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1977 GT500 Frame, Body, Chrome, Etc..

  1. Power Coating - Prep
  2. Powder Coating - Process
  3. Wire Harness
  4. Fork Boots and Battery Protector
  5. Seat
  6. Gauges
  7. Locks and Keys
  8. VIN Label
  9. Brakes
  10. Fuel Cock
  11. Tool Kit
  12. GT500 Project Menu

Powder Coating - Prep

One of the advantages of belonging to a local vintage bike club is the little pointers and tips people casually toss your way - it's 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. 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.

I've spent the past few days disassembling and getting them stripped down, taken lots of photos and bagged and tagged many of the smaller bits and pieces, nuts and bolts. Today I spent some time washing off the accumulated dirt and oil from 30+ years of use. I had briefly thought of doing this in my driveway using my pressure washer, but very quickly rejected the idea as it would flush various amounts of oil and grease down the storm drain. Instead, I took everything over to a local Shell car wash as they (supposedly) are set up to keep this sort of debris out of the storm water system.

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 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 try to be absolutely certain there were no traces of oil which would ruin the powder coat application.

The photo shows the two frames, as well as the other frame components which are all to be powder coated.

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Powder Coat - Process

I hadn't seen this type of paint/plastic application done before, so for me at least it was quite interesting. Essentially, the metal is electrically charged and then sprayed with a plastic powder - the charge causes the powder to 'stick' to the metal, after which everything is put into an oven and baked at 400 F for 40 minutes. Below to the left my parts are being sprayed, in the middle shows the parts fresh out of the oven and cooling down, and on the right back home and ready to be unloaded.

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Wire Harness

One of the many items you have to deal with while restoring bikes, is dealing with the sins of the previous owner's efforts to 'improve' the electrical system. In fairness some of the 'correct' parts are difficult to find, but it also seems as if things electrical confuse and confound many folks to the point where after continued improvement and change, nothing works at all !
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 was able to supply 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 !

Update: Sadly, Vintage Connections no longer sells to non-USA customers. Pity.

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 !

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Fork Boots and Battery Protector

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 as 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 this 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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The GT500 'A' and 'B' used a different seat and tank than the rest of the T500 line, and the seat mounting was a very poor design. The pan is only supported at the very front and at the rear, so the centre flexes and eventually cracks. As a result good usable GT500 seat pans are almost impossible to locate. Luckily, Suzuki just used the seat pan from the GT380/GT550 and welded on some brackets, so it is possible to make your own seat pan fairly easily. Below is a GT500 seat on top of a GT550 seat - and on the right is a shot of the underside of the GT500 seat pan. As can be seen, the holes for the hinges, catch and rubber cushions are all there for the GT550 - all that is different are the mounting brackets and the lack of a cut-away for the seat lock on the right side.

As luck would have it, I was able to find an original, intact GT500 seat pan that saved me a bit of work for which I'm grateful.

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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For the 1977 model year in Canada, the GT500 used a brown faced gauge set with kilometre markings. It took me quite a while to track a set down as they were specific both to the model and the year but I found a set eventually.

In 40 years of riding, this will be the first bike I've ever owned that reads in KM/H !

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 and 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:

  1. housing
  2. trip reset cover
  3. trip reset knob
  4. wire harness
  5. speedometer and trip reset and above it the tachometer
  6. under plates that hold the gauges in the housing
  7. chrome underside covers
  8. amber turn signal lens and beside it the Suzuki "S" emblem
  9. turn signal lamp holder rubber sleeve
  10. turn signal lamp holder

Item #9 typically perishes and rots away completely and is what provides a weather, and I suppose light seal for the turn signal indicator lamp. I replaced this with a short length of harness sleeving, and then re-glued the amber lens back into the housing. I also had to replace the turn signal lamp and lamp socket as it had corroded into a solid lump, and then re-sleeved the harness and replaced the connector blocks. The gauge cluster now looks much better than it did, and should last a few more years.

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Locks and Keys

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 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 !

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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 ASCO 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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Fuel Cock

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.
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Tool Kit

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 - possibly 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 to allow me to put together the correct tool kits. 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.
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