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actungbaby
Thu Aug 06, 2015 3:58 am
Honda ns 250 piston help

Help am after a piston for a bike i brought year or more ago . i given up on finding one as u cant buy new from honda and never seen one on ebay
I had given up but spoted a ns 125 piston on ebay will this fit its the same bore size 56 mm . i know from research the ns 400 pistons fit if cyclinders are bored out, but prefer not to do this.
as cyclinders  ive been told look good ditto the crank . anyone know the guedion pin dia of the ns 125 . i read where the ns 400 are the same diameter.

the machine has no body work but i got it for 300.00 nz whould like to get it going one day it needs alot work and i never worked on a two stroke honda . :D

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Andy
Mon Aug 10, 2015 3:47 pm


I wish we could help more, but we just not had anything to do with the NS250 yet.

What I would suggest is try to find out a part number for the small-end bearing and gudgeon (wrist) pin for the 125 and 250, and see if they cross reference at all. Also, we can often find out some dimensional specs from the Honda system, if you can come up with part numbers.

Maybe an NS250 parts manual off of Yahoo! Japan could help your quest.

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NS500Racing
Wed Aug 12, 2015 7:30 pm


I have some used original NS250R MC11 pistons, that seem ok, please PM me if you're interested.

Cheers Ian

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actungbaby
Mon Aug 31, 2015 3:55 am
ns 250 pistons

Thanks for you replys thanks very much the guy on ebay gave me some measurments of the ns 125 piston which was good of him. i go home and post them here so if i can help anyone else

 :D

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Andy
Mon Aug 31, 2015 2:21 pm


Great news! Hope you can get the motor back up and running. :)

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Alastair
Tue Sep 22, 2015 7:57 pm


Pistons are sized A,B & C.  The size is stamped under the exhaust port.  The difference is machining tolerance with A biggest and C smallest.

Volker Lorenz - www.lo-moto.de has the A grade listed - 13101-km4.  He calls it an NSR piston but it is an NS250.

http://i61.photobucket.com/albums/h75/Alastair_elmarie/NS400R/1203626991_13101km4023_zps6oslzyhh.jpg

Now what else were you looking for?

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actungbaby
Wed Sep 23, 2015 12:22 am


Thanks for that info very helpfull indeed i check later today

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Alastair
Thu Sep 24, 2015 7:45 pm


CMSNL.com also list 13101-KM4 piston A as well as 13101-km4 - rings.

They seem to have more than 1 piston.

If you need head gaskets, I have 3.

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Andy
Thu Sep 24, 2015 10:44 pm



CMSNL.com also list 13101-KM4 piston A as well as 13101-km4 - rings.

They seem to have more than 1 piston.

If you need head gaskets, I have 3.


"actungbaby", given the age of the MC11, scarcity of parts, and difficulty in keeping a 30 year old 2-stroke [that isn't an RD/RZ!] running, I think Alastair has probably just made one of the most selfless posts I've ever seen in my 20 years in the Honda community.

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actungbaby
Fri Sep 25, 2015 2:32 am


Thanks alistair thats very kind my life been so tough lately itsnot funny to have somone offer something is bit overwhelming . i wonder if am following a impossible dream given i have no money

and no next to nothing on two strokes never owned one . i used metal dish washer thingy and scubed and scrubed the carbon on the one piston i  have cleaned up okay it got a tiny puch mark type tiny hole on the crown

Only thing cause that is heat i guess as it got no valves ;-) i chould not find any markings am assuming it under the piston the a- c stamps 

i have taken engine to somone in the know and they think crank is a good one .what i wondered is isint the cylinder bores a special coating , that any reboring whould reqiure a expesive process of replating

as i dont have my glasses on i nerly fell of my chair when previous post seems indicate a web site where you chould buy some pistons from wow i been looking for over 2 years.

My ns 250 r i brought for nz $ 499 its missing all the body work the wiring is a complete mess it looks to have been raced and the auto oil injection seems been removed .frame and wheels are great brakes cyclinders even work well , i fixed up a 92 vfr 750 (crash damaged i have two 90.92 and a cbr 900rr 97 and a 80,s vt 500  :D  the Ns 250 is a huge long shot . i seems to think i need to take the engine apart and do the main crankcase seals . as i have read where if this isnt done you can wreak a 2 stroke engine is this true.

If i pull the pin on the project alistair you can have any of the engine parts that u need eg crank

ps a few details on the ns 125 pistons 

Gudgeon pin is 16mm diameter x 47mm if that helps.

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Alastair
Fri Sep 25, 2015 9:49 am



CMSNL.com also list 13101-KM4 piston A as well as 13101-km4 - rings.

They seem to have more than 1 piston.

If you need head gaskets, I have 3.


"actungbaby", given the age of the MC11, scarcity of parts, and difficulty in keeping a 30 year old 2-stroke 

Why thank you!

As an aside, I don't own nor aspire to own an NS250 or even NSR.  I only have the head gaskets because they form part of a South African NS400 gasket kit.  I run an NS400.

I do have the knack of being able to find Honda bits through a variety of sources though, so feel free to ask.  I need a model code and description of part.  I then merely point you at the vendor and let you get on with it.  The most recent  finds have been NX5 RS250 crankshaft parts for MarkR of this parish.

