prime on petcock not working

[buttonhook]

Ok I'm working on my wifes (girlie_rider's) 1982 gs300l. We started having problems with this thing losing power. So I pulled the carbs cleaned them everywhere!! It ran good for a little while then started losing power all over again. So I thought hey it has pulled some crap into the carbs again. So repeat and rebuild. But this time I noticed that when I was taking the tank off to have it coated so no more crap from the tank would get in there that the prime function did not work. So now I'm thinking it has to be the petcock right??
When I took it out the other day it really ran like crap (no power for about 1/2 mile) then it took off and ran great!! I rode it for miles and it never once acted up again. Ran perfect I even stopped for a coke and then started it back up a again perfect.

Then just now we were going for a ride and when she started it again sputtering when she reved it. I took the petcock apart and the gasket inside seemed perfect but like I said it would not go to prime. Now I'm stumped. I'm trying to get this thing ready for her to go to the dragon this weekend to meet everyone. She's super ****ed!!!!!

BTW it has just been tuned up all well.

[deves3000gt]

Does fuel flow from the petcock if you apply vacuume to it? If not then I would say that is your problem. If so then i wouldn't bother with changing the petcock (just yet). IMO good luck

[buttonhook]

Does fuel flow from the petcock if you apply vacuume to it? If not then I would say that is your problem. If so then i wouldn't bother with changing the petcock (just yet). IMO good luck

I'm going to check that tommorrow but I would think that it does at least some because of the way it "catches after a little bit"

[tkent02]

Is your gas tank vent clogged?

One other thing, you work on her bike and she's p:ssed at you?
WTF is this sh:t?

She can fix her own bike or walk.

[buttonhook]

Is your gas tank vent clogged?

One other thing, you work on her bike and she's p:ssed at you?
WTF is this sh:t?

She can fix her own bike or walk.

I took the cap apart and checked the vent everything looked ok. I then took the cap off and tried again the run it. still no luck.

Yeah she's ****ed...go figure. we just got done arguing about it. She's mad because I bought me a new bike a ninja(it was my forth bike all used before) and I bought her an old bike (her first). FYI I Just got done buying all new plastics for this thing as well as repainting the entire bike!! I also pulled the carbs and cleaned them twice! The spark is good, the air filter is good, new battery and everything was working until one day it just start acting up.

It seems everytime after I work on it and ride it when she's not home it runs good. then I tell her I think it's ok. then it's not!!

[buttonhook]

ok here's the update,

I took the fuel line and vac. lines off of the petcock. I replaced the vac. line with a new one I then put a remote fuel tank on the fuel line and put a fuel line from the petcock to a gas can. I started the engine. At idle the petcock does work under vac. on both run and res.(still no prime). But the engine still sputter!! I did notice that when I reved it the fuel from the petcock/gas tank stopped??? does that mean I have a vac. leak somewhere?? If so where is the best place to start looking??

[Calvin Blackmore]

Check for a torn petcock diaphraghm
torn or leaking

[buttonhook]

Check for a torn petcock diaphraghm
torn or leaking

thanks, I did and it seemed to be ok. the petcock did work under vac. (both res. and run)but not on the prime setting???
But I think I found the problem with the engine!!! \\/
I'm still going to replace the petcock but it's not the emergency it was this morning(I hope).
The 5/8" vacumn/breather line from the top of the engine to the air box was dry rotted and cracked!! I just replaced it. It seems to run great again. We will see when the wife gets home, if it will still work for her????

[buttonhook]

What the HEWLL is wrong with this thing?? It ran great this afternoon, then the wife got home got all of her gear on started it, it started fine. she started riding it and bang it does it again!!!!! I'm just about over it!!!

[DimitriT]

Coated tank you say. There's a little hole in the tank filler neck. Make sure it didn't get coated over. That hole needs to be clear for the tank to "breathe".

[buttonhook]

Coated tank you say. There's a little hole in the tank filler neck. Make sure it didn't get coated over. That hole needs to be clear for the tank to "breathe".

I went out and cleaned the gas cap again put it back on and it ran great again. I hope it does tommorrow???

[buttonhook]

I went out and cleaned the gas cap again put it back on and it ran great again. I hope it does tommorrow???

Nope!! still doing it again!! I can start it and it idles great then when you rev it up it sputter and will not rev up. if you keep giving it gas (for like 5 min.)it will catch and run great and not sputter again. I'm going to tear back into the carbs again I guess. is there anything I should look at and does it sound like it is running lean or rich???

[buttonhook]

ok update again,

I replaced the needle valves and seats. The new ones looked different than the old ones. The old ones did not have the screens on them and the seats looked alittle different. I also replaced the floats with new ones. I reset the float levels to 21-22mm. I then reassembled everything. It seemed to run fine again. \\/

But it does everytime I work on it for a little while. [-o<

One thing I did notice was that one rubber snorkels was missing the spring that goes around it and holds it to the air box. Now the snorkel seems to still sill tight againt the air box. but could that be the problem.

[buttonhook]

UPDATE!! all is well that ends well I guess.
I ended up tearing the carbs back out again on thursday. Luckly I had an extra set of junk carbs laying here. So I just replaced the floats, needle valves, seats, and main jets in the current carbs with parts from the extra set.

I put it all back together again and it ran great again....and still does. So something internal was wrong (I'm thinking I had a bad float).

But true to form this little GS did not give up easy. Me and the wife got up at 6:30am on fri. to meet everyone in robinsville. We got on our bikes and while hers was warming up I noticed that there was gas on the right hand float bowl????? So I started checking everything I though I had not tightened the screws on that bowl tight. So here I am with a Z shape screwdriver trying to tighten the screws. I wiped the gas off and check it again no gas!! Great right?? Wrong... We rode to the gas station 1/2 mile away,were I check it again....gas on the float bowl again!!!!! So I told her just ride staight to the autoparts store and we would fix it there.
So I disassemblied this bike again in the parking lot. I pulled the carbs and started double checking everything. After about an hour I found the problem. The BRAND NEW fuel line I had just put on the day before was cut. And was spraying gas on the side of the float bowl. So our ride didn't get to start until about 10:00am.
But it ran GREAT and we made the trip over to robinsville with out trouble(except the accident see Girlie_riders post on the wreck) we rode about 200 miles friday. And it ran better than it ever has. she had that little 300 up to 70+ with power to spare (I had it up to about 85 on the highway:-\"). So I guess the headache was worth it.

Thanks for any help!!