Running Rough at low RPM
 

Rode to work today and about 25 miles into the commute, as I was going to pass a car rolling the throttle on in 6th, the bike starting sputtering. I pulled over to get my ipod out of my ears so I could get a better idea of what was going on and found it doesn't want to idle. I decided to limp it to work and noticed above 3.5k RPM it's seemingly fine: no coughing and power is smooth. Below it is coughing and sputtering like crazy.

I get to work and throw voltmeter on the battery thinking it's possibly the regulator as the bike needed a charge today after only sitting for three days. I get 12.2 at idle and 13.8 at 5k. At this point it would idle, but not for more than 15 seconds or so then it dies, sometimes with a pop from, I'm assuming, too much fuel.

In the last two months I have rejetted (182.5/185 mains, 45 pilot, 2.25 out, clip ins 2nd pos) and did the TPS mod (518 was as close as i could get, and I did have to modify the mounting holes to get it that close. Think it could be the TPS way out of whack?

Any other ideas?

My first thought, did you sync the carbs? That could lead to rough running, and the situation that you stated at idle.


Hawkrider has a TPS write up on his site.



Didnt you get the memo about the new TPS cover sheets?

+1 on carb sync

Thanks, guys. The carbs are sync'd, unfortunately. What's weird is the bike has been running incredibly strong and responsive for the 300-400 miles since the re-jet and TPS mod and was running just as well until halfway through my commute today. I'm really leaning toward electrical/ignition as the rectifier is the original (8 yrs. old) and the battery is almost three years old. Last I rode it was Monday after installing a new starter switch and I had to throw a charger on it to get it to turn over - same as this morning. The battery was basically dry, so I just filled it with some distilled H2O and it's sitting on a trickle charge right now. We'll see. I'll check the TPS next if necessary, then pull/inspect the carbs and re-sync if I'm still having issues. I'll have the wife bring me home a new rectifier from the shop tomorrow as a last resort - $106 at employee cost!!

I think I need a new clutch now, too; a bike that doesn't want to run under 3.5k + Houston Friday traffic is a good recipe for baked clutch. I'm sure everyone next to me on the highway thought I didn't know how to ride - squid city! LOL

Negative on the TPS memo (?). I did see Greg's writeup though, which is what I used to do the mod.

Well, sounds like this just started right? Had it been sitting for while? Bad gas? There must be a gas filter in there somewhere....replace it? Clogged idlejet/low speed jet, pilot/whatever it's called. One slide not shutting all the way? Sounds like a general inspection and cleaning of carbs etc should get you back on track.

Watch the whole thing as this is one of the best movies ever but 2 minutes and 50 secs and 4:30 into it will explain it all:

http://www.youtube.com/watch?v=FfY2q...eature=related

I don't think there's a fuel filter anywhere on the stock VTR setup, but an inline one is a good idea to add.

LOL! I love that movie.

Well, apparently the cause was a dry/low battery. It has a non-serviceable Suzuki battery, but I pulled the caps off anyway. After topping it off and charging last night I dropped it in and she was back to her old self. I'm going to pick up a new battery today to be safe as I think this one is roached and I did dimple the caps on each end a bit prying it off.