My CBX build

[Russ]

Next was the frame and other black stuff.......

Frame was basically OK but with rust where the paint had rubbed off or got chipped.
Battery box was corroded with snapped fasteners, all due to 30 years of acid fumes / spills I suppose. You can see the battery retaining flap is missing.

Anything that needed blanking off was done with machining various blanks. These all had O ring grooves in to make a perfect seal to keep the blasting media out.

Master cylinders were particularly bad as they had been sitting in stale fluid for years

Frame and other steel stuff was stripped and then dry blasted so it didn't corrode.
The main stand wears where base rubs on the floor and they collapse a bit at the top where the stand top rests against the main frame. This makes both the tyre's touch the floor when the bike is on the main stand (only the front tyre is supposed to touch), this wear also changes the angle of the stand to the bike. It had plates welded top and bottom to compensate for the wear then dressed them off so they look original.
The side stand was pressed so the side of the pivot block was parallel with the down leg - in the picture you can see it curves away a bit which is just the weight of the bike on it over the years.
Is that all a bit anal

Had to do a couple of TIG repairs to build up the battery box and hinges but managed to save it

Amazingly there have been regular instances of the VIN plate being left on while being blasted Obviously it is then completely fucked, took pictures to prove the frame and VIN plate match as the paint will cover the frame number. Look at the weight of her........she's a big old girl.
The two holes in the VIN plate are originally held with 2.6mm brass drive-rivets, some people put 3mm aluminium pop rivets back in to hold it on .

I found a Belgium firm that sells the correct brass ones, although I got the size wrong the first time so had to buy a second set, we made a punch that fitted the head of the brass drive rivet and knocked them home. They look as they did when they left HM almost 40 years ago, well pleased.

Some of the Aluminium parts after stripping and vapour blasting, these are almost ready for matt black. If you look close you can see I've started to put the the blanking bolts on the threads and plugs for the piston bore etc. Each blanking bolt has a washer welded on so they don't have to use the actual component for hanging off when coating - as this can leave a small line where the powder doesn't cover. Some of the lesser important threads will just be cleaned out with a tap.
The blue stuff is heat resistant tape for going through the ovens.

The rubbers on the front foot pegs were worn and missing some blocks. Needless to say these are another thing not available from Hodna. A Dutch bloke called Wim makes his own in a shed somewhere in Holland, the old ones were removed with a hacksaw blade, Stanley knife, milling cutter in a windy drill and finally sandpaper. new ones were glued on with the same stuff they stick windscreens in with.

Next up is when the stuff came back from the coaters.

[Russ]

Sooo, delivery all wrapped up with a nice fresh coat of blackness.....

Before they were sent off the parts were stripped and inspected for damage. Bits of the frame was given a light going over with a "softy" pad on a 4 1/2" grinder, this was only to take the high spots off the welds for aesthetic reasons.
Again, the holes for fixings, head stock and any threads were protected with bungs or tape. The two main stand clamps for the pivot tube were out of shape due to stress cracks, damage was welded up and then heated and tapped back to shape using a suitable diameter dolly. New pivot tube will be used for the main stand. The side stand is also now straight and the repaired battery box has a door complete with hole for overflow tube.

First the gloss.........what a lovely job

This shows the frame spar that the VIN plate attaches to in the previous post, you can see the mounting holes for it.

And the matt...........

All the piston bores were cleaned up prior to coating

There are a lot more pictures, too many to post - I think there are pics of every piece that was done.

Credit for this lot was my good friend Imran - my coloured coater . He etch primed where needed, coated gloss and matt and coated the gloss with a clear lacquer. He did this lot FOC so deserves a mention, I did do a load of ally welding for him without charging though so hopefully it all equals out at the end of the day.

Next is the engine..........

[Russ]

Here we go with the start on the engine........It took me over a week to get this lot together, hope it's not too heavy reading with it not being a Zed

This is the whole point of the bike really, Hodna flexing it's 1970's technical muscle. If the engine is knackered or there is anything seriously wrong with it potentially there will be huge bills ahead . Worst case scenario a new motor, which would need rebuilding as well, and then non matching numbers. I know someone who spent well over £6,000 last year having his engine refurbished by a specialist.

