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RENOVATION PROJECT OF 1972 YAMAHA YR5
BY STEPHAN MORRIS

Parts 20-23

The R5 is a complete redesign from the previous R3 model, with very few common parts, and the last model before reed valves and disc brakes were introduced on the RD350A model in 1973. Many R5 design features went through all subsequent air cooled models until the LC in 1980 such as the frame and swing arm design, oil tank as side panel, crankshaft and crankcase design. Even the LC models still used the same base gaskets as the R5 demonstrating similar crankcase design, and it was not until the powervalve (YPVS) models came out in 1983 that 5 cylinder studs were used instead of 4.

The rebuild has been shown here in chronological order, it is possible to jump to any installment by clicking on the links below:

November 2008 - Part 20
Well Dave’s gone home so I am on my own now. It was nice to have him around because he understood what I was trying to achieve and helped a lot. There are some things that are 10 times as difficult on your own as they would be if there someone to hold the other end or help with lifting something. Two heads are always better than one as well, and Dave supplied the brainpower to raise our average IQ to something above moronic. We still clocked up all sorts of mistakes at which you have no doubt already chortled. What lies ahead for a simpleton like me? Read on…

Here is the clutch cover gasket sitting on the two dowels top left and bottom right. Paul told me that if I wanted to reuse such gaskets I must first smear them with oil so that at some point in the future they will come away from the gasket surface again easily. Unlike much of what Paul says that seemed to make sense so I did it.

The left side has no gasket because there is no oil sloshing around. The rotor is on the end of the crankshaft, and the bolt that holds the points cam threads into the end of the crankshaft.

Back on the right side the clutch cover is installed, and the oil pump is connected up to the oil feed pipe (larger diameter) from the oil tank that doubles as the left side cover, and the two oil distribution pipes (smaller diameter) that go to the base of each cylinder. The blue cable ties hold the hoses away from the possibility of any abrasive action from the oil pump cable you can see entering the case above the oil pump. (I can’t work out how this can be achieved without cable ties…) Autolube had been introduced by Yamaha about 5 years earlier then my R5 was made I think. Other manufacturers copied this very effective lubrication system. The problem before autolube was that the oil was simply added to the petrol and therefore the more petrol was used the more oil entered the engine, conversely the less petrol that was used, the less oil entered the engine. This meant that on small throttle openings but high engine speeds (such as when rolling off the throttle at high speed) lubrication became marginal and high engine wear or even seizures could occur. Autolube solved this problem by having the pump rpm controlled by engine speed, and pump stroke controlled by the throttle cable. The result was the correct amount of lubrication for all engine operating conditions. It is a bit fiddly to set the pump stroke with shims that go under the nut you can see on the top right of the oil pump, but ultimately worth it.

Here are the little banjo bolts to which the oil distribution pipes connect to deliver oil to the intake tracts at the base of each cylinder. Yamaha used to supply paper gaskets for sealing these bolts, but the copper washers they have now substituted are much sexier don’t you think?

Here is a shot of the top of the clutch cover showing the pipes mentioned above and the right hand cylinder with the banjo bolt connected. The oil pump cable with its adjuster enters the case just in front of the pipes. I have used a washer beneath the bottom adjuster nut to avoid damaging the powder coating on the clutch cover.

I was not looking forward to this bit. I am a bit dim when it comes to electrics – all I can do is connect things up how they were before I took them apart and hope for the best. In the case of the ignition system, those of you with me from the beginning will remember that the bike had a Piranha electronic ignition system that never did work very well because it was designed for an RD350, not an R5, and the installation was a bit of a bodge. So what did I have to copy? Look at all those little electrical bitties! Condensors, alternator brushes, stator wires, earth leads, contact breaker points, neutral switch wire. I had new condensors and points, but they were pattern items anyway…

 

I daren’t tell you how much time there was between this photo and the last. I think that most thingies are bolted on somehow and the wires are tucked out of the way of the whatchamacallits that go round and round and the thingamajigs that go up and down. I hope that the colours are right…

Yamaha specify one boot for the electrical connectors on top of the crankcase. I have doubled that to two for better protection from the rain, and it looks neater as well. Actually I am horrified to think that I would ever ride this bike in the wet, so the electrics could all be totally naked for any difference it would make, still it is nice to improve things where possible.

