Well boys and girls, here's what I found. She lunched the lower piston.









In the shadow of the third pic there's a good glob of piston material. Most of the other aluminum in the cylinder has no feel to it at all. Does it look like this cylinder is salvageable?

Thanks
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Craig
MC21 SP Rothmans
MC21 R fake Rothmans - track bike
MC21 SE R9N

Sorry buddy..... If it were mine I wouldn't put it back together with that jug. That is about 1/4 the damage that my lower was though. I should take pics of it and post them... I can't believe it ran after the failure, and good at that. My piston was a full seizure, all the way around.

Was the top one perfect?
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MC21
04 NSR50R
93 CBR F2
98 CBR F3 track bike
95 VFR750
89 FL400R Pilot
90 FZR 4/600

I bet that`ll clean up and run a treat with a new piston/rings!

Get in there with some soapy water and some wet`n`dry paper and carefully rub the alloy off. The nicasil is rock hard, so unless you`re a real animal you wont damage it (any more than it is already!).

You`ll more than likely find that the plating underneath is OK. It often is. What usually kills them is when a ring breaks up, or a circlip comes out, and a bit of steel makes its way between the piston and the bore and scores through the plating. When it's just molten alloy between the piston and cylinder wall, it`s usually salvageable.

Anyway, it`s off now, and you`ve got nothing to loose by getting in there with the 800 grit! Just go slowly and carefully!
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There`s no cure for stupidity… but with the endless supply of stupid people around me, I must be close to finding it!

The Lizard tells it like it is!

Read - Learn - Post... not - Post - Learn - Edit!

Vampire?

Well then, I have a cylinder I guess I could try and clean up....? Nothing came apart in mine, basicly started melting the piston.... Just trying to out run my buddies CBR929RR on the freeway did it in... He wasn't in front of me to often either Actually had to break the circlips out of the piston to get the wrist pin out !!! Stilll had 135 compression wet too. Maybe I shouldn't have gone with the 300 kit after all
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MC21
04 NSR50R
93 CBR F2
98 CBR F3 track bike
95 VFR750
89 FL400R Pilot
90 FZR 4/600

Does anyone know why the bottom cylinder always seems to give up? It sounds like it is quite common on NSRs. Is there a specific reason that we are not seeing? Just something to think about.

Better crankcase filling I've heard. The mixture has a straight run into the underside of the piston, so when it sucks, more gets sucked in, meaning slightly higher compression in that cylinder, hence some people putting thicker base gaskets on the front cylinder when you run it closer to the edge
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The Chopster

I wouldn't half ass it, just have them replated. At $150 a jug it's a small price to pay to do the job correctly. Plus I'd be willing to bet your exhaust bridge is cracked. Grab a magnifying glass and have a look.

Hit me up if you decide to go that route though as Millenium sets them up too tight and you have to request the proper NSR clearances because they see it as a CR125 barrel.

I'd rather have a cleaned up Honda bore than a replate any day of the week.

Yes the exhaust bridge might be cracked. Bet it cracks again once it's replated too.
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If I have to take the carbs off once more...

If it doesn't crack there I bet 50p it will crack between the exhaust and a transfer at some point!
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Andy.
NSR-WORLD.COM

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It could be worse....
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If I have to take the carbs off once more...

Yup I've heard the stories of the plating jobs across the pond but don't let that be the judge of a properly done replate. There is a lot of call for it over here in Karting so it's a proven technology.

I had the cracks welded and replated on 3 different NSR's and all is well.

Yeah, most are done by some dodgy American oufit
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If I have to take the carbs off once more...

Craig,

I have had a cylinder that looked like yours succesfully cleaned up. Besides elbow grease (and not alot of that), I think a weak sulfuric acid solution was used. If you do try to clean it up, look very carefully at the exhaust bridge for cracking.

Scott

Did Langcourt move to the U.S.?

Langcourt have been in the US for about 15 years.
_________________
Andy.
NSR-WORLD.COM

Please keep all responses to Forum posts on the Forum so that others may benefit.

Please DO NOT PM me for technical advice. My time is precious, and you will probably receive a faster response on the Forum anyway.

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