Running 1 Piston Ring

Chainlube

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Jan 5, 2020
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Case reeds are great, they make great power. They're used on a lot of outboard engines, but where are you going to put the carb on a bike?
 


FNTPuck

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Jul 2, 2018
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869
I would not run a chinagirl piston with one ring. They have horrible tolerances, massive ring gaps, and huge ringlands. There are pistons specifically made for a single ring, but they have proper ring end gap and are usually thinner rings. I have one on my built 74cc Tomos engine that I am putting on a 20" BMX. Its 45mm though so won't fit a chinagirl, but there are 47mm versions for other mopeds that can fit.
95295


Notice the super thin 1mm ring and the tiny ringland area. Ring gap is super tight when installed. It also has oiling holes for the bushing and is lighter weight - just a piston swap with no other changes adds a tach verified 700rpm to the top end range.
 

Jug

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Mar 16, 2020
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Case reeds are great, they make great power. They're used on a lot of outboard engines, but where are you going to put the carb on a bike?
I have a g2 reed meaning i would have to weld a thicker plate onto the case then tap it for the reeds. I have a 21mm pwk carb which is f***ing huge. As long as everything is sealed back up correctly and there are no air leaks it should work grear. The reeds go under the cylinder on the intake side, pretty much right under the cylinder.
 

Don_Parsons

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May 6, 2020
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I run what the factory sent me,,, not to worried about friction and heat since the complete kit was $240 to my door...

If i get 10 hours out of the motor I'm happen,,,
100 hours of operation would be awesomeness...

And a whopping 365 ish hours would be golden...

We can get replacement motors up here for about $87 Cnd funds shipped to the door,,, its cheaper to put in a new power plant when its time then £art around working on a worn out engine...

I can swap out a new motor in a 1/2 hour..

6 nuts and bolts with exshust,,, 4 wires,,, 2 cables,,, and drive chain...

Its not worth fixing 1/2 worn out factory Zeda 80cc engines,,, thats why they sell frugal...
 

YetiWoodz

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Dec 19, 2019
Messages
574
About how long do the cheap piston rings that come with the kits last or at least how often should you check? And the more durable ones?
 
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Frogslayer

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Jan 20, 2019
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1,455
My opinion, if you notice a power loss check the compression, quick and easy to do you don't even need new gaskets. If it seems low, you can put a tea spoon of oil down the hole and check compression again and see what you get.
 

Jug

Member
Joined
Mar 16, 2020
Messages
41
Only 8 nuts and 2 clips to switch out a jug and piston $20. Seems pretty damn worth it to me
Well if you love to port stuff to the max like third transfers and boost ports, rounding exhausts and stuff. It takes awhile to do all of that and getting it to work good. So getting a new cylinder would kinda be a little sh**ty to me.
 

Tyler6357

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Sep 28, 2011
Messages
1,108
Well if you love to port stuff to the max like third transfers and boost ports, rounding exhausts and stuff. It takes awhile to do all of that and getting it to work good. So getting a new cylinder would kinda be a little sh**ty to me.
Well, yeah, if you are going to count the work..... :)
 
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