Semi-abandoned Hammerhead 250

[KenMathisHD]

Did you bench bleed the master? Same procedure, lines from the master into a container of fluid. Top off the master, push the plunger in and out until no more bubbles are visible through the lines. Tighten the fittings, install the master on the kart. You may have to bled the system again as described earlier, not likely though. If you aren't getting fluid through the hoses this way you have internal master issues.

I did not, it’s the same master that was on the kart when I got it so I haven’t taken it off yet. I’ll pull it off the kart and see if I can bench bleed it. I can just fill the reservoir and run some clear tubing from the line hookups on the master to the reservoir, yea? That way it’s circulating the fluid that comes out back into the reservoir

 

[madprofessor]

Keep the tubes short going back into reservoir, and keep the ends submerged so you can see any bubbles, and not suck back any air.
The problem with releasing the pedal with the caliper bleeder open is you were only pushing a tiny amount of fluid to begin with.
Only a tiny amount of air would have been pushed out, so only a tiny amount will suck back in on release. If you're using a 2' tube into a bottle, that tube by itself probably holds 5 times as much air as you push out, so it's not going to suck any fluid out of the bottle on release, just regurgitate air back and forth.
If the bleeder is closed at the bottom of each pedal push, the fluid pushed will stay where it is on release, waiting for the next push behind it. Eventually the fluid will reach the caliper, having pushed out all the air ahead of it.

 

[madprofessor]

Alternate one-man method using your tube drilled through the bottlecap: Make sure the tube through the bottlecap is sealed (with silicone or anything that works) against leakage. Put a bunch of fluid in the bottle, screw it into the cap. Turn the bottle upside down and poke a hole in the bottle bottom to relieve air. Hang it near the caliper with the tube attached to the bleeder. Pump the pedal like crazy, watch for bubbles in the bottle, stop when bubbles no longer present. Close bleeder.

 

[KenMathisHD]

Keep the tubes short going back into reservoir, and keep the ends submerged so you can see any bubbles, and not suck back any air.
The problem with releasing the pedal with the caliper bleeder open is you were only pushing a tiny amount of fluid to begin with.
Only a tiny amount of air would have been pushed out, so only a tiny amount will suck back in on release. If you're using a 2' tube into a bottle, that tube by itself probably holds 5 times as much air as you push out, so it's not going to suck any fluid out of the bottle on release, just regurgitate air back and forth.
If the bleeder is closed at the bottom of each pedal push, the fluid pushed will stay where it is on release, waiting for the next push behind it. Eventually the fluid will reach the caliper, having pushed out all the air ahead of it.

I'm gonna see if I can't pull it and bench bleed it tomorrow and then try that alternative one-man method once it's hooked up

 

[madprofessor]

try that alternative one-man method

It's all about there being only fluid sitting at the bleeder when you release the pedal, so only fluid (no air) can suck back in.
Finer point: Just BARELY crack the bleeder open, so little there's actually some pedal resistance and the pedal maybe even goes down slowly.

Pump the pedal like crazy

You pump like crazy so you outrun the fluid sucking back in by pushing fluid from the master cylinder out faster than the bleeder lets fluid back in.

 

[KenMathisHD]

Looks like my lack of focus has made the decision for me.... This is why you don't keep your hands anywhere near brittle plastic. Lesson learned. At least I'll be starting off with a fresh master cylinder whenever it gets in. Is the procedure for bench bleeding a new master cylinder any different from bench bleeding an old one?

 

[KenMathisHD]

Also, here are the images of the bracket for the old speed sensor. Still waiting for the new one to come in. I guess now would be a good time to check why my front driver tire keeps losing air, the top of the valve stem appears damaged so that's probably the case. Are these valve stems typically made out brass or something similar? The metal looks awful soft

 

[KenMathisHD]

Used the old bracket to make a new better one, sprayed it with some rustoleum so just waiting for the pain to dry. It runs the bracket over the top of the bar so that the top of the bracket runs just under the rotor on the CV shaft, this puts the wire a bit close to the CV, but with some color matching zip ties for firm wire routing (cause that's all the stock wiring harness used anyways) it should both work and look pretty good. It puts the speed sensor pretty close to the magnet

 

[madprofessor]

Here's a bench-bleeding video with a guy bleeding an all new brake system (all air inside) that uses a packaged set of tubes and fittings, you can just make your own. He also does a one-man "gravity bleed" of the wheel cylinders, which I don't ascribe to since air bubbles rise in a fluid except in very tiny I.D. tubes. The upside-down bottle w/fluid above the caliper takes care of that.
How to Bench Bleed a Brake Master Cylinder - EASY! - YouTube

 

[KenMathisHD]

Here's the new speed sensor installed, does that look like enough clearance or does it need to be further away? The bracket worked pretty good, though I slightly undermeasured the length of the arm extending towards the rotor, so I had to bend it out slightly. It registers on the speedometer now though, I originally had it bent too close and the magnet took a bit of the shiny plastic off the edge of the sensor.

The last picture is the wiring setup for the speed sensor for how it connects to the front harness so I or somebody else can referense it later if need be.

