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01-06-2011, 11:15 PM | #1 |
Join Date: Mar 2009
Location: Southeastern Washington desert
Posts: 14,761
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I'm an idiot.
The Zong's got poor compression. I should have checked that first before dumping $200 in parts and a lot of time into it.
I can easily hold my thumb over the spark plug hole while cranking the motor. Adding some oil to the cylinder did not help so I think it's the valves. They are adjusted so that's not it either. I have $400 into it. Anyone wany a $200 project bike? Maybe Spud can get you a new motor inexpensively and you'd have a like new bike. As for me, I'm done with it.
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01-06-2011, 11:46 PM | #2 |
Join Date: Mar 2009
Location: Sardis, BC, Canada
Posts: 25,977
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If you send me the head, I can try replacing the valves for you. Alternatively, maybe you can find a Yamaha head that fits, like Spud did.
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Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer |
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01-07-2011, 11:34 AM | #3 |
Join Date: Mar 2009
Location: Southeastern Washington desert
Posts: 14,761
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Thanks, buddy but I think I'm gonna cash out. I'd rather not put more time into the bike, although it may be a simple bad valve and fixable very cheap. My heart's not into it, I won't turn a profit on it, so I'd just as soon let it go.
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01-07-2011, 11:06 PM | #4 |
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oh that sucks man, I shouldv thought of that ! whenever I was working on my RM250 or my TZR250 I uselly always check the compression !!! it actually makes perfect sense with all the symptoms you had on your bike !
Anyway I'll see if anyone around here wants it. Good luck with the sell ! |
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01-08-2011, 03:04 PM | #5 |
Join Date: Jun 2009
Location: orbital platform
Posts: 741
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Of course you realize: that a head gasket, blown between the cylinders (or the timing chain cavity), would cause the problem you describe?
Ok, I know, too easy, right? (nothing EVER works out that easy for me) For the want of a $6 gasket it's worth a look! |
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01-08-2011, 03:10 PM | #6 |
Join Date: Mar 2009
Location: Sardis, BC, Canada
Posts: 25,977
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My thoughts exactly.
And a buch of China Rider enablers will needle you until you take it apart.
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Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer |
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01-08-2011, 03:17 PM | #7 |
Join Date: May 2007
Location: Altamont, Kansas
Posts: 15,103
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Just do it. No cost involved in a top end tear down. Do it for the sake of future information for others. Call it research.
Also check into the yamaha sr250.
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You meet the nicest people on a Honda Clone. |
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01-08-2011, 03:27 PM | #8 |
Join Date: Mar 2009
Location: Sardis, BC, Canada
Posts: 25,977
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And take pictures. Lotsa pictures.
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Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer |
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01-08-2011, 09:30 PM | #9 | |
Join Date: Jul 2008
Location: Idaho
Posts: 25,054
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Quote:
Spud
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Spud "Never argue with an idiot. He will drag you down to his level, and beat you with experience." Mark Twain 2015 Zongshen ZS250GY-3 (RX3) 2006 Zongshen ZS200GY-2 (Sierra 200) 2005 Honda XR650L 2004 Honda CRF250X 1998 Kawasaki KDX220 Mods made to my Zongshen ZS200GY-2: http://www.chinariders.net/showthread.php?t=6894 |
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01-11-2011, 10:06 PM | #10 |
Join Date: Mar 2009
Location: Southeastern Washington desert
Posts: 14,761
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Another update.
I (tried to) pull the head. The valves look OK but there are vertical scoring marks on the cylinder so I think that's the problem. I was unable to pull the head all the way off. It does not seem possible with the motor still in the frame. I'm not sure I want to hone and re-ring or install an oversize piston. I'm still inclined to part it out. What's a motor for one of these cost, Spud? Are oversize pistons available?
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01-12-2011, 12:10 PM | #11 |
Join Date: Mar 2009
Location: Southeastern Washington desert
Posts: 14,761
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It came to me this AM how to remove the head with the motor in the frame. Will decide what to do based on Spud's avalibility of parts.
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01-12-2011, 07:29 PM | #12 |
Join Date: May 2007
Location: Altamont, Kansas
Posts: 15,103
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It may be possible to use yamaha parts. Let us know if it appears to has a broken ring or what went wrong.
Allen
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01-12-2011, 07:55 PM | #13 |
Join Date: Mar 2009
Location: Southeastern Washington desert
Posts: 14,761
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I looked at it again. No way to get the head off without pulling the motor and the swingarm/rear suspension. :evil: The head looks identical to the Yamaha. I don't know what's wrong. the cylinder is very lightly scored but otherwise it and the valves look OK.
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01-13-2011, 02:18 AM | #14 |
Join Date: Mar 2009
Location: Sardis, BC, Canada
Posts: 25,977
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Does it have a decompression device like a Honda? Maybe that's hanging open.
You could always hook up an airline to the spark plug hole and see where the air goes. That'll tell you where the horsepower is leaking.
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Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer |
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01-13-2011, 09:02 AM | #15 |
Join Date: Feb 2008
Location: Terrell and Grapevine Tx.
Posts: 1,585
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Any chance of a valve stuck partially open?
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