NSR 125 removing top end

[aLcOcK]

hi,
I have just bought my self an used nsr 125 engine

current one with gear box gone:
11,000 miles
V reg
starts first time everytime with no fail

used one off ebay:
19,000 miles
X reg
Gear box working

My current nsr's gear box has gone so i have bought this engine simply for the gear box to do a swap over as i want to keep my engine because it has 11,800 miles and is also a more recent reg i think.

so i want to take apart both engines just to swap the gear box over so i want to remove the top end of both engines and put them both back together.

Can you please give me a simple guide or even pictures on how to do this me and my dad will be doing this so we should be able to do it.
Every little detail will help and also warnings will also and what to do once the engine is back together such as compression and that.

many thanks for looking and even more thanks for helping me out

[alains]

look here , just ask which side play has the conrod on the crank (must be less than 0.6mm)
https://cgi.ebay.co.uk/HONDA-NSR-125R-FOXEYE-MODEL-JC22-ENGINE_W0QQitemZ300341273310QQcmdZViewItemQQptZUK_Motorcycle_Parts?hash=item45edbc22de&_trksid=p3286.c0.m14
____________________
the worst day fishing is better than the best day working

[aLcOcK]

[alains]

basicaly , take off fairings , radiator all bits attached from the frame to engine . here is the manual section 6
https://www.geneva-racing.ch/~alains/engine.zip
before swapping your top end i recommand to check the sideplay between conrod & crankshaft , it's very important for your top-end . this must be under 0.60 mm which is the max tolerance
if you want the whole workshop manual look here
https://www.geneva-racing.ch/~alains/NSRmanualDOC.zip (64 Mo)
____________________
the worst day fishing is better than the best day working

[aLcOcK]

[salty21]

if i remember right the conrod does have a fair ammount of side to side play on the crankshaft connecting pin thingy.....as in it will slide on the pin a bit, i take it you mean play in the big bearing? i could be wrong though
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04 NSR 125(sold) ---- 03 CBR 600rr(sold) ----90 pan euro ST1100 '' ----02 CG 125
94 CB400 Super Four ---- 2000 VTR SP1 (sold) ---- 08 ninja p8f(sold, meh) ----05 CBR600rr

[alains]

no , the crank is in 2 bits with 2 friction washers on each side of the conrod . when new the side play is 0.20 to 0.25 mm and after some years the side play get bigger . the limit is 0.60mm and if it's bigger this can dammage the piston , barrel and the bearings
____________________
the worst day fishing is better than the best day working

[salty21]

yeah my bad, had a look at my old engine today and it was the piston that has side to side play not the conrod
____________________
04 NSR 125(sold) ---- 03 CBR 600rr(sold) ----90 pan euro ST1100 '' ----02 CG 125
94 CB400 Super Four ---- 2000 VTR SP1 (sold) ---- 08 ninja p8f(sold, meh) ----05 CBR600rr