Odd thing happened today, my '28 hasn't been running well for a couple of weeks and wouldn't pull cleanly past about 10500 rpm.

So I'm just plodding along, cleaning up all the connections - no change, it didn't seem to be either plug (chopped it while spluttering, both looked OK) swapped coils over anyway - no change, checked for air leaks - all fine, checked reeds - OK, air box wasn't seated quite right though - it can't be that, can it? So out to check it - no change, then I thought I heard a click like the powervalve closing, so I slowed down a bit so I could hear better (odd thought really looking back) and it didn't seize properly, it just dragged so I whipped the clutch in and it totally died, i.e. it did seize really, and only being 1/2 a mile from home pushed it back the last bit I couldn't roll.

Both cylinders have compression but the front plug was a really light grey colour not even a hint of beige anywhere and I wasn't even going fast so I get in the carbs and the little button that holds the needle down is floating free as a bird, now I don't see how this can be the cause of the leaness, surely the needle floating about too high would make it richer? Everything else looks fine.

Anyway, I get it all back togeather and it does run, both cylinders do appear to fire, both pipes smoke and get hot, however it's anything but right, it doesn't like starting, backfires occasionally when starting and appears to drop onto one cylinder at low revs.

Obviously I'll get the front head off sometime for a look but anyone got any thoughts on what would make it run so lean all of a sudden?

Sooo, the RVF gets the Magtek's and the BT090 pro's then???
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Last edited by fontyyy on Sun Nov 13, 2005 12:31 pm; edited 2 times in total

Its not sounding good Fontyyy, from vast exsperiance i think you will of spun a ring maybe. This colours plug a very grey/tan. with low comp on one cylinder it will start but not easly and will normaly not tick over.

a needle floating up as you say will only cause it to go rich and wont of caused this... take your chambers off and have a look up the exhaust.
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If I have to take the carbs off once more...

Sheesh... That doesn't sound like a normal NSR teething problem. Have you had the barrels off yet?
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NSR300R - Why did i ever have a 250...

Cheers Steve, that's beautiful, just freaking beautiful

Barrels off, hell no, I'm off out for a beer!

Andy, was that 1 in million you said?
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Should of got a KR

Sorry, couldn't resist. Good luck, it may be nothing.

Enjoy that beer and then get the barrels off, it won't be that bad.
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Ive never had this trouble yet on an nsr but i can think of 5 nsr barrels and pistons that have gone because of a spun ring, its not that uncommon.

Still all you have to do is get the cylinder replated, new piston and find all the bits.... (findin all the bits is the best part). Was your motor due for its weekly full strip down yet Fontyyy?

You never know though, maybe a grey plug could beee... er... thinking... er.. no cant think of anything else.

I'll call you tomorrow or something fontyyy. Once you have recovered from the drink.
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If I have to take the carbs off once more...

had a similar problem...talked to an old bike mechanic..he advised me to remove the plug and give it a good wipe over with a drying solvent and then leave then out for a couple of hours on so it can dry out..jst a recomendation..seemed to work for me..
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read it and weep;
"91" mc21 nsr250SP....
47hp

mate thats harsh, spun a ring sounds like something that might happen if you fell asleep in kings cross station.

i'm in all day fettling in the shed, pop round on the RVF if you fancy it.
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MC21SP - Roth-tax
CBR400 - track
MC21R - sold
MC21SP - sold

Oh no! Sorry mate, hope it isn't too bad.

Maybe time for the 300 kit?
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BMW F800GS Bumblebee
Triumph 9551 Daytona Big boys toy
FJ1100 Sporting relic
GTS1000 oddball

nsrmonkey wrote:pop round on the RVF if you fancy it.

Mate, the way my finances are right now until the van is paid for (and you're paid back) I can just about run to that, nothing more, I'll have a peer up inside the barrel but it can stay on for now.

Thank the good lord for V4's.


20 mins later;

Yep, somethings not quite right up there, the rings (well, the bit I can see) are part of the piston now
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Yup this is indeed why god made V4 four stokes!

Still you didnt do bad, you must of done a whole 1000 miles before it all went wrong. Still at least this time you will try and repair it yourself.. think of the money you will save if youre doing this every 4 months!
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If I have to take the carbs off once more...

Or every week, if it's an MC18/300!
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Or every 45 miles if its an 21SE
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If I have to take the carbs off once more...

I think it was closer to 40 miles!
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NSR-WORLD.COM

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Last edited by Andy on Sun Nov 13, 2005 9:40 pm; edited 1 time in total

come on Andy buy an 18, you know you want to.
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faster-faster-faster-faster+pop. oh sh*t its fecked again.