Semi-abandoned Hammerhead 250

[Karttekk]

Plus it says the CD unit is actually larger than an AC unit. My mistake.

 

[Karttekk]

The trigger on the magneto tells the CDI when to fire I believe.

Fancy Scooter: Gas Scooters and Electric Scooters Retail and Wholesale

www.fancyscooters.com

 

[Karttekk]

Scroll to page 71, Section 4-7. Ignition system diagnosis. Might be similar to yours.

https://americanlandmaster.com/pdfs/LUTV/150cc-service-manual-14589R4.pdf

 

[KenMathisHD]

Scroll to page 71, Section 4-7. Ignition system diagnosis. Might be similar to yours.

https://americanlandmaster.com/pdfs/LUTV/150cc-service-manual-14589R4.pdf

This is fantastic, going by this I’m pretty sure my issue is the CDI. The voltage from the trigger jump to about 4V when stopping cranking, so my guess would be my multimeter isn’t fast enough to measure while cranking. The pickup coil ohms within spec, and I get that voltage all the way to the CDI, but none out to the coil. I’m ordering a new CDI from hammerhead today. We’ll see if that is the issue when it gets in

 

[KenMathisHD]

Got the new CDI in today, it was definitely the issue. After replacement, not only did I have spark, but it was way stronger than it had ever been before. No more stuttering or missing or bogging down, it feels awesome.

Now the next thing to figure out is why I’m not getting a reading on the tach. Would any of y’all happen to know how that’s wired or where a pickup for that is usually mounted?

 

[Karttekk]

On the American Sportworks buggy karts the speedometer pickup, magnet and wiring are behind the passenger rear wheel. The magnet is mounted on the axle and the pickup is right above it. Not sure if the tach has the same setup but it should be similar.

 

[KenMathisHD]

On the American Sportworks buggy karts the speedometer pickup, magnet and wiring are behind the passenger rear wheel. The magnet is mounted on the axle and the pickup is right above it. Not sure if the tach has the same setup but it should be similar.

It looks like the sensor and magnet that are supposed to be on mine are gone. The bracket is still there, though rather mangled up, and now I know what the couple wires that led back there go to. I ordered a new sensor, magnet, and mounting screw for the disc. How close does the end of the sensor need to be to the magnet in order for it to work properly?

I think I found where the tach sensor goes, and mine appears to have been replaced with a plug, or maybe damaged? It's on the driver's side of the motor above the belt cover. I'm not 100% sure it's what I found, but it appears to be in the right spot when comparing it to the parts manual, and the part I ordered online looks similar as well. In hindsight, I don't think I ordered the bolt for it so I'll have to see if I can get it at the local hardware store or something.

 

[madprofessor]

If the tach doesn't have to be part of a restoration, you can get a cheap induction type with LCD readout that requires no real wiring at all for $10 on ebay. They're internal permanent battery powered, and the single wire just gets wrapped around your spark plug wire 3-4 turns. That's it. They start up automatically when you crank the motor up, reading rpm for a 4-stroke single cylinder and counting the runtime hours.
Black Digital Tach Hour Meter Tachometer Gauge For Dirt bike ATV UTV Gas Engines | eBay

 

[KenMathisHD]

If the tach doesn't have to be part of a restoration, you can get a cheap induction type with LCD readout that requires no real wiring at all for $10 on ebay. They're internal permanent battery powered, and the single wire just gets wrapped around your spark plug wire 3-4 turns. That's it. They start up automatically when you crank the motor up, reading rpm for a 4-stroke single cylinder and counting the runtime hours.
Black Digital Tach Hour Meter Tachometer Gauge For Dirt bike ATV UTV Gas Engines | eBay

If I can’t get it working that might be the way I go. I’d like to get the regular tach working if I could, but I’m not even sure how it wires up. So far I have not been able to find any wiring diagrams showing the tach wiring for this kart or similar karts.

 

[Karttekk]

The holes in the sensor don't look to be slotted so it should bolt right up. No adjustment needed I'd say. Same with the magnet, bracket should already be there.

 

[KenMathisHD]

The holes in the sensor don't look to be slotted so it should bolt right up. No adjustment needed I'd say. Same with the magnet, bracket should already be there.

The bracket for it is pretty bent up and out of shape, I'll see if I can't get a picture of it.

