I'm doing some very short road testing on a just acquired '98 F3 (no history on this machine, mostly) and find I have no throttle response (dead spot, bogs down, etc) once the bike gets rolling and around 5,000RPM or so. It winds up smoothly on the stand and runs crisp in neutral.
I read the post about the speed sensor solenoid and the air intake switch thing but before I chase this it;s worth asking: The motorcycle is completely uncowled (naked) including removed front fairings. Will this lack of cowling affect the air intake system or doesn't matter? Before road testing, I drained all old fuel from the tank, replaced the fuel filter, and added fresh fuel with Seafoam. The bike has a Vance & Hines slip on. Thanks for the advice.

 

as long as the ram air box is still in place, the intake system will not be affected. if you have no f3 gauge set on the bike and the air solenoid has not been bypassed THIS IS THE PROBLEM. the gauges control the solenoid ground above 12mph. check out page 4 of my streetfighter build thread for some info and good pics about removing the air solenoid

 

Yup, original F3 gauge set from 1998. And yes, the ram air box is still in place - only thing off the bike is the plastics.

 

disconnect the electrical connector from the air solenoid and see if it runs any better

 

+1

 

That's my first task with this. As i said in the other post, the previous owner told me it runs fine with the speedometer DISCONNECTED...that would seem opposite of how the system is supposed to work, no?

I thought Honda's slogan used to be "we make it simple"............!

 

its really sneaky if you think about it if it is really for passing emissions tests to be able to rev all the way up with the solenoid closed at a standstill but only open it once past 12mph probably has something to do with emissions produced at idle.

 

Actually it makes sense! It seems highly probable that there is a “safe mode” for when there is no speedo.
In other words the solenoid is probably automatically grounded because certain signals do not exist when the speedo is MIA.
While the speedo is hooked up some signals do exist but the one that grounds the solenoid must be fouled up.
This is purely speculation but seems to be the case with a few people from what I’ve read.
I would just rip all that crap out and bypass the solenoid.

 

the air solenoid ground runs through the instrument cluster, if you disconnect the speedo are you creating an open circuit to ground. same as disconnecting the solenoid itself

 

With the speedometer connector off, it ran the same crappy way. I disconnected theconnector that send signal to the solenoid, no difference.

I then rerouted the hoses - taking the solenoid out of the system - haven't taken it for a ride yet. Really hoping this solves it. Although, in my testing, when the speedometer hit 15 MPH it ran like crap so I suspect the solenoid is stuck.