Author Topic: At my wits end (Read 7939 times)

Waldron · « **on:** August 13, 2007, 06:03:25 PM »

Guys, I am totally stumped. I'm begging; I'm on my knees...PLEASE HELP ME!

Ok, me:
15 years as an automotive tech, 3 years as a motorcycle tech. But I haven't worked "in the field" for about 10 years. I'm rusty, but I should know my arse from my elbow.

The bike:
2002 GSF1200S K2. About 4600 miles; I bought it about 3 months ago. From all indications, the bike sat for about 2 years or so, possibly after being dumped. There is not one single thing on this bike that isn't factory stock.

The history:
When I first got the bike, I switched to reserve (on the ride home). Right away, it started running poorly; it felt like a pilot jet was clogged (it would lose a cylinder at cruise, and get it back under throttle). It got better after I filled up and switched back to "On", so I kept riding it. It started running poorly again a few days later, this time it wasn't just one cylinder...it was across the board. I was going to pull the carbs then, but I saw the airbox drain in the manual, so I pulled the plug. There was about a pint of liquid in the airbox; after I drained it, the bike ran well again. A few days later, back to a clogged pilot. This time I pulled the carbs and cleaned them. I know I should have flushed the fuel tank, but the bike ran well (fantastically, actually), and I put it off. Weeks later (and after an 800-mile trip), I brain-spasmed and had to switch to "Reserve". At first it was no problem, but after a few days it started running like a pilot jet was clogged again. I took the carbs out and cleaned them, and it hasn't run right since. In looking for the problem, I noticed that there was water in the tank, so I flushed the tank, took the petcock apart and cleaned it out, and pulled the carbs and cleaned them (again)...THOROUGHLY! I figured I had found the problem, but I was wrong...it still runs the same.

The problem:
When I start it, it seems "normal" enough. But when I rev it, it just won't go over 3000 rpm...if I give it more throttle, it dies. If I give it full choke I can get it as high as 5000 rpm, but that's it. If I try to drive it around the block, it has power until about 1/4 throttle, and then it falls on its face. It did this before and after I cleaned the water out.

Troubleshooting:
I had a set of plugs I wanted to put in it anyway, so I went ahead and did that. The old ones were a bit on the dark side, but nothing terrible (pretty normal, actually). The new plugs are gapped to .026". No difference. After it ran for a minute or two, I touched each exhaust pipe lightly with a wet rag...all 4 are hot. I ran it with the fuel tank lid open. No difference. I put a tube on the drain of the #1 carb and drained off some fuel...it looks great, clean and dry. I blew through the overflow hose and the vent line for the fuel tank, and there were no obstructions. The vent lines for the carbs are open and un-kinked. I held the tank over a bucket and set the petcock to "Prime" and plenty of fuel flowed. The floats are set to 13mm. The pilot screws were 2 1/2 turns out; I bumped them up to 2 3/4 turns to richen it up slightly. The fuel in the tank is now 2 days old. I pulled the vacuum line that goes from the #4 carb to the petcock and PAIR valve, sucked on it and then covered it with my tongue; it holds vacuum for more than a minute. When I was putting the carbs together, I blew into the fuel line and rocked the carbs to shut and open the needles; when they shut, no air flowed. Nothing drips or runs. All 4 slides move to the top of their travel freely with a fingertip, and return easily as well. All jets are open; I sighted through all of them. With the petcock in "Prime", nothing overflows, and the airbox stays dry. The air filter is a little dirty, but nothing that could explain this behavior. Every passage that I sprayed carb cleaner into did the same thing on all 4 carbs.

Thoughts:
I figure it has to be something I did to the carbs...it ran really well until then (except for the clogged pilot jet). The rest of the fuel system seems fine, the ignition system seems fine...all signs seem to point to the needle circuit. I had some question about which way the needle jet went in, but it sure seems like it only goes one way. I have the main jet (#100) on the emulsion tube, and the starter jet (#60) in the hole in line with it. The pilot jet is in the offset hole.

At this point, I'm totally stumped. If I had the cash, I'd take it to a shop (hang the embarrassment), but I just don't have it right now. What I DO have is the wolds largest paperweight, and summer is passing me by. Again, I'm begging...whatever it takes, I'll do. Go ahead and brainstorm; you can't insult my intelligence (at this point, I don't think I have any left). HELP!

pmackie · « **Reply #1 on:** August 13, 2007, 06:15:25 PM »

You said in your other post that these is NO inline filter on the bike, but I'm reasonably sure that all 2002's had them from the factory. They sit under the tank, about 1/2 way between the petcock and the carbs. Check/change this fuel filter first.

Based on your description, it sounds to me like a fuel restriction problem, ie: fine at idle, but not as soon as you start to rev it. So, I'd be looking for any restriction first.

