I acquired a KDX80 when I was about 15 (over 6 years ago) and at the time I already had a KX80 so I figured some day I would find a use for a 2 stroke air cooled (compact) engine. I cut the belly of the bike out and parted the rest on eBay. The engine was tucked away until about a year ago when I found a very rare (front mounted engine) miniature Sears/Craftsman riding mower for sale $25. It had a blown motor, and I've always wanted to compete in the local tractor pull contest at the annual fair, so on she goes!







That we know of, it was released in 1971 but some of the parts could have been made as early as 1969ish.









I don't have much identification on this motor, but someone told me it translated to a 1984-C1 is this correct? I need to be able to buy parts, I am going to bore the cylinder but what else can you think of to boost performance? Does anyone know of any other carbs that fit or something?

^DX080BE012379^

 

Stripped it down:



Steel plating will help stabilize the front end:



Made my steering cutouts:



Engine mounts and the steel plating are only bolted down, good enough to get the machine moving. I will weld everything together before I run the drivetrain with a torque load:



Underneath:



Cut bolts flush:



Old rims on solid rubber:



New chrome split rims on X knub tires, and high speed 4 lug hubs (also widens my front track distance):



High speed hubs with grease fittings:



Front view old:



Front view new:

 

cool build,..like to see it run!!

 

Easier said then done.

 

sweet let us know how it runs

 

I just got back a hard drive I sent out for recovery that died years ago, here are the original photos of the tractor when I got it:





And here is a long lost project that was on there I forgot about, from when I was 16. CB350 twin engine on a Dynamark...lol

 

I'm thinking an oversized carb won't do anything but over speed the motor? Or would I actually get a better throttle response and launch? If I did it would be a KX80 or KX100 carb, does anyone know if the KX80 and KX100 both use the same body with just different jets or maybe the 100 and 125 use the same body?

If I brought the head to a machine shop and had it shaved what else should be done to run a higher compression ratio? Jets or intake port shape changed? Spark timing changes? Or can the compression just be raised without any other major changes...

 

2015! hahaha I am going to make this happen guys, I just pulled it back out and put it on the chopping block. So we know its a 1971 at this point right? I am measuring up the rear end so I can size wheels, get an axle and bearings with hangers then weld up after I have my rear end assembled. I will run a mini disc brake in the rear...most likely no suspension.



This is how she sits currently, Subaru Brat seat (not mounted), high quality metal tang wood steering wheel that I plan to cut into a butterfly (not mounted), look closely I have a Budweiser tap handle as a shift bar (not mounted), the hood scoop is the top off an old retro vacuum cleaner that had a light in the front (not mounted), engine is not functional I have things to sort out such as fuel delivery and exhaust routing...all controls: