Clinician
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MC-02-50b
by: deepcrk06 - Jan 23, 2013 17:04:16 GMT -6
Post by deepcrk06 on Jan 23, 2013 17:04:16 GMT -6
I recently was given this scooter, body is in good shape but the motor is shot, no compression at all, I am not sure but I think this is a 139qmb motor and I would like to completely tear down and rebuild it using a BBK kit. My question is what BBK would be good for this, also I live in the mountains so a lot of up\down hill riding so what cvt\clutch would be good for the hills and also speed. Any recommendations will be a big help.
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Clinician
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Post by deepcrk06 on Oct 24, 2012 14:24:10 GMT -6
Today I received my new carb, installed and bike runs just like it is suppose to if not better then before, now all I have to do is go back and redo the valves again as I have a valve tap, but other then that it is all good to go.
Thanks for the assist to all.
(( I did re-soak the old carb and completely blew the thing out with compressed air, slowly put everything back together again but once more I had the same probs as I started with. old carb to garbage and happy new one took care of my problems. ))
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Clinician
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Post by deepcrk06 on Oct 22, 2012 14:22:51 GMT -6
vacuum line from intake to fuel tank - sits higer then the motor - so I guess it a petcock, and yes the last pic of carb is the one I have.
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Clinician
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Post by deepcrk06 on Oct 22, 2012 13:20:10 GMT -6
From the intake - vacuum goes to pit cock to operate gas pump
on the carb their is no vacuum going to the acv diaphragm vacuum port as shown in your pic -- so on the carb their is just the bowl drain line, gas inlet and the en-richer to plug in. On my acv diaphragm their is no where to plug a vacuum line.
did not have chance yesterday or today to play with it. Just giving up and waiting on new carb.
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Post by deepcrk06 on Oct 20, 2012 16:32:48 GMT -6
Alleyoop, only connections on this carb is throttle cable, carb bowl drain port, fuel inlet and the electrical connection for the enricher. so I must have done something wrong putting carb back together again. Will wait till Sunday now when I have free time again to take it all apart and start over. Found a great breakdown pic to look at this time while I put it back together again to see what I might have done wrong.
As I said in the beginning, dummy here and have lots to learn.
Thanks for being patient with me and for your assistance.
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Clinician
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Post by deepcrk06 on Oct 20, 2012 14:15:12 GMT -6
First and foremost, Thanks for the assistance and suggestions.
Friend of mine had another 4 stroke carb that had the float bowel broke and housing cracked so I took the diaphragm and main jet from it and put it all in my carb. I still have the same problem. Is their something I am overlooking to get the vacuum \ air lines in the carb to get this to raise correctly?
I did order a new carb today also, just playing with things now to learn more about these carbs and the motor on this bike.
Again thanks to all who have responded.
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Post by deepcrk06 on Oct 20, 2012 11:47:18 GMT -6
further trouble shooting - nothing past idle -
for the fun of it - removed cover over the diaphragm - and as i increased throttle i lifted the diaphragm out - speed went up and was able to get full throttle while holding the diaphragm out of the carb - so i suspect something in carb is blocked or bad - so i am going to order new carb as that seems to be where the problem is - or am i missing something?
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Post by deepcrk06 on Oct 19, 2012 14:10:18 GMT -6
Continue trouble shooting, friend had a scooter that he modified so i replaced the goose neck (carb to head) intake. Replaced the air filter assembly, and all the vacuum hoses have been replaced new. Guess it time to buy new carb. (wish he still had his old one but he gave it to someone else) anything else I should check?
Bike use to run great, never had any issues with it starting or running and could maintain 35 mph with it on flat ground, did bog down little on hills but I expected that) bike has 3000 miles on it and this is first sign of problems I have had with it.
I changed lines one line at a time so I know they are correct.
If I want to replace carb, do you have a good recommendation?
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Post by deepcrk06 on Oct 19, 2012 13:24:59 GMT -6
HI All, need some assistance for a dummy here. I have a 139qmb 50cc engine, ran fine till I went over rail road tracks. Motor died. Got the bike home and found no spark condition. Replaced CDI and now have good spark. Engine will start and idle fine. Go to give it gas and it dies. Took carb apart and soaked, cleaned and dried it out. put it back together and still have same problem.
Compression: 90 lbs
Great Spark:
New pit cock vacuum pump
new vacuum lines and fuel filter
set and rechecked valves at .004 mm
bike idles great, just can give it any gas.
cleaned carb, nothing to adjust as it all preset.
Open to any and all ideas.
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