Search the Community

I have a 1990 VFR750 with some running problems, I'm looking for some help with this bike. First I'd like to add some backstory to this bike. I picked up this bike for a trade (rode for an hour to get it) and when I got it I got a chance to ride it. When I went to make the trade the bike would stall out about 10min after riding (but could punch it and get it up to 11k rpm and into 3rd and fourth gear) and the previous owner kept having to jump start it. He drove an hour to me (swears he had no problems up till the trade) but owner did let me know that he picked it up from someone who let it sit for a year. When riding for about 5-10 minutes the bike won't throttle over 5000 rpm and as soon as you let in on the clutch and throttle it would die. I put in a new battery and after about 10min of the bike running with choke on i was able to ride it with the choke off. Went and rode it for about 30min with a friend and it only died twice and i kept having to mess with the idle screw, sometimes it would idle at 4000 sometimes would feel like it was about to die. I had a friend come take a look at the bike and found that it had a aftermarket rectifier and fuel pump in it and the intake for the bike was partially tied shut with what can I only assume is hobby wire. As of right now with fresh battery it will only run with choke on at 1000 RPM as soon as you touch the throttle it dies. I have done some basic checks: All connections for charging system are clean and not burnt. I reinstalled the correct rectifier SH701-12 (owner said that was on the bike originally) Runs at 12.06 volts at 1000 RPM and it gets to 13.03 volts at 3000 RPM and seen it peak at 14 at 5000+ RPM (It is at 11.8 volts at 1000 RPM now I think I killed the battery starting the bike multiple times) Reinstalled original fuel pump Ran some mechanic in a bottle through the gas tank to help the carbs Engine oil is clean and at a good level. Low on clutch fluid Air filter is clean No hissing when idling All fuses are okay New AGM Super start battery It dies whenever I touch the throttle or idle screw it dies, I'm thinking bad stator or clogged carbs. Has anyone had this issue or can lead me in the right direction.

Hi All, I've bought the Power Commander 5 and Auto Tune kit, and today have just installed only the PCV (ran out of time for the Auto Tune). I loaded a generic map just to see how it goes, but it's running way too rich. Smoke out the exhaust indicates that, and it wasn't happening all day yesterday before the install. I have noticed an issue with the throttle position sensor, which I tried to calibrate by powering on the bike (but not turning it over), setting the left side to what the current voltage read, then turning the throttle all the way up and setting the voltage to the right. It did help, but I noticed a weird flat spot at around 22%. Even thou I turn the throttle on evenly and slowly, it will go up to around 22%, then nothing for a while (I still continue to turn slowly) until about 90% open (I'm guessing based on how far my wrist has turned the throttle), and then all of a sudden it goes fast to around 100% fully open. Best to have a look at the footage I recorded, and bear in mind that my wrist is slowly turning the throttle and the voltage is jumping around a bit. Also, if you turn up the volume loud you could hear a weird 'buzz'-like sound at near 90% open, which it seems is the give way area to where it goes fast to 100%. Anyone have any thoughts on this I would love to hear them.