I Blew my 2 Stroke Now What?



Frankenstein

In memory of Frankenstein 1991 - 2018
Joined
Jun 24, 2016
Messages
5,077
There's nothing cheap about it? Hmm I bet you could rode a Puch twice as hard for twice as long and you'd still have a couple decades left on the engine.

You just don't understand that these are extremely cheap, they don't last long and that's that. If the rings burned up and the big end crank bearing is in good shape then you'll need a head, cylinder, type "B" piston (hole is about half way up, type A sits lower,) and probably crank bearings and wrist pin bearing + wrist pin.

Bicycle_motor_works on eBay sells complete top ends which includes all but the crank bearings and head. If you are doing this then may as well get new crank seals (a thin and a thick one) to replace the ones you have unless they are in good shape, then use them until it leaks.

If after cleaning that big end bearing feels crummy then the crank may need replacing as well, which at that point it would be advantageous to just buy a complete motor sans the extras like the tank and all which you've already got. At least they are cheap enough to replace now and then. I would also recommend good synthetic oil especially if you are hard on it in the summer, it raises the price of gas to like 7 dollars a gallon but these don't use much fuel anyway. There are excellent cnc heads available too, if you upgrade to something with more beef on it then your temps will stay down longer just because of the increased mass and cooling surfaces, it really stretches a cylinder out if you can keep that flimsy chrome from cooking.
 

clvck

New Member
Joined
May 2, 2018
Messages
23
There's nothing cheap about it? Hmm I bet you could rode a Puch twice as hard for twice as long and you'd still have a couple decades left on the engine.

You just don't understand that these are extremely cheap, they don't last long and that's that. If the rings burned up and the big end crank bearing is in good shape then you'll need a head, cylinder, type "B" piston (hole is about half way up, type A sits lower,) and probably crank bearings and wrist pin bearing + wrist pin.

Bicycle_motor_works on eBay sells complete top ends which includes all but the crank bearings and head. If you are doing this then may as well get new crank seals (a thin and a thick one) to replace the ones you have unless they are in good shape, then use them until it leaks.

If after cleaning that big end bearing feels crummy then the crank may need replacing as well, which at that point it would be advantageous to just buy a complete motor sans the extras like the tank and all which you've already got. At least they are cheap enough to replace now and then. I would also recommend good synthetic oil especially if you are hard on it in the summer, it raises the price of gas to like 7 dollars a gallon but these don't use much fuel anyway. There are excellent cnc heads available too, if you upgrade to something with more beef on it then your temps will stay down longer just because of the increased mass and cooling surfaces, it really stretches a cylinder out if you can keep that flimsy chrome from cooking.

You guys are awesome with the information....love it....thank you guys!
 

Tyler6357

Well-Known Member
Joined
Sep 28, 2011
Messages
1,113
You will need: New cylinder, new piston w/rings, new wrist pin and clips, new needle bearing, new head gasket, new head. It's possible you can reuse some of your gaskets like the base gasket and intake or exhaust gaskets but it's best to get a new head gasket with a new piston and cylinder. Sometimes you can get a deal on an entire top end, just make sure you get the cylinder with the 32mm intake, not the 40mm unless you want to upgrade the intake to 40mm, and make sure you get the piston with the higher wrist pin location. You might be able to find some of these parts in black or for a cheaper price, I encourage you to shop around.

This is everything except the needle bearing--->https://www.ebay.com/itm/2-Stroke-Engine-Cylinder-Kit-High-Performance-Race-66cc-Motorized-Bicycle-Type-B/322934772539?hash=item4b3069933b:g:0pkAAOSwK6RZGKTP

Needle bearing (wrist pin bearing)----> https://www.ebay.com/itm/66-80cc-Motorized-Bicycle-piston-Needle-Bearing-For-10mm-Wrist-Pins/232125034154?hash=item360bbaeeaa:g:4lQAAOSwHMJYD-o1

Note: If you decide to upgrade to the cylinder with a 40mm intake you will need to purchase a new 40mm intake similar to this one----> https://www.ebay.com/itm/High-Performance-40MM-CNC-Air-Intake-Manifold-66cc-80cc-Motorized-Bicycle/152930755165?epid=25006498566&hash=item239b62225d

Here is a top end with a cylinder 40mm intake but you will still need to get the needle bearing---> https://www.ebay.com/itm/66-80cc-Motorized-Bicycle-Top-End-Set-for-ZEDA-80s-GT5-Engines-40mm-Intake/273236559162?epid=2272728012&hash=item3f9e2b053a:g:L8cAAOSw5UZZAIzo
 
