48 cc Stock Carb gasket kits

Discussion in '2-Stroke Engines' started by gearhead222, Aug 5, 2010.

  1. gearhead222

    gearhead222 Member

    Dear Fellow Members-Does anybody sell these? My carb is slowly leaking onto the crank case behind the head:( The bike idles fast cold and then the idle slows down to the point of dying while hot. Replaced the crappy intake tube with a higher quality cast aluminum one and used some good gasket sealant on both sides of intake tube. Was running fine for about 70 miles or so. This leakage and idle problem started about 1 mos ago and the bike has about 180 miles on her. Am wondering if the leaking gas/oil mixture will affect the engine gasket. Cannot find any OBVIOUS leaks but of course she's leaking somewhere! Thanx for any info:)-Gearhead
     

  2. srdavo

    srdavo Active Member

  3. gearhead222

    gearhead222 Member

    Thanx for the quick reply! Will do!:)-Gearhead
     
  4. gearhead222

    gearhead222 Member

    Almost forgot, but do I buy another carb to get parts? If so, that doesn't make much sense:(. Any idea where to buy carb parts? Thanx again, guys:)-Gearhead
     
  5. gearhead222

    gearhead222 Member

    Brainfart! I remember now how rough the ride is! Am wondering if the pounding of the bike's ride on the carburator float would change this adjustment and if just a little bending of the Float Tang would cure the problem! Any ideas ou there? Thanx again:)-Gearhead
     
  6. srdavo

    srdavo Active Member

    check with the vendors on the left side of the page for parts.

    here's some [good pics] of a disassembled carb.

    check to make sure your float is not full of fuel. Usually there's some gunk clogging the needle valve, keeping it from closing properly.
     
  7. GearNut

    GearNut Active Member

    The metal that the float "tang" is made out of is cheezy. I would not be the slightest bit surprised if rough roads could cause it to get bent.
    Other folks have experienced it getting bent for no obvious reasons before.
    One day it is perfect, the next day .....drip, drip, drip. And the tang is bent all the way up to the top of the float chamber.
     
  8. gearhead222

    gearhead222 Member

    Dear Gearnut-Do you recommend removing the float for leak inspection and bending the tang plus clean the float valve set? Any specific instructions on how to properly adjust the float and clean the float valve are greatly appreciated:)-Gearhead
     
  9. GearNut

    GearNut Active Member

    I recommend that you do all that you have suggested.
    Here's a link to AussieSteve's tutorial:
    http://www.motoredbikes.com/showthread.php?t=24867
    Even if you have the new style carb with the white auxiliary fuel valve built in, the carbs are similar enough that the tutorial will help out.
     
  10. gearhead222

    gearhead222 Member

    Am wondering if I can do this with the carb on the engine. Do NOT want to bugger up the airtight seal I now have with my carb. The gas leakage is more of a nuisance than anything else. I can put a paper towel in there and it will soak up the excess. More concerned about the heavy duty replacement chain and seat tube mounted spring loaded idler wheel that I will be installing. Thanx again!:)-Gearhead
     
  11. GearNut

    GearNut Active Member

    If you keep the carburetor attached to the engine it will make things more difficult to work on for sure. If you are concerned with the seal between the carburetor and manifold, just remove the manifold from the cylinder leaving the carburetor connection intact.
    Either way it's your call.
     
  12. gearhead222

    gearhead222 Member

    Thanx again!:)
     
  13. gearhead222

    gearhead222 Member

    Hard starting + fuel metering issues

    Dear Fellow Members-Having replaced the stock intake tube with a cast one, I eliminated MOST of my idle issues:) However, I now have fuel leaking out of the carb and air filter housing, which I understand is related to a bad float and/or fuel metering valve/valve float lever-remind me to stop riding over rough terrain!;) ANYWAY, it's more of a nuisance than anything and I don't want to risk messing up my carb/intake tube seal. Fpr now I;m just inserting a folded paper towel under the carb to catch any excess gas. Had problems with cold starting and thought perhaps my plug needed regapping/cleaning, which I did. The NGK plug was @ .025 or so and I regapped to around .022 with no change in cold starting. Once she heats up she runs fine. However, she idles fast cold due to the idle lowering to the point of dying once she gets good and hot. I realize that these carbs are pretty low tech in terms of build quality, but would appreciate any feedback here. More concerned with the drivetrain, as I tire of the stock chain stretching all the time and relatively rough chain ride with the fixed idler. Already purchased the heavy duty BMX chain and waiting on the Bajamotorsports spring loaded rubber covered metal idler wheel which I will mount on the seat tube with VERY little chain deflection:) She's been a great bike otherwise. Have around 200 miles on her and still running 16:1, although her speeds are varied from 8 to 19 mph still-Gearhead
     
  14. GearNut

    GearNut Active Member

    If you do not take apart the carb you will never find out why it is leaking.
    Be careful with the paper towel band-aid. Gas fumes are flammable of course and it would suck if your ride caught fire.
    Just curious here, what color is the plug?
    Good luck with the chain tensioner. I hope it is a quick install and works well for you.
     