I assume you cleaned the screen on the petcock (the part that sticks into the tank) when you had it off the tank?

I hope one of the 1200 guys can help you with the needle jet installation in the emulsion tube, as I have NOT had 1200 carbs apart.

Waldron · « **Reply #2 on:** August 13, 2007, 06:20:53 PM »

No, this bike definitely doesn't have one, nor does it look like it ever did. The fuel line is complete and unbroken from the petcock to the carb bodies, and is covered in what I assume to be the OEM braided sheath. Also, with the carbs out I can blow through the entire length of the fuel line without restriction.

Yea, I cleaned the screen...also, like I say; the petcock seems to flow more than enough fuel when set to "Prime", and for an extended time.

It sure does seem like a fuel restriction, doesn't it?

Edit: I think tomorrow I'll grab some clear plastic tubing and see what the fuel level does when I rev it; that will be a sure-fire test.

chupacabra · « **Reply #3 on:** August 14, 2007, 07:24:27 AM »

Check your o-rings in the top part of the carbs, and also check that the diaphrams are installed right and have no holes or tears in them. Check that all your vacuum line are hooked back up and check intakes manifolds for vacuum leaks also. I'm guessing the slides are staying closed, some kind of vacuum issue. I'm not tring to out do anyone, just took a guess that may help you.

DaveG · « **Reply #4 on:** August 14, 2007, 09:30:30 AM »

I have an 02 and can confirm no filter.
sure sounds like a fuel issue.
a similar problem on mine was the plugs but you changed yours. those small orings on the carb caps are tricky and easy to lose. if you missed them the intermeadiate curcuit would not work.

add a good dose of carb (fuel injector) cleaner to the tank (double or more the recommended dose) and see if it helps.

keep us posted.

Where are you? hands on help may be needed.

Waldron · « **Reply #5 on:** August 14, 2007, 10:45:55 AM »

Well, I put some clear tubing on the bowl drain, and the level never changed. The fuel in the bowl was clean and dry. Once again, I'm back to square 1 with this thing...I don't even know what to do next.

Red01 · « **Reply #6 on:** August 14, 2007, 02:11:12 PM »

Quote from: "chupacabra"

Check your o-rings in the top part of the carbs, and also check that the diaphrams are installed right and have no holes or tears in them. Check that all your vacuum line are hooked back up and check intakes manifolds for vacuum leaks also. I'm guessing the slides are staying closed, some kind of vacuum issue. I'm not tring to out do anyone, just took a guess that may help you.

This is exactly what I was thinking... especially those little O-rings... they seem to be easy to misplace.

Waldron · « **Reply #7 on:** August 14, 2007, 02:44:40 PM »

All 4 of the little o-rings are in place. I lost one, but I got a replacement from a hardware store that's slightly bigger, but fits into the recess in the carb body just fine.

Waldron · « **Reply #8 on:** August 14, 2007, 03:08:30 PM »

Is that picture one that you have laying around, or did you just take that? I'm curious about the needle jets; you wouldn't happen to have or be able to take one showing their orientation, would you?

Waldron · « **Reply #9 on:** August 14, 2007, 08:44:12 PM »

Guys, thanks for all the help, but I've reached the end of my rope with this thing. When I get the coin (at the end of the season) it's going to a shop, and then it's getting sold.

JamieK · « **Reply #10 on:** August 14, 2007, 09:55:00 PM »

A little early to be giving up as you've only spent a day or so trying to get help from this forum...have you tried maximum-suzuki.com? Lots of B12 experts there too. I spent over a month trying to get mine sorted after installing a stage I jet kit and full exhaust...going to do it all over again this winter with a stage II and pods. All I'm saying is if you like the bike take some time to figure it out and you'll have the pleasure and experience of making it right...if you don't like it then your decision is already made...best of luck to you which ever way you go

Waldron · « **Reply #11 on:** August 14, 2007, 09:59:58 PM »

No, I've spent 3 weeks trying to get a bone-stock motorcycle to rev over 3000. That's enough for me.

Red01 · « **Reply #12 on:** August 15, 2007, 12:41:39 PM »

Quote from: "Waldron"

Is that picture one that you have laying around, or did you just take that? I'm curious about the needle jets; you wouldn't happen to have or be able to take one showing their orientation, would you?

That pic was linked from Bill "Blade" Johnson's jet kit tutorial:
http://www.billsbikesnservice.com/stage2.htm

Banditmax · « **Reply #13 on:** August 15, 2007, 03:45:10 PM »

You tried putting you old plugs back in?

bikeb4cage · « **Reply #14 on:** August 15, 2007, 10:05:08 PM »

I am sure you have checked...but, have you checked the fuel line from the petcock to the carbs? for a kink, that is...not likely, but could be a simple cause.

Jay