Hi guys i have just picked up a MC21 SE. I was told by the previous owner it had not been delimited yet so i wasnt expecting much from it, i went out on it and decided to come back and do the wiresplice but when i looked at the loom the first O/Bu wiresplice has already been done?

The bike pulls well (i think?) up to about 120KPH then the power drops off a bit, the maximum speed i have managed to get to is 180KPH (on a private road...) and the bike is really struggling to get to that speed (took about a mile to get to that speed on a long straight) and it seems like there is no power up top in the higher gears. Once i got to 180KPH i dropped back as the bike didnt want to go any faster.

I haven't ridden a MC21 before so i cant compare it, but it feels a lot slower then it should be.

Any suggestions?

I havent managed to get it on a dyno yet as i haven't found one near me which doesnt shoe away 2 strokes.

Check the battery condition,adjust the r/c valves to spec.

The battery is in good condition but i will set the RC valves tonight and try again.

I have done a plug chop and the plugs are black as night... Going to check the jetting and more so the oil pump.

I would definetely be giving a new bike a bit of a check over anyway. I would be tempted to take the carbs of and give them a clean, while you are there you can check what size mains it is running, if the airbox is undrilled and has the standard filter they should be the standard spec (presuming it has stock pipes of course).

As Bushman suggested, check the power valves are correctly set and actually operate! Power valve servo's and PGM's will soon fail if they are coked up and seized. With this in mind you should be looking to pull them out and clean them, a simple job but you will need new seals and probably retaining clips, although if the power valves move freely by hand with the cables disconnected they should be okay.

I ran my mc21 with a standard pipes, airbox and a wire splice, a while back now but I dont think it pulled much more than about 115mph. With tyga pipes, drilled airbox and appropiate jetting it now pulls into the red line in top which gives 123mph on standard gearing.

Hi chaps the air filter has totally disintegrated , good job i had already ordered a new one!

The mains are the standard 128's, i will replace them with new anyway. Carbs were quite clean though.

Next on to the RC valves and the oil pump...

Hi Guys i set the RC valves up properly, set the oil pump up properly, cut out a new (temporary) air filter and a new set of plugs it now goes like a scalded cat !

When i put it back together the first time the airbox - carb rubbers were causing problems they are worn and mis shaped is that a common problem on NSR's and do you tend to just silicone them to the airbox or replace? I haven't looked how much they are yet and if they are even still available !!

Cheers

Good stuff.

Firstly let me say that I have never tried this myself but I have heard that one way to bring up old rubber to a useable state is to boil it in radiator coolant. I'm told if you simmer it in the coolant (undiluted) overnight, it can make the rubber more maleable and flexible. Stinks out the place though apparently.

I pulled apart my airbox / carb rubbers etc recently. I used 3M Weatherstrip Adhesive to keep the joins all airtight. It works really well - makes a much better and longer lasting seal than silicone. Permatex makes a similar product too.

The rampipes/inlet trumpets, or whatever you would like to call them, are NLA. I think most airboxes I've seen have had them pulled out at some point. They don't seem to be bonded in particularly tightly.

In an ideal world, I would say yes, they should be fairly well sealed, as any air drawn past the seal could be contaminated, but in reality it doesn't matter that much. If this is your "tinkering" bike, you'll soon be junking that airbox (and the rampipes) for pod filters or open carbs anyway!
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Andy.
NSR-WORLD.COM

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Hi Andy yes i have found they are discontinued I am going to try some sort of rubber adhesive i cant find the product foxmcscrooge mentions.

It is my tinkering bike but im not ditching the airbox JUST yet