Questions about GS450 carb problems and some vac routing

[boostthis89]

Ive read a bit on here before joining and it comes down to the carbs having an issue being gummed up on the gs450.
I am trouble shooting an 88 gs450 for a friend and the bike runs with choke wide open, but dies at very slow throttle movements, also dies when the choke is turned off.
She claimed that she had the carbs cleaned prior..
I did tear the bike down to the carbs and I found a few things...

there is a hose coming from what im guessing is the fuel gauge sending unit?? where does that go to?

do the overflows coming off the carbs just hang down or is there a specific place they need to attatch too? the bike is missing one of these but the other is intact.

on the valve that comes off the gas tank and feed fuels.. The diaphram on it seems to be working properly.. im guessing the "Prime" part on the switch just fills the carb bowls by allowing fuel to just fall in??
ON is the ON running position..
The vaccumm line attatching to this part draws vaccum and in return puts fuel to the carbs?? so I should be able to put a hose on it.. suck on it and push fuel out of the feed?


Any common area's of problems besides just tearing the carb down and soaking it overnight in cleaning solutions just to make sure its been done?

 

[apopleptic]

Welcome to the forums, not 100% sure on the 88, but here are a bunch of things that you can find in the forums from the search.
I own an 80 GS450. I assume there will be some similarities.

1. The overflows usually will hang down (anywhere but on the battery is my suggestion)
2.Not sure about your 'fuel gauge sending unit' if you have a vacuum petcock maybe that's the bit you are talking about.
3. sucking on the vacuum hose should make fuel come out the other part of the petcock into the carbs.
4. prime flows freely, on is the normal vacuum running position for the carb. leaving on prime will flood the carbs and get gas in your oil.
5. the choke adds extra fuel for when the engine is cold. personally I never use the choke. it should be shut off shortly after the bike engine is warmed.

My guess would be that you have some major leaks in your system causing a bad air/fuel mix. leaks around the intake boots. maybe around the air filter.

Watch out when soaking your carb since a lot of carb dip cleaners will eat the rubber bits. full disassemble is suggested.
Again not sure how similar your year is, but you can take a look at BassCliff's site for some useful info.
http://members.dslextreme.com/users/bikecliff/

 

[BassCliff]

Greetings and Salutations!!

Greetings and Salutations!!

Hi Mr. boostthis89,

The overflow for the fuel gauge send unit just routes past the battery to the ground. Are the hoses you call "overflows" really "vent tubes"? And it does sound like your carbs need a proper cleaning. What you describe is how dirty carbs act. You'll find lots of information in THIS GUIDE and a specific 450 carb clean-up guide HERE. Pay attention to the required maintenance lists in your "mega-welcome" below. Let's roll up our sleeves and get started.

Let me dump a TON of information on you and share some GS lovin'.

I just stopped by to welcome you to the forum in my own, special way.

If there's anything you'd like to know about the Suzuki GS model bikes, and most others actually, you've come to the right place. There's a lot of knowledge and experience here in the community. Come on in and let me say "HOoooowwwDY!"....

Here is your very own magical, mystical, mythical, mind-expanding "mega-welcome". Please take notice of the "Top 10 Common Issues", "Top 15 Tips For GS Happiness", the Carb Cleanup Series, and the Stator Papers. All of these tasks must be addressed in order to have a safe, reliable machine. This is what NOT to do: Top 10 Newbie Mistakes. Now let me roll out the welcome mat for you...

Please click here for your mega-welcome, chock full of tips, suggestions, links to vendors, and other information. Then feel free to visit my little BikeCliff website where I've been collecting the wisdom of this generous community. Don't forget, we like pictures! Not you, your bike!

Thanks for joining us. Keep us informed. I will put you on my prayer list.

Thank you for your indulgence,

BassCliff

 

[boostthis89]

Already found that carb cleaning tutorial on here for it!! im an Auto technicion so this carb shouldnt be a big deal.. I just am not farmilur with this bike and wasnt sure on them couple things as far as the routing..
I already have the carbs off and apart.. I was just wondering if there were any common problems besides dirty jets that I wasnt finding on the forum..

