I had a breakdown today...

Discussion in 'Motorized Bicycle General Discussion' started by CTripps, Nov 4, 2011.

  1. nightcruiser

    nightcruiser New Member

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    At this point with the head off already, revealing the piston and cylinder damage, and worry about stray ring metal in the crankcase, I would probably crack the bottom end open first before I order anything. After inspecting the bottom end, less any surprises I would clean it up and order the $37 top end kit. If anything looked bad in the bottom end when I would just order the $98 motor instead. There is also a good argument for ordering the motor right away, installing it on the bike and then take your time repairing the other motor and hang on to it as a spare. You never know when you will wish you had a spare!
    I guess some guys would just assume put out the extra $60 bucks right away and avoid all the work, other guys would prefer to save some money or consider ripping it apart and repairing it an adventure. To each his own on that one I guess....
     
    #61 nightcruiser, Nov 14, 2011
    Last edited: Nov 14, 2011
  2. CTripps

    CTripps Active Member

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    It's alive! (^) woohoo (^)

    The new motor fired right up, and it sounds good. Nice purr to it already, what a difference cleaning up the ports makes. (The motor I replaced with is one I had started cleaning up for a new build, thank goodness I had it. :))
     
  3. vincent713

    vincent713 New Member

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    Glad you got it up and running, now you can ride it to work tomorrow. (^) Niterider made a good point, it's always good to have extra parts!
     
  4. CTripps

    CTripps Active Member

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    Okay, more info... I meant this to be one post but hit the wrong button. No worries.

    So, it's wired blue/blue black/black for now, white's safely tucked away. Everything's sealed where it needs to be, torque's good on everything. I cleaned out a fair bit of crap, and Dremeled off a lot more (the shop vac's going be full of glitter). There was a lot of debris under the pressure plate around the clutch pucks that could have been pretty messy, and the flower nut was loose.
    With the guidance of the machinist in the house I lapped the head and jug on a slab of polished granite, using fine wet sand paper followed by toothpaste and baking soda until it was nice and shiny.

    Unfortunately the run to work in the morning is likely to be it's first real run. I buzzed up and down the lane a few times but my lights aren't great for seeing by and there's no light back there.

    rc: Hard to say, I think it had around 800 miles on it. I've always been a tinkerer on bikes, but I'm working my way there. I inherited my dad's "smart hands" when it comes to the toolbox. There's a lot of great info here and elsewhere on the net.. if I can figure this out, just abut anyone can. ;)

    vincent: Yep, that's the stuff. I'm a little uneasy about it but I'm trying it, we'll see how it goes. I was hoping not to sacrifice a motor for parts, now it looks like the first motor is the parts supply for at least a few things.

    Wrestling the old motor out of the frame was a feat, it had settled in and didn't want to budge. The old motor was my first install, before I found the forums here and learned a lot. It was installed straight out of the box with no prepping done. I've made excuses not to make the time to tear it apart and do it right since, and now they've come back to haunt me. That won't happen again.
     
  5. CTripps

    CTripps Active Member

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    The weather's changed my plan for the morning, going to take the cage instead of the beast. The wind this morning would blow me off the bridge if I tried it.
     
  6. rustycase

    rustycase Gutter Rider

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    Tnx for the link to the rtv, Vince...
    Yup, I've used that stuff before, as directed, when I had no other options.
    I would NOT use that for a head gasket. Period !
    and I'd only use it in place of a base gasket if there were no other option.
    ...perhaps a very small amount smeared on some sort of card stock cut in the shape of a base gasket with a razor...

    The stuff cures sticky and flexible... can't really be torqued properly because it always gives. and I'm sure it would not stand up to compression pressures.

    I dunno... not sure what to say... I just can not be positive about using this stuff for anything but it's advised use.
    ...GREAT stuff for smearing on an intake manifold to seal an intake leak at the carburetor!

    I suppose you could TRY it for head gasket use... I suspect it will blow out quickly and you can replace it with a proper head gasket easy enough when it fails the test. At least these 2 smokes are easy to work on !

    Good luck
    rc
     
  7. vincent713

    vincent713 New Member

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    specification says it can withstand up to 650F degree temperature. I don't think our engine gets to that temperature. I can't say how long it will hold up but it's been over 100 miles and still running strong. The stock gaskets are a joke, thin as paper. If you replace it with thicker gasket (which you would have to cut out and would be a pain) that would lower compression and lose power. I get really good compression with this gasket maker and no leak! I'll start a new thread and let you guys know if and when it fails.
     
  8. rustycase

    rustycase Gutter Rider

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    That's great if you are willing to run the testing, Vince!

    I'm a real hack, but prefer to do quite a few things the old-school way.
    ...but I've never lost a head gasket on a motor I built!

    I've known guys with lapped heads that ran nothing but a coat of silver spray paint! Not me! lol

    Then another fellow who gave axle grease a try... that was a messy failure !

    I do know the permatex products are very good... they use em quite a bit on aircraft engines, so that says a lot, to me.

    I'll look forward to seeing your results.
    Best
    rc
     
  9. vincent713

    vincent713 New Member

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    I believe the head is where it gets hot the most being where it ignites and explodes so I don't recommend using this gasket maker there. That's why they put a metal gasket on the head for this very reason. I've never heard of this metal gasket being blown. I remember when my base gasket blew, it sounded like I had a blow out on my tires. When I came home and examine, the tires were ok, so I knew it had to be one of the gaskets. When I took off the cylinder, sure enough it was blown on the right side, exactly where I heard the presssssshh!
     