I've run into a problem with trying to bleed the brakes though. I don't have any resistance on the pedal until I have it almost down to the floor, and then maybe a 1/4 inch of travel with resistance before it stops. No pressure or fluid getting to the calipers. My bet is the seals in the master are shot or rolled, but I'm not sure if it would be better to try and take it apart and check the seals or to just replace it with a new one. The calipers move freely, I was able to regrease the slides and reset the pistons and it sounded like one of them squirted fluid back through the line and into the master. I'm thinking that may have caused part of the issue I have with the master cylinder, though I don't think the pedal resistance wasn't any different before this. What would you guys recommend as far as the master cylinder goes? Should I replace it or try to take it apart?

 

[Karttekk]

The best way to bleed the brakes is get a clean clear plastic pop bottle, 2 feet or so of clear fuel or vacuum hose that fits the bleeder on the caliper and a fresh bottle of DOT 3 brake fluid. Put one end of the hose on the caliper, put the other end in the bottle with enough fluid in it to submerge the hose end (so no air gets sucked back into the hose), then top off the brake fluid in the master. Crack open the bleeder on the caliper. Pump the brake pedal up and down making sure the hose end stays in the fluid in the bottle. Watch for bubbles as air is being pushed into the bottle and don't let the master run dry. The pedal should eventually get firm as the air is purged. Once that happens, tighten the bleeder and top off the master and remove the hose. If this doesn't work, look into a master but I think you'll be fine.

 

[Hellion]

All metal, powdered or chunks, will be in the bottom of any oil. Nothing mixed in suspension.

Wrong, that is quite wrong. Metal particles can indeed and DO get suspended in the oil, giving it a shimmery appearance. In fact if the oil has a detergent additive package, it is designed to carry the contaminants in the oil "in suspension" so they can be carried out in the next oil change. Of course heavier particles of steel and chromium have a tendency to sink to the bottom with adequate time, but if you change the oil right after a run while it's nice and warm {always recommended} you're going to see whatever is in the oil churned up and visible.

Normal wear gives you microscopic metal particles, actual visible {or shavings you can feel, aka "gritty"} shavings are a danger sign. Now most of the internal engine bearings are flat shell bearings {like the main crankshaft bearings} which have a hard time generating shavings, unless there is major oil starvation.

Could be metal particles, could fine powdery sand or silica or other contaminants, which emphasizes the need for a respectable oil change interval and keeping on top of your air filtration. In other words, don't neglect it and make sure dirty air isn't getting past the air filter.

Might have to revoke your madprofessor moniker. Even a mad professor {Doctor Frankenstein?} had the basic smarts down pat.
I was appalled that you were unaware of the whole issue with ethanol in fuel.

 

[madprofessor]

put the other end in the bottle with enough fluid in it to submerge the hose end

Then place the bottle a little higher than the caliper bleeder fitting so air can rise away from the caliper, and only fluid from the bottle can flow down, like a siphon. Don't make the mouth of the bottle be much higher than the bottle's fluid level.

 

[madprofessor]

Hellion, I accepted that micron size particles won't overcome surface tension to fight gravity. Here's what I still wonder about.............Would it be true to say that given enough downtime all particles of metal would eventually seek their level (bottom of case)?
And what was it I missed about an ethanol mixture fuel that I should have known?

 

[Karttekk]

Just follow my steps, don't worry about bottle height.

 

[KenMathisHD]

Just follow my steps, don't worry about bottle height.

That's the way I was bleeding it when I ran into the pressure issue. I had a hose ran through a hole I drilled into the cap of an empty powerade bottle, put about an inch of fluid in the bottom of the bottle and hooked it up to the bleeder screw, then pumped the pedal and cracked the bleeder. No resistance from the pedal until the last bit of travel, and no fluid coming out the bleeder. Same for front calipers too. Master cylinder reservoir was full too

 

[madprofessor]

Did you press pedal all the way and hold it there while somebody closed the bleeder? Then let it up, get the bleeder opened, press and hold and repeat? It worked for me when a little air would suck back into the caliper when I released the pedal. Tried the bottle method, but the volume of a pedal pump was too small to make a 2' hose to the bottle work, too much air there, just pumped air in/out the hose until I got somebody to work the bleeder for me.

 

[Karttekk]

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.

 

[KenMathisHD]

Did you press pedal all the way and hold it there while somebody closed the bleeder? Then let it up, get the bleeder opened, press and hold and repeat? It worked for me when a little air would suck back into the caliper when I released the pedal. Tried the bottle method, but the volume of a pedal pump was too small to make a 2' hose to the bottle work, too much air there, just pumped air in/out the hose until I got somebody to work the bleeder for me.

I did not, I was doing it myself so I just put the hose over the bleeder, tried pumping the pedal and cracked the bleeder, then pumped the pedal more while the bleeder was open but didn’t get anything out. Tried this a couple times and didn’t get any fluid at all.