H-ard T-imes time machine: my build problems

Discussion in 'General Questions' started by crowvise, Aug 7, 2010.

  1. crowvise

    crowvise Member

    Not going too far back, when I first tried putting my carburetor into the intake manifold I knew nothin of o-rings. So I forced it in attempting to real the 4 holes. Well, 2 sections broke off. I jbwelded them back. They held fine for 5 days. A couple days ago I opened her up on a 3/4 mile ( slight decline) streach. Had to be going around 40+ near the end. Then it all ended. Motor began dying-then died. I tried to start her up but she'd only purr (like a sick kitten) if I kept peddling or twisted the throttle (yet no torque). MANY attempts= same result. I removed the light, shined onto motor: the whole carb had broken off. The 2 weld jobs & the 2 solid pieces, down to the o-ring. Yesterday I washed and jb welded again, hoping to use it until my new carb gets here. No dice. Anyway, how much damage could i have done 2 the motor w/ it (sort of) running off residual fumes and no carburetor? It did the same thing this afternoon several times and when I guessed air leak I pushed it in slightly, tightened the

  2. crowvise

    crowvise Member

    Tightened the retaining ring and tried several times to start with the same response as the night it broke off. Then while trying to start te new weld broke off (17-18hr cure time). But a new carburetor is coming so my main concern at this point is damage from it firing (often) without carburetor and oil, just chamber residue.
  3. Al.Fisherman

    Al.Fisherman Active Member

    I don't feel that you could try to peddle start it enough to do any damage.

    When will people learn, JB Wield is not the stuff some think it is. Yes in some non moving/non vibrating/non pressure applications it's ok.
    Last edited: Aug 7, 2010
  4. fm2200

    fm2200 Member

    The JB weld I have used in a moderate way, the piece broke apart after a short time, only good for static not weighted projects. It has no use for these vibrating gas bikes.
  5. motorpsycho

    motorpsycho Active Member

    thanks so much for saying this about jb weld AGAIN!
    jb weld is simply epoxy...there is no "WELD" involved with it at all.
    it will not withstand gasoline, and is not really strong enough to fix anything other than a static part that will never see heat, movement, gasoline, stress, or hold any weight.
    I'm not saying that jb weld is a terrible thing to use, but it is not the fix-all stuff that so many people think that it is.
    jb weld is brittle one it's dry, and it will crack over time, and if the surface is not prepped right, it will simply flake off. allow gasoline or oil to get into contact with it, and it will quickly deteriorate. Heat is another thing that will make jb weld fail. if you heat up jb weld, it will literally melt just like any other epoxy or glue.
    sure, the one tube says "steel" on it....but it's just a fancy way of saying that it's strong epoxy...as in "strong like steel".
    any 2 part epoxy is simply epoxy, and nothing more than that. if you look close at the 2 tubes of jb weld, you will see that one says EPOXY STEEL RESIN and one says EPOXY STEEL HARDENER. for one thing, RESIN is a form of plastic not steel or metal. jb weld is nothing more than a plastic resin 2 part epoxy that is claimed to be stronger than normal 2 part epoxy.
    welding is acheived when you are able to melt the surface that is being welded with a rod or wire, which will also melt and combine with the surface material.
    by melting the 2 materials, and penetrating the original surface. the weld becomes stronger than the original part (if done right).
    NONE of this is involved when using jb weld....and i really wish they would change the name to jb glue, and get rid of the words "weld" and "steel".
    This is their gimick, and a lot of people fall for it. It's a very clever marketing strategy, and this strategy has worked for many years.
    jb weld is strong, and don't get me wrong, there are certain applications that it will work for. but gasoline, oil, carburetors, exhaust, gas tanks, bike frames, engines, and things like that are not the things to use it on.
    Last edited: Aug 7, 2010
  6. crowvise

    crowvise Member

    Installed new carburetor yesterday. Tried starting. Same response as before. Added extra o ring. Replaced what little was left of intakegasket. Same response. Magneto is dead. Reading my above post, any ideas why? I think I might need a new cdi as well. Also, how/why does the engine sound like its running without a spark plug? Same response without spark plug when removed 4 test. "Runs" then begins to die (quickly when throttle applied). Sure sounds like a running engine, albeit a weak one. What is the operational theory behind that? Can i get some links to magneto and cdi? Operational theory; specifications; hypothesis as to failure in these hts? Anyone ever open up a cdi? I couldn't find much here with this search engine. I'm thinking of making my own in the distant future as much as i read on them failing . Cdi that is. Using rhos compliant components. Though I will one day wind my own transformer 4 ships and giggles. My magneto and gasket were dry.
  7. GearNut

    GearNut Active Member

    Your pedaling around did not do any damage to the engine to get concerned about.