 

[Bansil]

The question is "is the speed sensor close enough?"

Since you don't have brakes, you can't safely test drive it

...I got it, do you have a 8ft pc of metal tubing that you can put a chain or heavy rope through?

If so attach one end of chain to frame or trailer ball of a "pull" vehicle.

Pull tube up to "pull" vehicle frame or ball tightly, and attach other end of chain to front of gokart frame.

This will allow you to be pulled to test speed sensor, BUT you won't hit pull vehicle because you don't have brakes. The pipe will act as a brake....ugh...kinda.

Disclaimer: even with safety equipment, this is a really bad idea, you have a 99.99999% chance of atleast an ER visit.

Good luck buddy

 

[madprofessor]

I'd just pick up the front end of the kart and tie the center of the frame to the hitch ball. It's only the rear axle that needs to turn, correct?works.

 

[Denny]

Bansil’s way sounds more funner! Make sure the camera is on. But first you have to say the magic words. “Hold my beer and watch this.”

 

[KenMathisHD]

The question is "is the speed sensor close enough?"

Since you don't have brakes, you can't safely test drive it

...I got it, do you have a 8ft pc of metal tubing that you can put a chain or heavy rope through?

If so attach one end of chain to frame or trailer ball of a "pull" vehicle.

Pull tube up to "pull" vehicle frame or ball tightly, and attach other end of chain to front of gokart frame.

This will allow you to be pulled to test speed sensor, BUT you won't hit pull vehicle because you don't have brakes. The pipe will act as a brake....ugh...kinda.

Disclaimer: even with safety equipment, this is a really bad idea, you have a 99.99999% chance of atleast an ER visit.

Good luck buddy

As bad an idea as it would be, it also sounds like massive fun.

 

[KenMathisHD]

I adjusted the parking brake and got it grabbing, and with a sort-of brake working I decided to take the buggy around our neighborhood to see how it would do. If I had another person I'd have loved to have them in the truck behind me to see how well the speedo matched up, but as it is I got the speedo to register up to about 30 and decided that was as fast as I'd like to go with my only brake being the single caliper on the rear axle. I don't know how accurate that is, but it felt close enough so I'm satisfied with it for now. I'll need to get the new master cylinder in and the fluids changed before I attempt to go any faster. I also think I'll want to install a temperature gauge so I can monitor that.

In other news, after getting it up to 30 it started to smell a bit like a toasted graham cracker. The coolant type and age currently in it is unknown so I'm hoping it's just really old coolant and a flush and refill with a fresh mix might take care of it, but it makes me wonder if the head gasket is bad. It runs fine and doesn't seem to miss, but the smell concerns me, especially as it seems to be coming from the exhaust. I'm assuming I might find out once I change the oil. Barring that, I suppose it could be an old rubber gasket being cooked, but I don't have any leakage thus far. What're y'all's bets on the smell?

 

[Bansil]

In other news, after getting it up to 30 it started to smell a bit like a toasted graham cracker.

with or without chocolate and marshmallows?

Burnt coolant used to have the slightly sweet burnt shop rag smell out exhaust.

What does plug look like? Black rich, white lean grey good....other colors and build up bad

Can you pressure test the system?

If oil looks clean, it would be a leak into either intake side burnt rag smell out exhaust, or leak into exhaust which normally leaves a lightly white smoke and tell tale coolant in low spots (color wise)

 

[KenMathisHD]

with or without chocolate and marshmallows?

Burnt coolant used to have the slightly sweet burnt shop rag smell out exhaust.

What does plug look like? Black rich, white lean grey good....other colors and build up bad

Can you pressure test the system?

If oil looks clean, it would be a leak into either intake side burnt rag smell out exhaust, or leak into exhaust which normally leaves a lightly white smoke and tell tale coolant in low spots (color wise)

Without chocolate and marshmallows

I forgot to pull the plug and check, I’ll try to do so in the morning.

The oil appears clean, just the same faint glittery bits that I got the first time I changed the oil, but otherwise black and dirty. It doesn’t appear to have mixed with any coolant from what I can tell. It looks the same as the oil pictures I posted

I probably could have pressure tested the system before I screwed with it yesterday, however I broke the thermostat housing yesterday, so now I’ll have to wait until I can get the new housing, thermostat and temp sensor. Which sucks because I just got the brakes working….

How long does it take for the thermostat to open up on these? Is it generally pretty quick? It only starts smelling once you get on it and get it up in the higher rpm range doing about 20-30 mph. The radiators and cooling lines get hot, but not as hot as the motor and head, and I couldn’t see coolant circulating from the rear radiator with the cap off. I know the pump is working because after the thermostat housing busted, I fired the motor up for a quick second to see if the water pump was moving fluid at all (because open hole, might as well) and got a bunch of old coolant pushed out of said busted housing.

 

[Denny]

Might be at beginning stages of head gasket failure. Pull plug and see if it has been steam cleaned or has a green tinge to it. A sweet smell from the exhaust is something to be concerned about. Look over engine carefully for signs of leakage.