Buying a CX500 or one of its family (inc Turbo)
I will assume that you've checked that the seller has good title to the bike and that the engine and frame numbers correspond with the registration document (V5 in the UK). Verify the mileage on the odometer with at least one MoT certificate. A conscientious owner will keep all the old MoTs to show that the mileage is true.
The most imprtant thing to bear in mind is that with a bike this old, there are bound to be things wrong with it, or there are bound to be "things that need attention". CX and GL owners don't die of boredom ... forget any dreams about finding a mint condition CX which looks as if it just came out of the crate. Any unrestored bike which has been kept outside without a cover, will have corroded metal parts and generally look tatty. Even a 25 year old bike which has been well looked after will have some battle scars. All and any such defects and problems should be reflected in the price.
If you go for a fully restored model, you are saving a lot of work for yourself at a greater initial cost. Buying a CX or GL from an enthusiast owner probably means that the bike has been well looked after.
The Turbos are great bikes to ride and you will never have so much fun with 500 or 650ccs. But - and this is a big but - spares are an absolute nightmare. Whilst filters and consumables are easy enough - they use the same oil filter as the regular CXs - almost every other part is almost totally unobtainable. Easily broken parts like front indicator lenses, headlight glass and cosmetic items are carefully hoarded by Turbo owners. If you buy a Turbo and the engine blows up or the bike suffers accident damage, you will never be able to get enough parts to repair it. There are a very few interchangeable parts with the Eurosport range, but any engine, transmission or turbocharger parts are extremely rarely sold and are horribly expensive.
So ... if you want to buy a Turbo ... first of all ... don't. If you ignore this advice, be prepared to scrap it for spare parts if it gets damaged or suffers a serious engine problem.
CURIOUSLY even ordinary CX and GLs are worth far more in spare parts than as usable bikes - the Turbos particularly, as only 5,500 CX500TCs and 1,750 CX650TCs were made.
Personally, I would not buy a vehicle without an MoT certificate of less than 6 months remaining life. If I really wanted the vehicle, I would be prepared to pay for the cost of a new MoT test, but not any repairs that were required to pass it. One way to detect a dodgy bike with hidden faults is to make this offer - if the seller stalls or backpedals, walk away from the deal.
NEVER buy from a man in a pub. Always go to the seller's home. If the address on the registration document does not match the address where the bike is, ask the seller for an explanation. In the UK it is illegal for a trader to advertise a motor vehicle for sale and make the advert look like a private sale. This is because a trader has to comply with legislation such as the Sale of Goods Act. A private sale is a case of Caveat emptor, roughly translated as "Sucker, beware!"
If you can, take a knowledgeable friend along, who can look dispassionately at the bike and offer a second opinion of it.
If you phone up about a bike for sale in the paper, always say "I'm interested in the bike in the paper." If the seller says "Which bike?" he is probably a dealer; ask him if he is, or if it's a private sale. The local Trading Standards Office will be very interested in a breach of this law.
If it's pre-1981 (frame number less than 2034366 i.e. a CX500Z; in the UK an 'S' or 'T' registration), see if it has the two or three punch marks (left) adjacent to the engine number on the lower left crankcase, to show that the cam chain tensioner modifications were carried out. Even better, inspect inside the rear casing with a dental mirror and a lamp, to make sure that the long plate has been fitted, as per the camchain components page.
(Thanks to John for the clear photo.)
The engine should be stone cold before you try and start it, and then start cleanly, no shushing back through the carbs, and not smoking once started. They often only start on one cylinder (usually the left one), this is not particularly a problem, as long as the other one chips in soon afterwards. Nobody seems to know why this is, although one theory is that when parked on the propstand, fuel drains out of the right hand carburettor.
All the electrics should work; here is the checklist (remember that some countries have different lighting requirements): front sidelight / front dipped headlight / front high beam / headlight flash button / both rear sidelights / both rear brakelights on the front brake / both rear brakelights on the footbrake / horn / all four turn signals / starter button. On the instrumentation : neutral light / oil pressure warning light / high beam warning light / left and right indicator lights / instrument backlight for both speedometer and tachometer. Trip counter should reset. When in gear, the starter motor should not operate until the clutch is pulled in.
The cam chain and tensioner should last at least 35,000 miles and many go as far as 50,000 miles. Mechanical water seals do about the same mileage, if proper quality silicate-free antifreeze and distilled water are used in the radiator.
