One of the advantages of
belonging to a local vintage bike club is the little pointers and tips
people casually toss your way - its wonderful, and hugely appreciated !
One of the things our local CVMG club offers is a cut rate deal on
powder coating two or three times per year and so with one of these
coming up I had to decide what I wanted to get done. I have two bikes
on the go currently this one, and also a 1973 GT750, and while it
probably isn't too smart to have both of them in pieces at the same
time that is what I've decided to do.After washing all the parts I took everything over to the good folks at Consolidated Compressor here in Calgary to sand blast all the bits and pieces. I wrote about them previously here , and this time I also used their indoor glass bead blasting cabinet for the smaller items and the outside sand blasting stations for the two frames. I have to admit, for someone like myself who doesn't have to do this sort of thing for a living, there is a certain fascination about watching the old paint, rust and anything else that happens to get in the way and isn't firmly attached get blasted into oblivion !
I was careful to wear disposable mechanics gloves, as I did not want to touch any of the bare, clean metal with my hands as doing so could potentially cause the powder to not adhere. Once I had the parts back home, I blew out the grit from everywhere I could find, and also washed the freshly sandblasted parts down with brake wash, just to be absolutely certain there were no traces of oil which would ruin the powder coat application.
The next step then is to strip the donor GT750 bike down, salvage what I can and also go through the Rubbermaid tubs that came with the Kincardine GT750 bike to see what should be kept from it. I also have to tag and store all the bits from the GT750 as well - the photo shows the two frames, as well as the other frame components which are all to be powder coated. |
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The wire harnesses of both the 1973 GT750 and the 1977 GT500 were in very poor shape - many wires had been cut, poorly spliced, the correct connectors were missing, the protective jacket had been removed or it had just weathered away with age. Replacement wire harnesses are available in some cases from Suzuki, and also from some speciality suppliers such as KnK Cycle but items like handlebar switch gear are generally only available via eBay, and of course these will be the same age and often in the same state of repair as the ones you already have. I plan to rebuild the switchgear and repaint it as shown here, but the harness posed a few problems - chief among which was where to source the components. Luckily, I was directed to an outfit in the USA that supplies most of what I needed !
Vintage Connections sells the OEM style fittings, both the 2.8mm latching and non-latching box connectors used in the headlamp shells for the harness interconnects to the instrument pods, and handlebar switchgear, as well as the larger 6.3mm box connectors (latching and also non-latching) used for connections to the regulator panel and ignition coils under the tank. They also sell the black vinyl tubing in sizes suitable for you to replace the protective sheathing leading from the switchgear to the headlamp shell, and from the headlamp shell around the headstock to under the tank, and the leads from the ignition to the electrical connections panel and under tank connections. I like their crimper, although for smaller wire sizes (22 ga. for example) I use a second crimper or sometimes actually solder the joint, just to ensure things won't come apart at an inconvenient time !
While Vintage Connections was able to
supply most of the sleeving I needed, I ran into a snag trying to
replace the sleeving on the magneto, as they didn’t have the 10mm OD
size I needed for the magneto lead. I finally tracked down what I was
looking for at a place specialising in H-D wiring repairs and custom
harnesses called 4RCustoms.
Although what they had was in imperial measure, the 3/8 size was close
enough to to the job – the critical issue being that the lead passed
through a grommet and so it needed to be a tight fit to prevent water
leaking past it.
| After doing a 'hot' test just to ensure the lights, turn
indicators, brake switches and horn were all working correctly - I
rebuilt the handlebar switch gear. One of the things I find annoying is
that starting in 1977 in Canada, the headlamps were required to be
permanently turned on, which is fine once the engine is running. If the
engine hasn't started though, or if you are having trouble getting it
started, then the battery gets pulled down quite quickly so I wanted to
over ride the 'always on' feature and make it a more sensible switched
head lamp. On these bikes that's an easy fix as all you need to do is change out the on/off lever - the 1977 version (57712-33011) has a tab on the underside that prevents the slide switch from moving as you can possibly see in the photo. The current part number available (57712-33012) doesn't have this 'feature' so its an easy and inexpensive swap. With the switch gear refurbished with new paint, sleeving and switches it looked ready to go ! |   |
One thing about the GT500 variant is of course that there are a few items that are quite specific to those years and that model which are no longer available from Suzuki, and are in fact very difficult to locate anywhere which is a problem if you are trying to do a 'factory' restoration - the front fork dust boots for example. These were only used on three models of Suzuki - the 1974 GT550, and the 1976 and 1977 GT500's. As a result, they have not been available for quite a while and although many parts for other models show up regularly on FleaBay I have yet to see these. Luckily, via the Sundial Moto board (a must if you happen to work on older Suzuki's) I was able to locate a fellow in France who is making good quality reproductions of the original pattern, so I ordered two sets which arrived this past week.
