KX Riders
Maintenance & Technical => KX500 Original => Topic started by: karlosthejackel on April 12, 2014, 03:40:11 AM
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I removed the stator cover to check timing and while I was there I just rocked the flywheel lightly backwards and forwards. There is a "light clonking" noise coming from engine. I took the spannie off and there is quite a bit of movement in the piston I can even rotate it left and right very slightly. Being such a big piston im guessing there should be a bit of movement. is it normal? please say yes
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Sorry buddy.... No bueno....
Time to take her down before you blow her up :-(
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Well what can I say. Considering this engine has only just been split and rebuilt I think ive found some issues....
(http://i24.photobucket.com/albums/c14/karlos100/6360752C-CDD3-4286-B25C-DE39A3AC93F3_zpscoqwpktg.jpg) (http://s24.photobucket.com/user/karlos100/media/6360752C-CDD3-4286-B25C-DE39A3AC93F3_zpscoqwpktg.jpg.html)
(http://i24.photobucket.com/albums/c14/karlos100/3590A6B8-3CCD-4383-8315-7EAA4B6A50F0_zpstkfu1zpq.jpg) (http://s24.photobucket.com/user/karlos100/media/3590A6B8-3CCD-4383-8315-7EAA4B6A50F0_zpstkfu1zpq.jpg.html)
(http://i24.photobucket.com/albums/c14/karlos100/7E1D2265-1731-4281-A1FC-7B89E2DCFA72_zpsszryp8a9.jpg) (http://s24.photobucket.com/user/karlos100/media/7E1D2265-1731-4281-A1FC-7B89E2DCFA72_zpsszryp8a9.jpg.html)
The pin is worn out as you can see. The piston is cracked but I think the liner is ok, It looks like a crack in the transfer port but on close inspection it just looks like casting to me close up. The piston is a standard size wiseco but seemed a bit slack in the cylinder but then ive never had a 500 apart before
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yeah, you've definitely got some issues there....I wouldn't assume the cylinder plating is ok until you measure it, you may find it's beyond it's wear limit.
the factory castings suck around all the bridges, period.
depending how much you're willing to spend, I'd just have it stripped, all the bridges re-welded, and re-plated to the closest size to what it is now....you need a new piston/rings/pin/bearing/circlips anyways, maybe even have the head reshaped?...might as well just do it all now and be done with it.
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The cylinder has a steel liner is that normal?
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ahh...I didn't catch that...no it would've been installed by a previous owner.
it's not necessarily a bad thing, providing it was installed right...ports matched/cleaned-up..etc...sleeve isn't sticking up above the cylinder, you'd know if that was an issue as it would overheat and use coolant.
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looks ok to me. As its a liner is it plated?
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more than likely, no, at least from what I can tell in the pic...but I have heard of guys plating sleeves.
I'd still have that bore measured either way before you buy a new piston and such....one of the #1 reasons a piston cracks is due to excessive piston to cylinder wall clearance.
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Ive tried to measure with electronic caliper im getting 85.95 at the skirt end and 85.5 at the top
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What kind of caliper did you use?
Was it a Digital Vernier Caliper like this?
(http://upload.ecvv.com/upload/Product/20094/China_4_keys_Electronic_Digital_Vernier_Caliper_and_Calliper_Gauge200941810452510.jpg)
If so, did you use a Telescoping Gage along with your caliper?
(http://www.transcat.com/images/Photos/starrett_229C_lg.jpg)
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electronic caliper yes.
other thingy no!
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Ok, it can be difficult to use the back side of the calipers to measure the bore.
Although it's not unusual for the top of the bore to be tighter then the bottom as there is virtually no wear at the top.
If you were to measure the bore about a 1/2" from the top you would likely get a larger reading.
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Im off to a meeting on the KTM tomorrow ill try see if someone has a tele gauge. Im guessing if the readings are all over the place it will need another liner?
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Worst case scenario you can have the liner bored to the next size up that gives full clean up.
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Worst case scenario you can have the liner bored to the next size up that gives full clean up.
that's the route I'd go regardless, since a new piston is needed anyhow, might as well keep everything uniformly new.
