Before you start:
The following instructions should be read thoroughly before installation. Improper installation of your SK REV WHEEL may cause an unexpected failure. The stock starter cup can be used on all SK REV WHEEL models.
Fitment: Honda/Clone Taper
- Ducar 196, 212, 224
- Honda GX160, GX200
- Ghost 212
- Predator 224 Non-Hemi
- Tillotsons 196-268cc Engines
- Wildcat 223, 240
Flywheel Settings:
- Coil Air Gap: .040
- Spark Plug Gap: .028
- Prefered Spark Plug: Fine Wire Iridium(PT# K7TRI)
Tools you will need:
• Torque Wrench (ft. lbs.)
• Ratchet Wrench
• 19mm socket
• 8mm socket
• EC Flywheel Knocker (pt# 795)
• EC Flywheel Puller (pt# 9250P)
Installation Instructions:
1. Use an 8mm socket to remove the ignition coil.
2. Use a 19mm socket wrench to remove the flywheel nut.
2a. To remove the stock cast-iron or die-cast aluminum flywheel, install the flywheel knocker(795) and strike the flywheel knock to loosen it from the crankshaft.
2b. To remove billet aluminum flywheels, install the flywheel puller(9250P) and tighten each bolt equally until the flywheel comes loose.
3. Remove timing key. Use a good contact or brake cleaner to clean the end of the crankshaft to remove dirt and oil. Dry both the flywheel taper and crankshaft.
4. Add lapping compound(280 grit) to the crankshaft and work the flywheel back and forth to fit the flywheel taper precisely to the crankshaft.
Remove the flywheel and clean the flywheel and crankshaft with brake cleaner and a clean shop rag. It’s vital that the lapping compound is completely removed and there is no oily residue.
5. Install a new timing key. Offset keys installed clockwise will advance ignition timing.
6. Torque the flywheel or starter nut to 54 ft. Lbs. DO NOT USE IMPACT/HAMMER DRILLS TO TORQUE FLYWHEELS. The impact can crack or shear the key and damage the crankshaft or flywheel.
7. Reinstall the ignition coil and set the air gap between it and the flywheel to .040”. Torque the two ignition coil bolts to 140in/lbs. Too much coil gap or even too tight can simulate carburetor and other engine problems.
8. Experience true flywheel performance!
IMPORTANT WARNINGS:
REVWHEEL should be removed using the proper flywheel removal tool or kinetic flywheel remover.
DO NOT pry on the flywheel or use a 3-finger style flywheel puller.
DO NOT Heat this flywheel with a torch or any other heat source.
DO NOT beat on the flywheel with a hammer or any other hard object.
Closely inspect the flywheel for damage before every use. REPLACE FLYWHEEL If you see any indication of damage, dents, heavy scratches, cracks, or stress marks on the flywheel caused by improper removal or from on-track collision, it can cause flywheel failure, leading to injury or death.
DO NOT machine, modify, or attempt to repair the flywheel.
DO NOT start your engine with an impact or hammer drill; only use the correct external electric starters or recoils.
Ignition Tuning:
Using an offset Timing Key to Change ignition timing:
Ignition timing is measured in crankshaft degrees before the Top Dead Center or when the piston is at its max height in the bore of the block. The SK300 flywheel is set at 30° before TDC, which is about 12° more than a stock flywheel and nearly optimal for most gas setups. You can use an offset key instead of the standard timing key to change the ignition timing. To advance timing, you will install the timing key with the offset going clockwise or right. To retard or reduce timing, you can install the key with the offset facing going counter-clockwise or going left.
How to optimize ignition timing by reading the spark plug
The SK300 is set at 30° and is near optimal for most gas engines. However, by reading the plug, we can fine-tune the timing for your engine. After running the engine, remove the spark plug. Check the tip of the spark plug diode; it should be burned at about .020”. Also, The finish on the ground strap will form a varnish and discolor. The varnish should stop between ½ and ¾ of the ground strap’s length, which tells us we are using the correct heat range and in the optimal safe timing range. Going past ¾ on the ground strap, the timing may be strong but not for long, and the plug may be too hot, which is unsafe and can lead to detenation. Too much timing is one of the biggest reasons for crankshaft failures and sheared timing keys/flywheels.
