'87 Honda NSR250 'ELF Special'

Moa

Been Around the Block
Time to update the front page with the progress so far:

What we have here is a 1987 Honda NSR250 MC16, the MC16 was the first of the popular, but somewhat rare (depending on where you live) NSR series. The design of the bike borrowed heavily from the World Championship winning 250cc machines of previous years, and is full of GP inspired tech.

This particular bike has a later 1989 MC18 series motor, which has a much greater tuning potential over the MC16. These motors make around 55-60hp in stock unrestricted form, and the whole machine tips the scales at a featherweight 125kg dry.

The build will be done in two phases. Phase one will be restoring the bike to as new mechanical condition. There will be a few changes to stock parts too, but at this stage it's mainly just a rebuild. Then I can get it back on the road and enjoy all of its smokey goodness while I plan phase two.
[UPDATE] The bike is now running.

Phase two is where the fun begins. I've got plenty of ideas to make this bike something special, but that's for another time. I have decided on a paint scheme however. Here's the latest mock up:





[ORIGINAL POST]

So I picked up an NSR250 mc16 (1987 I think) for 100 bucks! I wasn't sure what to expect from it, but at $100, it was a steal.

Here it is the next day stripped down:
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The engine wouldn't turn over when I got it so had a peek down the spark plug holes and through the reed valves. There was a layer of sludgy water in the lower cylinder, and a bit of rust inside the crank case. Anyway I pulled the engine out and took the heads off. It looked like the sludge just spilled into the cylinder from the exhausts when I tipped the bike on its side, as the chambers were full of water.

The carbs, cylinders, heads, pistons, and reed valves were all taken off and given a good cleaning. It turns out the pistons weren't seized.

The heads look good, some slight detonation marks on the upper cyl head.
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Lower cylinder looks OK too.
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As for the upper cylinder and piston, there's quite a bit of scoring on the sides. I've never rebuilt a two-stroke before but I'm pretty sure these look like they can't be re-used. They're Nikasil plated cylinders too, which wont be cheap to re-bore/plate.
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Here's the bottom end.
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Doesn't look too good inside. Hopefully, the crank can be salvaged. I'll pull it out when I get a flywheel puller. The crank only turns a few degrees, then locks up, I can't figure out what could be causing that as it doesn't feel stiff when it turns.
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Apart from moisture getting inside the engine, the bike looks reasonably good mechanically. I would love to get this bike running again, but if it turns out to need too much work I'll have to just part it out, make some money, and get another two stroke project!
 
Re: NSR250 revival

It would be awesome if you could get it tiptop again ;) do you have any pic's from before you started stripping her down?
 
Re: NSR250 revival

I'm aboard!

The crank may not look too good when you tear it down, but it will probably be re-buildable.
It might cost a bit to get on the road but the $100 buy should make that easier to live with.

Crazy


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Re: NSR250 revival

andycafe said:
It would be awesome if you could get it tiptop again ;) do you have any pic's from before you started stripping her down?

No pics from when I bought it, I was too excited to get stuck into it. It didn't look like much though, just some badly painted matte black fairings with a few cobwebs. I'll post some more pics of the bits as I work through it.
 
Re: NSR250 revival

sweet, ive always had a soft spot for dingers both dirt and road ;D definitely gonna keep onboard ;)
 
Re: NSR250 revival

Hi Moa,

Nice little bike you picked up there!

How complete is it?
The MC16's are quite rare... the downside being parts are difficult to find, as compared to other models...

A great resource for after market parts for NSR's is Tyga Performance.

http://tyga-performance.com/site/index.php


Another great resource is NSR World

http://nsr250.net/forums/

The site is currently down, but hopefully will be up again - the PARTS MANUAL tab on the left (which has exploded diagrams) is invaluable, as this was a Japan released bike only, and as a result you wont find an English Manual. You can buy one from the site, which was done by one of the members/administrators though....

Good luck.

So, what are you planing on doing? Resto to original spec?
 
Re: NSR250 revival

Moa said:
Doesn't look too good inside. Hopefully, the crank can be salvaged. I'll pull it out when I get a flywheel puller. The crank only turns a few degrees, then locks up, I can't figure out what could be causing that as it doesn't feel stiff when it turns.

Could be your big ends, and possibly the conrods are damaged due to bearing failure... Ive had the same sieze there, and the crank turned so many degrees before getting caught up.

A bigger issue: For some or other reason, the cranks normally go on the right hand side. These cranks can definitely be fixed, Ive had a couple done, but finding a damaged crank with the right-hand components still good is a challenge.

Pistons and rings are easy to come by and relatively inexpensive.

Another guy you can try with regards parts is Mario Smit : http://nsr250spares.com/
 
Re: NSR250 revival

Hi Dale,

Thanks for the info. I've already been looking through NSR-World, they have lots of useful technical documents and such. The bike is complete as far as I can tell apart from a missing kickstarter and airbox.

