PARTS FOR A 1987 NC21

[christopher_heather]

Hi all,
I am trying to find a place where i can get parts for my 1987 nc21, i have been all over the web but it doesnt look like there are many parts websites. I need a head gasket mostly. Are any parts interchangeable between the nc bikes (nc24/30).
Any help will be greatly appreciated
Chris

[duncan]

Try Elliotts Motorcycles of Cricklade near Swindon or David Silver Spares of somewhere in Suffolk.Both have websites that Google could find for you.
Many if not most of the parts are the same as the NC24

[spooky]

nc30 head gasket should fit as someone on here has tried it as they could not get a gasket for their nc24.
nc21 and nc24 engines are very similar if not the same.

[christopher_heather]

Thanks, so you reckon the nc24 gasket will fit?
The reason i ask is because i have just bought the bike, fairly cheap :) but the bloke selling it gave a very vague description (ebay so i couldn't view it). All he said was that when it was running he noticed a milky residue forming around the exhaust end, that just makes me think the gaskets are going. Maybe someone on here can shed some light. I havnt got the bike yet, it is being delivered on Friday, i just want to get stuck into it right away. I will have a proper look once i get my hands on it.
Thanks for the help

[Neosophist]

Good luck!

Parts arn't that plentiful, especially aftermarket accessories but you can get most bits 2nd hand and major stuff new.

You can fit pretty much anything off an NC24 onto an NC21 engine.. Not much of the NC30 stuff will fit.

You can fit an NC30 head gasket if you can't get one for an NC21/24.

The head gaskets are pretty bullet proof on this bike.. if it's blown a head-gasket thats usually a sign of really bad neglect :/

The bikes pretty easy to work on once you get yourself familiar with all the components.

Since there a 20 odd year old grey import, for the extra time checking everything over and making sure it hasn't been messed up / faffed about with you'll save yourself a LOT of hassle in the future.

Initial Full Service / Inspection.

Engine:

*Change the Oil, Oil filter / Plugs / Air Filter*

-10/40 semi-synth motorbike oil is fine, i.e Fuchs Silkolene, will be fine.. 4l will run you about £19 you'll need 2.6 litres.
-The Plugs are C6EH9 (NGK) / U24FE9 (ND).

*Check the valve clearances*

-This job puts many off and costs a lot at the garage, it's really easy, and the NC2x uses lock-nut type adjusters so theres no costly shims to replace.. having the right valve clearances is VITAL to keep the engine running properly and have a smooth idle, no amount of messing with the carbs will correct out of spec clearances.

-Inlets: 0.11-0.15mm
-Exhausts: 0.18-0.22mm

*Check the carbs*

-You'll need to get the carbs off to check the valve clearences, while you have them off, remove the float bowls and make sure all the jets and passageways are clean, blow them out with some carb cleaner..

-The NC21 should have 110 jets in the rear carbs and 112's in the fronts.
-Float heights should be checked, there 6.8mm factory.
-Pilot screws 2.25 turns out.

*Replace coolant*

-Drain the coolant from the bike and remove the lower rad hose, flush with a running hose until the water runs clear! Make sure you have a motorcycle approved antifreeze and use a 50/50 ratio when you refil the bike.

-While you have the coolant drained crack the cover off the waterpump (its on an o-ring so you can just put it back on)and check the impeller blades are in good condition.. with the kill switch on crank the motor a few times and check the blades rotate properly. A shafted waterpump will cause over-heating which could have killed your head-gakset...

-When the coolants refilled you need to bleed it propely.. allow the bike to warm up on the side stand with the radcap off, when the temp reaches 1/2 way snap the throttle to 5000rpm and allow it to return to idle.. repeat this 4 times and turn off the engine.. allow the engine to cool and top up the coolant as necessary, then replace the rad cap.

Electrical System

The BIGGEST downfall of the VFR400 series is bad regulator / generator / battery issues... The NC21 has a finned reg/reg so it might be alrite... Make sure your battery is in good condition and check that with the engine running it's getting at least 13v across the terminals. There are a few tests you can do to check over the electrical system.

An older battery cannot take as much charge as a new one.. so the reg/rec has to burn off excess power generated as heat.. the stock reg/recs are made of chocolate and melt very easy, this then kills the battery and eventually the altenator unless fixed. Always worth keeping an eye on.

Exhaust System

The NC2x bikes use a collectorbox.. fortuantly you can get a replacement from David Silvers for about £130 for your NC21.. but if it's gone you'll need to remove the engine to get it off.

Check the box for holes / signs of rust.. the front pipes and where the end-can join all rot really badly.. as do the bends in the rear-downpipes.

Forks / Chain / Brakes / Bearings.

-Make sure you have the correct slack in your chain.. Sit on the bike and have a friend check the slack.. you should aim for 1" in the middle.

-Put the front brake on and push the bike forward.. this will make the forks compress, do this a few times and check for signs of leaking fluid on the fork tubes.. new seals are cheap and easy to replace.

-The brake calipers are of sliding desgin.. these often sieze as there neglected and people dont' clean and grease the sliders (should be done at least once a year, I do my sliders bi-annualy) If you have terrible brakes you might need to over-haul them.. again not a difficult job.

-These bikes often change hands many times and things get neglected.. bearings will affect the handling of the bike if there worn and can damage lots of parts if the go completely.

-Check the head bearings by rocking the bike backwards and forwards with the front brake on, you shouldn't here and knocking or feel any freeplay in the yokes.

-Lift the front of the bike up and grasp the front wheel at 12/6 oclock, you shouldn't have any up/down play.. try again at 3/9pm.. again you shouldn't have any play.. you can do the same for the rear wheel as its a conventional swining arm. Wheel bearings are DIRT cheap.


Sounds like a lot but it'll only take you a weekend if you have a mate helping you out :-) After that you'll have a bike that should be ready to go and run pretty good too.

Reside around the exhausts is probably just condensation, as it's cold.. and unless the bikes run warm regularly it'll build up quite a bit of condensation in it... do the above first and see how she goes.. you'll soon know if the HG's gone.. i've never come across one with a failed HG yet tho. Even the most abused race bikes tend to destroy pistons and rods before the HG gives up!

[spooky]

Ahh the expert is here. lol. what kept you Neo. you are always first. Duncan beat me too.
but what an answer.lol.

[Neosophist]

Ahh the expert is here. lol. what keep you Neo. you are always first. Duncan beat me too.
but what an answer.lol.

Haha.. the answer did get a bit big I must admit. And as for the late reply, well it's been a busy week! The ZXR's taking over

As for your inital point.. the engine internals are very similar. However, the NC24 does have some revisions to the cams, gearbox and valves.. mainly different profiles but you can get away with chopping an changing bits between bikes.. mostly.

As you are probably aware, the NC21 has different forks, a hydraulic clutch, conventional swinging arm, different exhaust system. The generator is also different, as is the reg/rec & its location.

The main frame is the same though so you can transplant engine(s) / swinging arms between the various models. I was toying with the idea of an NC21 swingarm on a 24 to allow different rear wheels more easily.

If either of you need any more info though don't hesitate to ask.

[spooky]

Cheers Neo.