King of the IT crowd

Put two off- roaders together and the first question from either is generally ‘what’ve you got on the go at the moment?’ This is often followed by ‘you’re doing a WHAT!?’ Occasionally it is ‘oh, one of those…’ but more often it’s ‘you must be mad’. You ch

With lots of bits away it was time to strip the engine and see what the damage was inside… a mix of worn-out and pristine.

The engine has sort of been ignored in this project for a while as there have been other things to deal with. With the frame now straight and cracks welded thanks to Barry at Rod Spry’s, I found an aerosol can of black paint tucked at the back of a shelf and in one afternoon I gave the frame a light coating of gloss black over the top of the red colour. Yes, you’re shuddering now and saying ‘what on earth has he done that for?’... or words to that effect. It gets worse too, as I did it outside... thus compounding every known crime against painting known to restorers. In my defence the frame will be properly refinished once we’ve used the bike in an enduro or two and made certain it is mechanically sound.

With the bench swept off, engine in a support cradle made from some bits of wood and plywood, drip tray on hand, tools at the ready and various containers in which to store bits and pieces all close by, the strip could begin.

Earlier attempts at draining oil from the unit had failed as at some time in the past the drain plug had been mangled by someone using an inappropriate tool – only a guess but probably an adjustable... and not a very good adjustable either. Then the job had been further compounded by use of a hammer and chisel, during which attention the drain plug had been fixed to the case and would now need drilling out. Luckily, taking off the clutch case meant the engine oil could drain out of the side… or at least if it had been a liquid instead of sludge. In anticipation of oil going everywhere I’d laid out newspapers, had plenty of cloths handy and a drip tray in place.

The clutch case itself was okay. It had been repaired with epoxy metal at some time but a friend, Martin Bratby, mentioned he was sure he had some IT bits from years ago tucked away and felt certain a new clutch

case was among them. He also thought he had an alloy fuel tank which Yamaha had to have made in order to sell road legal IT465S here in the UK.

To digress slightly, the UK banned the sale and use of non metal fuel tanks for road-going motorcycles in the middle of 1973. This had followed incidents in which poor quality glass fibre tanks split and motorcycles caught fire. In the main these tanks had been hurriedly produced to appeal to the café racer market and knocked out cheap. This tarred all makers with the same brush and even those conscientious manufacturers who made good quality components were banned. The ban extended to such plastics as polypropylene, and bikes imported to the UK had to have alloy tanks made in the UK by their importers. Naturally these tanks were an added cost to the unit price and were made as basic as possible while still looking like the factory part… from a distance… if you squinted…

Martin added: “The kick-start pinions will have the teeth worn off them. I don’t know what Yamaha made them from but it was good, I’ve got a useable pair of them too.” Sure enough, as predicted, the pinions were damaged and one of the reasons the engine wouldn’t turn over on the kick-start. Stripping out the clutch plates was easy enough and helped no end by the arrival of a Clymer manual for the IT range, then a genuine Yamaha manual – both of which made for light reading one evening. I’m a great believer in reading the manual

first, having learnt through painful experience how easy it is to break things. Once the plates were off and the tab washer bent back a suitable sized socket fitted on the clutch centre nut and the nut came off with little more effort than light hand pressure! Hmmm. The crank pinion was a little tighter, but not by much. The flip side of that is few, if any, of the Phillips head fasteners inside the case showed evidence of having been touched since the bike was assembled at the factory.

It’s always best to take loads of pictures – dead easy with digital technology – or make notes and sketches of the way things look before they’re apart, as memory will fail you at assembly time. Oh, and take your time – unless you’ve stripped and rebuilt such engines loads of times, in which case you’ll not be needing the info here…

The ignition side of the engine is featured in our tech section a few pages further on, so once the puller had arrived it came apart quite easily and went into a box to go to Westcountry Windings. There’s more details further on about the services those guys offer and what needed to be done.

Taking the head and barrel off a two-stroke engine is not exactly complicated – obviously no valves, cams, pushrods or whatever to cope with – just half a dozen nuts and washers to remove then lift the head off. A peek inside the barrel showed there was a piston in there – unlike a similar scene when I lifted the head off a Triumph 350 unit engine and found no pistons at all!

With the head off, the next task was to undo the four barrel nuts and lift the barrel off, carefully catching the piston before it clunked against the crankcase mouth.

All that can be done with the barrel and head is blast cleaning and painting them black after the bore has been checked and the piston measured. If all is well the bore will be deglazed, new rings fitted to the piston and it’ll be ready for assembly. If not then a rebore will be needed.