This is how Yamaha make one upper throttle cable actuate two carburetor cables and the oil pump cable.

Carburetors on now (the first of many times I can tell you!) and I was pleased with how pretty this area behind the cylinders was looking. The tacho cable joins the other three cables to run underneath the petrol tank.

Yamaha R5 engine

A wider view of the engine in the frame

Time to make some little hose brackets for the four clear plastic carburetor overflow pipes that route under the carbs to the gap between the rear of the crankcase and the front of the swingarm. This is a piece of 1mm thick stainless steel cut to more or less the right shape.

Filed off the edges…

Drilled a 6mm hole and bent to shape.

Here they are in position. One holds the gearbox breather pipe to breathe on the chain for what good it will do, and the other holds the four overflow pipes mentioned above.

Right then I will just fit the chain. Christ I can’t get this split link in! I checked the diameter of the spindle and it was about 5 thou bigger than it should be. Why on earth aren’t these sizes standardised?

No choice but to make it smaller in a particularly tedious way…

That should do…

In it goes.

These are the two nuts that go on the swingarm shaft, but there is no thread left! Why is it so short? In fact of course the thick powder coating and my desire to use washers both ends of the shaft to protect that thick coating have combined to create the need for a longer shaft. More work for Phil Denton.

Here is the sidestand damper rubber not quite meeting the muffler…

I can soon make a delicate adjustment with an old fork tube and some cloth to protect the finish…

To give the correct result!

Yamaha R5 header pipes

Headers look so pretty I put the photograph here for no better reason.

Just fit these rear footrests…

Oh dear! I did not notice when I sent them for powder coating that one was vertical and the other was not! A quick check in the parts books reveals that vertical is correct for the R5 and the angled rear footrests are for the later RD250 and 350 models. More work for Triple S this time.

All those cables and wires have to be routed and connected correctly. All will be revealed in the next exciting instalment of how not to rebuild an R5!

November 2008 - Part 21
Well dear reader it is 2 years since I started this project and it is still not finished. How do they do those restorations that you read about in the magazines that take 3 months? They must be far more organised than I am, probably have more time and money as well, and their lawns are greener than mine...
If I can get this on the road for next summer - or at least the period in the middle of the year when the rain is warmer - that will do for me.

Here is the kickstart assembly looking clean and shiny. I was pleased to find 10mm stainless steel E clips on eBay and I have used one to attach the kickstart lever to the kickstart boss.

The side panel chrome flash is greased prior to assembly. It is attached to the side panel by a tongue and groove type system where the tongue is on the side panel and the groove is on the flash. A 6mm screw then holds it in place. Locating these two parts together and then sliding into position is a recipe for scratching the side panel paint on the raised ridge around the recess for the flash. I protected the paint with some insulating tape during assembly.

Yamaha R5 side panel

...no scratches.

Here are the headlight brackets swaddled to prevent scratches, and the various cables and wires that go behind the headlight shell.

These are all the wires on top of the rear fender behind the battery box…

Joined together here

In fact there was a lot of pratting about connecting and reconnecting bullet connectors and block connectors, and sure enough the wires pulled out of this block connector, and inside it was damaged so that the wires would not stay in place.

So I had to replace it. I had only recently realised that block connectors can be easily replaced as pairs, and that you do not have to replace a broken block connector with an original item.

Here are the double connectors found in the headlight, covered with the plastic insulator that has gone green and hard with age. It was very difficult to insert the bullet connectors because of this hardening.

