Serious problem with F3... maybe fuel? Please help.

uansari1 · 05-04-2006, 01:20 PM

I apologize in advance for the long story, but I thought it would be prudent to be as detailed as possible.

First off, the problem I'm having was not happening prior to my taking the bike to the shop to have the air filter and spark plugs changed and the carbs cleaned/synched.

I picked up the bike and it seemed to be running fine. I rode the bike from the shop back to my neighborhood and when I turned up a relatively steep hill, the bike started hesitating while in 2nd gear. It basically stuttered uncontrollably and stalled out. I was able to get it started, but only when I held the throttle open. It would start and run rough and stumble at low rpm, then all of a sudden it would rev high since I had the throttle open and settle into a good smooth idle. When I would put it into gear and starting letting the clutch out while simultaneously getting on the gas, it would start stumbling and stall out again. The only way I was able to get it up the hill to my house is to slip the clutch while giving a lot of throttle. It seems that the engine keeps flooding, but I have no idea why.

I had the bike towed back to the shop and they were able to reproduce the problem easily. However, it's been 4 days and they still have no idea what it could be.

Does anyone have any idea or suggestion as to what the problem could be?! Any and all help is greatly appreciated.

Thanks...

RayOSV · 05-04-2006, 01:56 PM

Do you know how they cleaned the carbs? What has the shop done to try to isolate the problem so far? Could be some crap that was/is floating around in the bowls that mattered once you were headed uphill? Just a wild guess, sorry.

hybrid · 05-04-2006, 02:04 PM

actually sounds to me like its starving for fuel.........

the f2-f3 are notorious for being finicky about the fuel inlet line. its a formed line and if it was shortened because it had a tiny tear in it, once warm it will distort and starve the bike.

you getting it revved but no load applied tells me its not getting fuel. I could be wrong as Im not there and your description was detailed but still lacking in clues

uansari1 · 05-04-2006, 02:23 PM

I don't think it's fuel starvation. There's a heavy gas smell and once idling, a sharp turn of the throttle will cause a puff of black smoke. Also, I just spoke to the shop and he said when they pulled the plugs, they were covered in soot.

My understanding of how they cleaned the carbs was carb removal, total disassembly, cleaning with carb cleaner, and reassembly. I'm not sure if they used a dip or just used various bristles and carb cleaning spray. Either way, there shouldn't be anything floating around in the bowls, as they were removed and cleaned.

What other clues can I provide?

hybrid · 05-04-2006, 02:32 PM

honestly

it doesnt matter.......did you take this to a shop that employs trained mechanics or is this some hole in the wall?

Sounds very much like its got stuck floats or float then. There should be no other reason it would do that so soon.

Last oddball thing Id say is that the choke rail is bent and sticking open

uansari1 · 05-04-2006, 03:08 PM

The choke rail was bent a bit, so that part was replaced when it was in the shop (forget to mention that)... The shop I took it to is not a hole in the wall. The main tech is very knowledgeable, but he's not the one that did the work on the bike. He is looking it over now, though. It's a Honda/Yamaha dealership in town.

Redstar11 · 05-05-2006, 10:49 AM

Sounds like it could be running very rich. I would definately start with the carbs. Have the shop take them back apart and look for any abnormalities. Underneath the main jet is a guide that the jet needle slides into. You can actually see this guide when you are looking down the throat of the carb. WHen you remove the main jet and the emulsion tube, this guide can fall out. Everything can bolt back together normally and will cause the bike to run super rich at 1/4-to WOT throttle because of all the fuel thats allowed past the jet needle.

Thats a shot in the dark, but I've seen it a bunch of times.

Basically, it sounds like your carburetion is fucked, and whoever did the carb clean, needs to let somebody do it right.

Again, I'm with Hybrid, who in the fuck are these backwoods mechanics?

ajohn505 · 05-05-2006, 12:13 PM

Quote:

Originally Posted by uansari1

The main tech is very knowledgeable, but he's not the one that did the work on the bike. He is looking it over now, though. It's a Honda/Yamaha dealership in town.

That's usually the problem... there's one skilled mechanic in a shop and a half dozen trained chimps. More than cost, it's actually the reason I do most of my own work now.

Goober · 05-05-2006, 04:47 PM

Have em check the fuel pump and/or the fuel pump relay. I've had mine go out twice.

uansari1 · 05-06-2006, 10:00 AM

Quote:

Originally Posted by Redstar11

Sounds like it could be running very rich. I would definately start with the carbs. Have the shop take them back apart and look for any abnormalities. Underneath the main jet is a guide that the jet needle slides into. You can actually see this guide when you are looking down the throat of the carb. WHen you remove the main jet and the emulsion tube, this guide can fall out. Everything can bolt back together normally and will cause the bike to run super rich at 1/4-to WOT throttle because of all the fuel thats allowed past the jet needle.

Thats a shot in the dark, but I've seen it a bunch of times.

Basically, it sounds like your carburetion is fucked, and whoever did the carb clean, needs to let somebody do it right.

Again, I'm with Hybrid, who in the fuck are these backwoods mechanics?

Guys, thanks for the suggestions. I really really appreciate it. I'm intrigued with the idea of the main jet guide (or lack thereof) being the problem. The only thing that doesn't explain is why would the bike have been running ok for the 10-15 minutes it took me to ride to my neighborhood?

Keep it coming guys, thanks again!

uansari1 · 05-11-2006, 10:27 PM

Latest update... I asked the tech if it could be the main jet guide a few days back and he was sure it wasn't the guides. He just got a new set of needles in today and will try them out tomorrow. He thinks there's a chance the needles could just be worn and are letting too much fuel by. That still doesn't account for my having no problem with the bike for 10-15 minutes until I got to my neighborhood.

That's his latest guess... not sure what else it could be. It's been two weeks so far. I have no idea what else to do... at least it's supposed to rain for the next 10 days, so I'm not frustrated about not being able to ride anymore.

uansari1 · 05-15-2006, 03:01 PM

Just got a call from the tech... he said it was the needles. The old ones were seriously out of spec, according to him... So they're just synching the carbs now, and the master tech is going to take it for a nice long ride and tear it up on the bike. I'm so stoked right now...