What Does an Unbalanced Set of Carbs Feel Like?

[joeman001]

Hi All,

So i have had some problems with a weird tapping noise coming from the engine area on my 550es that i cant pinpoint. Some suggested that it might be low octane fuel but i have dumped the 89 octane for 93 with no change. I also checked valve clearances again and I ran it with my valve cover off and the cam chain was perfect and all the valves were getting PLENTY of oil.

My question is that could the vibration and tapping/rattling noises be because the carbs aren't balanced? I had to buy a new set of carbs for this bike off an 86 550ef and they work a million times better than the old ones but I only cleaned them and i never tuned or synced them. The only reason I ask is because I was really nailing it yesterday in 5th/6th gear and the bike would not want to pick up much more speed after 7000rpm and in 6th gear it seemed like the bike was almost stuttering as i could feel it jerking a bit and it would not go over 90mph.

I don't think there is anything internally wrong with the engine bc i had the oil pan off a couple of days ago and checked all the oil, filter and oil pickup for metal shavings, and only found 1 or 2 very small metal shavings so its not like the engine is about to blow apart. I love my Suzuki but this is pretty much my last shot in the dark before I end up selling it. Any help is appreciated in advance! (also i replaced the exhaust gaskets and that did not help either)

-Joe G

[fastbysuzuki]

You need to sync them then at best it is sorted if not you can rule that out and move on. Just how did you clean the carbs? Did you do a full strip and clean.

[phydeauxmutt]

Unbalanced carbs will be most noticeableat idle, then transitioning to low-throttle operation. In your case, each carb feeds two cylinders, so there is just one balance adjuster.

You say you "cleaned" your "new" set of carbs. How? If not done properly, blocked passages inside the carbs will not allow fuel or air to flow, essentially turning a cylinder off. That will greatly limit your power, which isn't all that much to start with.

[joeman001]

Yes absolutely stripped and cleaned to the bone. They were really really bad when i got them from the junkyard but all the rubber parts seemed to be just fine. The only thing I didnt do was split the two carbs apart when cleaning them. I guess i could try ordering a set of vacuum gauges to sync the two but i have never done that before. Do you think it will make much of a difference?

Thanks, Joe

[joeman001]

Hi,

As mentioned above i thoroughly cleaned the carbs. I made absolutely sure they were clean and checked float height, jetting, ect. I know everyone is like "Oh its only a 550 dont expect much" but this bike is supposed to do a 12.5 in the quarter mile when it was brand new and 120mph+ so for it to only do 90mph and feel slower than my camaro in a 0-60 means that something is wrong. Let me know what you think. Edit: Failed to mention that the bike idles at 1100rpm with no hiccups which does make me think the carbs might be balanced correctly or atleast close enough. Rpms also come down very quick and smoothly as well.

-joe

[zed1015]

Unbalanced carbs can cause clutch chatter and cam chain rattle.
Very common on the inline fours.
Get them vacuum balanced to rule that out and possibly cure the noise.

[phydeauxmutt]

Yes absolutely stripped and cleaned to the bone. ... The only thing I didnt do was split the two carbs apart when cleaning them.

Sorry, if you didn't split them apart, you did not "clean[ed] to the bone".

If you didn't split them apart, how did you get the carb bodies into the can of carb dip?

It has been said that any shortcut taken is just another opportunity to do it over and do it right.

[allojohn]

As above, you have not cleaned the carbs and you MUST replace the o-rings. Resistance is futile...

[LAB3]

Welcome to the hobby of antique motorcycles, you get to do things all over again til you get it right? As mentioned, replacement of o-rings is a must as is balancing. Granted, I've been known to skip steps over the years and ride a "good enough" bike for more miles than you can shake a stick at, perfection requires just that, perfection.

[joeman001]

If i distinctly remember i believe i did split the carbs because i remember almost stripping the damn Phillips head screw on the throttle plate. I did not however dip the carbs in carb soak because the last set of carbs that were on the bike i completely stripped and soaked in carb soak which did basically nothing. I dont know what berrymans did to their old formula but I does not work well even after leaving in for the recommended amount of time

[allojohn]

Dipping all the carb parts for 24 hours is necessary. Also, the Phillips head you damaged is infact a JIS head. You need a set of JIS screwdrivers to work these bikes to avoid further damage. A member here sells them...

[allojohn]

Here's the o-ring source - another member here...

[phydeauxmutt]

If i distinctly remember i believe i did split the carbs because i remember almost stripping the damn Phillips head screw on the throttle plate. I did not however dip the carbs in carb soak because the last set of carbs that were on the bike i completely stripped and soaked in carb soak which did basically nothing. I dont know what berrymans did to their old formula but I does not work well even after leaving in for the recommended amount of time

Removing the throttle plates is not necessary to dip the carbs, and as mentioned by others, they are not Phillips head, they are JIS.

I don't know what Berrymans did to their formula, either, but it has been evident for some time that the directions were written when the stuff in the can would actually do it in that amount of time. A simple change of one word is all that is necessary. The directions say to dip for 15-30 minutes, that needs to be changed to 15-30 HOURS.

[gustovh]

Napa makes a killer carb dip.

V