposed starter and drill the mounting holes out might do the same thing for you too. But give it a try.
ALSO make sure the starter gear is lined up with the ARC billet ring gear. I mean once you push the starter gear up into the ring gear of the flywheel make sure it goes all the way up and rides dead even with the ARC gear so they get full contact and wear well and last long.
Well there you go. I think that should explain it all. If not ask questions and I will try to help.
ATTENTION SINCE THIS IS NOT A DIRECT FIT FROM ARC YOU WILL HAVE TO DO WHAT IT TAKES TO MAKE IT WORK. ARC MAKES THE WHEEL BUT THEY DO NOT UNDERSTAND HOW TO MAKE IT WORK ON THE OPPOSED SO ASKING THEM IS LIKE ASKING A WALL. THEY SIMPLEY WON'T KNOW.
Thanks
Don
PS Call or e mail for wheel pricing.



Don Gienger
G Team Racing
G Force Racing Engines
www.g-team.us
701-400-4084 Here is the Starter I used

[THawley08]

Nice post Don 

[Ty]

Could this be done with a stock flywheel for an opposed  ?

[George Herrin]

Why cut a new key in the crank could you not just turn the hub in the flywheel!!! This would require you etching new timing lines in the flywheel to match the new location on the flywheel.

[THawley08]

i kinda wondered the same thing.

[Scurry Murry]

It seems to me Don makes his own key ways, if you take a closer look at the pictures the keyway he cut is just a tad deaper. He most likely uses a machined key, instead of the aluminum jobby.

[George Herrin]

BUT why the flywheel and hub are two seperate parts. use the existing keyway in the crank and turn the flywheel on the hub to get it back where it should be THEN etch new lines on the flywheel body for the timing. It worked for me and alot less work.

[Don Gienger]

Well Kids do the Math.
The bolt holes disappear under the hub.
Dudes I tried that but of course it won't work.
V Twin versus Oposed??? Hello!!!
Give it a spin and see what I mean!!!
I have had a couple of guys do it and have great success. I use something different for ignition but the other guys used stock to my instructions and had fun racing now. Just with a flywheel.
Hope that helps
Don

[C/P_Racer]

So its possible to still use a stock briggs coil on this setup? 

[Snowman18]

Yes with one of the adapters that come with the flywheel.

[Don Gienger]

Thanks Scott,
Yeah when I look at setting them up or seeing what works for the Opposed my first look is what will use the most affordable mods and OEM parts.
I have an Intek wheel and all the brackets and know how Briggs times their motors. So even though MY motor has home made ignition on it my first set up was for the stock Mag and parts.
Guys even I don't have the money to go and build what I want so I have to do it affordabley too.
ARC wheel
Dremel with cut off wheels
Starter mods slotting the holes and maybe changing the gear to the 12 hp tooth gear
Lower bolt heads for under the wheel for clearance
AND time is all you need to put the ARC wheel on your Opposed.
Does it get any easier?
$325 for a wheel from ARC and me SHIPPED to your door for that price!!!One more thing since one of my last post sounded kinda Co

The reason the hub won't work is a V Twin fires 90 degrees to each cylinder and the opposed is 180.
Again when I first place the wheel on the Opposed with the Mag in place and the timing figured out the hub turning just won't work. If you turn the hug to match the timing of the wheel needed to fire the motor then you would have to drill 6 new holes.
Heck I bought different hubs and tried them too.
I am not saying I don't miss things here and there NOR am I saying I am right no matter what. But again I can't say it enough I test and test and retest and then test again.
I know it all drives you guys and gals nuts that it takes me so long to do something. But if it don't work for me I won't pass it on to you. This takes time.
If someone gives me a challenge with whatever I make sure I figured out the best way and most affordable way to build it.
I have Asked ARC to rekey the hub. I have asked for Billet rods. I have asked for parts from ARC since what they do already is SO close to what we need.
But they won't.
One final thing. I am not done with this motor yet.
Don

[Snowman18]

Maybe E.C. Distributing can make a proper hub for the flywheel. One question I have for you Don is about exhaust on the O-twin, do you think it would be beneficial to make an equal length two into one header or just a plain header.

[FlatheadPuller]

Snowman, If you have room I would recommend a header. I have ran both on my puller and the engine runs better top end and under real heavy loads with the header. With a Zoomie setup it wouldn't stay up in the higher rpm like I need it to.
Dennis

[Snowman18]

Nice work, that's the beauty of the O-twin, there is tons of room in front of the engine (vertical orientation). May I ask what size pipe you used looks like one inch into two inch possibly.

[FlatheadPuller]

I used the stock flanges from a stock muffler into 1 3/8 into 2 1/2. The header is actually made out of a set of old SBC headers. It turned out nice. The opo twin has a sound all its own with a header. Mine is horizontal shaft so  I am unsure what there is to work with on a vertical shaft setup.