July 16, 2017 at 10:27 pm #83685
As I’ve been getting into autocross in rental cars (another subject for another day), I’ve been telling everyone who would listen that I wanted to get a shifter kart. One of those people sent me this listing, suggesting it might work.
I jumped on it right away. The seller turned out to be a very cool gentleman and I was more than happy to pay the asking price. What did I get? Well, I’m still figuring all that out. See, I know and love cars. This is another story. This is just a way for me to go fast and I know almost nothing about it.
So, that’s where this build thread comes in. Part of this is documenting things for my own sake, part of it is sharing experiences with the world, but quite a bit of it is hoping that I’ll get some useful guidance.
The frame itself is a Tony Kart, but I can’t tell what year. Several of the parts interfaces on the frame have quite a bit of play in them, from the pedals to the side bumper supports. This will need to be sorted out.
The engine is a ’99 CR125 that seems not to have run in some time. I was told that it has a 6-speed transmission and was modified for more power, but had trouble shifting which was diagnosed as possible bent shift forks. I talked to John Sefcik of SRS engines who specializes in stock CR125’s looking for information about the transmission since ’99 CR125’s came with 5-speeds, and he said it is almost certainly a ’96 or ’97 6-speed but there’s a “99% chance the problem is outside the engine.” He suggested it might be the linkage (which does have a fair bit of play) or the seat moving around and interfering with the linkage.July 16, 2017 at 10:28 pm #83686
The kart really did come with a ton of extras.
There’s a set of three used wheels, one brand new set of wheels, two old but unused sets of tires, a tire installing tool, a bunch of extra gears…
…extra hubs (one has some bolts that need extracting), possibly a flywheel tool?, exhaust bracket, aluminum alignment discs, ballast…
…a bunch of extra two stroke oil and a funnel (which I won’t bore you with a picture of), extra engine case halves, some random pistons and other engine stuff…
…MyChron 3 with data logger, laser alignment tool, kart suit and rib protector, trackside transponder, and probably some other stuff. Hopefully it’ll all come together into a fun project. For now, I’m pretty pleased with the purchase. Time to get it running!
July 17, 2017 at 5:20 am #83689
A lot of the parts that you talk about having “play” are supposed to have play. One [of the many] kart-chassis tuning methods is to tighten and loosen brackets which attach to the chassis – or sometimes removing them all together. This includes floor tray, front-bumper bracket, side-pod brackets, torsion bars, seat brackets, etc.
Your chassis looks to be quite old as the side-pod bars do not mount perpendicularly to the chassis – that’s always a quick tell. That was standardized sometime in the early- to mid-2000s.July 17, 2017 at 12:27 pm #83703
Do the brakes work? If it’s been sitting for a long time, as it looks, the best thing you can do is tear down the entire chassis and clean/inspect everything as you put it back together. New seals all around, engine and brakes would be a good start!July 17, 2017 at 6:45 pm #83708
It’s definitely old. The homologation date is ’99 so at least 18 years. I really don’t plan on being competitive, but it is already clear that finding ‘vintage’ parts may be a bit of a challenge.
The brakes don’t work well. I was actually planning on bleeding the brakes tonight, but valve on the included gravity bleeder won’t allow it to thread onto the master cylinder. Is it possible that it’s supposed to be reverse-bled?
I do plan to do a fairly intensive rebuild. I will obviously be looking for abnormal cracks and wear, but it’ll definitely be a learning experience. Any tips or information would certainly be appreciated.July 17, 2017 at 8:05 pm #83711
Don’t even waste your time bleeding it, most likely it will have all kinds of rust inside the pistons and calipers.
Your best bet is to take all the hydraulics apart, hone your cylinders and replace all seals. You can find cylinder cups from an auto parts from a rear wheel cylinder rebuild kit that will fit that diameter, and for the master cylinder seals you will have to contact a kart parts supplier, they can still get those old kart seals, just ask them.
And for your bleeding procedure, just buy a turkey baster, remove the plunger and use it as a funnel screw the tip into the threads and fill it up, jack up the front end of the kart put a wooden block underneath and start gravity bleeding your rear calipers. Then lower the kart down again, and start doing the front calipers.
Here’s a store that has your seals, contact them, or if you already know your size then just order them from their website.
Good luck. http://fastech-racing.com/brake-seals/July 18, 2017 at 6:28 am #83733
Okay. I had already picked up some steel wool to do just that. I guess I’ll move it up on the order of operations.July 18, 2017 at 7:27 am #83734
you may need to use an actual brake hone.July 18, 2017 at 9:53 am #83739
I still need to get one of the front calipers off the spindle and I broke two 90 degree fittings, but I’m so glad I took them apart. The pistons for the rear caliper, in particular, needed quite a bit of coercion to come out. Thanks for the tip!July 19, 2017 at 3:34 pm #83788
Can you post pictures of the caliper bores? Let’s see if they can be saved…or just need to be replaced. Stuff that sits a long time with brake fluid in it doesn’t do too well…July 19, 2017 at 4:51 pm #83790
I don’t have anything cleaned up yet, but I’ll post pictures of the bores when I do. I need to find a source for the 90 degree fittings that I broke and extract the broken ones. I would like to find the plastic and rubber pieces to fully rebuild the master cylinder, but I may be out of luck.July 19, 2017 at 9:07 pm #83793
Here you have it, you may wanna call them to verify the parts you need.
You may wanna hold and support those 90 degree fittings with another wrench next time so that they don’t break off, they are pretty fragile.July 20, 2017 at 5:14 am #83794
pics not working for me. try imgur for a host.July 20, 2017 at 11:32 am #83810
Should be fixed now. I had tried posting from my phone.July 20, 2017 at 12:42 pm #83814
As I’m ordering new seals, I’d also like to replace the old brake lines. They are currently braided steel, but I’m interested in switching to nylon as I presume that would be less expensive and have the added benefit of making it easy to spot bubbles in the system. I’d also be interested in switching to banjo fittings. Thoughts?July 20, 2017 at 1:19 pm #83821
Those master cylinders do not look Tony Kart style, maybe they were replaced by something else?
You can use plastic lines, but the fittings will be hard to find in metric, and nearly impossible to attach them to banjo fittings.
Look for good used ones on ebay, besides those brake hoses may still be good. They are nylon as well, they’re just cover in steel breaded mesh, and a nice rubberized coating that’s all.July 20, 2017 at 3:15 pm #83823
Rather than try to take pictures of every bore, I tried to choose the worst front, rear and master cylinder bores to take pictures of. Each has been lightly cleaned up with denatured alcohol and steel wool. I’m leaning towards buying a brake cylinder hone for everything.
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