Last edited:

clvck

New Member
Joined
May 2, 2018
Messages
23
You will need: New cylinder, new piston w/rings, new wrist pin and clips, new needle bearing, new head gasket, new head. It's possible you can reuse some of your gaskets like the base gasket and intake or exhaust gaskets but it's best to get a new head gasket with a new piston and cylinder. Sometimes you can get a deal on an entire top end, just make sure you get the cylinder with the 32mm intake, not the 40mm unless you want to upgrade the intake to 40mm, and make sure you get the piston with the higher wrist pin location. You might be able to find some of these parts in black or for a cheaper price, I encourage you to shop around.

This is everything except the needle bearing--->https://www.ebay.com/itm/2-Stroke-Engine-Cylinder-Kit-High-Performance-Race-66cc-Motorized-Bicycle-Type-B/322934772539?hash=item4b3069933b:g:0pkAAOSwK6RZGKTP

Needle bearing (wrist pin bearing)----> https://www.ebay.com/itm/66-80cc-Motorized-Bicycle-piston-Needle-Bearing-For-10mm-Wrist-Pins/232125034154?hash=item360bbaeeaa:g:4lQAAOSwHMJYD-o1

Note: If you decide to upgrade to the cylinder with a 40mm intake you will need to purchase a new 40mm intake similar to this one----> https://www.ebay.com/itm/High-Performance-40MM-CNC-Air-Intake-Manifold-66cc-80cc-Motorized-Bicycle/152930755165?epid=25006498566&hash=item239b62225d

Here is a top end with a cylinder 40mm intake but you will still need to get the needle bearing---> https://www.ebay.com/itm/66-80cc-Motorized-Bicycle-Top-End-Set-for-ZEDA-80s-GT5-Engines-40mm-Intake/273236559162?epid=2272728012&hash=item3f9e2b053a:g:L8cAAOSw5UZZAIzo

wow the perfect response thank you so much!
 

clvck

New Member
Joined
May 2, 2018
Messages
23
You will need: New cylinder, new piston w/rings, new wrist pin and clips, new needle bearing, new head gasket, new head. It's possible you can reuse some of your gaskets like the base gasket and intake or exhaust gaskets but it's best to get a new head gasket with a new piston and cylinder. Sometimes you can get a deal on an entire top end, just make sure you get the cylinder with the 32mm intake, not the 40mm unless you want to upgrade the intake to 40mm, and make sure you get the piston with the higher wrist pin location. You might be able to find some of these parts in black or for a cheaper price, I encourage you to shop around.

This is everything except the needle bearing--->https://www.ebay.com/itm/2-Stroke-Engine-Cylinder-Kit-High-Performance-Race-66cc-Motorized-Bicycle-Type-B/322934772539?hash=item4b3069933b:g:0pkAAOSwK6RZGKTP

Needle bearing (wrist pin bearing)----> https://www.ebay.com/itm/66-80cc-Motorized-Bicycle-piston-Needle-Bearing-For-10mm-Wrist-Pins/232125034154?hash=item360bbaeeaa:g:4lQAAOSwHMJYD-o1

Note: If you decide to upgrade to the cylinder with a 40mm intake you will need to purchase a new 40mm intake similar to this one----> https://www.ebay.com/itm/High-Performance-40MM-CNC-Air-Intake-Manifold-66cc-80cc-Motorized-Bicycle/152930755165?epid=25006498566&hash=item239b62225d

Here is a top end with a cylinder 40mm intake but you will still need to get the needle bearing---> https://www.ebay.com/itm/66-80cc-Motorized-Bicycle-Top-End-Set-for-ZEDA-80s-GT5-Engines-40mm-Intake/273236559162?epid=2272728012&hash=item3f9e2b053a:g:L8cAAOSw5UZZAIzo

crazy how the Original looks compared to my wrist pin beraing - all bearings are missing!
 

Frankenstein

In memory of Frankenstein 1991 - 2018
Joined
Jun 24, 2016
Messages
5,077
crazy how the Original looks compared to my wrist pin beraing - all bearings are missing!
Yeah that's a sign that it needs replacing. Though you could keep it as a spare in case of an emergency, or keep it on your keychain as a souvenir of some sort. Eating is not recommended unless low on iron.
 
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