I took a chance on the bike, maybe too big a chance, buying it unseen from Europe. As previously mentioned, the bikes that are available over here are either well into five figures, basket cases, or rough with high miles.
I chose this one because it had low owners and low miles, even though it was a non-runner and I hadn't seen it, was it a good choice........Hmmmm

I made a mild steel stand up so the engine would be easier to handle.

If you look at the front of the motor just under the head between pots 3 and 4 there is an oil stain, there are others and the bike is almost 40 years old so a few weeps are to be expected but there was a pretty bad reason for this one.
You can also see where I've started to clean the gasket faces on the exhaust ports, there are also a few exhaust studs that need replacing or helicoiling.

I started to have a weigh up about the oil on the front.
The CBX, and the other CB's, use a dual chain drive for the cam timing. The crank drives the exhaust camshaft (A chain), and the exhaust drives the inlet camshaft (B chain).
The "A" tensioner and adjuster for the chain is at the rear of the motor, the "B" tensioner is at the top of the motor and adjuster for it is at the front.

This schematic shows the basic set up;

All the following relates to the B chain, the numbers in bold relate to the schematic so it is easier to see what I'm on about........if anyone's interested in the technical shite
The locking washer (18) for the "B" tensioner and the blanking cap (17) seemed to be the source of the leak. There was a small hole in the blanking cap for the tensioner which wasn't supposed to be there, this can also be seen on the above engine picture.
I pulled the blanking cap out and looked up the hole, the locking bolt was visible.....but wasn't supposed to be .
A lot of older bikes use a spring-loaded adjuster with a tapered rod (6 and 8). Basically the chain wears, the locking bolt is loosened, the tension spring pulls the chain blade in to take the slack out of the cam chain which in turn moves the rod up a bit and the bolt is nipped up a bit further down the taper on the rod. There are some pictures to follow which make it a bit clearer.

Because I could see the thread on the locking bolt it meant the tapered rod (8) was too far down the hole and the bolt (14) was actually behind it, instead of resting on the taper....Time to take the cam cover off then.....

Only six shoulder bolts to get the cam cover off, it is imperative that the tachometer drive cap and shaft are removed first. If the shaft is left in it snaps the tacho guide off the top of the number six cam cap bearing. This is very difficult to repair and, as the bearings are line-bored, write's the cylinder head off - even now, after 40 years, this happens regularly . No broken bits or damage on this one though .

There are plastic plates to hold oil in front of the inlet cam lobes, the two pipes are oil feeds to the cam bearings. While the cams were in I used the opportunity to make a note of all the valve clearances.

I had a think and the only reason I could come up with for the scenario I had was that someone had thought the top end was a bit noisy. Then either the knob of an owner (or more likely bigger knob of a mechanic) had deduced that it was cam chain, not bothering to investigate, they had removed the tensioner cap and shoved a screwdriver in there while the engine was running to "tension" the chain and make it quieter? WTF?

The big worry was the chain was that tight it had knackered all the cam bearings in the head........Fuck knows why they had done something so stupid, if you don't know what you're doing why assume that you do, or worse still give it to a "mechanic" who says he knows?
I'm only assuming that it was a mechanic because, in their day, these engines were a bit daunting and expensive for an everyday owner? Anyway, rant over.

Left bank of the camshafts out, the cams / bearings were too long to be done in one at the time so cams were made in four pieces and have a UJ in the middle of each for alignment purposes. These are called Oldham couplers, these "tick" on an old motor and you have to source oversize ones - another headache, but these were OK. The bearings in the head were all inspected and found only to have minimal wear marks so luckily no harm done by the cam chain.

Rest of the cams etc. out, you can see the witness marks on both ends of the the "B" tensioner blade where it has been rubbing on the chain.

All the cams and caps out and on the bench for inspection.

