Freezing temps & pre-mix fuel...(intake gasket screw-up)

Discussion in 'General Questions' started by gone_fishin, Jan 17, 2007.

Tags: Add Tags
  1. gone_fishin

    gone_fishin Guest

    1st, the engine starts and runs great.

    today, i rode in 34deg temps, everything was fine, then suddenly i started to get a lot of top-end surging & dropping off, up & down, up & down without end. then...whenever i'd pull in the clutch, the engine would rev to the point of self-destuction, so i'd kill it. it would start right up again no problem, only to repeat the same symptoms.

    a check of the carb, line, and cable indicates everything's i experiencing something to do with a below-freezing windchill factor affecting the fuel & carb? i mean, i'm pretty sure that's it, but has anyone experienced the very same thing? does pre-mix get "gummy" below the freezing point? any solution?

    please don't tell me i have to wait for 40deg temps to ride :(

  2. gone_fishin

    gone_fishin Guest

    how embarrasking...i have a completely blown intake gasket. actually, it didn't "blow", it kinda turned into mush, then oozed on outta there :x
  3. try1897

    try1897 Guest

    Augidog, I had the same thing happen to mine. it was one of the red looking color gaskets and it turned to chewing gum or something like it. I cut one out of cereal box cardboard to use until I could get another and then had all sorts of problems getting one from anywhere. Finally Smurfer came to the rescue and sent me some gaskets he cut from heavy duty gasket material. He did a fantastic job and they worked like a charm. I also had the bottom gasket blow out between the jug and bottom end. I still owe Smurfer one for the rescue cause I've had no more problems with them...... Tom in WV
  4. gone_fishin

    gone_fishin Guest

    ...funny thing is the gasket was "still there" under visual inspection, i had to take the intake off to see the flaws.

    i went up to the grocer/hardware store & bought a sheet of black fiber gasket material for $2.50, should be good for about 10 more gaskets. back in the wind 8)
  5. psuggmog

    psuggmog Guest

    Augie, how flat is the gasket mating surface of your intake manifold? Mine wasn't very flat. I ended up lapping it by placing a piece of wet/dry sandpaper(the black kind) on a castiron tablesaw table and moving the manifold in a figure eight motion on top of the sandpaper. I kept checking by drawing on the surface with a sharpie and letting dry, then sanding again. When all the marker sanded off, I stopped. I used the marker like a poorman's layout dye and it drys faster as well. I also deburred the pipe end where the carb fits.
  6. gone_fishin

    gone_fishin Guest

    that's a good call, psuggmog, because i did an all-out blast up the beach and back just a while ago...when i got back i saw a bit of ooze at the top- and bottom-center of the new gasket, gonna put a file to the intake-flange tomorrow and that should be that 8)

    i've been lucky, my carb easily slides on enuff to seal the grooves & the intake pipe is really clean, as is the port itself, i should get a pic when i redo it :)

    (i just love using these gearhead smilies :D )
  7. psuggmog

    psuggmog Guest

    I have one of the new style steel manifolds. There was a burr on the inside of the pipe at both ends. Also a lumpy weld penetration on the inside where the pipe angles. The length of the intake passage can effect engine performance. I would imagine that ours are not the optimum length.
  8. gone_fishin

    gone_fishin Guest

    me too, the steel pipe. pretty clean, tho, all things considered.

    i think the specs are more for fit/looks than performance.
  9. well... i'm runnin my bike outside temperature is like 0~5 F degree.
    I freeze but not the motor.
  10. gone_fishin

    gone_fishin Guest

    gotta dress for the weather, i layer to the max...

    ok, this is what i did...tore it down & had a closer look:

    the main prob is that the round hole of the flange completely mismatches the "rectangular" port & there's only about 1/8" of overlap of the flange to the jug, a very weak spot to try to seal. i tried cork, figuring to "bake" a gasket in there, but it just squeezed out at the top and bottom :(

    btw-my port is very clean & the intake flange had already been surfaced pretty well, all i had to do was file a bit more off. the inside weld area was also nicely finished, but i touched it up w/a round file, anyway. that's about the best i can do with a "manual machine shop" :|

    so i made a new fiber gasket & used permatex 1A on both sides, had a good hard run and so far it looks fine 8)
  11. psuggmog

    psuggmog Guest

    I was taught by an 80 somethig year old man when I was a kid, that a file is a milling machine in the right hands. As part of his apprenticeship, he was given a lumpy piece of metal and told to file it into a cube with tolerances of +- 0.003" He said that he had to do that before getting to learn to operate machine tools.
  12. srdavo

    srdavo Active Member

    Nov 4, 2006
    Likes Received:
    hi psugg, what do you think the optimum length might be? do you think a couple inches longer would hurt or help?

  13. gone_fishin

    gone_fishin Guest

    my screw up is a lesson well-learned, the symptoms in my OP indicates an intake problem & may likely be the gasket.
  14. bird

    bird Guest

    i think length and type of metal have alot to do with how your motor runs. i was running a 1 inch flipped intake that was steel and changed it to a standard alum intake and it took away some speed. but on my other bike im running a standard steel intake and it runs fine. i think because the steel intake is smoother on the inside it has a little to do with it.