Expert: (Sidecar) Bob Kingsmill - 12/1/2008

Question
QUESTION: I have a 1984 Honda Magna VF700C.  Does this bike have a speed limiter or rpm limited?  If so how do I change it?  It looks to me like the fuel is fed through the reserve tank, or is there a switch just for the reserve tank somewhere.

ANSWER: I have no personal experience with Magnas, but I found the following information on the internet:

Some Magnas have rev limiters. You can tell if yours does by looking at the electronic ignition units - if they are the same size there is no limiter, but if one unit is larger it contains the limiter. The limiter cuts out one pair of cylinders (presumably the pair controlled by the larger ignitor) wt 10,900 RPM.

Since the limiter's cutout is higher than the engine's redline, I wonder why someone would want to disable it. I'm not sure, but I think that replacing the limited ignitor with another non-limited one will work.

From what I can find, the Magna's petcock has only ON and OFF, but no reserve position. The fuel flows by gravity from the main tank to the sub tank (the fiche does NOT call it a reserve tank - I think it's just a way to carry more fuel without making the main tank look bigger) and is then pumped back up to the carbs.

The fiche shows something called "SENSOR, FUEL RESERVE", but it does not appear on the schematic I found here http://server6.theimagehosting.com/image.php?img=vf750-83-87.JPG&album=24592&ful
Perhaps there is a "reserve" light in the instrument panel that lights up when the tank is low? I couldn't find that either.

If this doesn't help, please feel free to ask one of the other experts.

---------- FOLLOW-UP ----------

QUESTION: I noticed that on the Interstate, trying to catch up with some larger bikes, my 1984 Hondda Magna VF700C seemed to top out at 85 mph (it has a 150 mph speedometer).  I don't need to run around at 85 or more but would like to know that it could.

Answer
Just about everything I know about Magnas is in the first answer I gave. As I said, from what I was able to figure out, it would appear that there is a governor in one of the ignitors and I think that if you were to replace the one with the governor with a second non-governed unit it would no longer be governed.

The governor cuts out the ignition when the engine is spinning too fast - about 900 RPM above the redline. It does not measure the actual speed you are travelling at and is only intended to protect the engine from over-revving, so disabling it could lead to potential engine damage.

I would recommend finding a good online usergroup (forum) that specializes in Magnas and joining it - they will have actual hands on knowledge.