hi all,

my mc21R i just bought has been sitting in someones back yard for 4 years! ..ive replaced chain, sprockets(front+rear) and got a new set of tyres as they were bald.cleaned the powervalves to soem extent also. i have started it up a few times and starts ok...

i am gonna give it a ride soon. but yeah as i said it has not been ridden for almost 4 years. so my question is..are there any major things i should chek mechaincally before i have a lil go?i dont want a seizure or anythin.
(it has 22,000km's on it, and has not had a rebuild yet also)

cheers..
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Philip Ahn
MC21 NSR250R

im poor...

Change the transmission oil and the brake fluid!

I'd also be inclined to check/bleed the oil pump or run it on premix initially.
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Andy.
NSR-WORLD.COM

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And I'd take the carbs off and give them a good clean. 4 years of gum in there will not help at all. The last thing you want is a jet blocking and the engine siezing.

It's tempting not to bother, but you'll be soooo pissed off if it siezes and you could have prevented it.

Check the brake pads, and replace the fluid - it should be done every couple of years to be on the safe side.
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MC21SP Plaything
BMW F800GS Bumblebee
Triumph 9551 Daytona Big boys toy
FJ1100 Sporting relic
GTS1000 oddball

yeha i have already bled the brakes also. and the pads still have plenty of meat on them..although there is quite abit of rust on them..but that should wear off right after riding it a bit?

will clean the carbs tomrro.

how would i change the transmission fluid?

thanks
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Philip Ahn
MC21 NSR250R

im poor...

also...

with cleaing the carbs...it says on the instruction of the carb cleaner spray...

am i just meant to spray the carb cleaner into the carbs while at high idle as the instructions say? i do not need to take them off or anythin?

wouldnt all that crap go into the engine tho? would it just get burned up in there and be ok?
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Philip Ahn
MC21 NSR250R

im poor...

Put the can down and step away from the motorcycle sir!

As you rightly say, all the crap released by the spray will wiggle it's way round your crank before it finds it's way into the cylinder, and them bumble into the exhaust. Don't do it mate...
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MC21SP Plaything
BMW F800GS Bumblebee
Triumph 9551 Daytona Big boys toy
FJ1100 Sporting relic
GTS1000 oddball

Cleaning the carbs by spraying the juice down the throat of the carbs is like saying you've done a full engine rebuild 'cos you changed the plugs.

Another thing is that some carb cleaners are so volatile that they may detonate if you spray whith the engine running. never do this, just to be on the safe side.

The carbs need to come off, and you need to get right in there to see what's going on.

If there's any shite then it'll be in the float bowls, which the carb cleaner would never even go near just sraying it in.

Pull of the bowls and remove all the jets. You'll have great fun trying to get to the powerjets. They're hidden under an aluminium screw. you'll need a perfect fitting screw driver and probably a couple of whacks with the hammer to get those puppies loose. Then you'll need a nice small screwy that sneaks in to get at the jet itself. Be careful 'cos they're made of cheese and easy to break.

If necessary, spend a couple of quid and buy some new tools for this job. It's not worth messing up because of old worn tools.

When you've got all the jets out inspect thoroughly and clean as necessary. I use a special carb cleaner in an ultrasonic thingy, but popping the jets in a glass of Coke overnight has a very similar effect. I'm just too impatient for that and seeing as the ultra sonic cleaner was a present I intend to use it!

If there's any stubborn stains then I've got an array of cocktail sticks, pipe cleaners, cotton buds and some not too savage metal polish to get things back to spec.

Sometimes I even have to resort to the trusty broken throttle cable to use as a pokey. Just unravel the ends and you can make yourself a selection of different size pokeys from the wire strands. A primitive method that's been working for me for years.

Cleanliness is next to Godliness. Isn't that the saying? And I expect that God's out there in the shed right now cleaning His NSR carbs!

Matt@TYGA wrote:Cleanliness is next to Godliness. Isn't that the saying? And I expect that God's out there in the shed right now cleaning His NSR carbs!

Why doesn't he have his son do it? The kid can walk on water, turn water into wine, heal the sick, but can't clean a carb out?

Also, when you say you "cleaned the power valves" what exactly does that mean? Did you pull the shaft, and valves from the cylinders, and clean all the carbon off, then put then back in? Or did you just reach up in the exhaust port, and whip things down? Cause you really want to get in there, and get all the carbon off the face, bottom, top, sides, shaft, etc.

Thanks,
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Charles Gallant

Ha i know that one, i did that the other day, Bolt on the bottom side of clutch cover to drain, i did mine and it was a horrid grey colour....well worth it...

so with filling the transmission oil back up is there are appropriate level/amount? do u put it down that hole on the right side of the bike after takin the cap off right?

and with the carb cleaning...i want all the rubber/plastic stuff off right?
i heard carb cleaner will destroy that sh*t...

also..am i gonna need to take not of jet settings? isnt all of this cleanin gonna muck it up?(so can i simply unscrew the pilot jet,main jet etc and then screw them back in)

thanks...
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Philip Ahn
MC21 NSR250R

im poor...

I use contact/brake cleaner on my carbs with no worry about it hurting the rubber hoses and stuff. Spray it one, clean it off, and its dry before it can do anything wrong. I also spray it onto a shop towel, and clean things that way. I use PJ1, or Maxima (I like the Maxima much better).

If you do one carb at a time, then you don't need to worry about getting things put back together wrong. Of course you should take notes so you know what's in there when you need to go rejet it.

Transmission fluid? You need to use .75 liters when doing an oil change. When doing a gear box rebuild, use .85 liters.

Thanks,
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Charles Gallant

If you are running the stock needles and powerjets, be sure not to mix them up. They are not identical between your two carbs.
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Paul Herr
'88 FZR4/GSXR/YZF Frankenbike
MY BIKE PICS

i was talkin to some guy at the local car/motorcycle accessory store and he said that it was ok to spray into the carbs while it was running?
it even says on the directions on the can...
but yeah i wont risk it anyway...

hey.cgallant...so if i use the brake clean spray u dont even need to take apart the carbs?.

0.75
litres it is then for the transmission..

cheers
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Philip Ahn
MC21 NSR250R

im poor...

biatchy wrote:so if i use the brake clean spray u dont even need to take apart the carbs?.

I think you still do, if you really want to clean them properly.


Did you take your power valves out to clean them?

The best way to clean them is to use a bench grinder with a wire brush attchment. Whips the build up right off - looking almost new
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Jerry Lai
NSR250 [MC21SP]

I drain my float bowls at the end of each day. I Clean the carbs each day as well. After the weekend, I strip the carbs down, and do a full cleaning on them.

If your doing the cleaning on a street bike, you probably wont be doing them this level of cleaning, so you should strip the carbs apart when you do the cleaning on a street bike.

While you got the carbs out, check the reed valves to make sure they are all in place, not warn, or cracked. You can do this by just looking down the intake with a flash light. Check the corners really well.

Thanks,
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Charles Gallant