Hello fellow Vifferados! Hope to enjoy chatting with (at least some of) you from time to time. I have an issue with my 98 VFR800FIW (which I bought new in May 98). I was smacked down from the side by a minivan several years ago, which caused my VFR to impact fairly hard on the left side a chase me down the street. I took a while to heal totally (as did the bike) but I put it all back together and it shows no signs of wear. It does, however, have a residual problem. In times past, it would get 48-50 mpg and ran pretty lean. Now, it gets about 37-40 mpg. The plugs are somewhat sooty and the pipe blackens much more than it formerly did. I have determined that the airbox "flap" which opens to let in more air at 5500 rpm is acting up. When the bike is in gear and the clutch is engaged (especially if it is modulated in the least), the flap will move rapidly back and forth. I notice it at these times, and it is probably acting up at other times - either opening when it should not, or not opening when it should. I have checked by service manual techniques all components related to the airbox flap, but find no problems. The vacuum chamber connected to the flap holds vacuum as it should. Others of you have probably had some electrical issues, as have I. 2-3 batteries and 2 regulator-rectifiers. I wonder if something electrical is causing the flap problem. I have some weirdness with the electrical still - if I touch the "on" position side (back) of the kill switch at all, the engine dies. If I brighten the lights (I rarely do), sometimes the lights go out altogether. I cannot think of any other signs it is showing me. Anyone have any ideas?
The kill switch itself maybe messed up, the other stuff sounds like a grounding problem. Make sure all your grounds are connected, if they are all ok check for an amp draw w/ a DVOM as that would indicate potential shorts, then its just a matter of pinpointing which circiut is causing the the draw, this can be done to some degree by removing fuses & rechecking draw. DANIMAL may have some other suggestions, I beleive he could be considered our resident electrical/electronics expect.
Thanks. I was thinking along those lines. Will try to check that out. I know the vacuum is supposed to be regulated by the rpm as registered by the tach (which seems normal), but it may still be getting weird signals as it is processed thru the system. The impact could have loosened a connection or 2.
your hi beam low beam switch is just going bad.....so is mine....just havent gone to buy one lol.....the flap is controlled by vaccuum only there are no wires to it there for no electrical problem.....the diaphram is either weakening or you just need to change your spark plugs....you didnt say if you had done that or not....they are supposed to be changed at 16,000 miles...
Thanks. I think the manual actually calls for 8K replacement. I believe I did that at about 24K (I cleaned them at times before). Bike has about 29K now. Changed them after crash. U r right that the flap is controlled by a vacuum diaphragm. As I mentioned, it holds vacuum as it should, so I don't think it has a leakage problem. The flap is moved by an metal arm/wire attached to the diaphragm. There is an electrical connection to a module which controls the vacuum input, though. I even replaced that part to no avail (and to the tune of $100+). Something is causing the flap to get sporadic and improper vacuum, and I wonder if that module is getting bad electrical vibes.
Just pull the vacuum line off and plug it. The flapper will stay open then. Most 5th gen VFRs will rattle the flapper as you let the clutch out or pull it in. Disconnect, noise stops. Flapper being open will not hurt the bikes running one bit.