As you can see in the photo to the right, they look very nice indeed ! The original is on the left, and the copy is on the right - the new ones measure exactly the same as the old ones and will look very smart when I finally get them installed !
If you happen to need a set of these for your rebuild, send me an email and I'll pass along the fellow's name and contact information on request.
In addition to model specific items as with the fork boots above, parts being re-issued by the manufacturers replacements quite often do not match the original - an example would be the oil pump rod boot on the GT750 which originally had a pleated sleeve (16765-31200) and which now is only available as a plain seal (16765-31201). Another problem you run into, is that in many cases, the part you need was never offered as a separate component to begin with together with its own part number, so locating a NOS part to copy is not even an option. The rubber hoods that cover the water temperature sensors for the cooling fan and water temperature gauge that came with the wire harness for the GT750 for instance. While it quite easy now to restore the harness as the components for the wiring are readily available from several sources including Vintage Connections, the rubber hoods are unique, do not have a part number and were never available as a separate item. This means to get a good one requires you to scavenge salvageable hoods from other old harnesses.
With all of this in mind I have started to try to help the process along by collecting a few specific good NOS or used parts and have begun to arrange to have them copied and made available for sale - but not by me. While this may change in the future, currently I'm just interested in increasing the supplier list for folks who, like me, just want to keep these old girls running and looking original so other than satisfaction, I'm not making a penny on these.
For my 1977 GT500 rebuild, one item I'd been trying to track down for some time was an original style battery protector (33651-15000). While it would have been easy to piece something together that would do the same job, it would not have looked the same. This specific part has not been available from Suzuki for many years, and the NOS stock seems to have disappeared long ago also. The part was used on the T/GT500 series of twin cylinder oil burners between 1968 and 1977, and the Cobra and Titan models were, and still are, quite popular both as collectable bikes as well as for use on the vintage racing circuit.
After much searching, I was finally able to locate a used item in very good condition which could serve as a pattern, and then I hooked up with Gregg Clauss the owner of Clauss Studios in California. Gregg has been providing reasonably priced, small volume 'unobtainium' reproduction plastic and rubber parts for Lambretta, Vespa, Honda and Kawasaki plus many other makes for several years now, and is well-known on the US west coast in the vintage motorcycle world. As of last week, Gregg can now add Suzuki to his list of parts offerings !
In the photo to the right, you can see the original battery protector on the bottom, and Greg's copy is above it - I'm really pleased with how well it turned out. These replica battery protectors are now available directly from Clauss Studios so just drop him an email to get pricing and delivery info.
If you own a Suzuki Cobra, Titan or GT500 and care about its originality, I suspect you probably really need one !
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| I have recovered the seat using a kit from Pit Replica in
Thailand. As I think I've mentioned previously, I sent them my original
GT500 cover as a sample and they now offer GT500 seat covers specifically to fit the
1976/1977 model years as they are different from either the T500 covers
(too narrow and wrong length) , or the GT380/GT550 covers (same seat
pan, but the GT500 doesn't have the cut-out for a seat lock as the seat
is just bolted to the frame). The cost is reasonable and the quality
is acceptable. I was undecided as to whether I was going to use the correct stand-off's for the rear turn signals as I think they stick out too far. I can see me regularly catching the left rear signal with my leg every time I try to get on and off the thing, but we will see how it goes. The one thing I was missing though were the bushes to mount the rear seat bolts and through which the rear turn signal mounts are hung.. After several months of checking several sources, I had still had no luck finding these bushes, and so bit the bullet to have a dozen made from stainless. As each bike uses four of these, I now have two sets of spares left over which will be useful on the next project I have in mind. Roy Hansen at Cactus Machine came through for me again - he was the fellow who made the brake bell crank for my custom '1978' model GT750 . |
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| At first glance, the set I managed to pick up looked quite good, but upon closer inspection there were a few problems. The turn signal indicator lamp on this style of housing is slightly recessed and so water pools there – over time the sealant around the amber lens breaks down and then water fills up the lamp housing, corroding the bulb unit into a solid mass of rust ! As well and as was the case with the other areas of the wiring harness, the sleeving had perished and cracked and needed to be replaced. The clocks when fully disassembled can be seen here with the major parts numbered:
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| As I have done with other rebuilds, I wanted a matched ignition and
steering lock key set, so I re keyed the steering lock to match the new
ignition key. It is an easy change to make and I describe how to do it here.
