1981 YZ 250

Ardfarkl
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Ardfarkl 1/12/2016 9:21am
1/12/2016 9:21am
What type parts?
colinac34
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colinac34 1/12/2016 9:23am
1/12/2016 9:23am Edited Date/Time 1/12/2016 9:27am
Like a cylinder or a sleeve i know most minor parts that are needed can be found on ebay. But i can not find a cylinder or just a sleeve for my bike.
Ardfarkl
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Ardfarkl 1/12/2016 9:28am
1/12/2016 9:28am
A cylinder is a bitch. I have been looking for two years. Many different companies can re-sleeve for you though. LA Sleeve is just one.
colinac34
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colinac34 1/12/2016 9:43am
1/12/2016 9:43am
Yeah i heard la sleeve and wiesco will do it.
Wiesco will make one for $500 but thats alittle step for a sleeve

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Ardfarkl
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Ardfarkl 1/12/2016 10:10am
1/12/2016 10:10am
I had talked to some old school engine builders who liked the idea of boring it out and doing a mikaseal like a more modern engine.
colinac34
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colinac34 1/12/2016 10:16am
1/12/2016 10:16am Edited Date/Time 1/12/2016 10:17am
Problem is my nieghbor bought an oem cylinder for it when it was his then he had it bored out way to big. The max bore on that bike is 72mm he probably bored to 73mm so he messed up the sleeve then sold it to me than told me it only needed an ignition kit which it did.
450exc115
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450exc115 1/12/2016 10:18am
1/12/2016 10:18am
You need either a 80-81 YZ or 81-84 IT 250 cylinder and they do show up from time to time. You could also plate it and use aftermarket oversized piston.

450exc115
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450exc115 1/12/2016 10:19am
1/12/2016 10:19am
Wiesco should have up to 2mm overbore pistons.
colinac34
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colinac34 1/12/2016 10:21am
1/12/2016 10:21am
I have it in a shop but the mechanic said if we did that than at one point the sleeve would over heat and freeze the motor
colinac34
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colinac34 1/12/2016 10:22am
1/12/2016 10:22am
There is a 72mm piston in it already and is to small
450exc115
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450exc115 1/12/2016 12:02pm
1/12/2016 12:02pm
Yeah your SOL. They can't plate 1mm but it may be worth having the cylinder measured professionally and calling Eric gorr or one of the plating houses.
rob.boucher.547 1/13/2016 5:01am
1/13/2016 5:01am Edited Date/Time 1/13/2016 5:01am
put a LA sleeve in it
Many nos standard piston and ring kits
available
colinac34
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colinac34 1/13/2016 5:55am
1/13/2016 5:55am
I got a deal with la sleeve and bought a stock bore sleeve yesterday for $300.
To bad i have to wait 6+ weeks because it on back order.
colinac34
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colinac34 10/12/2016 1:00pm
10/12/2016 1:00pm
Does any one have a spare working 1981 yz 250h or just regular 1981 yz 250 complete carburator. I will pay for it if in working condition
nicko-31
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nicko-31 10/13/2016 6:46am
10/13/2016 6:46am
newmann wrote:
http://www.x-tremevintageyz.com/#!/~/category/id=2127175&offset=0&sort=normal That's a good start! www.vmxracing.com www.amsracing.com Those two keep inventory on hand. Also, there was a good bit of OEM stuff available from the dealer...
http://www.x-tremevintageyz.com/#!/~/category/id=2127175&offset=0&sort=…

That's a good start!

www.vmxracing.com
www.amsracing.com

Those two keep inventory on hand.

Also, there was a good bit of OEM stuff available from the dealer back in 04/05 when I was putting mine together.

Is this the same bike in your Avatar Joseph ??
newmann
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newmann 10/13/2016 7:08am
10/13/2016 7:08am
Same bike, different plates and numbers for the oldest son.
newmann
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newmann 10/13/2016 7:10am
10/13/2016 7:10am
colinac34 wrote:
Does any one have a spare working 1981 yz 250h or just regular 1981 yz 250 complete carburator. I will pay for it if in working...
Does any one have a spare working 1981 yz 250h or just regular 1981 yz 250 complete carburator. I will pay for it if in working condition
I may have your carb, let me dig. I replaced mine with a new Mikuni from Sudco. It was a running carb/bike when I got it.
newmann
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newmann 10/14/2016 9:53am
10/14/2016 9:53am
Sorry sir, no go on the carb. Think it ended up on a XR500 up in Massachusetts.

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ss-racing
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ss-racing 1/23/2022 7:00pm
1/23/2022 7:00pm
Cool thread. I've been looking at an 81 YZ250 that appears pretty much "ridable" but needs some work to be a worthy vintage racing weapon. Some of the bikes in this thread are unobtanium, but what are these bikes selling for stock ?


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