More bad news though........
The B tensioner clamping bolt had been sheared in the past, to get this out they had put a hacksaw slot in the bolt and head and wound it out. They had then Helicoiled it, presumably because they had made a balls of it and left the hacksaw slot in the cylinder head, which is why it was weeping oil.
Cleaned it as best as I could and put the AC TIG to work and welded the damage up, I dressed the weld off to form a new sealing face for the locking washer.

Also the B cam chain was found to be 2mm out of tolerance when stretched between the gears with a known tension on it. The chain is still available so a new one was put on order, the tensioner on the other hand was non stock from Hodna .
There are a few NOS places to get CBX parts from, one is Louis in the US. After exhausting all other avenues I emailed him............"yes, no problem. We have second hand one's at £250 and NOS ones at £450 + delivery". This is for a tensioner blade?

I thought Hodna would never make a specific part when they could get away with using a generic one? Wrong in this case, the 750's and 900's valves are different angles in the head which makes the CCT shorter.

Onto plan B then, I bought a NOS 900F2 blade set from David Silvers in the UK and done some working out. The 900 blade was 16mm shorter OA than the CBX. I made a tool for pressing the rivets out and also a small extension piece to make the difference up. A longer rod was manufactured with a taper milled on and was welded onto the other end of the blade pivot.
Before the work - the knackered CBX one on the top and the NOS 900 underneath with no wear.

The mount for the end of the 900 is also different so had to alter this;

The replacement part, complete with spring, looks a lot more bent than it should be but when in situ the cam chain straightens it out. The new rod is 11mm longer than stock to make up for the shorter blade of the 900, you can also see the milled taper on the bottom of it.

And fitted into the head, when the cams were put back the tensioner blade sat equally between the cogs with plenty of adjustment left and I'm sure it will work ok.

Small point which could have ruined my day, you can see the 6mm cap head bolt that fastens the CCT into the head. In my wisdom I replaced the mild steel hex one with a stainless cap head.........then promptly dropped it into the motor. What a knob, the mild steel one could have been fished out with a magnet, if you found it. Obviously the stainless one can't so I spent a couple of hours searching down the cam chain tunnel with a dentists mirror on a long rod. Eventually found it resting on a casting having not dropped all the way to the crankshaft. I got a piece of 3mm filler rod and put a blob of adhesive on the end, then, doing my best impression of a consultant gynecologist (complete with sticky out tongue) I landed it on the bolt. Two hours later the adhesive had set and I pulled it out.
If I hadn't had got it out it would have meant completely stripping the motor down .

If you are still awake I can do another post on the engine.................

[Coose]

I'm loving this even if nobody else is!
I particularly like the solution to the eye-watering camchain tensioner blade. I have a couple of old KTMs where a lot of the parts are obsolete, so to make the bikes work you need to improvise. I get scowled at by some of the purists, but I'd rather they worked than didn't.....

[weaver]

excellent stuff, keeping it coming

[chrispyduck]

This a superb thread...........and scares me to death particularly as i own one

[redzee]

Fantastic work Russ, as anal as you like, you have me riveted.....

As it happens I passed a silver CBX in Shrewsbury this evening, wasn't you was it Chrispyduck?

[chrispyduck]

Can't remember much coming past me

[Russ]

Always loved CBX's, but frightened I'd have to do a shim change at some point.

They are not too bad to do and at least they are on top of the buckets - you can change them through the frame spars with the motor in place. Ones on my ZZR14 are a nightmare, under buckets so cams out. Pushing a full day to do a shim change with all the fairings to get off and oil / coolant changes.
Russ

[Russ]

Part two of the motor then.....

As mentioned all the engine orifices were blocked up, this was to stop any media getting into the motor when it was vapour blasted. The motor sounded ok when it was running and I knew it would be a massive job to strip all the casings down. I could tell that the engine hadn't been stripped before so, considering the low mileage, it should be near enough as it was when it left Hodna all those years ago.
New gaskets were put underneath the exhaust bungs to be squashed with the makeshift clamps - you can see four of them fitted below.

