I have a 2000 F4 which i purchased about 2 and half months ago. When everything is in tip-top shape, the bike runs great, good throttle response, good pickup and rides great.

The problem is, every so often, for whatever reason, it decides it wants to run like crap. Here's the problem: It seems like sometimes when I put new gas in the tank, it makes the carbs go out of sync. I'll take the bike to the shop, they'll sync the carbs, tune it up and tell me it's good to go. I'll ride it for a bout a week or two, and after a few gas changes, sometimes 1, sometimes 4 or 5, it starts running bad again. The main symptom is that the bike gets really hot when it idles. The only time my cooling fan pretty much ever comes on is when this happens (especially in this cold weather). And as the bike gets hotter, the idle gets lower and it eventually stalls itself out. Another symptom is when it's hot and idling rough, I'll start off and the power surges, like I have to hold the throttle wide open and it surges for like 5 seconds before it finally starts going. Once going, it usually vibrates really bad.

At first I thought maybe it didn't like higher octane gas. I had just got it tuned up, it was running great, I ran low on gas, filled up with 91 at Sheetz and my the time I got home (about a mile away) it was back to running bad. I siphoned out the tank and replaced it with 87 from the Sunoco and it ran fine, until 2 tanks later, all of which were with Sunoco gas.

I just had the carbs cleaned and synced at my local Honda dealer, the bike was running beautifully, the best it ever has. All of a sudden today, I filled up the tank and it started running poorly again. I don't know, maybe it's not gas related at all, but it seen too coincidental not to be.

Anyone thoughts or suggestions are welcome. I know this is a long post, but I'm a little frustrated and just wanted to see if I could get some insight as to what might be going on.

Thanks for you help!

Ben

 

I hate to be redundant in my advice, but check out the r/r. It is a major issue with the entire line of hondas form the late 80's into the mid 00's. Look for heat sign on the r/r itself and the connector/s. i.e. burnt pins, warped/melted plastic, cracks in the epoxy-fill on the r/r itself. A lot of the symptoms of poor performance can be traced to electrical issues here.

Ern

 

Good advice from MadHattr059, but check to see if battery is getting a charge when the bike is running with a multimeter connected across the battery terminals. Rev the bike with the meter connected to around 3-5000 rpm and see if the reading is between 13.5/14.5 volts. If you see this figure then the R/R would seem to be charging the battery ok. The problem could be fuel pump related, but ignition also seems more likely. Let us know how the charging test goes?