Gs550es 5000 rpm fail

[countrycummins99]

so i recently picked up a 1983 gs550es it was my friends who is an excellent mechanic it starts pretty much instantly runs great until you get to about 5000 rpm at which point it starts to break up almost like the main jets are not supplying enough fuel carbs have been taken apart and inspected 3 times can find nothing wrong or dirty. also no vacuum leaks around the boots. it is my understanding that these bikes came pretty lean from the factor so i imagine the kerker exhaust only added to this problem was just curious if yall think im on the right track by getting some new jets for it?

[Agemax]

hi and welcome, you could be on the right track but surely, your excellent mechanic friend should be able to sort it out for you, or is that the reason he sold it to you, because his mechanical excellence did not include fault finding?

[terrylee]

If the bike had been sitting very long at all and not been running, you need to strip the carbs down, dip them in carb. cleaner, replace o-rings (get at "cycle-o-rings") and then adjusted fuel mixture screws (do a search on here, plenty of threads about it on here). Of course carbs will need synced. You may have to move up a size or two on the main jets due to the exhaust, especially if you not running a stock airbox and filter. If it runs well except at higher rpms it probably block mains or not big enough. There ar guys on here with more knowledge than me that should be along to answer more. terrylee

[countrycummins99]

Hey

ya my mechanic friend got the bike to the point it is now he said it probably needed bigger jets he just never cared to do it since he didnt ride the bike the other thing is if you leave the choke on the bike will run fine which indicates to me that the jets just aren't supplying enough fuel and the carbs are spotless inside so i know dirt is not the problem. as far as tuning the carb do i just put a vacuum gauge on each carb at 1750rpm and make sure their pulling the same right?

[Agemax]

1750rpm is a bit high for carb synch but yes that is the idea. you need 4 gauges and do them all at the same time. what main jets are you running at the moment?
you need to go up by about 25% on stock for a ball park setting.

[Nessism]

You might want to check the Newbie Mistakes thread linked in my signature to see if anything applies. The jetting shouldn't cause the problem noted, unless you have also modified the stock airbox.

[SVSooke]

1750rpm is a bit high for carb synch but yes that is the idea. you need 4 gauges and do them all at the same time. what main jets are you running at the moment?
you need to go up by about 25% on stock for a ball park setting.

Only need 2.The 83 550 has the siamesed carb and only 2 spots for testing.Tried to do one once but normal Suzuki spigots don't fit

[Agemax]

Only need 2.The 83 550 has the siamesed carb and only 2 spots for testing.Tried to do one once but normal Suzuki spigots don't fit

ah, ok. my mistake. i know some of the 550's had the siamesed carbs but not sure which models.

[countrycummins99]

You might want to check the Newbie Mistakes thread linked in my signature to see if anything applies. The jetting shouldn't cause the problem noted, unless you have also modified the stock airbox.

would the exhaust also cause the problem to?

[countrycummins99]

also

everything points to a lack of fuel and i know its not dirty carbs so i think the jets are my only option i know its getting clean fuel from the tank any other ideas are welcome i perused through the newbie thread but didn't see anything that pertained to this issues

[JEEPRUSTY]

Just to ask again but the airbox is installed right?

[countrycummins99]

yup

factory air box and filter

Just to ask again but the airbox is installed right?

[JEEPRUSTY]

Bugger............
Do you know what size mains you have in there?

[elrico]

Kinked,pinched,misrouted,split,cracked,worn fuel line or vacuum line.Correct operation of carb float valves with float height at correct height...?

[cowboyup3371]

I would personally still sit down and dip the carbs properly per the tutorials found on Basscliff's site. Then go through the rest of the maintenance lists as recommended.