I looked in my Vehicle Wiring Products catalogue for new ones, but there were none there. When I rang they said that if it was not in the catalogue they did not sell it. Very helpful. Thrown back upon my own resources I decided that I could just cut some suitable plastic hose to the right length, so I did.

Here are the new single bullet insulators that Vehicle Wiring Products can supply.

After a lot of grief with the wires behind the battery box I finally managed to get them into some kind of neat arrangement shown here.

…and here.

Here are all the grey wires and cables underneath the clocks behind the headlight shell not yet installed.

Yamaha R5 headlight wiring

…and the headlight shell now installed with the wires pushed to the perimeter ready to accept the headlight with the bulb socket sticking out of the back into the centre of the headlight shell.

Amazing that the rat’s nest above is concealed behind the headlight reflector.

Well having connected all the electrics I tried to kickstart the engine! It picked up on one cylinder only. I checked the spark and it was not firing on the left cylinder. A bit of investigation revealed the condenser wire was earthing out on the stator body as shown here.

A tweak with the 5.5mm spanner solved that problem and the engine ran on two cylinders.

Timing Yamaha R5

This is me trying to adjust the ignition timing with an old dial gauge screwed into the spark plug hole in the cylinder head, and an analogue multimeter with the needle swinging wildly.

Once the ignition timing was sorted it would run OK on part throttle, but would not idle. Carburetors off again and this muck was removed from both pilot jets which improved matters a little!

The carburetors were also leaking a lot of petrol so I replaced the float valves and checked the float height and that was another problem solved. The float valve is the brass hexagon closest to the camera in this shot. The other smaller brass hexagon is the main jet.

There are still some minor things to bolt on such as footrests and rear brake assembly and seat assembly, but apart from those, I am moving into the troubleshooting stage. I suspect that there is still a lot to do and report!

February 2009 - Part 22

Well I have been away in Egypt and South Africa for a month and got back for the first weekend in February 2009. Unfortunately during the time I was away no-one had gone into my garage and finished this restoration. Looks like I will have to do it! I will list here a few tasks that remain to be done:

1. Fit front footrests
2. Fix both leaking front forks
3. Fix choke mechanism
4. Fit seat
5. Fix the charging system
6. Install and set up rear brake actuation system.

Today’s pictures deal with tasks 1, 2 and 3. In fact 1 and 2 were completed over Christmas and 3 was done this weekend.

Here is the swing arm pivot shaft made by Phil Denton which has the shaft and the thread a little longer than standard to account for the thicker paint on the frame and footrest brackets. Not only does the swingarm pivot on this shaft, but it holds the footrest brackets on as well, so this had to be fitted before the footrest could be fitted. The replacement of an existing shaft with a new one can most easily be accomplished by finding a third shaft to push out the one in place, and then in turn pushing it back through with the new shaft, so that’s what I did and it worked!

I had noticed that at the very end of its travel, the kickstart lever would hit the right hand footrest bracket. This would do no good to the lever nor the bracket, so I decided to do something about it. I considered many options including things made of rubber, and things made of plastic, but I settled on this bit of brass that started life in the form of an earth lead connector as you see here.

I bent it and cut it into the shape that you see here so that the kickstart lever hits a piece of soft brass instead of a stainless steel 8mm nut. I will assess this design over time…

So here is the front footrest bracket fitted to the bike ready to receive a front footrest. You can see the two indentations left in the metal by the footrest in a previous life, now powder coated to a very high standard. Clearly I could not just refit the footrest and allow this lovely finish to be damaged in the same way…

…so I made a stainless steel fitment to protect that surface and the pivot surfaces from the movement of the footrest. It only took about 5 hours…

Here is the complete assembly. I only had to grind a little off the footrest pivot boss to get it to fit. Why didn’t Yamaha make it this way? I wonder if it is possible to patent something as unnecessary as this?

Similar situation with the rear footrests where the footrest bar uses the powder coated bracket as a pivot stop.

Solved in a similar way. This is the new powder coated left footrest bracket with the vertical footrest fitment.