The Turbos have a depressing habit of seizing up the turbocharger waste gate arm if the bike is stood for several years, or used so gently that the waste gate never opens. This is easily diagnosed on a road test. Find a long straight road and give the bike its head on full throttle. Watch the boost gauge on the dashboard. If it goes either right up the orange section or into the red, all is well (except by now you are doing 120 mph). If the engine cuts out and the "Fuel System" light comes on, the waste gate has stuck closed, the engine has boosted itself past the 18 lbs maximum and the computer has shut down the engine to stop it exploding. Flicking the kill switch off and on again reboots the computer, and the only solution is to remove the turbo unit and try to get it repaired. Major, expensive surgery. Walk away from the bike unless you can handle this problem.
Decoking shouldn't be necessary until the engine has done at least 40,000 miles. On a standard 500 or 650 this can be a roadside repair given that you have a spare gasket and the right tools.. At home it should take you no more than three or four hours per cylinder head. On a Turbo it's a serious, workshop job as a great deal of other things have to be removed to get at the cylinder head, and would take a competent home mechanic a couple of days, assuming that he can get the spare parts.
To listen to the interior parts of the engine, start it and let it idle. Put a long screwdriver or socket extension at the following places, and put the other end right into your ear. You can also use a child's play stethoscope to good effect! When listening, regular whirrings and rolling noises are ok, knocking and serious scraping are bad signs.
There are mp3s of the various engine sounds, these are linked from my main page.
> chromed cylinder head cover bolts (worn valve mechanism)
> inlet manifolds (ditto)
> exhaust manifolds (ditto)
> as deeply between the V at the top as you can reach (camshaft)
> on the cam chain tensioner locknut (cam chain and tensioner apparatus)
> water pump casing (camshaft and impeller)
> clutch casing (clutch bearing and gearbox)
> the 17mm head inspection port under the radiator (crankshaft)
> very low down on the bottom "corners" of the engine (big ends)
> at the base of each barrel (big ends and crankshaft)
Particularly check for:-
> cam chain tensioner bolt not tightened up (thread stripped, big job) or clearly vibrating loose. Does not apply to Eurosports.
> coolant weeping from under the water pump cover (failed mechanical seal, a serious job). Especially check, after a test ride, for coolant leaking from here, over the rear left crankcase, starter motor, and H-box. It's almost impossible to mask this if it's happened. You'll see traces of the brown stain in various nooks and crannies. Some unscrupulous owners will block up this hole using epoxy or sealant - we've had one case where the previous owner had stuck a steel rod up the hole to conceal the water leak! So use a small mirror to examine the left underside of the water pump area, right up against the rear casing.
> ZABCs : take a multimeter and read the blue and white wire stator voltages, as per the stator web page.
> a rattle which goes away after 3,000 rpm is probably a worn cam chain, as above these revs the engine itself will keep the cam chain taut.
> To check the manually adjusted cam chain tensioner life, rustle up a dental mirror and a torch, look inside the rear crankcase timing port. Or feel with a fingertip. The adjusting quadrant should have at least 1/4 of an inch of its slot visible above the locknut. If there is no visible gap, the adjusting arm is at or near the end of its adjustment and soon you will need to change the cam chain and tensioner. Unfortunately this check does not work with an automatic cam chain tensioner (500 Eurosports, all Turbos and 650s), and with these models, you can't tell the wear rate without an internal inspection.
> Another way to detect a worn cam chain on Zs, As, Bs and GL500s is to peer behind the radiator at the fan, which is attached to the front end of the camshaft. Put the bike in 5th gear and very gradually wind the engine to and fro by nudging the rear wheel. There should be no movement of the flywheel, visible and feelable through the timing aperture, without a corresponding movement of the fan. If there is slack in the cam chain, the crankshaft will be able to move a fraction without a corresponding camshaft / fan movement. This trick does not work with the electric fans of the 650s.
> No oil should be visible floating on top of the water, at the radiator cap.
> No water or white froth or scum should be found on the dipstick. If you find slimy yellow "mayonnaise" on the dipstick, or inside the rocker covers, there is a coolant leak, probably a failed mechanical seal or a blown head gasket.
> Check the soft 12mm oil filter bolt isn't rounded off, or that the filter housing has been spotwelded to the bolt. If so, it's not serious but you should replace them.
> Stand the bike on its mainstand and align the steering with the back wheel, you should be able to see all four wheel or tyre edges in a dead straight line, this is a good check for a bent frame.
> Check all 4 of the 14mm engine hanger bolts are tight just aft of the radiator, as the aluminium of the engine tends to crack, or the threads tend to strip, and the crankcase where they bolt into can't be easily repaired.
