1980 GS550E Bogs at 65mph

[Anonymous]

Please bare with me as this is my first post and my first motorcycle.

I just recently bought a GS550. I am currently working out the kinks from it's previous owner. Everything seems to be great except when i'm around 65 or 70 mph I hit the throttle and the bike actually SLOWS down in stead of pepping up. Can anyone point me in the general direction of the issue? Do I need to adjust my fuel/air mixture? A friend of mine thought that maybe the outter 2 was running too rich. How do I go about fixing this?

Also the engine seems to be running very hot. Is this normal? How hot should I expect the case to be?

[gspaul]

Any mod's to the bike that you know of,exaust,air filter,etc

[Planecrazy]

Several things can cause bogging at speed. One of the most overlooked possibilities is that the gas cap vent is obstructed, and after the bike has been running awhile at mid to higher rpms (like on the highway at 65mph) too much vacuum builds up in the tank and starves the motor of fuel.

To test for this you can try CAREFULLY running the bike with the gas cap open slightly and see if the problem disappears. Be VERY careful to make sure that you have adequately taken steps to make sure the cap can't fly off the bike, and that gas can't slosh out and cause a fire risk (or get up into your face). If the bike runs properly you've found your problem. Then it's just a matter of getting into the gas cap and cleaning or replacing the obstructed parts.

Others will be along soon to give you other ideas if this turns out not to be the problem.

Good luck and welcome to the forum!!
Steve 8)

[spots25]

i had a problem a lot like that, and it turns out the screens on the fuel inlet in the carbs were plugged up. I recommend doing the above first, and cleaning those carbs out 2nd

[Anonymous]

also check the screen, if it has one on the inlet for the gas tap which resides inside the tank. Any of the posobilities mentioned will cause the bike to run lean which also makes it run hot.

[Anonymous]

I am currently riding and messing with tyler6453's bike. I cannot see anywhere on this gas cap where there could be a vent. For those of you that had this gas vent problem before where would i look? It is a solid silver metal cap with a rubber o ring on the bottom. I would like to try this first as it is happening after a bit of riding. But the carbs are coming off this weekend anyway.

The bike has no mods. Thanks for all the suggestions. This should make for a fun weekend

[Anonymous]

You might take a look at this thread. Definitely worth a try.

http://www.thegsresources.com/_forum/viewtopic.php?t=36295&highlight=starvation+mystery

[Anonymous]

Carbs came off. cleaned bowls. Found one jet with screw tip ( number 42 Jet Main?) laying in the bowl. Bowl vent tubes are non-existent. Blew air through vent nipples and no obstructions. shot conctact cleaner through tiny hole in the middle of the gas cap and some junk and brown stuff came out of the two side holes.

That said. should the vent tubes be there as it is a stock bike? And the fuel mixture screws are set to two turns out. The bike idles nicely just around 1k. but after riding for awhile the bike does not want to stay running at idle.

perhaps that last bit needs to go into another thread but just thought I would bring it up.

thanks again for the help

[Anonymous]

Dang, I'm just posting to keep this thread at the top... Regarding vent tubes, they seem to create a problem even with stock bikes. As far as the rest of your question, I don't really have enough information to give a helpful response. Probably two separate problems (geez, surprisizing with a carb question ), maybe more info would help or someone who knows something....?

[Anonymous]

Wow! Took the bike on a 200 mile ride this past weekend. I think it was the gas cap vent. but I donot regret taking the carbs off.

Speedometer needle was gone! plenty of rpms left. The idle problem only happens after sitting in traffic now. I think the owner of this bike can live with that.

This bike thanks all of you.

[Anonymous]

so the bike has been running great and I took it to the beach over the weekend. On the way down it was running great and then the first stop light came up on us after riding for a good 65 miles straight and the idle dropped as i slowed and it stalled. didn't do it again till the ride back. It stalled almost every time we hit traffic and i just let it idle. It idles at about 900rpm usually. The problem goes away when the bike cools. But when the bike is hot it tends to do it constantly. any suggestions?

[Steve]

Adjust the idle to 1050 +/-50 as called for in the manual. :roll:

[chrissinc]

Agreed, at 900rpm its a little too low for consistant idleing. Try around 1100 and see if it works.