Texas Terror, part 2

jamyers

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Original build thread from 7 years ago: http://www.diygokarts.com/vb/showthread.php?t=14872
Basically it's a lengthened "ThunderKart" with an electric start Briggs 8hp flathead that I rebuilt, ported and relieved years ago.

So...6 years ago, the kart carburetor started flooding every time you drove over the least bit bumpy ground, I got tired of messing with it, the kids moved on to sports, etc, and the kart got parked in a shed.

A month ago, my son (now a college freshman) comes home due to Covid19, drags the kart out, and we start messing with it again. Cleaned, lubed, new gas and oil, but the Walbro LMT just wouldn't run worth a darn unless it was on nice smooth pavement, and then it was pig rich...and going around on a soccer field was enough to flood the engine out completely.

We found the old "Keihin" clone PZ26, drilled and tapped another hole in the angled intake manifold, got it mounted, disconnected the governor linkage, and whaddyaknow - it started, idled, and seemed to be able to take a load without flooding insanely.

So I took it for a spin around the Campgrounds - and HOLY COW that thing runs like a scalded dog! On a gravel road it's nothing to hit the throttle and have the rear end start coming around, and out on the large play field it pulled like a freight train! BIG SMILES for me - right until the drive chain broke apart in 3 lengths, leaving me to coast along still smiling.

Now I need to go get some more chain!
 

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jamyers

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Wow!! A blast from the past!! :D :D

Welcome back. Glad you got the kart sorted out

Hey, how you been? :wai: Great to be back!

Son and I just spent a half-hour blasting around Camp on the kart, it's never run this well - I need a tach now so we don't over-rev, lol. :cheers2:
 

jamyers

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Final chapter...

After yee-hawing around Camp all summer, the Briggs 8hp engine finally got to where it wouldn't start AT ALL. Checked compression, came in at a whopping 25psi. :oops: Pulled the head, and the piston is rocking in the bore and has about .020 max clearance. Rings are shot, bore is worn but not scored, could easily be bored and get a new piston / rings, but looking at $75-90 just in parts, don't make much sense right now - so it came off and went onto the shelf for laters.

We stripped the frame down, cleaned and painted it, replaced a blown rear tire, and swapped on a low-hour Predator with a Comet 30 that's been laying around.

Just put it up for sale on Craigslist and Farcebook, asking $600 - hopefully can turn it into some monies for Christmas and other projects!

Here it is in it's current glory, along with a video of it running this afternoon.
 

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jamyers

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Well....it didn't sell. Posted on Craigslist and Farcebook Marketplace, and all I got was a bunch of clowns asking if I'd take $300 for it - without even looking at it in person. Half the people didn't even read the ads, sigh...

Then right before New Years, the carb started acting up, grrr. Something screwy with the low speed pilot jet apparently, but I just couldn't get it cleaned up - which isn't right, I've never spent to much time cleaning and blowing out a carb. So...

I got a replacement carb, which serves me right as the replacement carb had little bits of metal from the manufacturing process stuck below the throttle shaft, which would stick the throttle at 1/2 way open at random intervals - NOT FUN when there are large oak trees around. Pissed me off some more, so...

I bit the bullet and picked up an intake manifold / adapter pipe to mount a known good clone of a Mikuni VM22 carb on it. The jets that were in it have NO markings on them, and my drill bits only go down to a #60, so I have no idea what's in it. BUT it idled best with the mixture screw 8 turn out, which tells me the pilot jet was too small, and while it idled, pulled at low rpm very well, opening the throttle more than 50-75% would cause the engine to just die out - which tells me the main jet is too small. Soo...

I dug into a box of jets I'd bought from Amazon for another kart/carb project, and lo and behold - apparently Keihin and Mikuni Clone carbs use the same jets! (at least these two, lol) A bigger pilot jet put the idle mixture screw back at 1.5 turns out, and I drilled the unmarked original main jet out with my #60 drill just to see how it'd react.

Also...

I had this really old and rusty exhaust header and "muffler" for a Briggs Flathead laying around, as well as a piece of chrome pipe that I think was part of an old shower handle or something (who knows?) The flange is a tiny bit smaller than the Predator, and the inside diameter is a tiny bit smaller and isn't "D-shaped" like the Predator head outlet, but I cut the flange off, cut the bolt holes outwards, fit the pipe over the flange, welded it up (Harbor Freight flux-core welder one spot at a time), then used a 3/4" pipe bender to get a large-radius 90-ish-degree bend.

Here's a video of the results. It starts super easy once warm, but when dead cold it's a pain - I haven't figured out the routine yet I guess.

 

jamyers

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Took it out last night, and WOW does it go! With my 180-lb butt on it, it has no problem spitting dirt all over the place when I hit the gas, and drifting around on the grass is no sweat. Took it out the back gate and down a paved back road, and flat out it clocked 39mph with a gps app, the fastest it's ever been! Steering is good and stable, now the weak link is the band brake which works, but not with the authority needed for speeds like that.

I think I'll try another run at selling it, either I get what I want for it or I'll give it to my nephew for his 2 boys to terrorize Huntsville Alabama with, MWU-HAHAHAHAHahahahaaaaaaaa
 

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