Carb flooded and massive backfiring?

[Guest]

So I am working with a 1982 GS450T; bought it somewhat disassembled. Wiring was a mess, carbs were off, no battery...not too too bad, I know a lot of guys have started with more pieces, but I've made some progress. I got a new battery on it, wiring seems functional, albeit, once I know it runs and runs decently, I plan on a complete overhaul.

Anyway, last night, decided to connect the hoses from the petcock to the carb and see if she'd fire up. Fuel lines connected, gas in tank, ignition "ON", kill switch "RUN", petcock "PRIME". I go to start it, it's cranking, there's exhaust spitting out, POP!, backfire, keep going, nothing. Try again, more exhaust, POP!, another backfire; look at carbs...they're leaking out of the overflows. Switch petcock to "ON"; leaking has stopped/slowed down...try again, same old story.

I know I need 3 things to cooperate so I check the airbox; clamps are tight, looks fine. Cross of air.

Next, fuel..well. There's definitely fuel. I didn't go through the carbs myself, I opened them up and did a visual inspection, but PO had them cleaned professionally, so I trust they're OK. Please note however, I did pull the pin off the LEFT carb float (this might be important in a minute). I put it back, closed them up, and put them back on the bike. One other thing I did notice, one of the bowl screws/bolts, wasn't catching all the way to snug it up, just spinning, so I may need to figure that out later, but again, just trying to get it running, not riding, overhaul will ensue.

OK so, air and fuel seem, OK?

Next, spark/electrical right?

This is where I was hitting google hard; I wasn't sure how to test a spark plug. I pulled the right plug first, it's fuel fouled. Black and stinky. Cool.

Next was ol' lefty; she's white and wet (giggity). But like, brand new white, not like lean white. Like, I'm betting these are new plugs.

I stuck a screwdriver in the spark plug wire connector and cranked; no spark, should there be one? I'm not sure...there wasn't though.

I guess my question is, not what the issue is necessarily, but where to start; hoping one of you vets can throw a dog a bone on this one. This is my first project bike, with some mechanical background, but I've never tried to make something run that started off dead.

[C_OUELLET]

this may be a long shot, may not even matter, but do you got the right coil going to the correct cylinder? I had them switched on my bike at one point when trying to get it running. It made a loud snap sound from backfiring and blew smoke out the intake. I eventually got it to run momentarily. Still needs work though.

[briggery16]

You know I had read that on the forums, and I lifted up the tank and the left coil is going to the left plug, right coil going to the right plugs; is it as simple as that to check? I guess I could just swap them and see..

[chuck hahn]

I am going with float hts way off and the carbs are flooding the cylinders. Then when the fuel does ignite its a massive explosion into the pipes.

Have you FULLY disassembled the carbs and added new orings? If not heres the tutorial on CV carbs. Just need some Berrymans dip, some carb spray and an air compressor to clean them well. Take the parts basket out of the can of dip and do both carb bodies at the same time. 24 hrs soaking in the dip.

http://www.mtsac.edu/~cliff/storage/gs/mc_maint/GS_CV_Carb_Cleaning_Series.pdf

Here are the orings. 1 kit will do your bike twice as it comes with orings for a 4 cylinder bike.

http://cycleorings.com/

[briggery16]

OK sweet, yeah a buddy suspected floats as well. I did take the float off/back on for the left float only; I didn't pay any attention to it honestly, that's probably it.

And thanks for the cycleorings link; I ordered the partial CV kit for twins, as I'm trying to keep the costs to a minimum for now, and every penny counts!

[chuck hahn]

Soak those carbs if you hadnt already too. The tiny internal passages must be as clean as possible for good performance. Snatch a wire off a wooden handled wire brush and poke all the holes in the jets and remember the pilot jet has a hole in the very tip that has to be opened up. basically follow the tutorials steps and youll be fine.

[chuck hahn]

Valve adjustment is critical also on these GSs so be sure they are within specs too. Third manual down here should be your bike..manual selections menu.

http://members.dslextreme.com/users/bikecliff/

[briggery16]

Yeah, I came across the BikeCliff manuals prior to even purchasing; to my surprise, it came w/ a clymers!

It also came with a spare valve cover and some loose valves, which actually kind of worried me. Upon further inspection, it looks like the valve cover is new(er), and I can see a silicone gasket was used in hopes to seal it up. Are gaskets a tough thing to do? Or is it just mainly being precise?

[chuck hahn]

I will PM you my number. Call me..easier to explain it in real time.

[briggery16]

OK so I'm pretty certain it's two things:
1. Floats; wrong heights or stuck.
2. Definitely leaky petcock. Had it set to "ON" and it just pours fuel. Checked it out, has the silicone "gasket" oozing out of the sides..PO had a time with this one. I'm going to buy a new one; I'm looking at G & S Suzuki, and I'm a little baffled by which one to get. There's two different petcocks listed on there. Anyone know which one is right? Part numbers are 44300-45372 (replaces 44300-34470) and 44300-45471 (replaces 44300-454700)

http://www.gssuzuki.com/fiche_section_detail.asp?section=92582&category=Motorcycles&make=SUZUKI&year=1982&fveh=2100

[chuck hahn]

I would think 1-1 is the one. Get 2 #4s as well to seal the bolts.

[hannibal]

I've read bad things about G&S. Their prices are very good, but service is lacking. Someone received the wrong part and had little luck getting them to correct the situation. Buyer beware!

If you're not set on buying a new OEM petcock, people often suggest buying one from Z1. I bought one form Z1 but haven't run it yet. Their website says both of the petcocks they sell are out of stock.

[briggery16]

Thanks for the heads up hannibal; I rolled the dice and popped on a used "working" gs petcock on eBay, $20 shipped. I was looking at $70 shipped through G&S...If it was my daily bike I would have splurged for the new one, but being as it's still in the "get it running" phase, trying to keep my expenses low, at least for now.

[briggery16]

So I pulled the old petcock, just to take a peek at it before the "new" one arrives....drained all the remaining fuel, which was maybe 1 cup, but in the meantime, should I do anything to the tank to prevent rust?

Petcock should be here by next week...don't want any extra de-rusting I don't have to do.

[chuck hahn]

I would duct tape over the holes and slosh just a little gas around to kinda coat it. Maybe give it a shake each day till the new ones in hand. The gas will coat it well enough to inhibit rusting