Scored Piston - broken Piston ring -- twice!

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gg90

New Member
Nov 14, 2011
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I purchased a motorized bike from a guy in San Francisco, and after riding it for less than 30 days, it broke down and he couldn't figure out how to fix it -- so he sold me a second engine at a reduced price (how dumb am I) and I put it together myself. It worked for 3 days ... After finally talking to a car engine guru in my family, it appears that both experienced a broken piston ring causing a scored piston. The label on the engine is Rico Group Inc.

I understand I can have the piston machined back into shape ... any suggestions on where to get replacement piston rings? Also, any recommendation on a good quality motor -- this seems to be NOT.
 
Al.Fisherman

Al.Fisherman

New Member
Sep 9, 2009
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Calera, Alabama
If it was me, I'd buy the cylinder/piston/rings from one of our vendors. Do a search as who will be the best to deal with. I saw a piston/rings/cylinder/head/head gasket for $60.00 + ship.
 
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rohmell

rohmell

Active Member
Jun 2, 2010
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New York
All my engines and parts come from The RICO Group, and I never have had any problems. What gas/oil ratio are you running?
 
rustycase

rustycase

Gutter Rider
May 26, 2011
2,746
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Left coast
I really don't think the bgf engines can be too much worse than the rest.
...we're missing some of the facts here, it seems...

And I'm also convinced that some of the vendors may put in extra work and do at least some degree of inspection and perhaps adjustment to the engines they sell for mainland china.

...If someone did a quick inspection for casting slag and mismatched gaskets it would do wonders for longevity !
rc
 
2door

2door

Moderator
Staff member
Sep 15, 2008
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Littleton, Colorado
rustycase said:
I really don't think the bgf engines can be too much worse than the rest.
...we're missing some of the facts here, it seems...

And I'm also convinced that some of the vendors may put in extra work and do at least some degree of inspection and perhaps adjustment to the engines they sell for mainland china.

...If someone did a quick inspection for casting slag and mismatched gaskets it would do wonders for longevity !
rc
Click to expand...
Chris Hill used to do that. Every engine he sold had been disassembled, cleaned and inspected. Unfortunately his prices were higher than everyone else and he closed up shop. Too bad. Now, you gets what you got. Good luck.
Tom
 
moonerdizzle

moonerdizzle

New Member
Jun 28, 2009
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Cheese head capitol
My engine from BGF was in really good shape, my only problem is it didnt have a set screw for the clutch flower nut. But that was no big deal to me. The motor was clean on the inside. And my tank looked clean inside, no rust, no dirt, no stuff rattling around.
 
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nightcruiser

New Member
Mar 25, 2011
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Did you recheck the head torque after riding it a few times? They generally come loose, if run with a loose head I would expect a to ding a ring, or two...

In my experience, if you want to buy a bike and just ride it you'd be better off buying a scooter... If you don't build the bike yourself you are left clueless about all the mechanics of the bike and are probably gonna walk head first into lots of failures simply because you don't have a clue! These bikes need regular maintenance, specially when a build is new....

As for your fix, I would order the top end kit from BGF from ebay for $37 delivered and rebuild the thing myself. When done with that you should have a better grip on the mechanics of the bike and will be better equipped to maintain it....

As for this quality of this motor compared to any other china motor, they are all a crap shoot, I don't think any of them are gonna be better than any other unless you have someone inspecting and correcting issues before they are sent out to you.
 
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gg90

New Member
Nov 14, 2011
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California
i was using 21 to 1 ratio for the gas and oil. i started with a little more oil in the gas when the engine was first being broken in then switched but i was also using the least expensive gas which i think hurt me in the end. with the second enginge i used the more expensive gas but i just think the piston ring broke and scored the top end. what is the best way to make sure everything stays in tune? thank you for your suggestions
 
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nightcruiser

New Member
Mar 25, 2011
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gg90 said:
i was using 21 to 1 ratio for the gas and oil. i started with a little more oil in the gas when the engine was first being broken in then switched but i was also using the least expensive gas which i think hurt me in the end. with the second enginge i used the more expensive gas but i just think the piston ring broke and scored the top end. what is the best way to make sure everything stays in tune? thank you for your suggestions
Click to expand...
I think I already answered your question, replace the top end (cylinder, piston and rings) and torque down the head. Then re-torque the head after about a hundred miles and keep checking the head torque every so often after that. You might also make sure that the muffler has some sort of support on it besides where it connects to the head, that's a lot of weight bouncing there on the head if there is no support on the bottom end of the muffler.
PS never torque or remove bolts (or spark plug) from a hot motor....
 
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nightcruiser

New Member
Mar 25, 2011
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gg90 said:
how do i change out the piston with the new one i ordered
Click to expand...
hmm, I'm pretty sure I spent some time searching this forum, and google, and youtube and found a lot of info that way. And looking at the diagrams of the motor on the websites that sell the parts... Basically you pull the head, then the clips on the piston pin, then the pin, then reverse. I bet if you search you can find a tutorial on doing it, don't know of one off hand though...
 
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gg90

New Member
Nov 14, 2011
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California
ok got it thank you is there any other lubrication or maintinance i should do to the engine while i have it taken apart or any other suggestions you might have to keep the engine in good condition
 
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