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Author Topic: Piston experiment  (Read 6854 times)

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Offline nirvanafan98

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Piston experiment
« on: May 17, 2013, 12:09:58 PM »
Going to take new piston with the 2 rings out and reinstall old piston with 1 ring and see if it runs better. Thinking new piston I bought is too tight . Not allowing rings to expand properly to work . :evil:
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Offline sandblaster

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Re: Piston experiment
« Reply #1 on: May 17, 2013, 03:49:04 PM »
You could always measure the pistons and the bore.
Then compare with the clearance specs for the piston type and you should know right where you are at.
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Offline motopunk

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Re: Piston experiment
« Reply #2 on: May 17, 2013, 05:37:50 PM »
Quote from: sandblaster on May 17, 2013, 03:49:04 PM
You could always measure the pistons and the bore.
Then compare with the clearance specs for the piston type and you should know right where you are at.

yes... and 2 rings are always better than only one.. better compression, pistons runs with more stability in the cylinder... etc.
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big 2 stroke bikes are weapons for real men, who donīt fear death or devil. ;O)
ī83 kx250, ī87 kx250 (with 360 big bore), 87 kx500, ī93 kx500 sfc

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Offline nirvanafan98

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Re: Piston experiment
« Reply #3 on: May 18, 2013, 04:47:47 AM »
Thanks , I'm sure I screwed up . The piston is so tight it's hard to get cylinder over the rings . :cry:
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Offline sandblaster

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Re: Piston experiment
« Reply #4 on: May 18, 2013, 05:04:17 AM »
That's a bummer....
Even a cheap Digital Veneer Caliper can save you some grief...


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Offline wierdo

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Re: Piston experiment
« Reply #5 on: May 18, 2013, 10:09:04 AM »
have you checked the ring gap? motorrad had trouble with rings before, never assume new is perfect.
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Offline 81cr450

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Re: Piston experiment
« Reply #6 on: May 18, 2013, 12:30:24 PM »
Quote from: sandblaster on May 18, 2013, 05:04:17 AM
That's a bummer....
Even a cheap Digital Veneer Caliper can save you some grief...




DONT buy that particular mitutoyo  caliper though, it doesnt shut off automatically. Mitutoyo is good stuff but you do want one that shuts itself off as you will space it & leave it on for days or months on end.
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Offline sandblaster

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Re: Piston experiment
« Reply #7 on: May 18, 2013, 12:35:17 PM »
Geese man, I'm trying to help the battery companies out  :-D
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The four stroke engine: That's one stroke for producing power and three for wearing the engine out.

Offline 81cr450

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Re: Piston experiment
« Reply #8 on: May 18, 2013, 03:11:45 PM »
My Boss borrow's mine & leaves it on, he'll be buying the batteries so what should I care. I just wish I would have thought about auto off, that exact tool doesnt have it, details details details

Sorry for the hijack, just one I wish I would have thought of
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if I only had a pair, I could actually ride this thing

& to the people I like  FYYFF

Offline nirvanafan98

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Re: Piston experiment
« Reply #9 on: May 18, 2013, 03:49:32 PM »
I never checked ring gap . Sorry to say . Went off of the information my local shop told me . How this all started , I had a compression release installed . Bike ran great but was hard to start . So when Larry installed the compression release . I decide to rebuild the top end while it was apart .  It's an 87 k 500 . Couldn't find a 87 piston . So I bought an 88 , 2 ring piston .There is 2 brown streaks on the cylinder wall , where the pin in the ring grooves are . Assume oil is getting past the rings  is not why it runs like it did before. Now it smokes I think a little to much and runs like a car with a clogged catalytic converter . I think I wasted couple hundred dollars on the rebuild kit . The compression release works great . Have 3 bikes , my first 500 though . :-D
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Offline nirvanafan98

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Re: Piston experiment
« Reply #10 on: May 18, 2013, 03:55:03 PM »
My local Kaw Dealer told me about this site . Learned a lot since I joined. Read the Forums a couple of times a week to learn something new . :roll:
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Offline motopunk

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Re: Piston experiment
« Reply #11 on: May 18, 2013, 04:40:41 PM »
i think the pistons might be the same from 83 - 2004 . but there is always to watch out for right piston-clearance and ring gap .. :-)
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big 2 stroke bikes are weapons for real men, who donīt fear death or devil. ;O)
ī83 kx250, ī87 kx250 (with 360 big bore), 87 kx500, ī93 kx500 sfc

---  www.der-motopunk.de.tl  ---

Offline sandblaster

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Re: Piston experiment
« Reply #12 on: May 18, 2013, 04:45:24 PM »
When it comes to engine work, trust no one..... I have seen too many builds go sour because of it.
Get a Clymer and verify the specs..
Do I sound cynical?  :lol:
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Offline nirvanafan98

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Re: Piston experiment
« Reply #13 on: May 18, 2013, 05:18:48 PM »
Here's a picture of my 500 . Bought this bike used last fall.  :evil:
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Offline motopunk

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Re: Piston experiment
« Reply #14 on: May 18, 2013, 05:39:11 PM »
Quote from: sandblaster on May 18, 2013, 04:45:24 PM
When it comes to engine work, trust no one..... I have seen too many builds go sour because of it.
Get a Clymer and verify the specs..
Do I sound cynical?  :lol:

you sound like the real life, where some guys dont know what they have to do for installing the right pistons...  :wink:

i saw some strange things in blown engines... 1. place an old aircooled simson s70-engine.
 the guy installed a new piston, cylinder and plug. as he cames to me with the blown engine, ha said there were always a knocking in the engine since his rebuild 4 days ago! but he couldnīt locate it and rode it and kaboom after 50 miles.   :evil:
i pulled the cylinder and found a big hole in the piston. cause, the idiot had installed a wrong plug with to long thread that hits the piston all the time... :|
i cleaned the crankcase without splitting, installed new piston and right plug with the short thread that is needed on it and voila... than it was one of the best engines, as it run again..  :-D
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big 2 stroke bikes are weapons for real men, who donīt fear death or devil. ;O)
ī83 kx250, ī87 kx250 (with 360 big bore), 87 kx500, ī93 kx500 sfc

---  www.der-motopunk.de.tl  ---
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