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+1
I would also clean up the transfers and intake bridges while I had it all apart.
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yup, providing the person/company who installed the sleeve did it correctly, the ports/transfers should've been cleaned up and matched already....but we know how that goes these days :wink: :lol:
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I was think more along the lines of...
From this
(http://www.oem-cycle.com/forum/download/file.php?id=736)
To this
(http://www.oem-cycle.com/forum/download/file.php?id=739)
And from this
(http://www.oem-cycle.com/forum/download/file.php?id=874)
To this
(http://www.oem-cycle.com/forum/download/file.php?id=753)
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ahh there ya go...it's all about being specific on what you mean. :-D
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All your base are belong to us :-P
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ahh...going jibber-ish now. :lol:
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Hi guys hope you are well and happy new year!!...im sort of opening this thread back up. Ive not had any time to play with the k5 that's why ive been quiet but in the last two weeks ive got the bottom end out,started to strip it and have also bought the tools to measure the bore properly etc.
Good news on the cylinder is that the liner measures up to new spec so it will just need a nice hone and a standard slug putting in there.
What piston would you recommend between proX ,wossner or wiseco? Ive read about the forged pistons need a good warm up before use which is how I roll anyway!
Im refreshing the crank and whatever else I find on the bottom. Best recommendation on a conrod would be cool as well.
As im in the UK im struggling to find parts at the right price. Ive bought a rad valve for it to get rid of the crazed inlet boot which was a great price from the US inc all charges
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I'd run a Wossner piston and rod.
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I'd run a Wossner piston and rod.
Is there anyone in the US that you recommend to supply me both at the right price? Im struggling to find a wossner pison over here in UK but have found a rod but uk prices aint cheap!
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Alward25
http://www.kxriders.com/forums/index.php?action=pm;sa=send;u=1752 (http://www.kxriders.com/forums/index.php?action=pm;sa=send;u=1752)
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Thanks Mike! :mrgreen:
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I was think more along the lines of...
From this
(http://www.oem-cycle.com/forum/download/file.php?id=736)
To this
(http://www.oem-cycle.com/forum/download/file.php?id=739)
And from this
(http://www.oem-cycle.com/forum/download/file.php?id=874)
To this
(http://www.oem-cycle.com/forum/download/file.php?id=753)
when did knife edging the dividers come back into fashion{80s tuning} :-)
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Hmmm.
Team Green used it well into the 90's.
Every major engine builder I have received cylinders from still use it today.
I guess my question is, when did it go out of fashion?
Is there are documented dyno runs that proves or disproves this practice?
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Yes
my early 90s tune tzr250 knifed but aimed in a certain direction
(http://i246.photobucket.com/albums/gg119/cr500-af/kx500%2088%20cases/SAM_0711_zps30a91e90.jpg)
2002 rsa cylinder Aprilla dyno 100s of cylinders ever year {moto gp racing}
(http://i246.photobucket.com/albums/gg119/cr500-af/aprilia_cylinder_bottom_view_zps36be0ed4.jpg)
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Thanks for posting some pics.
Now, do you have dyno numbers with and without the knife edge specific to the KX500?
The reason I ask is because I built a bottom end with a completely stock top end all new.
Ran it for about a month then pulled the top end off and ran a cylinder that I knife edged.
Still stock port timing and the difference was amazing.
Then again butt dyno's can be deceiving which is why I ask for specific dyno numbers.
Thanks!
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Did you knife edge it yourself?
Most tuned cylinders Could have loads more work done [radius bottom tranfers, cylinder matched to cases,casting flaws removed ,exhaust polished etc.
Loads of other factors could also vary a cylinder ;slighty differant port timing from factor {the vary by few degree}, a plated cyclinder will usually lose a few hp to orginal
someone could have removed base gasket surface {I have A Cylinder with .08mm removed from bottom {more low down power}
the most current RSA cylinder aprilia which I shows the complete opposite of knife edging.
but there is no argument that the RSA aprilla motogp is the pinacle of current two stroke development.
you would be crazy not to follow in there footsteps,
300 cylinders a year Between casting and dyno took about 3 months
3-4 cylinders a day
There were 2 dynos working every day.
over last decade of two stroke development
Most good tuners dont show there work online , here one kx540 cylinder that looks pretty good {no knife edge]
LOOK at the work on intake side,/ radius bottom cylinder /, intake ribs removed/ radius bottom tranfers/ rear case ports enlarge
(http://i246.photobucket.com/albums/gg119/cr500-af/_57_zps3a21fb64.jpg)
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The cylinders that I have seen aren't online.
