Honda F3 engine

[eh427]

Does anyone know how much more horsepower an F3 has over an F2 and can you tell an F3 over an F2 by looking at it, serial number?

[mdr14]

The F3 has About 5-10 hp plus or minus over an F2, depends on how well the rings seated. The 97&98 motors had a wee bit more too.

The F3 had the speedo driven of the transmission, so there is a place on the cases for that sensor. the F2 speedo was driven off the front wheel.

So yes, You can tell the difference there... Of course there are several other tell tale signs, but that is the easiest to see with the motors side by side.

[H-man]

Thanks Matt.  I certainly benefitted from your response.

BTW, I have a '94 F2 that is still running strong (well, strong enough for my meager abilities).  How or when can you tell it's time to "freshen" the engine?  And what is this "freshen-ing" process? :-[  Is there a limit to how many times it can be done or a rule to follow when it may be better to cosider a new bike or engine (before sending it off for "freshen-ing")? ???  ???

TIA  8)
   H-man

[mdr14]

I have seen some F2 F3 motors run strong with over 40,000 street miles, with motorwork.

As long as your cylinders are round and within spec you can keep on honing and re-ringing.

With the F2 & F3 Honda made .25mm over pistons up to 1mm overbore.

You have to be careful on freshening the valve job. If the valve seats were properly cut (valve job), a head can get up to 4 valve jobs before it either needs to get tossed or new seat inserts intalled.

If you still have good compression & low leakage, along with making good power, you may not need to freshen the motor.

ALthough the above mentioned indicators will not tell you the condition of the rod bearings, etc.

Although I must say the F2/F3 motors rarely seized rods. But it is a must on the F2 to put a manual tensioner in place of the stock hydraulic tensioner.

I remember many "back in the day" It was not rare for someone to brake cam chains.

The F3 tensioner does go bad regularly too, But I usually replace those with stock units. Most people do not take the time to maintain the manual units.

[H-man]

Thanks a ton Matt :)

My winter project list has grown.  But I'm happy to spend time in the garage tinkering with the bike.

   H.