Motorized Bicycle Engine Kit Forum  

Sponsors



Go Back   Motorized Bicycle Engine Kit Forum > Motorized Bicycle Mechanical Components > Heads and Cylinders

Heads and Cylinders All about your porting, compression, rings, cylinder and piston modifications to your bicycles engine

Reply
 
Thread Tools Display Modes
  #1  
Old 06-27-2016, 03:28 PM
BlueSmoker BlueSmoker is offline
Motorized Bicycle Member
 
Join Date: May 2016
Location: Finland
Posts: 31
Default Piston replacement interval?

How often do you need to change piston rings and the piston?
Reply With Quote
  #2  
Old 06-27-2016, 04:04 PM
Kioshk's Avatar
Kioshk Kioshk is offline
Motorized Bicycle Elite Member
 
Join Date: Oct 2012
Location: Connecticut
Posts: 1,124
Default Re: Piston replacement interval?

In my experience, it's always been the cylinder that needs replacing due to wear. Any times I've needed to replace a piston or set of rings was when the cylinder-wall deteriorated and caused damage to the rings/piston. I've had to replace upper-ends on the average of once every 6-months. On the rare occasion, a needle-bearing will fail and a needle will get sucked into the chamber causing damage. I've had pistons with defective index-pins that loosen up over time, and slowly gouge the cylinder-wall (compression will gradually diminish until the chrome-shell flakes off). One really bad jug I had a few months back just started shedding its chrome like a dog with mange after a couple of weeks' use. So, if it ain't broken, don't fix it.
Reply With Quote
  #3  
Old 06-29-2016, 10:58 AM
bairdco's Avatar
bairdco bairdco is offline
a guy who makes cool bikes
 
Join Date: Aug 2009
Location: living the dream in southern california
Posts: 6,287
Default Re: Piston replacement interval?

I changed mine everytime I blew up a motor. These motors rarely last long enough to worry about piston ring service intervals, and will usually seize up unexpectedly when a ring snaps, retaining pin pops out, bearing fails, or gremlin eats it.

And when they do fail, usually takes out the whole motor, as all the broken parts grind around inside like a cement mixer.

Then, piston and ring replacement is easy. It's already assembled inside a new motor.
Reply With Quote
  #4  
Old 06-29-2016, 11:44 AM
YesImLDS's Avatar
YesImLDS YesImLDS is offline
Motorized Bicycle Elite Member
 
Join Date: Jun 2013
Location: Columbia, Missouri
Posts: 934
Default Re: Piston replacement interval?

Fix it if it is broke. I've never replaced a piston as regular maintenance but whenever I put in a new jug I would put on new rings to set into that specific jug.
__________________
Check out my Youtube Channel here!
https://goo.gl/U5gfMo
Reply With Quote
  #5  
Old 06-29-2016, 05:31 PM
BlueSmoker BlueSmoker is offline
Motorized Bicycle Member
 
Join Date: May 2016
Location: Finland
Posts: 31
Default Re: Piston replacement interval?

Okay, how many miles have you ridden your bike then without piston change? I just don't like to worry about the engine all the time.
Reply With Quote
  #6  
Old 06-29-2016, 09:42 PM
YesImLDS's Avatar
YesImLDS YesImLDS is offline
Motorized Bicycle Elite Member
 
Join Date: Jun 2013
Location: Columbia, Missouri
Posts: 934
Default Re: Piston replacement interval?

Quote:
Originally Posted by BlueSmoker View Post
Okay, how many miles have you ridden your bike then without piston change? I just don't like to worry about the engine all the time.
My bike is more performance oriented and doesn't get ridden often, but when it does it's hard miles usually. I probably have over a thousand miles on this piston. My original performance build went over 2000 miles. That is until I revamped everything.
__________________
Check out my Youtube Channel here!
https://goo.gl/U5gfMo
Reply With Quote
  #7  
Old 06-29-2016, 10:40 PM
Kioshk's Avatar
Kioshk Kioshk is offline
Motorized Bicycle Elite Member
 
Join Date: Oct 2012
Location: Connecticut
Posts: 1,124
Default Re: Piston replacement interval?

Quote:
Originally Posted by BlueSmoker View Post
Okay, how many miles have you ridden your bike then without piston change? I just don't like to worry about the engine all the time.
Rough estimate of about 2000-miles to a top-end & 6000-miles to a bottom-end for me.
Reply With Quote
  #8  
Old 06-30-2016, 06:33 AM
bairdco's Avatar
bairdco bairdco is offline
a guy who makes cool bikes
 
Join Date: Aug 2009
Location: living the dream in southern california
Posts: 6,287
Default Re: Piston replacement interval?

It's a crap shoot. Had one motor last five blocks, then the main bearing blew, and another that lasted 3 years as my main transportation.

That one had no chrome left in the cylinder, piston was totally scuffed up, and still was fast and worked fine, til the chain broke, whipped around and cracked the case.
Reply With Quote
  #9  
Old 06-30-2016, 10:39 AM
2door's Avatar
2door 2door is offline
Super Moderator
 
Join Date: Sep 2008
Location: Littleton, Colorado
Posts: 16,254
Default Re: Piston replacement interval?

Thousands of miles on several different engines. I've never replaced a piston, cylinder, rings, or had any reason to. I don't abuse my engines but I don't baby them either.
What am I doing wrong?

Tom
__________________
Age and Treachery Will Always Triumph
Over Youth and Skill & "Charlie Don't Ride"
Reply With Quote
  #10  
Old 07-01-2016, 05:17 AM
bairdco's Avatar
bairdco bairdco is offline
a guy who makes cool bikes
 
Join Date: Aug 2009
Location: living the dream in southern california
Posts: 6,287
Default Re: Piston replacement interval?

Tom, if you want to blow one up, try racing them and squeezing 10+hp out of it to try to keep up with guys that have more money than you.

If that doesn't work, forget everything you've ever learned about these motors, assemble it according to the instructions on a huffy, and think it's as reliable as a 1977 italian moped.
Reply With Quote
Reply

Tags
interval, piston, replacement

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -5. The time now is 03:46 PM.


Sponsors

Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
MotorBicycling.com