They are ones that I have had pass through my shop.
I did all the work myself.
I used the same cylinder in totally stock trim other then a plate job.
What I did wasn't a knife edge but more of a symmetrical laminar edge but close enough for this conversation.
I cleaned up the transfers, intake bridges, boost ports, floor ports, cylinder to case match, casting flaws removed, and polished the exhaust port.
The degree wheel shows that the cylinders timing is dead nuts on stock specs or as close to dead nuts as my eye can see which is why I use a HUGE degree wheel and my reading 8-)
So, any of these things I did could help gain a few HP.
The pics of the Aprillia cylinder are dramatic but if I'm looking at it correctly they are trying to move the flow further around the cylinder while maintaining the correct cross section so that they do not loose velocity.
I wouldn't Knife edge that cylinder as I wouldn't think it would gain much and in fact might loose some HP.
Until I see dyno numbers specific to the K5 that disprove the practice I will continue to clean up my cylinders as I am very happy with the results.
But then again I'm stubborn :lol:
Oh... I'd like to see more pics of that K5 cylinder :-)
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{{" l cleaned up the transfers, intake bridges, boost ports, floor ports, cylinder to case match, casting flaws removed, and polished the exhaust port."]}
Do nothing only knife edging to a stock cylinder is probadly the only way to prove the point
I have no personal experance on the matter , only that two stroke tuning has change since the late 90s , the info is now out there due to no more two stroke in moto gp
My tzr250 motor with the early 90s tuning {shown in pic early} was the sweetest twostroke i have every driven,
{[ " "" I will continue to clean up my cylinders as I am very happy with the results."""]} nobody is saying dont clean up cylinder it was the knife edging shown on the first pictures
50bhp from 125{Probably more than a few 500 :-) these cylinder are $$$ second ones are around 5k
(http://i246.photobucket.com/albums/gg119/cr500-af/rswhrtkitcylinder_zps342c2d22.jpg)
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(http://i1240.photobucket.com/albums/gg485/alward25/97%20KX%20500%20build/IMG_1981_zps0c03de1b.jpg)
(http://i1240.photobucket.com/albums/gg485/alward25/97%20KX%20500%20build/IMG_1987_zps535b2be5.jpg)
My Team Green Cylinder, runs much stronger than my other engine without porting.
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Of course its going to run stronger its got loads of work done, {loads of work on intake side} cant see exhaust
it looks more like a narrowing of the areas than pure knife edging in the early sandblaster photes
If aprilla had stuck with the 90s porting way, would the have won so many world titles in the later years?
looks like they should have asked a team green mechanaic to show them and saved millons
Moto gp titles
250 cc class
1995, 1998, 1999, 2002, 2003, 2006, 2007, 2008, 2009
125 cc class
1996, 1997, 2002, 2003, 2004, 2006, 2007, 2008, 2009, 2011
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https://www.google.ca/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&uact=8&ved=0CCYQFjAB&url=http%3A%2F%2Fwww.macdizzy.com%2Fwings.htm&ei=yCezVOPXJ8_yoATk2oLQDg&usg=AFQjCNGyR5XBu7UWu4lT80iafjZtjGIxUA&sig2=CX44JGrM-N2QB18u4r5Www&bvm=bv.83339334,d.cGU
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(http://i1240.photobucket.com/albums/gg485/alward25/97%20KX%20500%20build/IMG_1981_zps0c03de1b.jpg)
(http://i1240.photobucket.com/albums/gg485/alward25/97%20KX%20500%20build/IMG_1987_zps535b2be5.jpg)
My Team Green Cylinder, runs much stronger than my other engine without porting.
Any idea what your exhaust port timing is?
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Stock, for now
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Stock, for now
Well... pump it up till she glows in the dark....
Then I wanna ride it :-P