| | | Bicycle Engine Kits Most motorized bicycle engine kits are either a 2 stroke or 4 stroke. Both need careful installation and setup, find out from our professionals here! | Seized Piston Discussion at Motorized Bicycle Engine Kit Forum in the Bicycle Engine Kits forum. So what kind of oil are you using and how well mixed is it?
Don't forget - if your oil ...  | | 
04-09-2008, 10:15 PM
|  | Master Bike Builder & Forum Sponsor | | Join Date: Dec 2007 Location: Duvall, WA PNW
Posts: 1,405
| | Re: Seized Piston So what kind of oil are you using and how well mixed is it?
Don't forget - if your oil is too rich it will make the engine run fuel lean.
It is possible you have a broken ring......... | 
04-09-2008, 10:16 PM
|  | Master Motorized Bicycle Builder | | Join Date: Jan 2008 Location: north carolina
Posts: 3,071
| | Re: Seized Piston You want to lower the needle so raise the clip up on a groove. how far down was it. Should have been in second from the top to start.
the say the piston should be a light brown color. When I sezied mine it had five minutes burn so it was like new. i would think a serious build up of carbon around the rings might seize it. But that is just a guess.
If your head gasket is leaking it might give you a problem but if it fires maybe not. When you had the head off did you turn the engine over to watch the piston move? When I tore mine down I could see the piston move past the intake port.
In my case the C clip was installed wrong and got sucked into the cylinder and jamed a ring. now that seized the engine for sure. I had to knock i loose with a hammer to get that darned clip out. then of course I broke two rings so had to order more and wait for them to show up. When I finally got it put back together and it started, i thought I was really something.
anyway you don't have any missing pieces do you. lol
Last edited by deacon : 04-09-2008 at 10:21 PM.
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04-10-2008, 09:54 AM
|  | Senior Motorized Bicycle Builder | | Join Date: Mar 2008
Posts: 69
| | Re: Seized Piston the needle clip is 2nd from top. fuel mix 25:1 with snowmobile oil. I put a new plug in yesterday and after 10 minutes it was black. Should I try mixing 30:1 ? Move needle to top clip ? Mix pee with it ? Or what ?
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04-10-2008, 10:02 AM
|  | Master Motorized Bicycle Builder | | Join Date: Jan 2008 Location: north carolina
Posts: 3,071
| | Re: Seized Piston Sounds like a definite fuel air mix kind of thing.
Let me ask you one thing at a time.
1. how much do you have to choke it to get it to start?
I'm thinking running too rich and the engine is over heating. If that is true try moving the needle down but it might be that your needle seat is too large. But try moving it down first. Of course Norman would know more about this than me.
Last edited by deacon : 04-10-2008 at 10:10 AM.
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04-10-2008, 10:27 AM
|  | Motorized Bicycle Apprentice | | Join Date: Feb 2008
Posts: 17
| | Re: Seized Piston might want to try replacing the original carbon sparkplug cable with a regular automotive copper sparkplug cable. Probably 7mm . Just unscrew the old one and replace with new. You will probably have to screw the original fitting to the top of the sparkplug since most automotive plugs use the larger connect. Also test the voltage output... a weak spark could mean an incomplete burn. Next tune up, I'm saving the wires and fitting one to the bike. | 
04-10-2008, 02:14 PM
|  | Custom Builder / Dealer | | Join Date: Mar 2008 Location: Venice Beach, CA.
Posts: 354
| | Re: Seized Piston I'm still thinking that if your piston is chewed up, that would cause low compression & burning rich! Pull the cylinder and check it... it's real easy!
The very fact that your engine seized up, means you should check it out anyway!
Last edited by VENICE BOY : 04-10-2008 at 02:17 PM.
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04-10-2008, 02:34 PM
|  | Master Motorized Bicycle Builder | | Join Date: Jan 2008 Location: north carolina
Posts: 3,071
| | Re: Seized Piston If you pull the piston check with someone here before you try to reinstall the rings. I broke mine before I learned the trick to it. | 
04-10-2008, 05:57 PM
|  | Moderator | | Join Date: Jan 2008 Location: Ashtabula county, Ohio
Posts: 3,074
| | Re: Seized Piston Quote:
Originally Posted by VENICE BOY I'm still thinking that if your piston is chewed up, that would cause low compression & burning rich! Pull the cylinder and check it... it's real easy!
The very fact that your engine seized up, means you should check it out anyway! | I second that.
__________________ If it ain't broke, and you mess with it long enough, it will be. | 
04-10-2008, 06:10 PM
|  | Master Motorized Bicycle Builder | | Join Date: Jan 2008 Location: north carolina
Posts: 3,071
| | Re: Seized Piston I say again if you pull the jug and take it off to check the piston PLEASE ask someone for directions on reinstalling it. I can not stress enough that unless you are sure you know ASK.. There is nothing hard about it but if you don't get the rings in right they will snap. I know I broke both of mine from stupidity. I was able to do it right after someone showed me how, NORMAN mentored me through it.
Last edited by deacon : 04-10-2008 at 06:12 PM.
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04-10-2008, 07:40 PM
|  | Senior Motorized Bicycle Builder | | Join Date: Mar 2008
Posts: 69
| | Re: Seized Piston I'm not going to pull the jug unless or until it seizes again. It seems the more I do the more problems develop. I'm crossing my fingers that it is running ok now. I am out-of-town until tomorrow night and hope that on Saturday I can give it a good spin. If it seizes again I will probably shelf it and use it as spare parts for my next project.
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