> Check that the left and right cylinder head cover chromed retaining bolt holes aren't stripped. If they are, the covers cannot be tightened down. It is almost impossible to conceal the resultant oil leak from between the covers and the cylinder heads or from weeping out of the spark plug water drain hole. Having to rethread these bolt holes is a common task as the engine ages.
> Check front pistons on brake calipers are not seized, run chalk lines out from the centre of both faces of the discs, and spin the front wheel (or just push the bike along), gently squeeze the brake, all lines should be worn off equally.
> Rear brake - check the adjusting arm is not moved round (a cheat to extend brake life). Looking from alongside and underneath the left silencer, the forward angle between the actuating rod and the chrome brake arm should be visibly less than 90 degrees, i.e. the junction of these two parts should be well behind a vertical line from where the chrome arm enter the brake hub.
> No oil leaking from the underside of the shaft hub, at the rear wheel.
> Frame rot tends to occur on (a) the inner face of the pillion footrest brackets; (2) topside and underside of the swinging arm; (c) inside faces of the rider footrest brackets and lower engine mounts. Sometimes this can be welded, sometimes it's too severe.
> Hold the front brakes on hard, and pump the front forks up and down; there should be no oil leaks or smears around the chromed fork legs. Particularly check this after a test ride. The chrome on the upper fork legs should not be pitted. (Stained aluminium parts like fork lower legs are easily polished up, though.)
> Underside of the swinging arm should be clean and rot free (expensive replacement).
> Clean gearbox selection. They do tend to jump out of 2nd, particlarly under a lot of power. No shaft drive sounds are normally audible, and the actual shaft is virtually unbreakable.
> The engine sounds very lumpy when cold, but purrs when hot, I can send you WAV or MP3 files of a cold and warm start if you want to know what it should sound like.
> No catching or grinding noises from the fan area (fans can break, or dislocate from their hub).
> Poke a thin wooden stick through the dipstick hole and into the sump and have a fish about, is there debris or muck at the bottom of the crankcase? Shows neglect in oil and filter changes.
> When fully warm, the engine should idle absolutely comfortably at 1,100 rpm, struggle as you lower the tickover to under 750 rpm and stall if you go much lower. The flywheels are very heavy and it needs to idle at about 1,100 rpm (needle just over the tip of the 1 on 1,000). A really well maintained engine, with freshly balanced carbs, will idle as low as 600 rpm when fully warmed up.
> On revving after that, the engine should pick up without hesitation and rev freely on a road test to well over 7,500 rpm to check for stator failure (sorry, neighbours). Stator or coil failure shows on a road test as hesitation or bogging at about 5,500 rpm.
> The temperature gauge, when the engine is fully warm, should be pointing straight forwards over the front wheel and should not climb more than 2/3 of the way clockwise. Under normal circumstances the temperature never goes much higher than the 12 or 1 o'clock position, and if it does so in traffic in hot weather, it should go straight back down again once the bike is riding normally. A fault here is probably the thermostat, an easy fix, but the radiator may need reverse flushing and de-gunging (again, an easy fix). However if the radiator itself leaks, this is an expensive problem, as CX radiators are rare. Sometimes the cooling fan dislocates from its hub, or breaks a blade, and this will wreck the radiator.
> No exhaust blowing from the H-box or its 4 junctions (dead give-away is black stains over the chrome junction clips).
> If the engine seems to rattle for no reason, wrap a towel tightly round each H-box junction in turn. A leak here can make the engine sound tappy. Easy to fix and not at all worrying.
> No water leaks especially from the junction of the chrome transfer pipe to the water pump, and at the transfer pipes to the cylinder heads. Hoses should be good at top and bottom of radiator.
> Put the bike on its centre stand and from dead astern, grip the rear wheel. Try and twist the wheel and try to move it left and right between the two halves of the swinging arm. There should be no lateral movement. If there is, the swinging arm bearings are shot and this is an MoT failure.
> To check for worn or damaged steering bearings, put the bike on its centre stand and push down on the rear, to lift the front wheel off the ground. The handlebars should go from full lock to full lock with only a light touch, and there should be no notched or stiff rotation. Now grip the fork legs by the very bottom and pull the forks firmly fore and aft; again there should be only a very slight 'bendy' movement and no clanking or rattling. Another potential MoT failure.
If you are not confident with the model, take a more knowledgeable friend along.
Paying cash and waving banknotes under the seller's nose is a very strong incentive.
If the bike is really, really what you want, pay the asking price before someone else comes along and snaps it up!