Hi folks,

I've got an MC28 that's fairly clean, but the top end seems a bit ratttly at least until it warms up. I'm in a real dilema because I want to sell the bike, but would feel better if it didn't have the rattle. It seems to run fine.
Assuming the top end is stock, would you say I'm opening a can of worms if I wanted to pop it apart and swap-out the pistons and rings? Is it difficult to determine which replacement pistons to purchase? I assume I can't purchase anything until I commit first and pop it apart. Is this true?

RZ Rob
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Keep the Rubber Side Down

Rob, you can only get one piston and one ring set anyway which will work for any of the cylinders. It's slightly small but should be within spec. I found this out the hard way (seized my SP and had to get help here) but was able to set up my racebike so it has less ability to seize (used the largest barrels I had). Anyway, if you leave the heads on, you can do the rebuild with new pistons, rings, and base gaskets. A top end kit will have a lot more in it including the piston pin, clips, needle bearing, head gasket, powervalve seal (I think). So what I'm saying is you can order everything now and wait till it gets here to take it down. It'll only be a can of worms if you've let a piston slap around enough to hurt a cylinder but you won't know that until you take it apart.

Regardless, it's a one day thing if you want to fix it. Just keep putting your fasteners back where they come off of, and when you go to reassemble it you won't believe how fast it goes back together.

Craig

How about doing a compression check to see if there is anything to worry about first?
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MC21SP Plaything
BMW F800GS Bumblebee
Triumph 9551 Daytona Big boys toy
FJ1100 Sporting relic
GTS1000 oddball

Dave has a good point, they make some odd noises at the best of times.
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I sincerely appreciate your comments. I've owned quite a few 2 strokes, and while the compression may still be +100, that rattling is making me a bit nervous. Like I was saying, it seems to settle down after she gets up to temp. I might just sell it like it is though and make it the next guy's problem.

The bike had a bad petcock and I think the gas in the crankcase might've washed down the walls. I'm totally speculating though.

Anyone want to buy an NSR with a slightly rattly topend?

RZ Rob

Title? Model/Year? $? I'm on the east coast but a couple friends have taken interest in NSRs since I got mine last year. Let me know.

Thanks,
Craig

RZRob1 wrote:The bike had a bad petcock and I think the gas in the crankcase might've washed down the walls. I'm totally speculating though.

That looks like an odd thing to say. What do you mean by it?
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MC21SP Plaything
BMW F800GS Bumblebee
Triumph 9551 Daytona Big boys toy
FJ1100 Sporting relic
GTS1000 oddball

craigsutton wrote:Title? Model/Year? $?

It's a '96 MC28. I think it is an SE (I seem to recall a small sticker on the subframe saying SP01 SE..). It has the dry clutch, credit card ignition and seems to really scream (all things considered). It's registered and plated in Maine right now, but I was going title it in California as I thought that'd be more desirable. I'm thinking it'll pull $7K.

It has the stock Repsol tank with a golf ball size dent from the clip-ons on the right side. I put the aftermarket plastic on it, but I think the quality is amazing. It also has new Tyga stainless pipes. The bike is very clean and complete. It has copy OEM mirros and turnsignals too, but OEM fastners and brackets. I think the bike could be shipped anywhere in the US for $500.

Dave Ett wrote:

RZRob1 wrote:The bike had a bad petcock and I think the gas in the crankcase might've washed down the walls. I'm totally speculating though.

That looks like an odd thing to say. What do you mean by it?

What I mean is that when the bike sat overnight etc., gas would continue into the carbs, and the float valve couldn't hold it back. So, I'd start it, and until I cleared it out, gas would piss out of the pipes. Then she'd come alive. Unburned gas washes the cylinders. This isn't good.

RZ rob[/img]
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Keep the Rubber Side Down

does it have magtek wheels??
you sure its not the exhaust springs vibrating on the tyga pipes??

I have had a few of those springs snap , i didn'nt notice any extra noise . Do a compression check like the guys recommend . How do you notice a rattle top end with a dry clutch

dunkenb wrote:does it have magtek wheels??

Not in the picture it doesn't
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Please do not PM me technical questions, if you can't find it on the Forum start a thread

LOL I was thinking the same thing.

Neal wrote:I have had a few of those springs snap , i didn'nt notice any extra noise . Do a compression check like the guys recommend . How do you notice a rattle top end with a dry clutch

The Dry Clutch is an external sound, and it's only pronounced when you pull in the lever.

Also, the noise goes away after she warms up. After I take her around the neighborhood and let her bark a bit, she purrs like a kitten.

Thanks though for the help.

Oh, and I haven't really paid much attention to the bike in awhile. It's kind of been gathering dust in the corner of my garage.

RZ Rob
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Keep the Rubber Side Down

RZRob1 wrote:let her bark a bit, she purrs like a kitten.

There's your problem, she's all mixed up. Perhaps a lab report or a cat scan would help?
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MC21SP Plaything
BMW F800GS Bumblebee
Triumph 9551 Daytona Big boys toy
FJ1100 Sporting relic
GTS1000 oddball