You could of course change the ignition switch to match a steering lock if the steering lock key was the only key you had, as the ignition switches are actually much easier to take apart. In the photo to the immediate right, you can see the tool I made from a small Allen wrench, ground down to fit the release hole at the base of the lock cylinder barrel. What you are doing is pushing a small release tab which you can see in the photo to the far right. When this tab is pushed in, the lock tumbler will drop out of the cylinder - or at least it should if it isn't corroded or gummed up with old grease etc. ! Once you have it out, then you can just re key the lock by swapping the spring loaded tabs around - it helps to have a selection of these as they are obviously of different shapes to fit the various shoulders and valleys in the key you are trying to match up. Obviously, this is also a useful thing to know how to do if you are dealing with broken keys, or just locks that are not working correctly - having the lock cylinder out of the barrel makes it much easier to clean, but be very careful to not lose the very small springs !!! |
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| Another item I was
missing was a VIN label for the front headstock. Reproductions of these
are readily available for the GT750 and other models, but not for the
GT500. A fellow member of the Sundial board had previously run into the
same problem and had sorted out a solution with a fellow in Michigan. Jerry (his email address is jrure@aol.com) offers a very handy service as he will duplicate exactly what you need, at what I think was a very reasonable price. The labels are the same sort of aluminium foil material as the originals, and you have the option of having the VIN number and build date printed on the label, or left blank so you can stamp it on yourself. They also have a clear vinyl covering that you could leave on, or remove for a more original look. Recommended. | . |
| The other issue I'm playing with
is what to do about the front brake.
Suzuki used two different suppliers of front disc brake components for
this model (and for other models too of course) being ASCO and Tokico,
but no longer supply all the bits you need to repair the ASCO
callipers. For the master cylinder, which is also ASCO, kits are
available. The only difference from what was originally installed and
the replacement parts appears to be the shaft that the brake lever
pushes on is a larger diameter on the new kit, but everything else
seems to be the same. For the calliper however, there is no longer a full ASCO repair kit available as the calliper piston is not offered, although you still can buy the seals individually. After doing a bit of checking, I've decided to use a calliper piston from the Tokico supplied calliper kit as the bore is identical to the ASCO cylinder housing. The only differences I can see are that the the Tokico piston as used on the GT550 is perhaps 0.4 mm longer in overall length, and the groove for the dust seal is slightly different. I'm hoping that the difference in length will not mean that I'll have trouble remounting the calliper housing on the rotor with the new brake pads, but I'll cross that bridge when I get there ! Update: The brakes work fine, so using the GT550 piston as a replacement for the no longer available ACSO one is the way to go. I'm also using DOT 5 fluid, not because I need to, but rather to ensure I don't damage the paint at all. The hose I've used is a black jacketed braided stainless steel which looks very similar to the original, but should provide a more positive brake feel. |
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| A perennial problem with
the fuel system is getting the vacuum operated fuel cock to work
properly. For some models of fuel cock used by Suzuki, the diaphragm is
not available so care must be taken to not damage it at all. Assuming
the diaphragm is OK, then with a bit of luck, you can just clean the
pintle valve seat, replace the sealing washer with a viton o-ring from
a local supplier and you are good to go ! I used a bamboo chop stick to
burnish the seat in the valve casting, and then flow tested the valve
by taking an old coffee can , cutting suitable holes in the bottom and
used a spacer block from a GT750 fuel cock on the inside with some
spare gaskets top and bottom to seal. The valve is opened by drawing on
the vacuum line, and if fluid flows - I used isopropyl alcohol - and
most importantly then stops, you are good to go. | . |
| One of the things I mention in my on-line book "A Field Guide to the GT750"
is that the original tool kits are often one of the first things lost
with these old bikes - often because they were border line useless I
suppose and 'real' tools from an automotive tools supplier were so much
easier to use. However, for a restoration, having the original tool kit
is a big plus, so I have been collecting original Suzuki tools so I can
put together the correct tool kits as I do these restorations. Note
that while Suzuki does still sell tool kits listed as being for this
model, the actual tools that are in the kits are: not stamped with the
Suzuki 'S', are not the same selection as the original tools, and also
often include tools not required for your bike. The tool kit that would have been supplied with the 1977 GT500 would have included what you see listed in the photo to the right - and I have one of these on the bike now. | . |