Footrest now in place.

Both fork legs were leaking fork oil slowly from the bottom. I took them both off, retorqued the damper rod retaining bolts and replaced the copper washers. I had to make a special tool to prevent the damper rod from rotating and allow sufficient torque to prevent the oil leak. I put the forks back together and re-installed them on the bike. I thought that I had fixed it at first, but no, they were still leaking!

Off with the forks again. I looked at the surface on the bottom of the sliders where the copper washer seats. Both sides looked a little rough as you can see here at the bottom of the hole. It was not easy, but I managed to get a smoother surface using a grinding attachment on the Dremel.

This is the damper rod assembly that fits inside the fork tube the 10mm x 1mm pitch socket cap bolt that holds it in place and the 10mm copper washer that seats on the surface in the photo above. I reassembled both fork tubes and replaced them on the bike. Still they leaked… How could that be possible? Then I discovered the reason which meant that all of the above work had been unnecessary. I felt a little dribble of oil above the front wheel axle bolt. How could that happen if the oil was leaking past the copper washer at the bottom of the fork? My stupidity soon dawned upon me. The oil was leaking past the Philips head fork drain screws shown two photos above because the little gaskets had perished. From then it was a 2 minute job to replace them on both sides…

The next task was to get the choke working. Back in the summer the relatively warm summer had allowed me to start the bike and keep it running after 25 – 30 kicks, and when warm it idled very well. Trying to start it in winter ambient temperatures was impossible, however in trying I noticed that it would fire on the right hand cylinder for a second or two, but never the left. This obviously narrowed the problem down to the left hand carburetor. For what seemed like the fifteenth time I removed the left hand carburetor and stripped it down again to see if I could find any problem. The choke plunger when closed blocks a small fuel jet that bypasses the main venturi of the carburetor and feeds fuel into a small bypass air passage. All the drillings and pipes that constituted the system seemed clear. It wasn’t until I began to reassemble the carburetor – far from convinced that I had solved the problem – that I realised that the fuel actually passes through the hole you can see here at 4 o’clock in relation to the thread for the float bowl drain plug. It then passes up the larger diameter tube that finishes flush with the float bowl gasket sealing surface.

This is an external view of the float bowl showing the casting that contains the small angled hole that connects with the larger diameter hole seen in the photo above.

The vertical brass tube coming through the float bowl gasket fits into the larger diameter hole and draws fuel from the float bowl to the bypass air passage. Of course what had happened was that the sharp angle between the two holes had clogged with dirt so that no fuel was getting through.

Yamaha R5 carburetor

It was soon unblocked and the choke system now allows easy starting whatever the temperature!

May 2009 - Part 23
Well the rain is warmer here in the UK so summer must be almost with us. I think that I will just go for a ride on my newly restored R5. In my dreams! I go into the garage and there she is still in bits on the workbench where she has stood neglected for several months. Sorry that the completion of this project is dragging on dear reader, but now I will tell all…

You will recall that in instalment 22 I listed 6 tasks that remained to be completed, and that numbers 1, 2 and 3 were finished as described. This instalment deals with tasks 4, 5 and 6 after a bit of fun with some plastic. 4. Fit seat 5. Fix the charging system 6. Install and set up rear brake actuation system After these are done, I will test ride the bike and troubleshoot anything that is not right. If everything goes according to plan, this will be the penultimate instalment. (That means “the one before last” Paul), but when has anything in this sorry saga of errors ever gone to plan?

In an attempt to forestall the erosion and scuffs of paintwork by the cable routing designed to ensure such occurrences, I have protected various items with a thick adhesive plastic film that you can see here on the headlight shell, preventing contact with the speedo cable.

This is the rear of the petrol tank which gets scuffed by the seat. You can see the plastic film, and some clear hose which I have cut lengthwise so that it fits over the ridge that you can see underneath it here. I hope that the seat will hold it in place when fitted.

