GS 450 Fuel Starvation

[thevillaindylan]

I have a 1982 GS450T, K&N pod filters, mac perf. 2 into 1. I have jetted with 125 main and raised the needle 1 step. I have a new petcock, the carbs are clean, float height correct.

Problem - Bike will idle like a champ. As soon as I put it in gear and begin to accelerate the bike bogs down. After a short period, the bike will die when I give it gas. It then will not start until I let it sit.
Checked the plugs, they're clean. Thats why I believe it is too little fuel.

Please help. I'm gonna snap.

 

[teddux]

Dammit.
:-k

Try duct-taping your pods 'till it woiks.

 

[Mekanix]

Run it with half choke and see if that helps. If so, try a larger main.

how well does that new petcock work?

Run it until it stalls and try to drain one of the float bowls after.

good luck

 

[davidduarte]

try running some Sea Foam in it. Did you clean the carbs, or have someone do it for you? This past weekend, a buddy of mine helped me tear down the carbs and clean them. He used compressed air to blow the different jet ports out, and we removed and cleaned all the jets. That along with using his parts cleaner, and the carbs from my 80 GS450 are cleaner than they have been in 30 years. Good luck!

 

[teddux]

try running some Sea Foam in it. Did you clean the carbs, or have someone do it for you? This past weekend, a buddy of mine helped me tear down the carbs and clean them. He used compressed air to blow the different jet ports out, and we removed and cleaned all the jets. That along with using his parts cleaner, and the carbs from my 80 GS450 are cleaner than they have been in 30 years. Good luck!

I live by the sea, would that woik?

 

[Guest]

Dammit.
:-k

Try duct-taping your pods 'till it woiks.

Dude, could you please only post serious answers in the tech forum? People come here looking for solid solutions, not jokes or quick fixes. Save your humor for other areas.

 

[teddux]

Dude, could you please only post serious answers in the tech forum? People come here looking for solid solutions, not jokes or quick fixes. Save your humor for other areas.

I just removed my "ignores" and you start already?

You want serious?

Okay, past time anyway!

A CV carb only operates efficiently by CHOKING UP the INTAKE.
This is so the DIAPHRAGM has an EXCESS VACUUM than other regular carbs to OPERATE.

The explanation is basically COMMONSENSE.

By ENLARGING the JETS in a CV carb will NOT accomplish anything other than making the carb spit fuel more EASILY into engine.

This is what is being done herein because the REGULATOR for the DIAPHRAGM has been ALTERED.

So, fixing an induced problem by inducing another "MOD" is not really a fix.

If you ALTER the CALIBRATED INLET on a CV CARB, you have just screwed it. PERIOD.

By increasing the JET size doesn't solve that problem as the DIAPHRAGM NOW has some serious ISSUES.

By CHANGING or altering the NEEDLE, we are now moving AWAY from a CV carb in entirety.

And this will just go on and on and on UNTIL you can just remove the DIAPHRAGM and THROW it AWAY as it will NO LONGER be a CV CARB.
Sheesh.

 

[spyug]

I just finished a carb cleaning and rebuild on a 400E. When I tested the bike it ran ok at higher revs but still seemed a bit boggy lower down the range. We had the bike in for a certification and my wrench said he felt it "fuel" starved at the lower revs.

The bike is stock with standard airbox, headers and mufflers. What he noticed right away was that the "overflow" tubes were not routed correctly and one may have been pinched. We straightened those out and she now runs fine.

According to the "pro" these carbs need their overflow tubes connected and unkinked to allow the carb to function correctly. If the tubes are missing or have tears or holes close to the carb body they should be changed.

Have a look at that.

In addition, make sure the petcock is clean and working correctly and that the fuel hose is not kinked. Don't run an inline fuel filter either as this will slow the fuel flow.

Pods are notoriously free flowing and will create a lean situation especially if they are the cheaper Emgo kind. I usually stuff them with filter foam ( available in the lawn care section of Home Depot and other such stores) or tape about 1/2 to 2/3 of the outer mesh.

See if any of this helps. Stick with it....you'll sort it out.

Cheers,
spyug

 

[teddux]

People come here looking for solid solutions, not quick fixes.

WoW!
And, wtf do you call changing to pods and then changing jets in a CV carb?
Definitely NOT a quick FIX NOR a "SOLID SOLUTION".

You are ALSO NOT taking into account that a SuZuKi GS450cc engine is actually MORE COMPARABLE TO a SuZuKi GS900cc (IF EXISTS) by single combustion chamber standards.

Hence, YOU CANNOT use the same jet sizes that you claim successful on other'n a 450cc.

I just removed my "ignores" and you start already?

You want serious?

Okay, past time anyway!

A CV carb only operates efficiently by CHOKING UP the INTAKE.
This is so the DIAPHRAGM has an EXCESS VACUUM than other regular carbs to OPERATE.

The explanation is basically COMMONSENSE.

By ENLARGING the JETS in a CV carb will NOT accomplish anything other than making the carb spit fuel more EASILY into engine.

This is what is being done herein because the REGULATOR for the DIAPHRAGM has been ALTERED.