All the shims were either swapped, changed or ground to get the optimum clearance - about 0.005" on these motors. All back into position, they are on top of the buckets on the CB's so no cams out if you need to do them. The numbers are just to let me know where they were and the size.

Cams back in, just got to fit the rocker cover

Interesting cock-up from Hodna, rare for them. The early factory service manual shows No. 6 cam lobes 180' out, correct orientation is shown in later books. This was the 30 minute engine rebuild, the engine ran "lumpy" for 30 minutes and then blew up. Must have caused devastation to many an owner, some of the manuals are obviously still out there, waiting for their next victim.........

The sump was removed and pick up strainer was cleaned, this filter just stops any big bits going into the pump with a paper jobbie on the front of the motor doing the proper filtering. The gears all look good with no marks or chips. On the outside of the motor left and right just above the filter there are the oil coller flow and returns, these aluminium bungs had O rings to seal and clamping plates made.

The filter housing always seems to get damage to the fins for some reason, the two outside ones needed building up on this one.

All cleaned off with just a slight colour difference to say it's been repaired, when it's painted you won't be able to tell.

Nylon bungs were turned up for the inlets and were clamped with the original carb rubbers as new rubbers were on order.

Now that all the holes had been blanked off it was back down to Imran's for it to be vapour blasted. This was a bit of a gamble to be fair, his machine is pretty big with a turntable so the motor can be turned through 360', the motor is 110kg (240lb) so is not easy to handle. The mild steel engine stand was designed for the vapour blaster in mind, when the first pass on the base was done the stand was turned on it's back and it could be blasted through 360' again. Pawel, my friendly Polish blaster, spent 4 hours doing this with no complaints - again FOC thanks to Imran.
The result is a motor that is keyed and ready for paint. The clutch, ignition advance timing gear cap, crankshaft and camshaft end caps and alternator covers were also blasted and will need to be re-polished and fitted with new gaskets.

All masked off and ready for primer and paint, this is the clutch side. I did remove some of the bungs and caps to see if there was any of the media behind them, luckily all had held back the pressure of the blaster. Obviously all the masking tape has to do is keep the paint out of the internals so it's a bit slap-dash.

And the alternator side, showing caps with O rings for the starter, two for the head oil feed pipe, oil filler dipstick (a pain as the thread was a bastard pitch and form so had to grind a bespoke tool to screwcut it on the lathe), oil cooler feed and also nylon caps for the gear shift and sprocket seals.

Ready for the engine paint............

[Russ]

Engine part three.........
Did a lot of research for the correct paint type for the engine. Bought enough Motip VHT paint to do it twice (and didn't use it ), sprayed aluminium sample pieces with different paint, with and without lacquer. Then put them all in the oven at 200'C and compared them with unbaked ones etc.etc. I took months to make a decision, once it's done there was no going back so had to be right.......
Looked at engines from the US and how they were done, there was also a lad from Hampshire who has done a couple of really tidy refurb's so asked him but eventually settled on an Aluminium colour from Rustoleum. A renowned engine builder replied to an email saying he used normal "rattle can" wheel paint and tests it in the oven, if it doesn't blister or discolour after a couple of cycles it should be OK to use - apparently most of the colour changes after heat are from a lacquer if you put one on, so decided I wasn't going to use it. I didn't test it for petrol / solvent resistance.
Added an adapter plate to the mounting frame so it could be rotated on an engine stand.

First the primer;

Then the top coat;

I let the paint go off for a couple of days before doing any more work on it.

The cam cover / end caps, crank covers and the clutch covers are normally polished but they take an awful lot of keeping clean and the only real way to keep them that way is to remove them and do them off the bike on a regular basis. I had a think about polishing them all up but decided this wasn't a route that I wanted to go down so sent them to be ceramic coated with Cermakrome, this was fekin expensive but it's thermally very tough, virtually bulletproof and never looses it's shine - also sent the exhaust header collars for the same treatment.