 

Same arrangement on the side of the steering head. I hope that the plastic stays in place, but I am not entirely confident that it will…

Well dear reader I hope that you can recollect the very first instalment where there was a picture of this exact bike with a new seat in a plastic bag perched on top of the frame? Here is that seat 30 months later still apparently perched on the frame rails waiting to be fitted. In fact it is fitted as well as it can be, and obviously is completely wrong because the line of the top of the seat is too high. It is the original R5 seat pan which had plates welded to it for strengthening because of the extent of the corrosion, and then new foam and seat cover. I think that the welding distorted the seat base so that it simply does not fit as it should. New seats are of course unavailable. I have ordered a pattern one from the US which has a fibreglass seat base, so that at least it will not corrode! I will go to Dave’s daughter’s wedding in Indianapolis next month, and I will bring it back to sunny Lincolnshire . I am praying that it fits!

The Egyptians made a stainless steel rear brake actuation rod for me. Cosmetically it was a complete mess, so last year I cleaned it up so that it looked OK. Annoyingly, when I fitted it, I could not get the 6mm adjuster nut to thread onto the rod sufficiently, no matter what I did. I ran a die up the rod and a tap through the nut. I cleaned the thread to ensure that there was no debris. Nothing doing.

Then I decided to measure the thread. You can see in the photo above that the first part of the thread is OK, but here the idiots managed to get the pitch completely wrong…

…and then further up the thread it was OK again. What an achievement! Prats. (Are but who was the one that paid for it Stephan? -Paul)

I ordered another one from Phil Denton which of course was perfect in every respect and here you can see it fitted just below the swing arm and in front of the rear footrest.

I had been dreading trying to fix the charging system due to my ignorance of anything electrical as you know. Additionally, I knew that all of the electrical items in the middle of the bike would have to be removed for checking. You can see above that it looked like open heart surgery. I had done the things even an electrical moron like me knew should be done such as checking connections for breakages and correct colours of wires and making sure that the brushes looked OK. When those tasks yielded no result I knew that I had to enlist the help of an expert, but the nearest I could find was Martyn Whittington . No, actually, not only is he an expert on bike electrics and an old and loyal friend, but he has a gift for connecting with people equalled only by my wife. My plan was to call him and ask him to explain to me how to do the various technical fault finding checks over the phone. Not that easy, because he can’t see anything! I also knew that I needed to replace my old analogue multi meter bought from Tandy 30 years ago. I got one off eBay with so many functions that it could probably track ICBM’s and land Apollo 17 on the moon. However when Martyn wanted it to beep that proved too difficult! So began a series of long calls to Martyn with the phone on loudspeaker while he guided me through the various tests and attempted to explain the principles behind what he was saying. “Do you now understand how we are going to do this?” he would ask. “Yes of course” I would say “you tell me what to do, and I will do it!”

So at the end of all this checking and rechecking amidst all the banter, the fault lay with the wiring to the brushes. This is a before photo…

…and this is an after photo. Not much difference you say? Well you are right. It is not an excuse for my stupidity however. The green and black wires going to the left hand socket head screw for the brush holder assembly are supposed to be in contact with each other, but not the stator body, nor the brush holder assembly. Yamaha had supplied special fibre washers to achieve this, but of course yours truly just used them as spacers without discerning their true function. The devil is in the detail as we saw with fixing the choke mechanism as well.

Look at all those wires! Martyn had all this in his head when he was speaking to me! No room for anything else obviously.

There is the phone that connected me to Martyn’s hovel in darkest Devon , and a pack of 120 fuses just in case! Why is the battery in a plastic tray you ask? Well because I had to remove the battery holder to access the regulator and rectifier for checks, I placed the battery on the top frame rails so that I could keep it connected to the wiring loom. Kickstarting the bike would never cause it to fall off, spill acid, strip chrome off the exhaust pipe and crack the battery case would it? Well, yes actually, it would. One step forward two steps backwards. How many more episodes can you stand? You don’t have to log on…

 

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