  10. rustycase

    rustycase Gutter Rider

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    Here's some info I found at the Permatex site

    permatex rtv red

    http://www.permatex.com/documents/tds/automotive/81160.pdf

    ..NOT for use on a head gasket AT ALL
    ..NOT for use in contact with gasoline

    .............

    This page is for the Moto Seal 1 Ultimate Gasket Maker Grey
    ...it resists gas...

    http://www.permatex.com/products/mo...cle_MotoSeal_1_Ultimate_Gasket_Maker_Grey.htm

    This is Permatex stripped Thread Repair
    ... up to 128ft lbs torque, Grade 5 SAE, Grade 8.8 Metric

    ...Interesting...
    Best
    rc
     
  11. vincent713

    vincent713 New Member

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    What exactly is lapped head?
     
  12. CTripps

    CTripps Active Member

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    The contact surface has been polished to be as smooth and flat as can be, same for the top of the cylinder it matches up to.

    The parts are all painted, so it took a little bit to get to metal, and then a while longer getting the nicks and grooves from the factory. I wish I'd taken before and after pics to show how many scars and scratches there were in both surfaces under the paint.
     
  13. vincent713

    vincent713 New Member

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    I see now...how did you make the surface smoother?
     
  14. CTripps

    CTripps Active Member

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    A while ago I picked up a slab of granite, polished one side like a countertop, so I used that as a work surface (others use glass, I didn't have any I could get at easily that the wife wouldn't kill me for using, and she's trained as a machinist and was telling me about granite 'lapping tables' and such - but it has to be an absolutely flat surface). I don't recall the grit counts exactly, but really fine down to 'are you sure that's sandpaper?'.

    Put a sheet down, sprinkle a little water on it, put the contact surface against it and move in circular motion with smooth, even pressure. I switched directions from time to time, and wiped off the sandpaper now and then. One past the paint, switched to even finer grit and went at it until the surface was nice and smooth and shiny. After that I took up the paper, sprinkled some baking soda on the slab, a bit of toothpaste and a bit of water makes a nice thin paste. Then back to polishing the surface against the slab. The idea being that the final contact surfaces are as close to completely smooth and level for the most contact you can get.
     
  15. vincent713

    vincent713 New Member

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    Great idea, sounds like it would take a bit of time doing. I'd have to wait until the weekend when I'm off to do a job like this. Thanks for the tip!
     
  16. CTripps

    CTripps Active Member

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    It did take time, but at least it's aluminum so it's easier than it would be with steel. It's hard to describe exactly what you're looking for in the finished surface.. it's a sort of satin-like shine that's almost a glow, like the edge of a well honed blade.
     
  17. corgi1

    corgi1 New Member

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    Used to level theromostat housings similarly but I just rubed them level on a flat cement floor or crub,the paper gasket and sealer made up for any slight scratches left ovre
     
  18. killercanuck

    killercanuck New Member

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    Hey corgi! Don't get "Rub it on some concrete or a curb" into Newbies heads! :p

    Lapping is time consuming, I should've taken before/after pics too, stock finish is a mess for sure. On glass- all wet(need wet paper btw ppl, water will just wreck regular paper). I started at 300 until the major nicks/gouges were gone, to 600 to get out the 300's lines and ended on 1500 three hours later(total) for a nice polished finish. If you harvest a wife/gf's picture glass, make sure it's washed good before putting it back :p Granite slab is a great idea.

    CT, did the baking soda w/toothpaste leave a nice finish? The 1500 did a good job, just curious about that paste.

    Heh heh, speaking of blades, I wonder what a 6x6" honing stone would go for. Or even a rough stone... Probably more than a years worth of 300-1500 grit, lol.
     
    #78 killercanuck, Nov 18, 2011
    Last edited: Nov 18, 2011
  19. rustycase

    rustycase Gutter Rider

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    KC, I recently bought a 6" 600grit diamond flat lap for another project for $17 including the freight... same same as a honing stone, almost. Any grit is available. rocklady1 on ebay.

    In the past I had lapped mc cylinder heads using clover compound on a 12" square of thick glass. It worked fine. I guess the clover compound is just silicon carbide in a grease medium.

    and CT, it's not really necessary to have a magnificent mirror finish on the mating surfaces... I've done many, and basically just look to see that they are 'frosty' in a uniform way all across the gasket bearing surface.
    Best
    rc
     
  20. CTripps

    CTripps Active Member

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    The paste worked well finishing from 1000 grit paper. It isn't a mirror finish, but a uniform shine with no blemishes. I'm sure there's a compound someone reliable makes and sells but for the shoe-string budget it performed well.
    A 6"x6" honing surface... how about the side of a bench grinder wheel? Lay it flat on something that'll keep it from sliding and add a few drops of oil before working it.. If it were tried against the wheel on the grinder I doubt it would work (and with the grinder on it would just eat the aluminum, too easy to grind unevenly too).
    I lucked out finding the slab, it's about 12"x18" and about a half inch thick, polished one side. It's just one of those things I saw being thrown out somewhere one day that I knew would be useful somehow in the future. I find a lot of stuff like that.
     

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