Maybe I should also mention that I do make rubber bits too.  I'm currently selling tank rubbers for NS400R on EBay and have produced and successfully tested inlet manifolds.  If you have a pattern, I can probably reproduce it.

http://i61.photobucket.com/albums/h75/Alastair_elmarie/NS400R/DSC_0016_1_zpsl6wynwua.jpg
Alastair

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Alastair
Fri Sep 25, 2015 4:36 pm


Thanks alistair thats very kind my life been so tough lately itsnot funny to have somone offer something is bit overwhelming . i wonder if am following a impossible dream given i have no money

and no next to nothing on two strokes never owned one . i used metal dish washer thingy and scubed and scrubed the carbon on the one piston i  have cleaned up okay it got a tiny puch mark type tiny hole on the crown

Only thing cause that is heat i guess as it got no valves ;-) i chould not find any markings am assuming it under the piston the a- c stamps 

i have taken engine to somone in the know and they think crank is a good one .what i wondered is isint the cylinder bores a special coating , that any reboring whould reqiure a expesive process of replating

as i dont have my glasses on i nerly fell of my chair when previous post seems indicate a web site where you chould buy some pistons from wow i been looking for over 2 years.

My ns 250 r i brought for nz $ 499 its missing all the body work the wiring is a complete mess it looks to have been raced and the auto oil injection seems been removed .frame and wheels are great brakes cyclinders even work well , i fixed up a 92 vfr 750 (crash damaged i have two 90.92 and a cbr 900rr 97 and a 80,s vt 500  :D  the Ns 250 is a huge long shot . i seems to think i need to take the engine apart and do the main crankcase seals . as i have read where if this isnt done you can wreak a 2 stroke engine is this true.

If i pull the pin on the project alistair you can have any of the engine parts that u need eg crank

ps a few details on the ns 125 pistons 

Gudgeon pin is 16mm diameter x 47mm if that helps.

Hi

If you look on the outside of the cylinder under the exhaust flange, there will be a stamped letter.  That tells you whether you have A, B or C cylinders.

If you're short of cash, probably best to move the bike on.  Restoring any bike gets very expensive.

Alastair

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Andy
Fri Sep 25, 2015 6:12 pm


Maybe I should also mention that I do make rubber bits too.  I'm currently selling tank rubbers for NS400R on EBay and have produced and successfully tested inlet manifolds.  If you have a pattern, I can probably reproduce it.
That is extremely interesting and useful to know, Alastair. We have projects coming up that you could very well help with, I think. :)

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actungbaby
Tue Sep 29, 2015 3:09 am


Thanks alistair i keep with the Honda ns 250 r i got the expansion champers painted ages ago there in the hot water cupboard so they wont rust .

I have a friend who owns a Honda Ns 400 r someone imported it from canada to the usa then he brought it here . then my friend roger got it

he had it off the raod for a few years as the rear cylinder was flooding i thought be just a carb float problem or reed valve thing and suggestions

he said was real beast when it got around to 7000 wanted to weelie . he raced back in the 70,s in england 

I took some photos of my engine on my phone i upload them when i can oh how can i find on 
 
CMSNL.com also list 13101-KM4 piston A as well as 13101-km4 - rings. i searched in the past and got nothing is the the first number the part number

i found gasket sets on ebay .

thanks again

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actungbaby
Thu Oct 08, 2015 3:07 am


I still havent found the a. b c stamp i have wiring chart from previous owner if anyone wants i scan and post on here

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Alastair
Thu Oct 15, 2015 8:10 pm


Picture is upside down, but it should help.
http://i61.photobucket.com/albums/h75/Alastair_elmarie/NS400R/DSC_0003_zpsduatpt35.jpg

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actungbaby
Tue Nov 17, 2015 11:06 pm


Thanks Alistair i take a mean upside down video also with my phone thanks i go check it i feel stubid but looked and looked

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actungbaby
Thu Nov 19, 2015 9:47 pm


Checked and they are A cylinder code

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Alastair
Fri Nov 20, 2015 7:40 pm


Checked and they are A cylinder code

And the pistons I've pointed our are A.

In the words of Ronnie James Dio, "you're the lucky one"  It'll be a search for the sacred heart next :D

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actungbaby
Mon Nov 23, 2015 12:21 am


Oh cool well i have been lucky all my life till 2 years ago when things gone bit pear shaped you mean i can buy one from you that be great . id thought was a impossible task to be honest

I just but the engine in the spare rooms warddrope on a shelve so but out the damp of the shed . the pipes are still in the hot water cupboard ;-)

there one just apeared on the local auction site 

Thanks mate i am determinded to get this bike going first cheapie bike i brought was a vt 250 f and engine was shagged then brought a vfr 750 so that was great then a vt 500 still working on that

need coils i done the head gaskets but have no spark .then i brought a cbr 900rr fixed that then another vfr 750 have them all still i spent nz @2000.00 on the vfr 750 as i had replace the front end 

brought it crash damaged but love that bike frame bit bent though but what the heck i still can enjoy it .engine is so sweet its done 50,000 miles its a usa import.

i am impressed with the little ns 250 the pipes where so solid and lots steel i sanded and sanded them to get rust off . the rear silencers arent standered think bike was raced mostley

as it has good tires brakes are good etc  :P

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actungbaby
Thu Jun 09, 2016 7:34 am


Finally i was handed a piston and rings last week amazing so am very happy and one know of a wiring loom whould be apprecated

thanks again for all the help
