I’m often asked how to return an engine to service after a long lay-up. The starting point would be an engine which hasn’t been started in several years. Hopefully, the crankshaft will turn freely without heroic measures. You should always check this before buying an old bike that’s been sitting. I “pass” on most opportunities to buy bikes with frozen engines. Bikes with frozen engines usually have a myriad of other problems that make them poor candidates for serious restoration efforts.
Here’s the method I use to resurrect GL1000 engines safely. This procedure is very effective in safely cleaning engine internals and removing varnish from the starter clutch rollers. The process works well for most internal combustion engines.
- Verify that the crankshaft will turn with the Kickstarter …don’t use the starter yet! (Just make sure the engine will turn a bit.)
- Remove dirt and debris from spark plug recesses with compressed air.
- Soak the area around the spark plugs with penetrating oil (like PB Blaster) and leave overnight.
- Remove spark plugs (very carefully!).
- Squirt about 2 tablespoons of penetrating oil into each cylinder …this will help free up your rings and lube the cylinder walls.
- Replace plugs.
- Check fuses, main fuse, battery cables, starter cable and wiring to/from starter relay for integrity.
- Install a fresh, fully charged battery.
- Address coolant status. Drain and re-fill as necessary for initial startup. Tap water is fine for now.
- With kill switch “off,” spin the engine on the starter (or Kickstarter) for a few seconds…this will distribute the oil in each cylinder.
- Let the bike sit overnight.
- Drain the old oil.
- Replace the oil filter and replace oil with the cheapest 30W you can buy.
- Clean / replace air filter.
- Rectify ALL problems with the fuel tank. There should be no rust whatsoever in tank! Suspended rust in fuel will KILL any subsequent carb rehab efforts!
- Install a new fuel filter.
- Do whatever carb, ignition work, etc. is required to start the engine and verify that it will run correctly. Now would be a good time to try the “In Situ” carb cleaning method detailed here.
- Start the engine, allow the engine to warm up, but DO NOT RIDE!
- While the engine is warm, drain the oil.
- Replace the oil filter (again).
- Fill crankcase with a 50/50 mix of cheap 30W and Dextron auto transmission fluid. Really!
- Start the engine and run for 20 minutes at 3500 – 4000 RPMs on the center stand…DO NOT RIDE with this mixture in crankcase…any loading might damage your engine. This will clean your engine internals and free-up piston rings. Don’t be alarmed …your engine will SMOKE quite a bit with this mixture. Your neighbors will be very impressed with your pageantry!
- While the engine is warm, drain this oil/Dextron mixture.
- Replace the oil filter (again).
- Refill crankcase with high quality, motorcycle-spec 10W-40 oil.
- Address roadworthiness issues like fresh coolant, fork oil, etc.
- Address safety issues: brakes, tires, lights, loose fasteners, etc.
- Address legal issues: registration, licensing, insurance, taxes, updated will, etc.
- Road test and evaluate deficiencies. Obviously, do this first ride with GREAT CARE for your own personal safety.
- Address deficiencies as required.
- Adjust valves.
- Re-visit tune-up issues as required for smooth running and full power.
- Do a benchmark compression test.
- After you put 100+ miles on the bike, do another compression test (the values often rise as the rings free-up).
- Change out fluids again at the 100-mile mark.
I learned this method from an “old school” mechanic many years ago. This technique has never failed me. You may be tempted to skip a few steps in your rush to “see if it will run.”
My advice: don’t take any shortcuts! Take your time and you’ll be rewarded with a sweet running engine.
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