    If you do not have an intake manifold designed with a groove in it just for an o-ring, loose the o-ring and instead silicone the carburetor onto the manifold. Just a thin coat of black RTV on both parts will get-r-done. If you use too much RTV it will just make a mess of things and get pushed into the throat of the carburetor from the manifold side.
    I recommend Hylomar for the cylinder gasket, but RTV black will also do.

    Have you tried a new spark plug?

    Did you solder and heat shrink the wire connections? If not, I highly recommend doing so. The factory plug together connectors are junk.
    Also, if you are using the factory kill switch, try disconnecting it. They are known to short out internally.

    The engine will make a running like sound because as the piston is moving up and down in the cylinder it is still gulping in a fresh intake charge and blowing it out of the exhaust.
    You are just lacking the wonderful BANG in between all of that.

    Here are some ignition specifications that I copied down:
    I am sorry that I do not know who the original posters of them are.

    Black to Blue 1150kΩ 7.6 meg Ω
    Black to Plug 2.6kΩ 2.17K Ω
    Blue to Plug 1150kΩ OPEN

    Blue to White 327Ω 349Ω
    Black to Blue 327Ω 347Ω
    Black to White 2.1Ω 2.1Ω
    Black to Gnd 0Ω 0.3Ω
    Blue to Gnd 327Ω 347Ω
    White to Gnd 2.1Ω 2.3Ω
    Spark plug gap .025” to .030”
    Due to manufacturing tolerances, resistance values may vary.

    Attached Files:

    Last edited: Aug 10, 2010
  8. crowvise

    crowvise Member

    Tried 3 different spark plugs. Disconnected kill switch at first no start. As to the sodering i had to get a tip. I did. Then couldn't find my solder. Bought some. Was going to do that after i installed the new carburetor. Though, now that i think about it i may just crimp the female ends tighter with pliers. Think i'll still replace the connectors with the ones i originally set aside for that purpose. Still crimping the females. The stock connectors are ugly and loose. As to the cdi readings (thank you): i got black (pos lead) to blue (negative lead)= 1.828 mega ohms. Reversed leads= open (or higher than my 2M ohms meter- doubtful). Black to plug= 8.45 kilo ohms (both ways). Blue to plug= open (both ways). Magneto data unnecessary. It tested near those parameters when first installed. Now nothing. So i definitely know it is shot. What do you think of my cdi readings? If it is dead too i'm gonna bust that ******* open and see what type of Capicitor and diode are inside so i can replace then with higher...
  9. crowvise

    crowvise Member

    Temperature coefficient range. Find out the peak inverse voltage (at wide open throttle on a fully broken in engine- and again after all performance mods are made) and select appropriate diode. Anyhow, thanks 4 the schematic. I can't really take it all in on this crappy little phone though. I'll be making a copy at the library sometime in the future. Oh, has anyone upgraded their cdi's internal components yet? The only downside would be for vendors. Well back to the magneto: so you think that carburetor incident had nothing to do with the magneto going dead?
  10. professor

    professor Active Member

    Yes, the carb and cdi are unrelated.
  11. crowvise

    crowvise Member

    terrible coincidence. gonna have to brianstorm as to what may have happened then. thought maybe the spark w/o carb...
    ... gotta learn more about engines.
  12. GearNut

    GearNut Active Member

    Your readings on the CDI look bleak.
    I do not like them at all.
    Tear it open and have a picture fest for us?
    I have read a thread about somebody that did rebuild their CDI, even rewound the high tension transformer inside it. Apparently the potting inside them is rather easy to remove. I always figured that the potting encases everything inside the plastic box, like a Jello salad. If my CDI goes south you bet I will be opening it up!

    The thread may have been on the "other" site, or here, I am not sure.