Dirtbox Venom mini-buggy upgrade/rebuild!

[andrew1320]

that last pic is creepy!!

Build is going along nicely though.. keep it up

 

[mysteryboy28]

rear fenders done.

picked up a nice lil 125cc 2-stroke 3-wheeler for $100 today. the guy had just rebuilt the motor (ran it out of oil and burned up the motor). no seat, and a seriously leaky front tire. shifter kart time! lol. motor runs fantastic. the guy (i keep wanting to say kid - he's 19 years old. lol) is a regular motorhead, and lives right around the corner from me. says he'd love to help me with motor stuff, and i told him he was welcome to come use my tools and hang out any time.

it"s been raining non-stop around here. rain equals lots and lots of icky squiggly squishy gross worms. i've stepped on so many... it's so gross. lol.

 

[mysteryboy28]

it's freaking cold out! only 38 degress. wtf??? not supposed to start warming up again till sunday. grrrr... i really wanted to get the front fenders done today

edit: it snowed a bunch too!

 

[mysteryboy28]

front fenders done.

carbs still giving me crap. tried cutting q-tips in half and sticking them on a drill and polishing the inside of the needle/seat on both carbs. worked great for the carb that was being problematic - but now the other carb is giving me crap. bah! will give them one more go, then maybe try some new plugs since i've fouled this set up pretty good.

 

[greaser]

wow it looks sick. carbs can be a pain in the arse sometimes but you will get it.

 

[B man]

you putting lights on it?

 

[mysteryboy28]

Yeah, headlights and a working brake light.

 

[mysteryboy28]

buggy seems to running better after using some starting spray on the carbs. i think what might be happening is the plugs are fouling from too much oil when idling. at a low RPM there's quite a bit of smoking, so not enough fuel/air going through to burn off the oil. i think bumping the idle up a notch might help. but a couple puffs of starter spray seems to clear out whatever was in the cylinders, and the buggy hauled a$$ down the road.

welded on a bracket to the exaust, and drilled a hole through the frame to bolt it in place.

welded some nuts onto the battery frame to hook bungee cords to.

welded a tab to the frame to bolt the front brake hose tee to.

 

[exenos]

Seriously go out an buy a couple sets of jets that are smaller than whats in the carbs and play around with those, the smoking will probably go away. The engine is jetted a few sizes too rich right now.

If you have 260 mains in the carbs right now get a set of 250's 240's and 230's and give those a try. The only possible problem is if you sell a buggy to people who don't know enough to re-jet it when it gets colder.

 

[mysteryboy28]

curious, if it's smoking due to lack of fuel and air (too much oil), why would less fuel help? when it's not fouling, the plugs turn a nice caremel color.

i agree that because air is thinner in warm weather than it is in cold weather that you would want to jet slightly smaller. but from what i've read, the difference isn't super significant, and the slight richness helps to keep things cooler.

 

[mysteryboy28]

fabbed up the mounting tabs for the 4-point harnesses. will weld them on after i tear the buggy apart. disassembly will commence thursday night. then i will do finial welds and lots of grinding! warm weather this weekend, good for painting!

meanwhile the starter finally gave out on me. the starter gear shoots out, but won't crank the engine, and then won't even retract when i release the key. i was careful not to exceed 30 seconds of cranking at a time (as stated in the manual) while sorting out the carb issues. but it was just too much for the starter. i even tried a brand new battery. looking for a replacement starter now...

 

[fowler]

Turn the key and hit the starter with a soft faced hammer (or piece of 2x4)

It is likely the brushes are just stuck

Also make sure the starter is getting its full 12 V
If u were cranking close to 30 seconds then the soliniod may be cooked

If it won't start in 10sec then its not going to start
30 secs is way too long
It says don't crank for more than 30 but that assumes u are only going to push the limit once or twice

If the pinion won't retract then that's good
It likely means that the motor is applying some torque to it

I'd at least pull it apart to see if there's anything to fix
Brushes are easy to replace, maybe the armature needs undercutting

Worst case u can see how it work

 

[mysteryboy28]

Brushes are easy to replace, maybe the armature needs undercutting

Worst case u can see how it work

brushes? like a hair brush? undercutting? like not cutting enough? armature? you lost me. lol.

ordering up a brand new starter with 1 year warranty. it wasn't too pricey, and saved me a lot of time messing with trying to fix it or finding a good used one with unknown life expectancy.

note: in the future, 30 seconds is too long. tooooooo long.

 

[DaiSan76]

brushes? like a hair brush? undercutting? like not cutting enough? armature? you lost me. lol.

ordering up a brand new starter with 1 year warranty. it wasn't too pricey, and saved me a lot of time messing with trying to fix it or finding a good used one with unknown life expectancy.

note: in the future, 30 seconds is too long. tooooooo long.

Brushes
http://image.made-in-china.com/2f0j00uvptyMQkheci/Electric-Motor-Brush.jpg

 

[fowler]

brushes? like a hair brush? undercutting? like not cutting enough? armature? you lost me. lol.

ordering up a brand new starter with 1 year warranty. it wasn't too pricey, and saved me a lot of time messing with trying to fix it or finding a good used one with unknown life expectancy.

note: in the future, 30 seconds is too long. tooooooo long.

Ha ha
Fair enough
First off I got it wrong
It's the commutator that u undercut
There's at least 2 brushes in every motor 1 positive 1 earth
The armature is at least 1 electro magnet on a shaft ,there are also magnets on the houseing of the starter
These are field winding
When u apply power 12 volts it goes to the field windings and to the brushes
The brush touchs the commutator and transmitts a current to the
Armature
Then back it goes back out the commutator to the negative brush to earth
With currect flowing though the armature it turns it magnetic
This attracts it toward a field winding
as it spins around to the first feild winding commutator is now also spun around and is now in a differant position
The current is now reversed and the armature is attracted to the other feild winding
The proccess repeats and u get spinning

What I described is like a 1 cylender engine
The commutator is like the cam shaft

As u can imagine two bit running together ( brushes and commutator ) this causes wear so eventually the brushes wear out
Also each little gap in the steps on the commutator can get smudged over and u get a dead short
So u can replace the worn brushes and cut out each step in the armature

U may as well pull it apart now and do a little research as to how it works

 

[fowler]

Sorry cant work out how to edit a post in tap talk

 

[mysteryboy28]

Brushes
http://image.made-in-china.com/2f0j00uvptyMQkheci/Electric-Motor-Brush.jpg

so THAT's what harbor freight was including with a lot of their power tools. i had no idea what they were, and was just throwing them away. oops. lol. i mean the tools are pretty much throw-away tools, but still... it's nice to know.

 

[DaiSan76]

so THAT's what harbor freight was including with a lot of their power tools. i had no idea what they were, and was just throwing them away. oops. lol. i mean the tools are pretty much throw-away tools, but still... it's nice to know.

Those screws on the side? That is how you take the brushes out and scrape them...with a brush. Then your grinder works again. It's almost as if they knew they had problems with the brushes.

 

[mysteryboy28]

buggy completely disassembled. grinding and final welds underway.

meanwhile, the best wife ever decided to help out. she rocks.

http://www.youtube.com/watch?v=1oK7UsRlSYA

 

[greaser]

awesome lol my wife would last about 5 seconds, she isn't mechanically inclined at all but she puts up with my $#!t so I am happy.