Gs450 can't figure this out.

[Yubjub]

I took a liking to my dads old bike and been trying all winter to get it running right. It had only 6k miles but sat for many years. When I did get it started it backfired constantly had almost no power. I had the carbs cleaned and it was better but still not right.
After a couple hrs of sitting I noticed a puddle of gas under the bike and on top of that there is gas getting down into the oil and then it doesnt start. Change the oil it starts right up and the process repeats. There's Also an oil leak coming from the front of the top end so I know the gaskets are probably shot.
I've always been a car guy so I'm new to tinkering with bikes but I'm not afraid to get my hands dirty. I found this forum and here I am looking for some experienced gs owners willing to help me out.

[Big Rich]

It's the petcock. There is a diaphragm that is supposed to open when getting a vacuum from the carbs. Either your petcock is on the prime position or the diaphragm is bad.

[pete]

Also, have you checked your valves? Probably want to check the state of the intake O rings and boots and things while you're at it.

[Charlie G]

What they said.

[Yubjub]

Obviously im gonna check the forum search when I get time after work today but i thought I'd ask as well.. Is there any tear down diagrams for the carbs and engine on the forums. I could do it without but would feel more comfortable with something to reference while I tackle this project.

[spyug]

BikeCliff's website has copies of the manuals and lots of interesting and informative tutorials done by some of our leading "gurus". Everything youi should need will be there.

Did you get his mega welcome with the information laid out for you?

Spyug

[Charlie G]

http://members.dslextreme.com/users/cbsaunders/gs/gs450_carb_cleaning_guide.pdf

This link is from Basscliff's site. It will help you with carbs. Good luck.

cg

[Yubjub]

That would have been the smart thing to check out first. I did get the welcome I just haven't explored the site much yet. Ill be sure to check it tonight thanks for the quick responses.

[Buster-boy]

Gas under bike means petcock is shot or it's in PRI position like the other guy said. Oil from top means head/valve cover gasket or possibly the camshaft plug/caps on the ends of the head. Gas in the oil means bad head gasket, cracked head, bad valve o-rings/seals or bad rings (not likely rings).

IMO the best thing to do would be do a compression test first. That'll tell you if your gaskets are shot. If that doesn't check out tear it down, replace all the gaskets, check the valves, replace petcock.

Z1 Enterprises sells a pretty good full engine gasket kit.

Been there, done that three times because I tried everything else first.

[rlong74]

Check everything.

[Charlie G]

I have read of a bad petcock flooding the carbs and washing gas into the engine through the intake. Don't run the bike with gas in the oil. Checking the petcock is fairly easy. Engine off and cold. Disconnect the fuel hose ( Not vacume & have a cantainer ready)from the petcock while it is in the on position. If gas comes out it's bad. My 1980 450e has a petcock which has a brass screw, in addition to the lever, which is turned to get the bike to prime. Prime by passes the vacume function of the petcock and alows gas to flow into empty carb bowls of a bike that has been sitting along time. It took me awhile to figure that out. The screw turned one way or the other primes the carbs. I can't remember which way, as I only did once a couple of years ago. What year and style is your bike?

When my petcock went out, it would randomly have no gas feeding to the carbs and die. Drove me nuts for a month till I figured out I had a vacume petcock. Pre-GSR days.

cg

[Yubjub]

Well I ordered a rebuild kit for the petcock. It deffinatly is letting gas through. As far as gaskets go that z1 site I couldn't find any gaskets for the bike. I'm guessing ebay would be the way to go with that?

[pete]

I believe calling Z1 is a good option if they don't have what you need online.

I haven't called them (expensive call from here) but I had a follow up question on the stainless bolt set I ordered and they gave me pretty quick replies via email.

Try to use genuine gaskets if you can, and there's a dealer over there I bought my rings from because they were 1/3 of the price here which is www.boulevardsuzuki.com.

[Yubjub]

Well thanks to all the great info on this site the bike is ALIVE! I rebuilt the petcock, checked my compression 125 in both cyl, and cleaned the carbs up really good.... As soon as I put her back together this afternoon she fired right up and rode nice and smooth. I put about 200 miles on it since this afternoon and not one problem. I still have the oil leak to deal with but for now shes at least back on the rode.

[Charlie G]

Glad to hear a happy ending. You know it really dosen't stop with getting it running. There is always something that needs to be serviced. Good luck.

Charlie G