New Rider
Currently Offline
Posts: 37 
Likes: 1
Joined: May 20, 2016 16:26:12 GMT -5
|
Post by blazejin on Dec 31, 2019 11:21:45 GMT -5
Well here is something new for me. I got this 50cc with a long case engine, thought the person just installed the rings wrong so I tore it down and reinstalled the rings drove it to the store, and on the way it started bogging and losing power. I limped it home and it started white smoking from the valve cover hose and I was like ok the rings have had it. so the next day while it was cool I went out turned it over a few times and with no luck. I went to start tearing it down and took the dip stick out and it blew out oil in my face , Ha Ha lots of pressure . I thought it was the oil pump on the first go around so I left the valve cover off and cranked it and oil seemed to flow like a river. Why all the crankcase pressure. Thanks
|
|
|
|
Post by tortoise on Dec 31, 2019 12:01:41 GMT -5
Why all the crankcase pressure. Overfilled oil level? Obstructed valve cover vent? Crankcase pressure should vent via the cam chain chamber and out the valve cover vent. Don't know what we don't know! Recall reading where one rider actually thought filling engine oil to the TOP of the dipstick port was proper. |
|
New Rider
Currently Offline
Posts: 37
Likes: 1
Joined: May 20, 2016 16:26:12 GMT -5
|
Post by blazejin on Dec 31, 2019 12:08:38 GMT -5
I know for a fact the oil was not overfilled, there was white smoke coming out pretty good from the valve cover hose so I don't think its that and the cam chain chamber is a big open port where the chain rides from cam to crank , how can that be stopped up ?
|
|
New Rider
Currently Offline
Posts: 37
Likes: 1
Joined: May 20, 2016 16:26:12 GMT -5
|
Post by blazejin on Dec 31, 2019 14:18:32 GMT -5
Ok, I think I may have found the problem. The A9 cam I had got off Amazon was shipped in a bubble packet, I did not look over the sprocket I just checked the barrens on the cam and they were good. so when I took it apart this time I noticed some scaring on one of the lobes then seen that the sprocket was warped and missing a tooth. It had to have been damaged in shipping. Cause on 1st start up there was no strange sounds so it had to have been like that. It was in time , I don't see how that would cause the pressure build up as it may have been warped but no ports were blocked. I have it all back together, just have to torque it down and put oil in it and I shall see. I will post the end results.
|
|
New Rider
Currently Offline
Posts: 37
Likes: 1
Joined: May 20, 2016 16:26:12 GMT -5
|
Post by blazejin on Dec 31, 2019 17:21:21 GMT -5
Well the cam needed replaced, and I did and that was not the problem, it did good till it heated up on my store run and started like it did be for lose of power and under throttle it was like the hotter it got the less throttle I can give, mainly going up hill with load. I babied it home and I guess I am going to open up the stator side and see what is going on in the oil pump area. Be for I started it I left the valve cover off and the oil was pumping hard coming out the center of the rocker set. if anyone else knows anything please let me know. I will try the oil pump in the AM Thanks . Also both time I tore it down it was the Black center oil ring that was burnt flush with the piston, the rest seemed fine
|
|
New Rider
Currently Offline
Posts: 37
Likes: 1
Joined: May 20, 2016 16:26:12 GMT -5
|
Post by blazejin on Jan 5, 2020 9:41:44 GMT -5
Ok well it seems there is nothing wrong with the oil pump, all that's left is to split the case and check the crank and chain, and all the oil ports. I did tare down the top end in it again and this time the center black oil ring was fine, it was the top compression ring that was stuck halfway on one side of the piston. I have pulled the engine and going back to my short case. I am starting to think that its just bad rings and or piston all together . Unless its like the 150cc to 50cc swap to where you have tp have the engine at a 10 degree pitch for the oil splach thing so it don't burn up. I don't see where it would matter, I will update next weekend as it is back to the drawing board.
|
|
New Rider
Currently Offline
Posts: 37
Likes: 1
Joined: May 20, 2016 16:26:12 GMT -5
|
Post by blazejin on Jan 6, 2020 15:34:27 GMT -5
This thing is crazy, switched engines back to short case, I used the same head and piston, just put new rings and it is doing the same thing. when its cold it runs fine un till I get a mile or 2 down the road and only on up hill after its hot it starts chattering losing power, I pull over it idles fine then I can take off about 20 yards and it starts it again. I changed plug, and the bell clutch came off the long case. I am going to change the bell clutch next weekend and the cdi and coil wire, if anyone has any thoughts about the situation please feel free to give me some feedback. thanks
|
|
|
|
Post by tortoise on Jan 6, 2020 16:27:24 GMT -5
going to change . . the cdi and coil wire Might also Ohms test the trigger/pickup/pulsar coil. For clarification, is the short case conversion no longer doing this . . . "next day while it was cool . . took the dip stick out and it blew out oil in my face" |
|
New Rider
Currently Offline
Posts: 37
Likes: 1
Joined: May 20, 2016 16:26:12 GMT -5
|
Post by blazejin on Jan 6, 2020 17:09:32 GMT -5
Thanks, I will check the pick up as well. there is no pressure building up like with the long case, its just like after it gets hot going up hills it flutters very bad like it chatters out and loses power. with WOT and keeps on till I let off back down to idle. then after a few sec. I am able to go for about 20 yrds before it starts again. I can have it on the center stand with WOT without a load and it is fine. getting hot up hill with a load is the persisting problem. Thanks for the info on the pick up.
|
|
|
|
Post by chewbaca on Jan 8, 2020 0:00:38 GMT -5
if you have pressure in the case it can be caused from blowby
check for scoring on the piston or cylinder wall
smoke from the vent hose is not a good thing
|
|
New Rider
Currently Offline
Posts: 37
Likes: 1
Joined: May 20, 2016 16:26:12 GMT -5
|
Post by blazejin on Jan 10, 2020 13:33:25 GMT -5
Ok it was not the pick up. I did change out the cdi and the coil, as I was pulling out the drive way it would not go hardly at all. lol both my tires were flat. (slow leaks) soooo I pumped em up ran to the store and back all went well, the real test will be Saturday morn. when I take it on a much longer ride. I did notice from where I had the stub nose breather on it with the hose going to a catch bottle that it had about 2 bottle caps of gas in it that got past the head thru the valve cover. witch makes me think when I go for the long ride it is going to happen again. I am going to take a back up carb with me, maybe I am looking at a type of flooding issue. I will post results. seems like I am narrowing it down though.
|
|
New Rider
Currently Offline
Posts: 37
Likes: 1
Joined: May 20, 2016 16:26:12 GMT -5
|
Post by blazejin on Jan 18, 2020 8:04:50 GMT -5
Ie all comes down to you get what you pay for, had a run of just plain out cheep bad rings.
|
|
