Clone Vibration

Brian Degulis · Posted: Fri Nov 23, 2012 2:26 pm Post subject: Clone Vibration

We put together our first clone for my 12 year old son. We built the engine with all permissable up grades stuck it on an Extreme Kart frame and WA LA !!! I'm impressed with the performance for the money invested. The vibration was a little tough to get used to compared to a 2 stroke. So I decided to mount the seat with springs on the bottom and gromets on the struts. It's rigid but it floats enough to isolate most of the vibration. Makes for a much smoother feel and less fatique.

John Matthews · Posted: Sat Nov 24, 2012 9:40 am Post subject:

Seat mounting is one of the most critical tuning tools we have with karts, I don't know how the springs will affect handling but I can't imagine they will be better than washers or hard plastic spacers handling wise.

If you're getting excessive vibration I would seriously check out the engine, clutch, and possibly change out the flywheel. It shouldn't be enough to make your 12-year-old uncomfortable under normal circumstances. If in doubt check with some of the other racers at your track, if your engine is vibrating enough to make you change the seat mounting there may be something far worse going on.

Just my 2 cents but I've built a lot of engines and know what can happen when out of balance stuff breaks loose Shocked

Safety fast!!!!

Cheers,
_________________
John Matthews
Heartbeat Power, LLC.

Walt Gifford · Posted: Sat Nov 24, 2012 2:07 pm Post subject:

Not sure if that's WKA legal, might be considered moveable chassis components. To my mind I wouldn't want my seat held on by two pieces of 1/8 wire. Then again I'm a pretty heavy guy.

Gif Cool

_________________
FAA certified jet engine and aircraft technician
Nicholson Speedway class champion 2001
Yamaha KT100 Service Center
40 years karting experience

Brian Degulis · Posted: Sat Nov 24, 2012 3:43 pm Post subject:

We actually had a guy familiar with clones run it and he called it normal for an aluminum flywheel engine. The seat struts are welded triangulated braces and they have rubber bushings. So if a spring were to break the front of the seat would just drop down to the tab I can't see how we could loose it. I guess we could go back to rubber all around but it is a much smoother ride this way.

Brian

John Matthews · Posted: Mon Nov 26, 2012 6:55 am Post subject:

I don't doubt it's smooth, and until you start winning probably nobody will question legality.

The only issue I see is chassis tuning (since you're already running a billet flywheel). Lots of times drivers complain of different things and crew chiefs do their best to fix them. Problem is racing isn't about being comfortable, the seat needs to go where it needs to go for performance and if the driver is a little uncomfortable they need to deal with it for the 20 minutes they're on track. If you're just recreational karters then it's nothing to worry about but if you're trying to build a competitive package I'd ditch the springs and go with a more solid mount. The way a seat transfers weight to the chassis really is one of the most important aspects of getting any kart to handle.

Cheers,
_________________
John Matthews
Heartbeat Power, LLC.

Bernie Lacotta · Joined: 21 Mar 2006 Posts: 168

Brian Degulis · Posted: Mon Nov 26, 2012 8:02 am Post subject:

We saw no change in handling at all and I wouldn't expect to see any. Seat positioning is critical I don't think rigidity in mounting is critical at all. I've got shifters with the tillet plastic seat which flexes like a wet noodle. Many seats ride on rubber bushings and add no rigidity to the frame. I can find nothing in the rules requiring a rigid seat mount.

Brian

John Matthews · Posted: Mon Nov 26, 2012 9:25 am Post subject:

Go with what works for you as long as the tech man doesn't have a problem with it.

The issue I'm talking about isn't the seat "adding rigidity" though, it's weight transfer allowing the inside rear to lift. If the drivers weight can't help lift the inside rear you'll be scrubbing speed off in the corners which translates to higher lap times. I don't know how a spring under the seat will affect this but I only use hard plastic or metal washers for seat mounting.

Of course YMMV but picking up the inside rear is pretty basic to getting the best times from any sprint chassis (dirt oval uses stagger).

Cheers,
_________________
John Matthews
Heartbeat Power, LLC.

Brian Degulis · Posted: Mon Nov 26, 2012 9:38 am Post subject:

Weight distribution is the same with rigid or soft mounting. If you put 100 lbs on a scale or 100lbs on a spring that's on a scale it still reads 100 lbs.

Brian

John Matthews · Posted: Mon Nov 26, 2012 10:35 am Post subject:

Brian Degulis · Posted: Mon Nov 26, 2012 5:23 pm Post subject:

Maybe without seeing and feeling it you've got the wrong idea. Those springs wouldn't compress and bottom if he drove off a cliff. The seat does not move when you get in they're much to rigid. The side seat struts are welded and triangulated to the frame with the seat mounted in the traditional way. It hasn't made him any faster or slower as I said it's had no effect at all other than to dampen vibration a bit.

Brian

Bernie Lacotta · Joined: 21 Mar 2006 Posts: 168

Brian Degulis · Posted: Mon Nov 26, 2012 7:54 pm Post subject:

Well I apreciate everyones input it's logical information. For now I,ll wait and see. I'll be sure to post any positive or negative effects if I see them.

Brian

John Matthews · Posted: Tue Nov 27, 2012 7:27 am Post subject:

Let us know how it works out technically, and what the officials say when your son starts winning Wink

Cheers,
_________________
John Matthews
Heartbeat Power, LLC.

Walt Gifford · Posted: Tue Nov 27, 2012 7:40 am Post subject:

WKA Tech 251.12 Suspension Components:
Use of suspension components of any type, including springs, shocks ect. is prohibited.