NSR 125 R1 cylinder

steven843 · Renault 5 Driver Joined: 09 Oct 2008 Karma :

Hi, I have the uk spec 2001 nsr 125 r1. I recently had to get a new piston and cylinder. When i took the old one off it had a D code on the bottom. I brought a new one (genuine honda parts) and this one has a C code on it. After doing some research I found that there is an A,B,C,D,E available for the nsr 125. What i want to know is what is the difference between the codes and how do they affect your bike? many thanks. steven.

buddy · Trackday Trickster Joined: 07 Mar 2009 Karma :

im not 100% but i think that they are SLIGHTLY different bores, for when ya use oversized rings and stuff
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alains · World Chat Champion Joined: 08 Jul 2004 Karma :

yes , the difference is about 0.005 mm by letter
here is the chart . a C in a D is OK
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steven843 · Renault 5 Driver Joined: 09 Oct 2008 Karma :

steven843 · Renault 5 Driver Joined: 09 Oct 2008 Karma :

alains · World Chat Champion Joined: 08 Jul 2004 Karma :

no difference . as the coating is very hard the thicness must be marginaly different this why they made different pistons and the barrel determines the piston size . it's acceptable to re-fit a piston with a letter + or - without unconvenience
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the worst day fishing is better than the best day working

steven843 · Renault 5 Driver Joined: 09 Oct 2008 Karma :

ok but why did they make five different cylinders then and is it just the nsr 125 that has this?

alains · World Chat Champion Joined: 08 Jul 2004 Karma :

no they dont make different barrels , they fit all barrels with different pistons . you cant find different barrel , you will only find the kit or the piston alone . honda says :
- 12000 kms (7500 miles) rings change with de-coking and you must look the letter under the barrel (you are obliged to dismount top-end)
- 24000 kms (15000 miles) piston-rings change with de-coking (so if you have done what i said you can order your spares first)
- 36000 kms (22500 miles) top-end change
you may do not respect this schedule but it's at your own risk . regarding others 2 strokes bike price of spares are not very expensive
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the worst day fishing is better than the best day working

steven843 · Renault 5 Driver Joined: 09 Oct 2008 Karma :

ok last question cos i think i get this now, does it matter what code you put in your bike? also do just nsr's have this code systems, many thanks alains

alains · World Chat Champion Joined: 08 Jul 2004 Karma :

no matter you fit what your provider send you
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the worst day fishing is better than the best day working