Current Development On This Bike Is To Be Found On the NSR250 Forum Thread Titled
New Member with An MC18...wait.....no...an MC16...yes MC18
http://www.nsr250.net/forums/viewtopic.php?t=15220
Some time ago (Nov 9th 2019) I bought this 1988 NSR250R MC18 at a live on-line auction. I really didn't mean to. I had previously bid on two RZ500's and a KR-1S and missed out. This was the second last bike of the collection. I clearly got too excited, ended up bidding too high and won. What didn't help was the auctioneer shouting "Come on- this is a $10,000 motorcycle!" Whoever he was, he had no clue of the bikes condition and misrepresented the bike he was selling. I'll always begrudge him for that- but my fault for falling for it. And then I got nailed on two different taxes, auction commission and the cost of actually getting it to my garage. I should've tried to bail out of it but I've always tried to do the right thing and stick to my word. Very expensive being honest...or is it stupid? In other words...read the small print before you launch into anything like an online live auction.
But what about the bike?
Despite the fact that the rear of the bodywork is ziptied together to hold it on....the bike looks fantastic with what seems like brand new replica Rothmans Honda clothing, but I took that off and, yes, it's a dog in sheep's clothing, and worse, according to the engine number it's an MC16 in an MC18 frame….and they said it was an ‘89 but the title is ‘88.
Restoring this might be more than I bargained for because these were only sold in the Japanese Domestic Market so access to spares will be a different process.
But in my mind, I've been preparing myself to shop as far away as Thailand and go full Tyga, upgrading it to an NSR300 with their spectacular looking bodywork, pipes, rearsets, everything....but the engine upgrade kit starts with the MC18….so I'm not so sure what to do with it now.
On the positive side, a while back I started it and ran it up the street and back...so at least it's not seized.
How I got it.
How I want it....well....not the single sided swingarm, USD forks or Brembo brakes, but I'll take everything else please.....
The original (and more unaffordable) MC28 SP.
.I think this was one of Tyga's first Rothmans repros' attempts. It shows more accurately how my bike will could in the end. For example with the standard swingarm, forks and brakes.
It's a beauty....from this distance....
This part- all zip ties
Original air box. No filter in it but....original air box.
11,335 kms? Not likely...well maybe not on this engine. Plus....the footrest rubbers are worn smooth...never a good sign.
Everything that could rust, did rust
I would bet the bike had never been ridden with this bodywork...and, it seems good quality.
Honda equivalent of power valve system...the RC Valve exhaust system.."is continuously varied by a computer controlled timing system."
Have to look close but it reads MC16...something something something.
Hmmm...supposed to be that size? Possibly.....the oil level is actually up to the threads there....or is the did the dipstick break off. I'll have to order me a manual.
This is the first time I've seen flat slides up close
No, these are not flattering pictures...
Severe sun damage to switchgear or is it supposed to be grey?
Everything that could rust...etc.
Nice welds though
Tear Down begins in earnest…
It's a small bike...
I have a feeling someone painted the radiator...
collecting the parts
already starting the hunt for new(er) switchgear
starting the collection that will be going to the powdercoaters...not much....reckon this stuff....
the side stand....
clock mounts...this one and....
this grey one...
and triple tree bottom....
bought all the official Honda parts that Tyga had in stock...
they send lots of stickers too.....
preparing to drain coolant....
assuming there's some problem with the original temp gauge if this thing is wired up to the bike...interesting that it appears tp be set to Tokyo time.
radiator was full so we know it's not leaking...just needs a good clean and taken back down to the metal
Cylinders/Heads
Carburetor Rebuild…
started 3/12/21
Carbs are off.....these will take a while to get back to looking brand new.....
one's a bit leaky...
interesting contract of colors...
and I'm not really sure why....
what's fascinating is the difference in size of the jet at the top of the picture...
even by just looking at it you can tell it's much bigger....could drive a bus through this one....
Been getting some great advice from the NSR250 forum. Andy, in particular, the webmaster in charge, is a fountain of NSR250 information. It was he who pointed out that I didn’t have and MC16 motor in an MC18 frame— ALL the engines have a prefix of MC16. Was a relief to know that.
Trying to get ahead of the game by ordering things, some of which have to come from CMS (Holland) and Japan.