Humidity/Dew Point can impact engine performance. Drier conditions will run less ignition timing than wetter conditions. The reason is that water vapor or moisture reduces ignition efficiency, similar to how an octane booster prevents detonation. Keep this in mind when tuning your engine's ignition timing.
How to optimize ignition timing with a dyno
Timing is for torque. When you make passes on your dyno, you look at your peak torque rpm. Peak torque is where you reach the highest mechanical efficiency of your engine and where you are tuning for your ignition timing. Most may try tuning for horsepower, which can lead to engine failure. Remember, too much ignition timing can increase the cylinder pressure before the top dead center, making the piston want to go in the opposite direction, which stresses the crankshaft. Most crankshaft failures don’t occur at high rpms but in the mid-range, usually around peak torque, because of too much timing. You want to increase timing on the dyno until peak torque decreases power. Then, you want to back up about 2 degrees or more, making the ignition timing safer and without giving up much in performance. You can also check the ground strap with a new plug. If you are trying to get more horsepower out of your setup, check your carburetor tuning, or you may need more cylinder head or camshaft.
Troubleshooting Ignition and related tuning problems
Ignition Kick-Back
One of the benefits of the PVL ignition coil is retarding timing below 1800rpms to make it easier to pull start. Pull the recoil until the engine is up on compression stroke to make starting easier. You may feel the engine build compression and get tight, then release and get tight again; that’s the compression or EZ-spin mechanism on the cam helping to bleed off some compression. Pull through to start the engine once the slack is removed from the recoil. If you pull quickly from the recoil housing without the engine up on compression and with slack out of the pull rope, it may jerk or kick back out of your hands. If you are having issues with kickback, check the ignition timing if the timing key has sheared and is out of time.
Rev-Limiting effect:
If the coil gap is too tight, less than .012, or too wide, more than .065, you may experience a rev-limiting effect. It’s best to have a tachometer to know where this occurs. In some cases, you may be running into the valve float. If you have the spring clearance, add a .040 shim under the valve spring to ensure you don’t run into the valve float.
In some cases, rev-limiting can be caused by carburetor tuning. Always check your fuel tank vents, which should have a fitting with a minimum of ¼-Inch hole, to ensure your fuel tank is not the problem.
Hesitation at low speed:
Bigger duration camshafts with overlap can cause off-idle problems and slow-speed acceleration due to reversion. In some cases, more ignition timing can help. However, don’t exceed our recommendations for optimal timing.
In some cases, it could be a carburetor tuning issue. Again, check your tank vents and fuel flow to the carburetor. Try adjusting the idle fuel mixture before adjusting the pilot jet.
If the hesitation remains, your stall or clutch engagement is too low for your engine's camshaft and setup, and it’s not producing enough torque off idle. Most aftermarket cams require 3400rpm or higher engagement.
No Spark:
- Remove the spark plug from the engine and check for damages, fouling/carbon buildup, etc. Check for spark by removing the spark plug from the cylinder head but leaving the coil attached, then pulling the engine recoil. If the spark plug doesn’t fire, it’s either a bad spark plug or a bad coil. Try a new plug. If it doesn’t fire, it may be the coil.
- Check the coil with the voltmeter; use a different coil if you don’t have a meter. Also, ensure the lead wire is in the coil and spark plug boot.
The engine is difficult to start and/or doesn’t stay running:
- Ensure the coil is mounted correctly with the coil wire going upward or in the clockwise directional
- Check coil gap
- Check spark plug for fouling/carbon build-up
- Check the timing key and timing. If the timing key sheared, it may be due to installation or kicked back from too much initial ignition timing.
If issues persist, you may not have an ignition problem, and you need to look into either fueling or mechanical issues.
