Reader Question: Mummified ’83 Silverwing?

Here’s the latest reader question, along with my reply!

Kyle asks: I am having my grandmother ship a 1983 Honda GL650 Silverwing to me. It was my grandfather’s who passed away about 5 years ago, but he was suffering from Alzheimer’s. So the bike hasn’t been started or ridden for over 12 years. It is not an Interstate model. I am not exactly sure how many miles there are on it, but my main guess is over 15,000 miles. I do have a decent amount of engine knowledge and have been researching this type of motorcycle for a couple of months now. I was just wondering what you would do first and how to get this thing running and back on the road. You seem like the guy to talk to about this kind of motorcycle.

My reply: The good news is this is a great bike! As near to being un-hurtable as a bike gets. But 12 years of just sitting will require some de-mummification.

First thing is – do not try to start the bike.

The tank and carbs are full of stale gas and god knows what else. The engine is filled with ancient oil and spinning it with the starter could cause damage.

At the very least, the tank will need to be drained and inspected for rust. If it has rust inside, I advise you to get the tank boiled out and coated with a product like Kreem, which will seal the inside surfaces to prevent rust flakes from being fed into the fuel system.

The fuel tap will also need to be taken apart and cleaned; you can get rebuild kits on eBay or from your Honda store.

You may luck out and find the tank is clean inside. Still, drain all the gas.

Both carbs will also need to be drained (remove the screw in each fuel bowl) and (probably) also cleaned out. Minimally, with the fuel bowls off, remove and clean the main jets, which are easily removed with a small/stubby flat blade screwdriver. It’s easiest to clean the carbs with them off the engine, but you don’t have to do this if the carbs are not full of gunk. Removing the fuel bowls will tell you that. If you find gunk, the carbs will need to be disassembled and cleaned out.

Inspect thee rubber boots – technically, the intake manifolds. If they are cracked (vacuum leaks) you will need to replace these. Any small parts needed for the carbs are readily available at any Honda (bike) store.

I’d also replace the rubber fuel lines at this point – inexpensive and important.

Check the throttle for free play and lubricate all cables/pivot points. If the push/pull mechanism feels sticky, don’t ride the bike until it isn’t!

Once you’ve gone through the fuel system, the next thing to do is the oiling system. Drain the engine oil and remove the filter. Fill the engine with fresh oil – I’d recommend synthetic because it flows faster/easier and install a good (Honda) filter. Get enough oil (and a second filter) to perform two oil changes. The oil and filter you just did is just to get the bike running – and get the crap out of the engine.

Buy two new spark plugs. With the old plugs out, spray penetrating/lubricating oil into the cylinders. Don’t install the new plugs just yet; let the engine sit at least 24 hours. In between, you can drain the engine coolant and replace with fresh. Look inside the radiator and make sure it’s not filled with scale. Check all rubber hoses and replace any that are not pliable or which are cracked and brittle. I’d also replace the thermostat since it may be sticky from all those years sitting and if it is, the bike will overheat.

Bleed the brake lines thoroughly and refill the entire system with fresh brake fluid. Check that the front calipers are not seized up. If they are, you will need to rebuild them. Carefully look for any signs of fluid leaks in any part of the brake system, from the master cylinder to the calipers.

If the rear wheel rotates freely, the rear drum is not locked up from rust/sitting. Try this with the bike on the center stand. If it spins freely, try using the foot brake. If it stops the spinning, the rear brake is probably ok but at some point I would want to pull the wheel to check the condition of the shoes.

Drain the rear axle/shaft drive and refill with fresh fluid. I personally would do this twice, too. Drain the old fluid out, refill with fresh. Then manually rotate the wheel (on the center stand) to circulate the fresh fluid and let it mix with the old fluid that didn’t drain the first time.

Now drain it again and refill.

The shaft drive on these bikes is the one “big thing” that can fail and you don’t want it to as the replacement cost is very high. With only 15,000 or so miles, yours should be fine. Making sure the fluid is fresh – and the level isn’t low – will help that shaft drive last a very long time. The thing is to not ride the bike before you service that shaft drive!

Check the air cleaner – it’s under the right side cover. It will likely need to be replaced. Make sure there are no squirrel’s nests/old acorns and such in the air box!

Ok, now – it’s next day – it’s time to manually rotate the engine using a breaker bar.  There is a bolt on the front of the engine put there for just this purpose. Remove the lower radiator shroud/cover and you’ll see it.

A shop manual is your friend!

Use the bar to turn the engine over – being sure the gearbox is in neutral. With the plugs out, the engine should turn easily/freely. If it feels “tight” then it is time to spray more penetrating oil (WD 40) and let it sit some more before you try again.

If the engine turns freely, which is likely – install the new plugs. With fresh gas in the tank – and a fresh battery – it’s now time to attempt to start the bike.

Unless someone diddled with the ignition system, it should not be necessary to do anything to the ignition system, which is electronic. The timing should be fine. No points. Assuming the coils are good (which they ought to be, unless the bike was stored outside) and with fresh plugs, it ought to fire.

Once it fires, let it warm up and then gently rev it to around 1,500 RPM or so and do that for a few minutes. Climb on – bike on center stand/rear wheel off the ground – and run it through the gears at varying RPM up to about 3,500 for another few minutes. Watch the temperature gauge; you should hear the electric fan come on as the bike gets warm. (If the fan does not come on and the bikes gets hot, shut it down before it overheats and figure out why the fan did not come on.)

Shut the engine off and change the oil and filter.

The bike should now be ready to ride!

Be sure to get new tires before you ride, though 🙂 The ones on the bike are almost certainly flat-spotted and dry rotted.

That ought to do it! Keep us posted on this. I’m happy to help with any advice as the owner of an ’83 GL650 myself!

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