So far have ordered/collected
Left hand case (Yahoo Japan)
Tyga Carb rebuild kits
Honda Air filter (Tyga)
Honda clutch side gasket (Tyga)
Honda fork seals (Tyga)
Honda reed block gaskets (Tyga)
Honda clutch arm seal (Tyga)
Honda countershaft seal (Tyga)
Honda exhaust spring gaskets (Tyga)
Honda kickstart seal (Tyga)
Honda rear master cylinder rebuild kit (Tyga)
Honda front master cylinder rebuild kit (Ebay)
Honda Speedo joint (CMS)
Honda master cylinder cup & rubber (CMS)
Honda fork bushes, washers and o-rings (CMS)
Honda grips (CMS)
Honda (used) kill switch (Yahoo Japan)
Generic Left hand switchgear (Amazon)
HEL Front (2) and Rear (1) Brake Lines black w/stainless banjos (via Andy on forum on here-as promised: excellent price for TI members)
Brakemaster.com Front and Rear caliper rebuild kits w/pistons
NGK BR9ECM Spark Plugs (Advance AutoParts!)
Things still on the list:
Rear tail light panel
Set of coolant hoses
chain and sprocket kit
Top end re-build kit once I see what barrels I have.
Maybe
set of forks: on closer inspection my fork tubes are more pitted than I thought
Plodding away on things: It's always just a little disappointing when you walk into the garage and the bike looks the same is it has for a week. Jobs like cleaning carbs can make you feel like you're getting nowhere fast. Now dismantling them and giving them a dip in the ultrasonic bath (something which I honestly think is pointless) and will then take to a friends house to get them vapor blasted tomorrow (something which makes looking at the end result....almost good as sex)
Confirmed the carbs and their ingredients...and Andy is correct...the needles, and in fact every component, differ for each carb. Wonder how many people re-assembled them wrong and never figured it out...
Keihin TA20A
No.1
Main 130
Slow 38
Needle BPD, Power Jet 70
No. 2
Main 132
Slow 38S
Needle BPE, Power Jet 75
Needle jets have no markings.
these flat o-rings are probably part of the reason for the excess fuel everywhere...
TPS (throttle position sensor) just one of the many electronic aids on this bike....
Not as complicated as I thought...
Carbs and bits back from blasting...great job as always from www.motoresurrection.com
Little did I know that behind this screw in the bottom left....
there lies a power jet. Removed it and made sure all was clean...
Set the float height at a very high 13mm measured from the top of the float to the base of the carb which means the floats are really quite high within the float bowl before they start compressing the float valve....I think I might bench test it to ensure it does in fact close and not pee all over the place. Been there.
One is done....at least I thought it was until I saw that the throttle shaft felt washers were practically non-existent- so while awaiting these parts went onto the engine....
Brake Rebuild…
Clutch
Engine Teardown
Doing my best to get rid of this crud before I take the engine out.....
Admire the basic engineering of this case....plastic and so light but mounting holes are reinforced with steel bushings
you can't tell but this drive sprocket as a lot of play.....
...and the lock tabs are not correctly situated
Preparing to relieve the bike of it's less than supple chain.....
I put a space heater under the motor for an hour or so to get the lifeblood warm and flowy. Looks pretty clean.
Hmm....no crush washer.
Looks like someone took this racing lark to heart. Sump plug drilled for lockwire.
Scrutineer's paint dabs on the suspension plates.....
....and on an engine mount bolt....
Anyway...moving on finally discovered the barrels are C barrels.
Engine-Right Hand Side
Engine ReBuild
This edges are not only rough but attached to huge 'wings' that are not apparent on the other port
View from the 'inside' on the motor-kind of miss shapen like an upside down L
the other port however- cleanly rectangular
Supposedly this is because decided to get rid of these rough edges Turn 1 on the NSR Forum said : " Those odd lumps are there to make the case volume the same in both sides so equal amounts of fuel/air mixture gets to both cylinders."
A little smoother now.
Cleaned up the studs with a wire wheel
..carefully and slowly ran the case threads with an M6 1.0 and an M5 where appropriate...
..then it was bath time...
...making sure oil ways are pristine...
paid attention to these needle bearings for the shifter and clutch actuator. Once dry, hit them with some aerosol electronic cleaner and then some compressed air had them spinning...finished off with a little two stroke oil....
Make it stand out