THis bikes been in a friends garage for a few years and i hate seeing it go to waste... PLan on helping her out and getting it running so she can enjoy it again

 

[Steve]

I will answer your questions the best I can:

there is a hose coming from what im guessing is the fuel gauge sending unit?? where does that go to?
That hose is just an emergency drain, in case the gasket ever leaks. It will direct fuel away from the hot engine and exhaust, so just route it back, over the airbox and down, between the pipes.

do the overflows coming off the carbs just hang down or is there a specific place they need to attatch too? the bike is missing one of these but the other is intact.
You don't have "overflows", they are vent tubes. They should be routed up, over the airbox. Not sure about your particular model, but some airboxes have loops on the back side for holding the tubes, sometimes there is a loop on top of the filter housing (if your is separate). Basically, they just hang in some still air to provide an atmospheric reference for the float bowls.

on the valve that comes off the gas tank and feed fuels.. The diaphram on it seems to be working properly.. im guessing the "Prime" part on the switch just fills the carb bowls by allowing fuel to just fall in??
That is correct.

ON is the ON running position..
Also correct. You should leave it here when you stop the bike, too.

Basically, it stays in this position unless you have run far enough to get to the REServe part or the carbs are empty and you need to PRIme them.

The vaccumm line attatching to this part draws vaccum and in return puts fuel to the carbs?? so I should be able to put a hose on it.. suck on it and push fuel out of the feed?
Yes, you can suck on that line and fuel should flow, but it won't be "pushed". The vacuum just opens the valve and lets gravity pull gas to the carbs.
WARNING: If there is a hole in the diaphragm, you may suck gas through it, so use a vacuum pump, not your mouth.

Any common area's of problems besides just tearing the carb down and soaking it overnight in cleaning solutions just to make sure its been done?
Since you say you have seen the carb cleaning guide, you already know about the overnight soak (make it a full 24 hours if you don't know the condition of the carbs), only soak metallic parts (no diaphagm, filter screens, etc.) make sure the carbs are COMPLETELY apart (including the covers over the idle mixture adjustment screws), put them back together with new o-rings from cycleorings.com, replace the o-rings on the intake boots, sync the carbs.


That should handle the carbs, but don't forget the valve adjustment. It should to be done, and NEEDS to be done before the carb sync.

.

 

[boostthis89]

thanks steve!!!

I actualy started taking the carbs apart, the bowls and jets looked very clean all accept for ONE.. one of the smaller jets was literaly closed shut... I figured what the heck all of this looks very clean inside ill just clean it a bit more and spray out everything i can find as well/disassemble and then put it back together..

Put it back together and it purrs like a kitten now..
Ill be doing a valve adjust for her and syncing the carbs as well though.
Glad to see another bike get back on the road..
hopfuly with 6k original miles on the bike i wont find too much other things wrong with it, but I know how it goes with cars that sit for a while, bikes are probably the same lol

now just to find her some reasonabley priced tires!

 

[SgtRauksauff]

now just to find her some reasonabley priced tires!

Not sure what your definition of "resonabley" is, but I just ordered a set front/rear for my 450L , 100/90/19 and 120/90/16, for ~125 shipped from motosport.com. They were the Kenda K657 Challenger.

--sarge

 

[boostthis89]

hey sgt .. small world!! you go to shawano last weekend??

I was looking at the Kenda Challengers actualy!

 

[Steve]

Challengers are OK, but don't tend to last very long.

Many of us are in the process of trying to find out how long the Shinko 230 Tour Masters last.

Depending on the size you are needing, a pair of them is about $120 from Motorcycle Superstore.

.

 

[SgtRauksauff]

hey sgt .. small world!! you go to shawano last weekend??

I was looking at the Kenda Challengers actualy!

Hey man, small world eh? No, I didn't go to Shawano, there was an AutoX at Jefferson, closer by about 2 two hours.

I'm not expecting great things of the Challengers, but at 125 shipped, they'll be perfect to actually drive on to find what needs to be fixed on the bike instead of the dry-rotted tires from 1987 that are currently on the bike. They don't LOOK bad from the outside. Hell, the front even still has the blue film over the raised white letters! But I'd rather not have an explosive decompression any time soon, 'specially on the roads around here.

--sarge