  15. gearhead222

    gearhead222 Member

    I understand, but it is such a PITA disconnecting and reattaching the carb and risking intake leaks:( BTW, I do let the engine cool down prior to putting the towel underneath the carb. Am wondering if the gas/oil mixture would damage the case halves gasket? Have you ever adjusted the float valve lever? Will keep you all updated on the chain drive:)-Gearhead-PS-I am still running a 16:1 mix with 200 miles on the engine-is it time to switch to 20:1? the plug is toasty brown at the insulator, but turns to a wet black at the electrode. Have at least another 1 gallon of 16:1 mix. Is there an easy way to dilute this to 20:1 or just use it up and then switch? I am using inexpensive 2 stroke oil-not the $$$ synthetic stuff.
     
    Last edited: Aug 8, 2010
  16. GearNut

    GearNut Active Member

    Working with the carburetor is not too difficult. Re-sealing the gasket at the cylinder head is easy with the correct sealant. I recommend Hylomar, available at most any auto parts store. A little goes a loooong way. You only need a thin coating on both sides of a clean gasket. It is easiest to apply with a q-tip dipped in acetone used to spread it around.
    When it comes time to disassemble the assembly in the future, it will just come apart really easy, usually with the gasket in perfect condition to re-use. Nothing much to scrape clean and no burnt gasket stuck on to scrape and scrape and pry off.
    Silicone sealant on the other hand is a pain to work with comparatively speaking.

    The fuel will not damage the case seam gasket in any way. It might make the very edge swell up a bit but that will not harm anything.

    Have I ever adjusted the float lever?
    I have been rebuilding small engines ranging from weed whackers to Harley Davidsons for 27 years, so yeah, I have adjusted a float lever or 100 thereabouts.

    16:1 is waaay too much oil to break these engines in with.
    The Chinese print the instructions as though you will be using straight 30wt automotive oil, which is common in China for these engines, not proper 2-stroke pre-mix like we have. 24:1 is very good for break in, 32:1 thereafter, speaking for common good quality pre-mix oil. Switch to 32:1 after the second gallon or 400 miles.
    To convert 16:1 into 24:1 add one half gallon of gas to the fuel mix you all ready have.
    I recommend getting rid of the cheap pre-mix fuel you have though.
    Add it to a full tank of gas in a car or truck, it will not hurt anything.
    If you choose to use a high quality synthetic such as Opti2, follow the instructions carefully for that type of oil. It mixes at 100:1 and that must be followed exactly.
    Cheap pre-mix oil like what is found in Target, K-Mart, Walmart, ect is not horrible for these engines but is really is not good either. It certainly will reduce the overall lifespan of the engine, but it is better than automotive oil.

    Your spark plug color does not sound bad, considering you are burning 16:1 fuel.
    You will have to re-adjust the needle clip position after switching to the higher pre-mix: fuel ratio to keep the carburetor dialed into the desired air/ fuel ratio.
    Move the clip up one notch at a time untill you get a nice chocolate brown color on the spark plug. Test often to insure that the engine is not too lean or damage can occur.
     
  17. gearhead222

    gearhead222 Member

    Thanx again for all of the info! Feel free to laff, but I would still like to drain the gastank, turn the bike upside down to clean out the fuel supply valve, check the float and possibly bend the float valve lever tang. Guess that I can measure and mark the correct float distance on a strip of cardboard to inspect my float adjustment. Thanx again!:)-Gearhead
     
  18. GearNut

    GearNut Active Member

    I will not laugh, there is nothing funny here. You do what you gotta do.
    The first time I ever got inside a carburetor I was scared that I would ruin it. 10 years old and nobody to tell me what to do or how to do it. I discovered that they are very simple inside, they must be absolutely clean inside, and that clear silicone melts into a useless goo when used as a gasket sealant around gasoline or 2-stroke fuel.
    Your cardboard idea will work fine.
     
  19. gearhead222

    gearhead222 Member

    Am wondering if the tang pivot pin is a tight compression fit. Can I remove it to bend the tang with just finger pressure and a small drift punch? Can I bend it with my fingers or used needlle nose pliers? Am seriously considering emptying the fuel and turning the bike upside down to do this, as I do NOT want to remove the carb from the intake tube. Again, thanx for any help:)-Gearhead
     
    Last edited: Aug 9, 2010
  20. GearNut

    GearNut Active Member

    The pivot pin is a loose fit into the support towers. You can see on the shape of the float bowl where the pivot is as the bowl fits around the towers to prevent the pin from sliding out. The float fork or tang is easily bent with your fingers. Be sure that both tines of the fork are evenly bent so the float pushes evenly against the fork.
     
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