So, fixing an induced problem by inducing another "MOD" is not really a fix.

If you ALTER the CALIBRATED INLET on a CV CARB, you have just screwed it. PERIOD.

By increasing the JET size doesn't solve that problem as the DIAPHRAGM NOW has some serious ISSUES.

By CHANGING or altering the NEEDLE, we are now moving AWAY from a CV carb in entirety.

And this will just go on and on and on UNTIL you can just remove the DIAPHRAGM and THROW it AWAY as it will NO LONGER be a CV CARB.
Sheesh.

WHAT YOU SHOULD REALLY BE DOING IS INCREASING THE VACUUM EFFECTIVE AREA ON THE DIAPHRAGM!!!
HENCE, DUCT TAPE!!!
OR START DRILLING.

 

[Guest]

WoW!
And, wtf do you call changing to pods and then changing jets in a CV carb?
Definitely NOT a quick FIX NOR a "SOLID SOLUTION".

You are ALSO NOT taking into account that a SuZuKi GS450cc engine is actually MORE COMPARABLE TO a SuZuKi GS900cc (IF EXISTS) by single combustion chamber standards.

Hence, YOU CANNOT use the same jet sizes that you claim successful on other'n a 450cc.



WHAT YOU SHOULD REALLY BE DOING IS INCREASING THE VACUUM EFFECTIVE AREA ON THE DIAPHRAGM!!!
HENCE, DUCT TAPE!!!
OR START DRILLING.

Dynojet seems to have been able to make them run without using duct tape.

https://cart.jetkit.com/p-584-jet-kit-450-cc-suz-83-gs450-standard-float.aspx

 

[teddux]

Dynojet seems to have been able to make them run without using duct tape.

https://cart.jetkit.com/p-584-jet-kit-450-cc-suz-83-gs450-standard-float.aspx

The engine and carburetors are stone reliable if left stock, and the modified versions I've seen have been temperamental, to say the least
http://www.thegsresources.com/reviews/gs_80-81_450_review.htm

Page last modified: 03/15/10​

1980 GS450S / 1981 GS450L review
by Alex Matthews

http://cgi.ebay.com

Fast shipping.. very helpful... (

)
Mar-24-10 17:18 Suzuki GS450 GS 450 S T L E Carburetor Carb Jet Kit (#)US $39.50

Great Guys-helpful and great customer service!!! A+++++++++++++++++

 

[Guest]

OK, you think the bikes run better if left stock. So what is your point in providing a link to a jet kit? Your posts are confusing at the least.

 

[teddux]

OK, you think the bikes run better if left stock. So what is your point in providing a link to a jet kit? Your posts are confusing at the least.

I do as you and you BIATCH about that too.
YOUR HISTORY IN THIS SECTION SHOWS THAT'S ALL YOU DO, attack others that participate.

For the "noobs", don't modify your carbs as being instructed by a lot of people in here.
It seems most of them are on a commission to wherever they send you to buy parts to illegally modify you US REGISTERED STREET bike.
Note that all the stores selling these mods have a NOTICE: FOR OFF-ROAD VEHICLES ONLY!!!

TO the rest of people of the 450cc world, b4 i F*K with my jets AND YOU as these "pornstars" would have you do, this is what I recommend if you want MORE from your carb:

Now, have ANY of you DONE this??????????????????????? on a 450cc?

And, I don't have to comply with ANY EPA regulations, it's just MORE SENSIBLE to change the carb itself.
______________________________________
I need my bags unpacked, renobruce, TODAY!!!

 

[hampshirehog]

For the "noobs", don't modify your carbs as being instructed by a lot of people in here.
It seems most of them are on a commission to wherever they send you to buy parts to illegally modify you US REGISTERED STREET bike.
Note that all the stores selling these mods have a NOTICE: FOR OFF-ROAD VEHICLES ONLY!!!

US rules don't apply in the UK and it's prefectly legal to do fuelling modifications over here (though Mr Plod is less accepting of silencerless exhausts).

TO the rest of people of the 450cc world, b4 i F*K with my jets AND YOU as these "pornstars" would have you do, this is what I recommend if you want MORE from your carb:

I echo the warning ......if you haven't got much experience of tuning in carbs. It's also very difficult for someone to guide you through the exact process when they're sitting at a PC perhaps 1000s of miles away. The experienced guys can only give you general guidance and point you in the right direction - not the exact numbers

Now, have ANY of you DONE this??????????????????????? on a 450cc?

Not me. Seems an expensive sledgehammer to crack a nut. Call me old fashioned but I still prefer carbs to FI - heck I can only just about manage to turn this computer on but I could have dialled the carbs in for no more than a few bob.

 

[davidduarte]

I have no desire to play engineer with my 450. To what end? I don't know if the time you'd spend would be worth however many horsepower you might gain, and how useable would said hp be? Would you have big flat spots? I think the upshot is that unless you have loads of cash, time, and a dynamometer to play with, it's probably not worth it for 90+% of people to try to mess around with. As right now, this is my only bike, I don't want to wrench on it more than I have to. I'd much rather ride it, and keeping the engine stock is IMO the best way to do it.