NSR250 rebuild - 'The ELF Special'

[Wil_K]

That's the way !

There is a mc16 on gumtree in aus , maybe they would sell the tank loose as the bike is stripped .

I'll just stick with the MC18 one. It fits the lines of the frame perfectly, and mounting it won't be a problem when I build my custom subframe. I think it looks better too. There's actually plenty of NSR spares in NZ (not much good engine parts though), even an mc16 tank on trademe at the moment. I believe the NSR was pretty popular down here, but have become somewhat rare lately. I guess when the engine inevitably wears out, people just scrap them rather than go through the painful process of finding parts to rebuild.

Oh, another advantage of the MC18 tank is it has the bolt in surround for filler cap, the MC16 just has a one piece cap. This means I can use a number of aftermarket caps. I was planning on using a race style non-lockable cap.

[Wil_K]

Looks professional, more info?

Engine Rebuilders Auckland did the job for me. Welded, drilled, tapped, and resurfaced. Thought I'd give them a go as they're just down the road from my work. They did a good job apart from the thread is in slightly crooked, which it makes it slightly hard to slide the head on as the stud sits at a slight angle.

[Wil_K]

The Tyga Performance rear sets I ordered, arrived today. Spent the morning installing them and bleeding the rear brake system.

[Neal]

Looking very good !

use some Loctite on the small " toe " parts of the gear change and brake pedal , mine vibrated loose once before .

[Wil_K]

Looking very good !

use some Loctite on the small " toe " parts of the gear change and brake pedal , mine vibrated loose once before .

Thanks for the tip Neal.

[Wil_K]

Stoked! I just scored a complete MC18 R5K + spare motor for a very good price.

[Wil_K]

Here's what I got:





Spare motor and other bits:

[Neal]

Oooo your hooked now !

[Wil_K]

It was an unfinished project, the guy spent 2800 on it apparently. Ended up giving up after his mechanic botched the engine reassembly and caused a crack in the transmission part of the case.

I've already split the cases on one motor. The crank feels good, he said it had new seals and some other work done but he couldn't remember exactly. All the gaskets and crankcase sealer look fresh, so there's definitely been some work done that's seen very little use.

I'm going to re-use that crank in my motor. I'll be tempted to replace the right side bearing though, as it's a bit noisy. Do you know a source for these Neal?

[Wil_K]

Actually the bearing is good, was just the bearing cage rattling a bit. The bearing was quite dry, I put a dab of oil in there and it now turns smoothly and silently. Is lubrication and issue for the primary side bearings? A guy told me they're usually the first to go. Turning the centre bearing, it feels like the centre seal is good too. I believe I will use this crank as it is.

[Neal]

I have looked for main bearings before and found some that will work except that they never had the pin in them . Until now I have not used a rebuilt crank only new or very good 2nd hand ones . Finding someone to do the work I wanted done to convert and modify pins was impossible in SA .
In a few months time I will start to play with cranks again . Deet is the only one in know on this side that can supply nsr bearings .
I use a syringe with some 2T oil to place a few droplets in key places when I bolt things up .

[Wil_K]

We have power...electrical power. Petrol power coming soon, pistons and gaskets will be ordered before the end of next week.

[Wil_K]

Mmm, shiney new top end parts, plus new crank outer seals as I discovered the old ones were actually the wrong size.

[Wil_K]

Bottom end re-assembled:

[Wil_K]

And the top end:

Cylinders have been professionally honed. The top one looks almost brand new inside. The bottom one good, with some minor scoring. Power valves and exhaust ports have been de-carbonised.