1994-2003 Honda Magna VF750C spark plug change

Changing spark plugs is usually a simple task.  If you have to maintain a Honda Magna, you are in for some knuckle busting!  The Magna's V4 engine was derived from the sporty VFR750F of the era.  They really crammed this engine into a cruiser frame which made spark plug changes a bit difficult.

The Honda Magna has two issues with access on the front cylinders.  First, the plugs are deep within the cylinder head.  Second, there is little clearance for tools due to the location of the radiator.

Right, rear cylinder.  Look at how deep these spark plugs are!

Here is my documentation of how I change the plugs in the front cylinders.  It took me approximately an hour to complete.

Note:  I distinguish left and right as if you are sitting on the motorcycle.

Materials
4 NGK CR8EH-9 spark plugs
Anti-seize lubricant

Note: I found the spark plugs at Autozone for less than half the price of the local Honda shop.  They had to order them, but had them the next morning with no shipping charge!

NGK CR8EH-9 spark plugs

Tools
10 mm wrench
10 mm socket
Socket wrench
Hex allen wrench from Honda tool kit
Spark plug socket from Honda tool kit

Procedure
1. Remove right side cover.
2. Get tool kit.  You'll need the hex allen wrench and the spark plug socket.

Spark plug socket from Honda

Radiator pivot
3. Remove the lower radiator hose bracket.  It is secured by a 10 mm bolt.  I used an extension bar to quickly remove.

Location of lower radiator hose bracket

Bracket removed

4. Remove the lower radiator mounting bolts using the hex allen wrench on both sides.  This will allow the bottom of the radiator to pivot forward to improve access to the spark plugs.

Lower radiator mounting bolt with hex allen wrench, right side

Right side, front cylinder
5. Pull out the spark plug wire.  It should simply pop off.  Position it out of the way the best you can.

Plug wire removed

6. Insert the spark plug socket.  Work it onto the spark plug head by gently twisting the tool.

Spark plug socket practically vanishes within cylinder head!

7. I was able to use a 10 mm socket and socket wrench to initially work it lose by turning counter-clockwise.  Due to clearance problems, I had to switch to a 10 mm wrench to get it lose enough that I could use my fingers.  HERE IS THE TRICK: You get the most clearance for tools and your hand by positioning them such that the tools are accessed from the front side of the engine, below the radiator.  Don't damage the radiator or fan.

I was able to squeeze my socket wrench in here just to pop the spark plug loose.  Don't work at the angle shown in the picture.  Pivot the radiator bottom forward to allow proper alignment.

8.  Pull out the spark plug socket.  The spark plug should come out with the tool.  If not, push down on the socket until the spark plug seats into the tool.
9.  Gap the new spark plug.  I used NGK spark plugs which are pretty well set at the factory.
10. Spread anti-seize lubricant on the threads of the spark plug.  Do not get any on the electrode or firing point.  I do this by putting a dab of anti-seize on a clean paper towel and gently rotating the plug over the lubricant.
11. Push the new plug onto the spark plug socket until it seats and its flush.

Push spark plug into the spark plug socket

12. Slide the plug and tool into the cylinder.  Try to aim directly into the hole so you do not pick up crud with the anti-seize lubricant.
13. Screw the spark plug in as tight as you can with your hands.  This is to prevent stripping the soft aluminum and cross threading.
 14. Using the 10 mm wrench, tighten the plug clockwise the equivalent of one half turns.  If you make it too tight, you could strip the threads.  Too lose will cause engine damage.
15.  Put the spark plug wire back on the plug.  You should hear a solid click when it set.

Left side, front cylinder
16. Repeat steps 5 through 15.  This side is a bit more difficult due to the wires for the coolant fan and the temperature sensor.  I was not able to use a socket wrench on this side and had to use the 10 mm wrench.  Remember that its easiest to access the plugs from the front of the engine and below the radiator.

Left side is a bit more difficult.  Had to use a 10 mm wrench here.

Remounting radiator
17. Push the radiator back to its initial position, aligning the mounting holes on the frame with the radiator.
18. Put the bolts in the radiator mount.  First make them finger tight on both sides and then tighten a bit using the hex allen wrench. Don't make it too tight.  The mount is insulated with rubber which you do not want to crush.
19. Reinstall the lower radiator hose bracket.  Make sure the plastic coil around the hose is spread evenly on the radiator hose before you fully tighten the 10 mm bolt.  See the picture on step 3.

Back cylinders
20. The back cylinders are much easier.  Follow the basic procedure.  No clearance issues here.

Completing the job
20. Put away the Honda tool kit.  Getting all the tools back in the storage bag can be a challenge in itself!
21. Put the right side cover back on the motorcycle.