Flooding Carbs Even after Rebuild

[Knobbynut]

I have had my Bandit 400 for about a year now and have been having problems with it flooding out and getting bad mileage. Plugs are black on all 4 cylinders. I have rebuilt 2 separate sets of carbs for this bike and have had the exact same results. It must be something I am doing but do not know it. I cleaned all passages thouroughly, installed new o rings,  rubber plugs and adjusted the float to spec. The bike ran ok before I rebuilt the carbs. I mean ok as in not great but ok. But at least it got 40 mpg and didnt flood out before rebuilding. Now it runs great at high rpm but will not idle without sucking gas and fouling out plugs and it gets about 20-25mpg and wants to seriously die out with out constantly opening the throttle to keep it running. I bought a second set of carbs on ebay and have the exact same results after my rebuild. I did at one point for about 2 days have the bike running excellent (like a dream). Then I opened up one float bowl and removed the float assembly, installed new o rings and new rubber plug, then my real problems began (I lost that cylinder and could not get it back then decided to rebuild the carbs with o rings and rubber plugs). I cannot get this bike to idle anymore without seriously flooding out. I checked the float needles and they look good (besides it was running great before I took the one float bowl apart). It seems it has something to do with the o-rings or rubber plugs even though they are new. I must be missing something. Is there a common problem that people do to these carbs durring rebuilds that cause this symptom? I have made sure that the choke is completely off (even if they were on it would run good cold one would think). I am almost completely sure this is a carb issue (fouled plugs/bad mileage/dark smoke out exhaust). Are the floats really touchy? I am at my wits end with this thing. There is more to the story but I do not have enough room here and this is already long enough. Any help is greatly appreciated.

[Vidrazor]

Sorry I can't offer an answer, but I have to say my bike has suffered a similar fate after getting it back from the shop last Friday. I too had intermittent problems with fuel delivery, and last week they became permanent.

Turned out my carbs had rust and other junk and the shop cleaned them out. The first day I got it back it ran great. The next day it started stalling at idle.

We put fuel line cleaner fluid in it as a stopgap measure until I brought it back after the Labor Day weekend. That appeared to work intermittently, but not much came out of that. As the weekend progressed the situation got worse. I got home from a day's ride and when I went back that evening to ride out, I couldn't start the bike.

I have big long hill by my apartment and took the bike down it to bump it. After a couple of bumps I finally got it going. Unfortunately I was paying so much attention to this issue that I didn't realize how much speed I had gained from keeping the engine rev'd up, turned at the bottom a bit too fast and wiped out. Annoyingly the engine was still running with the bike on it's side!

This morning I limped the bike to the shop and had to bump it down that same hill again. This time I was almost at the bottom before that damnned engine finally fired up. I was getting pretty nevous.

I don't understand this strange symptom, and it's surprising to me that you appear to be suffereng the same fate after a carb cleaning (and in your case, a rebuild). That doesn't hold too much promise for the situation with my bike.

I'm one step removed from junking my '400. If the repair bill from the wipeout is high enough, that's exactly what I'm going to do. I saw this beautiful red Nighthawk 750 today and started thinking that's where I should be going. I wish Honda still made those today, I'd buy a new one on a heartbeat.

[interfuse]

Are the floats really touchy? I am at my wits end with this thing. Any help is greatly appreciated.

I'd check the float height again. I f'ed it up the first time I did it. A couple of mm's difference and the bike won't run right. Here's a link that describes checking the float height in detail.

http://www.factorypro.com/tech/float_height_adj_procedure.html

Instead of a float height tool I use a venier caliper that I've modified with a piece of plastic so it extends all the way to the top of the float.

While you're at it make sure the floats are all stuck onto the carbs really good. It should be difficult to pull the floats out of the carb body.

[Maniac]

The floats in the Bandit 400 don't really seem to be able to fully shut off the flow of fuel. Thats fine when the engine is running, because the engine is going to be using some fuel.

But... when the engine is off, thats another story. If your fuel petcock is bad and allowing gas through even without vacuum applied to it, you will eventually flood out the engine.

[Knobbynut]

Thanks guys, I think I will try readjusting the floats so they close a little sooner (nice link). I am starting to think that may be my problem since my petcock doesnt leak (been sitting on the bench for a week (full) now with out any leakage).

Vidrazor, sorry to hear about your wipe out. It sounds like you are ok though considering you are interested in getting it fixed or getting another bike. I was having a similar thought about getting a Nighthawk too (nice bike). I would rather get this running if I can because of limited cash. I was afraid that this could be an on going problem (which it has been so far). But if I adjust the floats and it fixes it, then I know what I did to mess it up and how to fix it, I wont be as afraid of it breaking down (then I will kick myself for being too stupid to figure it out all this time).

I've been playing with this thing just about everyday for the last couple months it seems until I went on labor day vacation. It was driving me nuts thinking that gas is over $3 a gal and then my bike starts acting up and I have to drive my gas guzzler to work. I will let you know if/when I get it fixed. (Hopefully soon!)

[interfuse]

I've been playing with this thing just about everyday for the last couple months it seems until I went on labor day vacation. It was driving me nuts thinking that gas is over $3 a gal and then my bike starts acting up and I have to drive my gas guzzler to work. I will let you know if/when I get it fixed. (Hopefully soon!)

Patience is a virtue.

I've had my carbs off countless times adjusting and readjusting. In the end its all worth it.

Once you intimately know the carbs, fixing your bike won't be a big deal.

If you're planning on doing your own carb work you might want to invest in a carb sync tool.

[Maniac]

Checking the floats can't hurt, mine were off by just a few mm and it caused flooding. Couldn't hurt to check that the oring under the valve assembly isn't pinched (see pic, item 33)

[Knobbynut]

Yeah, I agree I was getting pretty frusterated there for a while. I finally got to see what its like to NOT work on my bike for more than 3 days in a row. So I am slow to get back to working on it. I did make my own synch tool from a bunch of vacuum gauges I bought from ebay but I really do not have a use for them until I can get the carbs working correctly. I will readjust the floats when I get off of my mini (motorcycle working) vacation. I will post again with the results when I get to doing it. Hopefully someone out there can learn from my mistakes so they dont have to go through this like I did. I probably should have posted these questions sooner (this has been going on (on and off between carb fittlings) for quite some time now) which is why I was so fed up with the thing (since about last year at this time). I was reading this forum up and down getting tips. I kept seeing signs of progress back and forth. I tried to never adjust the floats knowing that I could screw them up until recently when there were basically no other options. I was thinking "well it ran good before so it shouldnt be the float adjustments since I didnt touch them". Even after everything I really havent tried to adjust them to the lean side of the spec yet which is what I am going to do now. Previously I used a caliper to measure then and put them in the middle of the service manual spec. Thanks again for the helpful info.