On the whole I'm pleased with the outcome. The silver is a touch on the bright side but I've seen all types of finishes on them and the colour will definitely bring a viewers eye down to the motor, which can't be a bad thing.

Things are slowly coming together now.....although I was determined not to get anything else but something came up and I went and bought it.......DOOH! This will slow me down even more, the Hodna might be finished later this year .

[damien.wrl]

That engine is a thing of beauty... would be proud to have it on a Stand in my lounge but it would be a shame not to be able to hear it

[Russ]

So, while the engine bits are away for their expensive coating......

I had already had some sub assemblies together, forks, clocks, etc. The main stand was put onto the frame, then head stock, handle bars and forks. The G clamp at the bottom of the stand is to stop it accidentally folding up and everything collapsing .

Bottom yolk was in good shape so was not polished or laquered.

Swingarm with new plain bronze bearings (originals were plastic?) and footrest brackets were put on. Front pegs with Wim's new rubbers

Rear wheel and chain, chain is endless so needs to go in with the swing arm

Headlight frame with rubber mounts and clocks go on, the horn was stripped and polished / powder coated.

The the battery box and rear tank mount with new fixings, everything is rubber mounted with spacer dowels.

Then a call from the ceramic coaters.....engine bits are ready to be collected

Quick trip up to Warrington to pick up the parts. The rough procedure is they clean and blast them, then coat in a finish and colour of your choice, bake them and then polish with a finishing media or tumble bath. As I've said the finish is very tough, but it's not as aesthetically good as polishing or chroming, The few casings and covers I sent were pushing £450. Given the choice again I would have got the stuff powder coated silver.

Cleaned all the gasket surfaces off ready for the new joints, checked the cam timing for the umpteenth time, new plugs fitted and oiled the cam bearings and lobes.

Cam cover on, the rubber gasket has a mind of it's own and is a bitch to keep in place while the cover goes on.

Clutch cover on with new actuator shaft seals, timing gear and cover back on.

Alternator cover wasn't painted as the early ones were magnesium and gasses out with the heat of the ceramic coating process.
The drive on these alternators are a spring loaded friction drive, bit like like a clutch plate. They are "troublesome" and this one was out of square to the shaft splines and had witness marks to indicate it was overheating, made a mandrel up and faced it back on the lathe.

Motor almost ready to go back into the frame, got to put the carbs, cables and some other bits on....then get two or eight others to give me a lift

[Russ]

Can put some of the sub-assemblies back on now.

Got the carbs on with the control cables already fitted. I was waiting for over a year for the engine breather hose (the short one coming out of the rear if the alternator) on "back order", in the end I kept buying various second hand ones from other bikes off eBay and this one is made from a center section of a 929 fireblade I think?

Carb to engine rubbers are luckily still available, after 40 years the originals were very brittle, air box connectors are thinner material and a bit more flexible when heated a bit and went on to the inlets OK.

After fitting the airbox we rigged up a Heath Robinson lifting arm from box section on the end of the engine hoist.

Very little clearance so we had to get it near enough and then shove it into position and let the lift off.

After a bit of heave-ho-ing it's in the frame with the bottom engine mount in, we manually lifted it up a bit then put a trolley jack under the sump to get more control of it as there are plenty of bits to get caught and things need to be attached as it goes up.

And it's finally in with the rest of the engine mounts on.

From this side you can see what I mean about the ceramic coating not being as aesthetically pleasing as polishing, I'm being a bit picky though .

The original engine had figures printed onto the rear of the motor, these were the engine assembly date - on the picture below you can see them. Obviously the ones printed at the factory were removed when the motor was vapour blasted.
Hodna used the Japanese notation method so 53.7.7 means this one was assembled on the 7th July 1978 (53 being 1978). The number below states that this was the 12th engine built that day - confusing I know, but that's the way they did it.

The engine serial number should also be within about 200 of the frame number, if this is the case it is almost certain it's the original engine and frame.

[damien.wrl]

Fortunately I was wearing sunglasses when I saw these latest pictures, quite like the ceramic finish... looks a bit more factory than mirror finish