Diablo Shop 503

[Go Go Diablo]

Hi all,

Starting a new Diablo 503 restoration and thought this would be a good place to document what I go through for a typical 503 restoration. This may be an unusual restoration as many of the parts will be NOS (New Old Stock), but old stock or new stock, much of the process is the same. So, here we go.
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I was lucky enough this past summer to come across some NOS parts being hoods, a 502 chassis, tracks, seats and ski seater tub. How neat is that!
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The 502 chassis was converted into a 503 chassis by relocating the motor mount holes, adding the support bracket for the bottom motor mount and adding a battery box. The chassis, handlebars, hood, ski seater tub and other various chassis parts were sandblasted.
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These parts were professionally painted at a local body shop with base coat / clear coat automotive quality paints. The paint color they matched was this "Implement Red" that is a common red.
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The white color matches the new white Nacelle Covers offered.
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Before painting your hood, fit your nose cone. You may well have to modify the hood corners a bit to get the nose cone to fit as needed. Sometimes all that is needed is to cut into the upper corners of the hood just enough to bend in the corners and reweld them.
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[Go Go Diablo]

Any good restoration required sandblasting of chassis and parts. One of the most used pieces of equipment in my shop is a cabinet sandblaster that I changed up to use a pot sand blaster (from Harbor Freight), uses an external exhaust system and a good internal light. This set up allows you to blast for a good 20 minutes or so and then reclaim most of the sand to reuse.
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The exhaust system is a typical dust collector that one might use in a wood shop. The system takes all the dust and gets the mess outside. I have two dust collectors side by side. I use one for the cabinet blaster and the other for ventilation in the paint room when painting. Both are controlled by a switch inside the paint room.
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It takes about 4 to 6 hours to blast all the black pieces of a Diablo not considering the underside of the chassis. Then off to the powder coater. I find having the parts powder coated black is very cost effective for what you get back versus spraying the pieces with conventional paint.
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[Go Go Diablo]

Parts are back from powder coating. Shown are the parts I had painted. The parts that are missing (kind of a "Where's Waldo" thing) will come from my new parts inventory and are already powder coated.
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One of the first things I do to a freshly painted chassis is tap out the track adjuster holes so I'm not ramming the track adjusters through paint. Be careful doing this. The last thing you want is for a tap to break off here.
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Fit the muffler next. This 503 will get one of my new reproduction mufflers. Get it mounted with the bolts in place and you can tighten the bolts later when you flip the unit over.
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[Go Go Diablo]

On to the bogie stations.

All these stations were NOS and most of them had a grease zerk pressed into them. The zerks being only pressed in usually pull out the first time you put a grease gun on them. If you use grease zerks, you have to tac weld them in place. I do not use zerks or grease and I will explain shortly.

I removed the zerks and welded the holes shut. I also add reinforcement welds. Because these stations were NOS, they were pretty tight to start with and adding welds made them even tighter with a little warpage going on. I was able to straighten them enough to get them to turn freely again. With used bogie stations, this is usually not a problem.

For the single mount stations, add reinforcement welds on the inside of the U brackets.
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For the double mount stations, add reinforcement welds to the inside of both U brackets. Do not try and add weld to the outside of the U brackets as there is a brass bushing there and you will burn right through the steel tube into the brass bushing.
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Obviously, do this all before you paint them.

[Go Go Diablo]

A little discussion about oil versus grease in the bogie stations:

Theses bogie stations are designed with a solid axel going through a hollow tube with a brass bushing on each end.
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My experience with grease is sooner or later no matter what you use, grease can get firm. A grease gun can create a significant amount of pressure as you know. When grease in the tube gets firm and you force more grease into the cavity, you can hydraulically push the brass bushings out of the tube and they end up against the tire rim and then they start spinning with the wheel instead of being stationary in the tube. When that happens, they don't last long.

I have found oil works so much better. The cavity in the tube acts like a reservoir and a simple hole in the tube allows you to use a steel tipped oil can to pump a little oil into the tube. You can see the holes in the previous pictures. Add oil once a year and my bogie stations have never froze up.
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With reinforcement welds added and now painted, we are ready to move on.

This is when I drill the holes for the lubrication ports. Once drilled, I force some compressed air into the port and spin the rims and this blows the debris out of the tube cavity. At this point, you can oil them now or put them in place and then oil them.

Install your bumpers. On the double mount bogie stations, the bumpers should be in the hole farthest away from the pivot and the bumpers should have a thick washer under them to improve the "lift" of the station which helps get the tracks off the sprockets cleanly.
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For the single mount stations that are used in the rear by the idler sprockets, the bumper should be in the hole closest to the pivot and uses a thick washer under the bumper as well for the same reason as above.

For all the single mount stations in the middle, the bumper should be in the hole farthest from the pivot and no washer is used.

[Go Go Diablo]

If your rubber tires are cold, do yourself a favor and warm them up. They go on so much easier.
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I put a thin layer of grease on the painted rim so the tires seat properly.
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Then using a screw driver, I walk the new tire onto the rim. When you have done all that, you have a beautiful set of bogie stations ready for whatever you can give em when you are out riding.
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Not my most used piece of equipment in the shop, but my Harbor Freight 12-ton press may be the most required tool in the shop. Without it, rebuilding gearboxes and motors would not be possible.
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With a press, a gearbox rebuild is fairly simple by following a few suggestions. To start with, disassemble the gearbox. Most of it is pretty straight forward. For pressing out the upper shaft, place the housing in the press and press the shaft inward.
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Clean up your parts. Putting the gearbox back together and expecting it not to leak requires a few tips. For the sealing surface of the housing, I lightly use a disc grinder to clean up the surface. It not only removes old gasket material but grinds smooth those bolt hole areas that are bulged out toward the cover.
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For the covers, the bolt holes typically get pulled inward over time. Put the cover holes over a vice and tap the hole areas outward so when you tighten the cover bolts, there is some give in the covers to push on the gasket.
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The chain in a Diablo gearbox is a standard size 50 chain without a connecting link. I would worry about a connecting link in the gearbox as the clearances are quite low and if the connecting link pops off, well, you know what happens then. Try and use a continuous chain.

Inspect your seal surface on the large gear. Seals often wear a deep groove in them and if they are damaged, the surface can be repaired using a SKF 99172 Speedi-Sleeve.
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Inspect your idler gear. If the bushing is worn, replace it. If the tack welds between the bolt and backing plate are broken, reweld them.
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Put a drain hole in your gearbox. Put a 1/8 NPT thread hole in the bottom and use a flush plug so it does not get caught on something while you are ditch digging through the swamp.
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[Go Go Diablo]

To start re-assembly, put the outer bearing in the gearbox and press the inner bearing onto the upper shaft.
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Then place the gearbox in the press such that the outer bearing is supported by the press plates. Place the shaft into the housing and press the shaft through the housing.
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Press the bearing onto the lower shaft and put that assembly into the gearbox installing the snap ring to hold it in place. If you have a poor fit here, you can use Loctite Retaining Compound to fix that. I do not press this lower shaft into place for fear of breaking the housing. I set the shaft / bearing in place and use the weight of the shaft to install by holding the upper part of the gearbox with my left hand, hold the shaft with my right hand and gently hit the lower part of the gearbox downward on to the bench top and this is enough downward momentum to work the bearing into place.

Once all together, don't forget the two spacers on the shafts. On the 502/503 gearbox, these spacers are the same size.
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Put your sprockets and chain in place. Install the idler sprocket and tension the chain. Make sure the chain is tight and the assembly turns over freely.
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