Shifter Karts

[SweaterDude]

So i found a way that i can get a Complete 125cc (2stroke) kart at a reasonable price.:rockon: And since these carts retail at about $8000 new, that really isnt an option for me. My question is: Does anyone here kart or have any experience in building them. The one i can buy doesn't run and its older, which is a good thing oddly enough, but the frame should be in good condition. The engine is a honda cr125s (stocker) and it has 4 wheel hydraulic disc brakes. The frame is Trckmagic, which is a major brand but not super high end. I dont have it yet, im just looking into what problems i might face as far as rebuilds and such might go.

Edit: the real thing is that ive never worked much with 2strokes and don't know how much i could be getting into. four strokes are easy, clean the carbs, flush the tank, new plugs, ready to go.

Thanks,
Chris

 

[SweaterDude]

Bump.

I bought the kart a week ago. Its not actually complete but its close. I did however get it for a lot less than i initially thought because its is an incomplete kart. The motor is indeed a honda CR125r and the guy gave me the only carburetor that he had left, which turns out to be a TM modified Mikuni 38mm that was on a former world championship winning kart. the motor that kart used was blown so he didn't feel too bad giving me the Carb. I took the carb to the honda shop to see what was different, turns out the slide, spring, guide, needle-valve, and float bracket are all different and it weighs about 2/3 of the regular carb:rockon:

 

[FinalImpact]

Bump.

I bought the kart a week ago. Its not actually complete but its close. I did however get it for a lot less than i initially thought because its is an incomplete kart. The motor is indeed a honda CR125r and the guy gave me the only carburetor that he had left, which turns out to be a TM modified Mikuni 38mm that was on a former world championship winning kart. the motor that kart used was blown so he didn't feel too bad giving me the Carb. I took the carb to the honda shop to see what was different, turns out the slide, spring, guide, needle-valve, and float bracket are all different and it weighs about 2/3 of the regular carb:rockon:

A 38 seems pretty huge for single 125cc. My 650 kawi cam stock with a 38 and runs happily with a 44mm. The point, a 125cc simply may not move a enough volume to make use of that carb. So what you end up with is a sluggish turd unless its basically geared for WOT in 5th @45mph. Anything below and it'll likely fall on it's face. I suggest some reading to see what they came with stock. So is it kick start or do you need a juice box and shaft? Reliable operation may be a consideration.

Looks like a great project tho!

 

[iSteve]

Actually a 38 will work well with this engine in a kart. If I remember my old CR125 came stock with a 34mm. The smaller wheel size of the kart will let this engine rev.

And hold on when you ride this thing. I got to try one several yeas ago these 125's are crazy quick with 0 to 60 times around 3 seconds and they stop just as fast.

 

[irish190]

Looks like a super fun project, cant wait to see it when its done.

 

[SweaterDude]

The 38mm is the stock size for the cr125 engine. this one has just been modified and blueprinted for more power:Flash: but on the downside i need an electrical guru (i believe motogiro is the forum electrician) because i didn't know which model engine i have until after i bought the wrong CDI box ('98 instead of '99) and i only have a few days to make the decision to keep or return the CDI box. still need a little more $$$ before i buy the exhaust and radiator.

my engine is a 1999 honda cr125r 2-stroke dirt bike engine. and it supposedly revs to 13,000

 

[Motogiro]

The 38mm is the stock size for the cr125 engine. this one has just been modified and blueprinted for more power:Flash: but on the downside i need an electrical guru (i believe motogiro is the forum electrician) because i didn't know which model engine i have until after i bought the wrong CDI box ('98 instead of '99) and i only have a few days to make the decision to keep or return the CDI box. still need a little more $$$ before i buy the exhaust and radiator.

I really couldn't tell what year would work for that motor and the later year may be okay but I would stick with the same year if possible so as to may sure all signals agree.
What exhaust does it have?

Cool project!

 

[SweaterDude]

I really couldn't tell what year would work for that motor and the later year may be okay but I would stick with the same year if possible so as to may sure all signals agree.
What exhaust does it have?

Cool project!

the '98, '99, and 2000 models are all different CDI's i have found out. but the '98 and '99 are both two plug boxes where the 2000 is a single. ill post pics of the wiring with my mismatched parts, that might be able to work.