Once the head and barrel are off, the crank case screws can be removed and the second

of my homemade pullers can come into play to part the cases. On the IT – and possibly other Yamaha and non-yamaha engines – there are tapped holes at strategic points to allow for a puller to be screwed in and the cases to be pulled off the crank shaft. It’s a much gentler dismantling process than belting it with a soft faced hammer.

Once inside the cases, the gear box can be removed for later cleaning and inspection, though all looks well at first glance. The crank itself will go to someone with more experience than me to inspect and replace the big end or whole con rod if necessary. This may be needed, as even to my limited knowledge there’s a lot of play in the bearings. Speaking of bearings, were these cases to be used again the various bearings would have to be dropped out, but we have a spare set of cases already stripped and undamaged to which new bearings will be fitted. The old cases will eventually be stripped and taken to someone who can repair them, but it isn’t urgent at the moment.

Plated parts

I’ve a confession here, and it’s that I’m not that much of an originality fetishist. When it comes to fitting fasteners and studs to bikes then there are things such as stainless steel parts and anodised alloy and titanium to make things better. However, this rebuild is to be as close to catalogue as possible, so that means refinishing fasteners.

There is a huge choice of surface coatings available, from chrome plating to zinc passivating, and it is nice to be able to follow what was on originally. This is helped by there being traces of the original surface coat on many of the parts. It also helps that we have a colour brochure of the IT465 and it is possible to see certain parts are bright, other parts are dull and still others are passivated. There are a fair number of metal parts needing plating on this bike... but for now all we’re having done are the engine bits.

Most of the fasteners were removed from the engine during the strip down, but things such as the barrel and head studs needed to be removed later. I’m sure you know the time-honoured method for removing studs is to take two nuts, screw them on to the stud then tighten them against each other and unscrew the stud by fitting a spanner on the bottom nut. If the stud is sticking then some heat from a heat gun will help in the extraction… usually. The six head studs came out reasonably easily, the barrel studs defeated me… even with a blow torch to heat the case. In the end a stud extractor and a long breaking bar was needed, plus a lot more heat and two people… one to hold the case down, the other to work the bar… thanks Mick!

Once out though, everything could be cleaned up, the threads revived and finish confirmed. It may be possible to find NOS – New Old Stock – fasteners, and that will be an option, but at the moment we’ve gone with plating the old ones and have dressed the hexagons, wire brushed the crud off, degreased them all, rinsed them and bagged them according to the finish required.

Then off they went in the post to Chrome Restoration Specialists in Kent. Which is as good a finishing point for this chapter of the King of the IT Crowd.

All that remains for now is to clean the workshop up a bit for the rebuild when fasteners, bearings and gaskets arrive.

It is time to start work on the engine and see what’s inside, hopefully no horrors await us.

Well, we’re getting there, taking things slowly as it’s so easy to damage things during the strip down and you just know that what is damaged will be rarer than a rare thing with extra rare added. Removing the clutch case let the oil drain out… into a tin foil tray acquired from a supermarket and originally containing a rather nice lasagne. First task was to remove the ignition system. This needed a puller, which wasn’t in the editorial workshop… Before ripping the stator from the case it’s a good idea to check see if there are timing marks to line up things when refitting. This is the reason why the engine wouldn’t turn over on the kick- starter, this is apparently common on IT465S. Kick- starter cog is equally worn. Always an interesting moment, I once lifted a head off a Triumph engine to find the pistons missing… It wasn’t possible to remove the drain plug from the cases. We tried… hard… but thanks to a previous ‘mechanic’s’ attention it was f… f… fixed in good and proper!

At first glance things don’t look too bad in here, there will of course be a closer inspection later. Though the cases will be repaired at some point, which makes for a nice feature, we managed to find some good used ones thanks to a contact made on the Yamaha IT forum. Splitting the crank cases needed a puller, simply made from some thick steel and three bolts, it looks better than laying into the end of the crank with a soft faced hammer.

A simple way to hold a stud or bolt while the threads are being cleaned up, a bit of wood, a hole the correct size, a saw cut and it is finished. There was all sorts of crud in the carb, we sent it to CC Clean Carbs in Guildford to be soda blasted and sonic cleaned. This selection of fasteners, studs and the like is ready to be parcelled up and sent off to Chrome Restoration Specialists in Kent, who can apply various zinc based finishes. There are a number of parts which need pullers to extract them during a strip down. The three bolt one was made in a few moments, the flywheel puller came from Motoduro. Currently the talk of the Yamaha IT forum, the ‘rattle can’ finish is only temporary and once the bike works it will be stripped and refinished properly.