My plan is to restore the bike to working order, starting with the engine. Once I get all the mechanical aspects sorted, I'd like to get it re-registered and put back on the road. I'll probably keep the original style fairings, but with a non-original paint scheme.
 
Re: NSR250 revival

Way too cool! I'm onboard and following. Lets see what happens! I wish you luck in finding the parts...
 
Re: NSR250 revival

Did a bit more stripping down today.

Pulled the clutch out using my homemade clutch rotor holder
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Still waiting on the flywheel puller I ordered so I can remove the crank.

Hack-sawed off the old rusty chain:
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Pulled the brakes as they were seized up and locked to the rotors
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I'll have to rebuild or replace them, I think they are common to a number of Honda models though, so parts shouldn't be an issue. Front brake rotors will need replacing too.

Anyway, it's pretty much down to a rolling frame now, and a nice looking frame too.
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Pulled just about everything off and boxed/bagged it, no loose bolts etc. left unlabeled. Hopefully it won't be a nightmare putting it back together.
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Next step strip the rest of the frame, then give everything a good cleaning/polishing. Then it's on to rebuilding the engine, but first I need to sell my XL185 to raise a bit of cash. There's a local Honda parts stockist http://www.econohonda.co.nz/ who seem to have just about every Honda part you could need, including a few new and used NSR MC16 cranks! Only problem is, their stocklist is 3 years out of date, and they don't seem to answer emails, but I'll give them a call tomorrow.
 
Re: NSR250 revival

Good luck selling your other bike man, I really want to see this bike going again :)
 
Re: NSR250 revival

I hope that parts source still exists, it's so disappointing when you think you've found everything you need only to find a cyberspace dead-end!

Crazy
 
Re: NSR250 revival

Moa said:
... who seem to have just about every Honda part you could need, including a few new and used NSR MC16 cranks!

I would snap up a crank as soon as you could if there's one available! Even MC21 (the most common) cranks are getting scarce! I destroyed the crank on my MC28 6 weeks ago (200 miles on my last rebuild of the crank!## ) and after searching for spare cranks eventually gave up and bought a nos one. You can pay up to $1700.00 for a nos crank. I got mine for half that, thankfully.

Try and get an airbox if you can. These motors have a couple of flat spots when using pods...

Was your PGM unit in there with the bike? If so, great, and try and determine if it is still functional. This is another expensive part that blows that will determine whether this build is feasible or not. Not trying to be a naysayer, just mentioning... Second hand units can come in at around $200-$300.

Another option may to be to find a good MC21 motor and fit that instead of fixing up the MC16 motor. The wiring harness
with PGM etc would also be easier to get for a newer gen motor. Just a possible suggestion if you find MC16 parts are too difficulty to find, or are too expensive as a result of being hard to find... my 5c
 
Re: NSR250 revival

Your teardown is looking good though! Its amazing how light these bikes are, and they weigh almost nothing without the motor right?! That subframe is a bit heavy (relative to everything else) , Tyga make really nice lightweight sub-frames, but that's for another day.

Once you get into these bikes, they really bite hard. They truly are exceptional little pieces of engineering. Honda's build quality is also second to none.

The fact that its a V-Twin two-stroke is also a slam dunk for me.
 
Re: NSR250 revival

Your build inspired me to do a little research on this bike, and holy crap, what a rocket ship!

Apparently the '87s were not restricted, unlike the later models.

I'll be watching this one - thanks for sharing!
 
Re: NSR250 revival

Dale said:
Was your PGM unit in there with the bike? If so, great, and try and determine if it is still functional. This is another expensive part that blows that will determine whether this build is feasible or not. Not trying to be a naysayer, just mentioning... Second hand units can come in at around $200-$300.

I have to say I wasn't sure what a PGM unit was at first, but after looking around nsr-world.com, it seems that the MC16's weren't fitted with them. The first gen MC18's look like the first to be fitted with PGM units.
 
Re: NSR250 revival

Worst cb650 ever said:
Your build inspired me to do a little research on this bike, and holy crap, what a rocket ship!

Apparently the '87s were not restricted, unlike the later models.

I'll be watching this one - thanks for sharing!

From what I gather, these models do not have a top speed limiter, or electronic power restrictions. They are somewhat restricted by the cylinder porting and small carbs though. Since one of my cylinders need replacing, I may just swap the top end for MC18 parts. If what various internet sources tell me is correct, swapping the MC16 carbs and cylinders with MC18 parts is enough to yield ~55hp (from 45hp), certainly a lot in a 125kg bike! ;D
 
Re: NSR250 revival

Called econohonda this morning, asking about the crank, really nice and helpful place. They have several used cranks available for $200 + extra for new seals etc. They're not guaranteed, but given their scarcity, that seems like a good deal to me :D

Dale, you might want to keep them in mind if you find yourself needing another difficult to get nsr part in future, they deliver worldwide.
 
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