As for the exhaust, it doesn't have one. I have an FMF gold series fatty pipe and silencer that fit a CR85, but the expansion chamber is not big enough and it wont mount up anyway.

I need a cart specific exhaust bend and mounting bracket so it'll end up being $500 for the full system and mount. A radiator with mount will run another $200 and i need a front sprocket, chain, and J-arm shifter which will be another $100. and if i cant get this CDI to work with the coil then it'll bring me to an even $1000 to mechanically complete the restoration.

 

[SweaterDude]

the top row is all on the coil and the bottom row is all CDI box. The solid green wire is the ground, but one of the plugs from the coil has a solid green wire that goes into the connector but the CDI box does not have a solid green wire (just a green with a stripe). also the CDI has the banana plugs backwards of the way that the coil's are (female on black w/ stripe vs. female on solid black)

if i need to i can post a video on sunday night for a better idea about which i am speaking.

 

[DefyInertia]

Awesome.

You'll find that 2Ts are easier to work on than four strokes. No valves to adjust...just keep the top end fresh.

 

[Cameronhall]

this is so cool!!!!! ive been flirting with the idea for some time now. i think this is above me though. wish you best of luck to you. really cool project, and please keep us posted!!!!!!!

 

[SweaterDude]

OK i finally uploaded the vid to YouTube. here's a little better idea of what i am trying to do.

[ame=http://www.youtube.com/watch?v=a0yyE8JL-xY&feature=plcp]Cdi issue - YouTube[/ame]

 

[SweaterDude]

Hello world, its......... Update Time!!

just ordered the remainder of my needed parts today:sinister:

talked to the guy from sharkshifter.com (Mike) and got deals on the Radiator, Full Exhaust w/ hanger, and FREE SHIPPING. looks like im gonna be holed up in the Mancave for the weekend:rockon:

 

[SweaterDude]

Oh i forgot to mention that i went ahead and bought the '99 CDI so there is no way to mess that up now

 

[PhotoAl]

You will have a ton of fun with that kart. Shifter karts can be very quick. Have watched and photographed them several times at Barber's. They are quite difficult to catch on camera as they change direction so quick. Have seen karts spin three times then catch and go on - all without running off the track. See you are from Nashville - karts are racing at Barber's in July if I remember correctly.

 

[SweaterDude]

You will have a ton of fun with that kart. Shifter karts can be very quick. Have watched and photographed them several times at Barber's. They are quite difficult to catch on camera as they change direction so quick. Have seen karts spin three times then catch and go on - all without running off the track. See you are from Nashville - karts are racing at Barber's in July if I remember correctly.

gotta get it running and get used to driving one first. Barber is a fun track though, i used to drive with my dad in the SCCA Modified Vintage Class (MVC) in a 1976 BMW 2002, but this should be much more exciting.

 

[ste]

looks like a great project
have fun
i tried these once at a local track, a few friends and lots of beer:thumbup:

 

[SweaterDude]

News update: Parts are in and on. i am now literally waiting on a front sprocket bolt and washer, because i need them to be able to roll start the engine (there is no electric/kick start).

Things left to do:
-make brackets for ignition coil and CDI (aluminum strips @ home depot)
-buy a kill switch (maybe)
-put hoses on radiator (have the wrong dia. need to exchange)
-take a few links out of the chain
-get sprocket bolt
-replace crusty fuel lines (have new ones)
-tune carb once running
-tear up the neighborhood/church parking lot

 

[SweaterDude]

Bump.

Ok, the bolt should be in Thursday. I have to do some research as to whether the CDI runs on a Normally closed circuit or a normally open circuit as to which kill switch i need, and if it's normally closed then i need a switch just to fire.

need to do list:
- just bought a chain break tool so i can finally take those pesky links out
- align front/rear sprockets
- bleed and adjust brakes
- readjust throttle and clutch cables (and check the choke as well)
- find out circuit type (N/O or N/C)
- safety wire every castle nut on cart and tighten all bolts
- other little stuff im probably forgetting about for now...:spank:

 

[SweaterDude]

Bump!

Brakes are bled:thumbup:

Spindle bearings are fine the brakes were just sticking and i didnt have the kingpins tightened down.:spank:

goin' down to swap wheels/tires in the morning

If all goes as planned i wont be able to hear the fireworks over the cracklin' of my expansion pipe.