My mc18 has never ran smoothly it ticks over and smells rich and has a bit of a flat spot mid range

I have purchased a set of carbs from eBay from a low mileage bike but they are mc21 not 18 as stated in the listing can I fit these? Also I have checked the tech section and both carbs are running the same 81 needle is this ok?

Sorry for all the questions jody

When you're trying to track down issues, you're already fighting a losing battle by not using stock, correctly set parts. One problem can easily mask another, or compound it.

Therefore, these types of question are unanswerable I'm afraid.
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Andy.
NSR-WORLD.COM

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I own a 1989 MC18 R6k.
If I had a set of MC21 carbs lying around, I would make sure that they were jetted very close to standard and chuck them on the bike and go for a spin just out of pure curiosity.
I do not know the difference between the J81E and 2QZ needles, but I cannot imagine the difference is going to cause major problems. (I could be wrong).
That's just me, personally, and I would be pretty paranoid about things potentially being too lean.

I think you should be fine.
But that is nearly the same as saying, things could possibly NOT be fine.
Sorry if this post is not helpful.
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[color=#808080][size=9]Yes,.. I too know how to waste Time and Money,...

hi thanks for the reply that is what i have done and it runs great the other carbs i had on the bike had 35 not 38 small jets and the gaskets on the top of the slides were torn and silicone'd up badly so leaking in air also they were way out of balance

the bike is getting there slowly got a set of pistons and small ends to fit and a new rad to go on soon