Open 4 strokes

mike clements · Posted: Mon Dec 12, 2011 8:04 am Post subject: Open 4 strokes

I miss the open 4 stroke class we had years ago. Thirty 4 cycle opens on the grid, all lined up and running, ready for the race, sounded like a NHRA Fuel dragster waiting to do a burnout.
Instead of the old Briggs and Honda flatheads, the Animal and the clones in fully modified form would make for some excellent racing. Sprint, speedway and enduro: All would make for some excellent competition. This sort of class brings out the best builders and tuners in the country. The Innovation and handy work in these engines is second to none. It's just not as visible to the majority of karters today as it was 20 and 30 years ago.
I have a very nice Briggs model 15 ohv open motor, just completed, sitting on the shelf awaiting it's turn on our enduro kart. Not too hard to make HP from this combination. With a 3" bore and a stroker crank, these engines will make upwards of 36hp on clean alcohol with the 3 valve billet head. We also run a 1" deck raiser on them to correct the rod angle and provide more hp and torque. The PVL ignition is another key to building performance in these engines. Several guys around the country are building these engines now.
We are currently building a 3" bore Honda with a stroker crank, big valve, raised port billet head, etc , for use on a new, never raced CKS laydown enduro kart I have here. Sue Cubel is going to drive it at our local enduro tracks at Firebird Raceway. Can't wait to watch it run. Very Happy

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Began kart racing 1959. Made many friends along the way.

mike clements · Posted: Wed Dec 28, 2011 1:32 pm Post subject:

We just received a brand new, never opened, Raptor flathead, dual bearing crank, cast iron bore, all the good stuff. We still have customers racing these and nos engines are getting hard to find. It's a very good day here. Cool

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Began kart racing 1959. Made many friends along the way.

Charles Kaneb · Posted: Tue Jan 17, 2012 8:57 pm Post subject:

Mike,

Up north Briggs sells a 399cc, 21 hp engine for snowblowers.

I can't find it on their website.

It would be my choice for this kind of race, though!
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"If you're still in full control, you're not going fast enough" - Fred Frame

mike clements · Posted: Tue Jan 17, 2012 9:42 pm Post subject:

Is that a V-Twin ?
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Began kart racing 1959. Made many friends along the way.

John Matthews · Posted: Wed Jan 18, 2012 6:56 am Post subject:

I'm pretty far up north but not quite to Canada. Briggs might have some different engines there but I doubt they have a 399cc 21hp model.

In my Briggs book the largest snow engine is the 1650 Series - Model 21Mxxx or 21Pxxx It would be a 342cc. The 21hp engines are 385447 models, that's over 600cc's and yes a v-twin.

Briggs does have a v-twin on a kart, I believe Dave Klaus has even driven it Shocked

It's got to be a monster....

Maybe he has the model number mixed up with the HP?

Cheers,
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John Matthews
Heartbeat Power, LLC.

Benn Herr · Joined: 18 Jul 2001 Posts: 1584

mike clements · Posted: Sat Mar 31, 2012 9:45 pm Post subject:

I have recomended to the IKF 4 cycle tech committee to work on the reinstatement of the 4 cycle open class. I would like to see all modified 4 strokes allowed in one race at the same time. The old flatheads at 14.5 ci, the new ohv motors also @ 14.5 ci but at a slightly higher weight. Then include the Animal limited mods at a fair weight and also allow the Tecumseh Stars, the Briggs 305's, etc each at a fair weight that allows everyone a level playing field. Even the dual stocks could join in. I am all about innovation and the larger variety of karts, engines and configurations we can get, the better the show and the more prestigious the win will be. JMO.
MC
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Began kart racing 1959. Made many friends along the way.

Bob Vehring · Posted: Mon Apr 23, 2012 7:45 am Post subject:

Mike, I'm with ya, well, I wish I could say I was.
I tried several times up here to get interest going but no takers
This is what is wrong with this sport and why it doesn't get any respect.
Show me some other sport where the top national classes are stock engines other then this or I think Moto x
To me, racing is making the most out of every part of it.. By the time you make stock engines, stock clutch, stock pipe, spec chassis and tires, you have taken most of the racing out of it.
All thats fine for local track, beginers racing, but most racers don't want to have to learn all that anymore.
You can't blame price, my open Briggs kart has 1/2 or less of the price of a TaG kart in it, goes all season and is 2 sec. faster per lap.
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Bob Vehring
www.4cyclecentral.com

Peter De Saegher · Joined: 26 Mar 2010 Posts: 57

Used to work for B&S in europe in the 90's and had the luck to test the V twin prepared in Germany with injection. Shocked

Torque & Power, noise ( like a ducati )

Embarassed

Weight and chassis handeling

There are still very good tuners in Germany , tuning Vanguards.

mike clements · Posted: Thu Feb 21, 2013 3:57 pm Post subject:

Current movement in the open 4 stroke classes are modified Briggs Animals, Briggs 305's and 342's, Honda Clone GX-390's, GX-200's bored and stroked, still have the older Briggs flatheads and Honda flatheads and also plenty of the modified Tecumseh Stars. Kohler and Robin-Subaru are also running.

Some guys are running the Honda MX CRF450R engines as well as the Speedway Bike Jawa engines. Those are very fast, but they skirt the effort to learn to build your own HP.

Still, I'd like to see one big 4 stroke race per year, somewhere. Very Happy

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Began kart racing 1959. Made many friends along the way.