Carby Soaked air filter, NO power, (I have to pedal to keep it running) New carb, same prob

StrangeTechnician9

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66 cc bought w/ the racing carb. Ran very well while I was breaking it in... rode it in the rain one time (im not sure if that has anything to do with anything)

anyway, after a few weeks it ran terrible.

you could sit there and watch all sorts of fuel spitting out where the air filter goes.

I could ride maybe 2 minutes at most before the filter was soaked and I had to either take it off or pedal to keep the engine running.

Adjusted the float over and over and over again for weeks until the carb broke from trying to tighten it enough to keep it on the intake.


YAY to get rid of this eyesore in the shed I bought a new carb... some SHA clone that they have on pistonbikes.com for way too much money, I bought the exact same one from 1977mopeds.com and got a $15 deal :) go me.

Put the new carb on and it started right up... at WOT it seemed to have almost 1/2 the power I expected it to have. after running it with the rear wheel off the ground for a good minute and a half, the performance dropped, and after about 5 min trying to adjust things, it wont even stay running for 5 minutes at WOT, half throttle, Idle... It just doesn't matter what I do.

I've been trying to get it to run at least "ok" so I can sell it, for about a year now.

Can anyone help me? I've heard some things about reed valve kits, but I'm not familiar with them nor will I pay an additional $100 or more for one to have this engine run like its "SUPPOSED TO"

Thanks in advance
 
sounds a bit like a leaking crank seal or a case screw that isn't tight
 
66 cc bought w/ the racing carb. Ran very well while I was breaking it in... rode it in the rain one time (im not sure if that has anything to do with anything)

Check the magneto coil for any corrosion. It may have gotten wet and is no longer producing the correct spark. You can check it with an Ohms meter or DDM to verify that it is o.k. it should read near 200K Ohms set a a low scale.

Hopefully it doesn't look like this:
Magneto.jpg

Here's a guide for no-start cnditions or run correctly: https://docs.google.com/document/d/1aBeJuoS--VQWwXysc07rpscTUbPzgc93xjiQBgsyFjc/edit

Good Luck,

Chris
AKA: BigBlue
 
also runs great when I cut off the gas from the tank just before it runs out of fuel in the Carb. just like the old Carb did

that definitely sounds like you're too rich - if leaning the needle & lowering float level help a bit, then think about buying a new main jet
 
I've been trying to get it to run at least "ok" so I can sell it, for about a year now.

You are not even in the ball park. I spent 2 years of pain and heartache getting my bike to run the way i wanted.
My advise is: just accept that you've got another year of pain ahead of you and don't complain too loudly, because your neighbours want to sleep at night and not be kept awake by sounds of fierce cussing coming out of the garage at all hours of the morning.

Yes, the reed valve intake makes a big improvement to low and midrange power, but it won't fix a carburettor that's in a shambolic state of operation.
 
Ive tried one size bigger and one size smaller jet. also checked th ohms on the magneto with my multi meter. replaced cdi, plugs, plug cap, cleaned exhaust.

i did not change out my piston rings which i may have fried breaking the engine in with too much gas not enough oil... im bad at that.

Im thining about rebuilding the engine again to replace the rings. any thing else i should replace while its torn apart? ill take pics next weekend when im off work long enough take it all apart.
 
One single jet size larger or smaller is an insignificant number if we are talking #75 to #76 or #75 to #74. You need to jump 3 jet sizes to feel a noticeable change.

From what i'm seeing you are poking a stick in the air trying to fix things without any real direction of process. Maybe it's best to hand the job over to someone who knows what they are doing, because i'm sensing an impending f*&^up if you go any further, and my word, you can really f#$% things up when trying to get the case halves apart without a case half splitter (and reassembly) tool.
 
You are not even in the ball park. I spent 2 years of pain and heartache getting my bike to run the way i wanted.
My advise is: just accept that you've got another year of pain ahead of you and don't complain too loudly, because your neighbours want to sleep at night and not be kept awake by sounds of fierce cussing coming out of the garage at all hours of the morning.

Yes, the reed valve intake makes a big improvement to low and midrange power, but it won't fix a carburetor that's in a shambolic state of operation.

I'm 1/2 way there :) lol
 
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