So, I bought another NSR on ebay recently..
This one is an MC21, some may have seen it but for those that didn't here's the run down, guy I bought it off said it used to be raced at Lakeside international raceway and was then sold to a guy in Gladestone who did some trackdays on it, the guy I bought it off had owned it for four years and is in his 50's and very ill so hence why he wanted to sell.. I paid $1500 for the complete bike and a box of new and good used parts worth around $2000 alone..


So far I have done..

* Replaced bottom head (it had corroded between water journals and dome)
* Due to the leak I had to pull the exhaust off and drain the coolant and sludge from it..
* Flushed and replaced coolant..
* Drain / clean and replace premix oil.. Also new oil lines fitted..
* Drain and replace gear oil..
* Removed carbs/manifolds and reeds, cleaned them up and replaced, also did away with the airbox..
* New fuel lines..
* 1 wire splice mod done..
* Replace rear master cylinder and fill with new fluid..

Yet to do..

* Replace fork seals.. (have the fork seals in the spares)
* Rebuild front brake calipers.. (have the rebuild kit in the spares)
* Get new battery..
* Get new tyres..
* Get Tyga pipes.. (months away, run it as is for now)
* Get carbon reeds..
* Remove oil injection..


Furthermore one of the previous owners fitted a 190 rear tyre, the side walls are vertical, so I will be replacing with race slicks and wish to know is a 160 rear the correct size to run??

Also with the other wire splice mod, is the light green wire's that need to be spliced the ones running from the gearbox?? If yes, do I splice before or after the connector/plug??




_________________
Paranoia about failure will ensure nothing but failure to ever reach potential.



MC18 Race bike project..
MC21 Race bike..

The 160 rear tire sounds right. I got one on mine and the bike turns great.
As for the splice work, I don't think it matters where you do it, as long as it
is done. I did mine between the motor and the plug. If you are thinking to
race the bike I would recommend rather to run premix as it is a safer way to
spare the engine. It is to easy for the oil pump lines to get blocked with
something and then your whole motor is shot. I hope that I helped you
with something.

One question, How can one fit a 190 rear tyre to these bikes? I have a
160 rear tyre and it fits very snugg. I don't think it is possible to fit anything
wider than a 160 unless it is a different swingarm.

The correct size tire for the NSR250 MC21 is a 150.

Harold wrote:I would recommend rather to run premix as it is a safer way to spare the engine. It is to easy for the oil pump lines to get blocked

Have you or anyone ever heard of this happening? I don't think I've even heard of an oil pump failing on an NSR...
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MC21SP Plaything
BMW F800GS Bumblebee
Triumph 9551 Daytona Big boys toy
FJ1100 Sporting relic
GTS1000 oddball

Dave Ett wrote:

Harold wrote:I would recommend rather to run premix as it is a safer way to spare the engine. It is to easy for the oil pump lines to get blocked

Have you or anyone ever heard of this happening? I don't think I've even heard of an oil pump failing on an NSR...

Ive had an oil pump oil my rear tire before. Not sure it was the oil pumps fault however. Something about putting a later model MC21 oil pump on an earlier mode MC21 set of cases...

Seems that oil feed for the right crank shaft bearing not having anywhere for the oil to go but all over the engine, and then onto the rear tire.

Best fix for that? remove oil pump and go pre-mix.
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Charles Gallant

I have had 2 cases here in South Africa where it did. After a long period of time dirt inside oil bottles can block the lines. Its like driving without oil.

For a race bike it is more safe to ride pre mix especially with open carbs.

Am I missing it or is there no upper fairing stay?

If yo look carefully there is a bracket behind the upper fairing. This is also
not worked on standard fairings. Some brackets seems to be missing

Harold wrote:I have had 2 cases here in South Africa where it did. After a long period of time dirt inside oil bottles can block the lines. Its like driving without oil.

For a race bike it is more safe to ride pre mix especially with open carbs.

So you're blaming the designers for bad maintenance? Hmmm. Might as well blame the tyre designers when your pressures are too low!
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MC21SP Plaything
BMW F800GS Bumblebee
Triumph 9551 Daytona Big boys toy
FJ1100 Sporting relic
GTS1000 oddball

Thanks for the info..

Defo going to be getting rid of the oil injection, for the simple fact that it is easier to work on the bike and it reduces a small amount of weight..

Most definately got a 190 rear tyre on it now, it looks like the side wall has been pulled in so much on the rim that the profile is vertical, also pulling it in away from the swingarm.. Both front and rear are rock hard they've been on it for over 4 years..

Looking at these GP250 tyres..
http://mc.bridgestone.co.jp/en/products/racingbattlax/index.html


The upper side fairing brackets are missing but it is all very rigid..
_________________
Paranoia about failure will ensure nothing but failure to ever reach potential.



MC18 Race bike project..
MC21 Race bike..

Dave Ett wrote:

Harold wrote:I have had 2 cases here in South Africa where it did. After a long period of time dirt inside oil bottles can block the lines. Its like driving without oil.

For a race bike it is more safe to ride pre mix especially with open carbs.

So you're blaming the designers for bad maintenance? Hmmm. Might as well blame the tyre designers when your pressures are too low!

HEHEHE

I blame the petrol companies when I run out of fuel.

It wouldn't have happened if petrol wasn't so bloody expensive!!!

Andy

Bandit7

Hahahaha no I blame people who don't clean their bikes often enough.

And don't get me wrong, The NSR for me is the best design 250cc
motorcycle in the world that is way I have one.

I rebuilt the front calipers today..

Having probs bleeding them.. Do I just keep pumping the lever like there's no tomorow or do I put a rubber band around the lever holding it on so the gravity does the rest??
_________________
Paranoia about failure will ensure nothing but failure to ever reach potential.



MC18 Race bike project..
MC21 Race bike..

Have you blead (<don't know if that's a word) brakes before?

Pull the leaver in while opening the bleed nipple, close the nipple just before releasing leaver.

Do that about 100000000 times until there are no more bubbles.

Andy

Bandit7

p.s. I keep posting so I can get to the 100 post milestone.

Yeah I have bleed brakes a 1000 times before, just not from scratch (as in there's no fluid in the lines or calipers)..

Speaking to some mates about it and they reckon that they have used a rubber band to hold the brake lever on and let it gravity feed itself overnight..

I tried the normal way by pumping the sh*t outta the lever (for 15mins) and I was getting absolutely no pressure in the system..
_________________
Paranoia about failure will ensure nothing but failure to ever reach potential.



MC18 Race bike project..
MC21 Race bike..