Stock clone upgrades

Robert Hall · Posted: Wed Nov 28, 2012 10:09 am Post subject: Stock clone upgrades

What all can I do for upgrades to a stock clone and still stay within WKA rules? The only thing I've done so far is the AR39010X plug. Now I'm wanting to freshen-up for next year and was wondering about springs, carb/jets, timing, etc. I do not want to have a non-conforming engine. On the outside chance I do win a race, I want legality to be a source of pride. Thanks

John Matthews · Posted: Wed Nov 28, 2012 12:26 pm Post subject: Re: Stock clone upgrades

Robert Hall · Posted: Wed Nov 28, 2012 1:18 pm Post subject:

Makes sense. Thanks John. Maybe my money would be better spent on driving lessons and tires

Tim Salvino · Joined: 20 Nov 2010 Posts: 261

John Matthews · Posted: Wed Nov 28, 2012 3:22 pm Post subject:

There's nothing wrong with freshening your motor if it needs it, or trying to get the most out of it. That's part of what we do as racers but driving and setup are definitely the best way to improve lap times for most of us Wink

It's just that the concept of clone racing was to keep it simple and not worry so much about the engine. It's changed a lot since I put my first clone on my daughters kart in 2006 and not really for the better IMHO.

Hopefully we'll be able to make it down to Lansing next spring and we can hang out....

Cheers,
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John Matthews
Heartbeat Power, LLC.

Michael Knauf · Joined: 31 Oct 2011 Posts: 58

One could build a really good clone with only a few tools and some basic knowledge.

The hardest part is carb, at least for most. I would recommend just springing for a Dover carb.

The rest of the parts are so cheap why not spend the time messing with the engine? If you screw something up you can buy a new part for a few bucks.

IMO don't worry about max stroke cranks and such.

Get the latest legal cam, some good springs, flywheel and some keys (pm if you want to know what one).

Measure the pop up, head gasket and head cc with a buret and figure out your cc's and then get the head machined down to where you need it to get the min.

As far as the bottom end a good hone to set your piston cylinder clearance will help a lot. Here is an area you can experiment. Blocks are cheap so if you go too far on one, just buy another and build it a little tighter.

Make sure you clean everything with soap and water to get rid of any grit when you hone. Not sure what is legal with the rod, but if you can hone it, do it.

Valves, just lap them in good and set the lash to 0.001" intake and exhaust. You could degree your cam but 99% sure it will be legal if you get a Dyno CL cam.

You should be able to buy the motor, and all the parts for around $300-$400 depending on what flywheel you use. You might have to invest in some tools to do some of the engine work but you'll be able to maintain your engine and do your own rebuilds.

Like I say, clone parts are so cheap just replace parts when wore. No boring allowed anyway for BSP, so that keeps it simple.

A couple other things from my clone experience. Buy solid dowels for the side cover and serrated flange bolts. Add some grey RTV to the threads before installation and torquing and you'll have a better chance of not losing them... my loosened up 3 times on me until I did all three of those things I mentioned. Still not bulletproof either. Plan on pulling the cover and resealing periodically.

Also some of the side cover gaskets don't match. Check before you button everything up. I just used a dab of black RTV where the cover doesn't match the gasket even though it wasn't technically legal to do so. No performance gain, so screw it.

Also the other thing I forgot to mention is check the end play on the crank. Some engines are too tight so you need to double gasket them to get enough clearance.

You should be able to build and maintain a competitive motor like this. I would still work on your kart setup and driving but there is a difference between a motor that is out of the box and one that has these things done to it.
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Mike

Scott Farmer · Joined: 30 May 2009 Posts: 16

Valves, just lap them in good and set the lash to 0.001" intake and exhaust. You could degree your cam but 99% sure it will be legal if you get a Dyno CL cam.

In my opinion the 99% mentioned here is a very optimistic estimate
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Scott

Michael Knauf · Joined: 31 Oct 2011 Posts: 58

Maybe so. But what is a home builder going to do? Twist cams? Buy another?

That was never the intent of this class and plenty of people build their own still.

They do make the minus cam if you have an issue... but that is only lift, not duration.
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Mike