1982 Seca 550 Carb Cleaning

Bought a low mileage very nice original 1982 Seca 550. This is my second 1982 Seca 550. My first one is where I want it to be mechanically.

This bike hasn't been run in some time. I got it started and is only running on 2 or 3 cylinders. I took the carbs off, gave them a quick clean. One of the main jets was completely plugged. I opened it up. Also took out the pilots and soaked them but I never saw a fuel outlet in these??? Put it all back together and it runs but not much better.

Sooooo.... I am going to take it all apart again and try to do the job correctly this time. I am going to order new Mains & Pilots. What else should I be looking at in these carbs? I don't want to do this a third time so any helpful hints would be great.

I am very familiar with snowmobile carbs and dirt bike carbs for two stroke motors but haven't been inside a four-stroke carb before. Are there other things to clean? Replace? Check??

Thanks in advance.....

 

Have a look: http://xjbikes.com/Forums/viewtopic/t=31061.html

I wouldn't replace the jets, per se; unless they need to be replaced. I WOULD replace all the rubber parts and the beanie screens and get serious about carefully cleaning and inspecting everything else. Float needles may need to be replaced; likewise the float valve seats, depending on condition. Sometimes they're fine and just need to be cleaned.

Float LEVELS are very important once they go back together. They need to be accurately wet-set.

Now about the other Seca (I've got a pair as well)

"where I want it to be, mechanically"

Hmmm.

When was the last time you checked the valve clearances? Required very 5000 miles, often ignored. How close are you to a burnt valve?

In RE: BOTH bikes-- have you pulled the rear brake to check for this? http://xjbikes.com/Forums/viewtopic/t=15874.html

Again, both bikes: The original front brake lines had a lifespan of 4 years-- are yours original? They have the date embossed in them or stamped into the metal ferrules-- see if they're original.

 

bigfitz52,

My first 1982 Seca 550 has 9,800 original miles on it. I had the valve clearance adjusted last year on it by a local vintage bike mechanic. I personally replaced the front brake line with a black covered stainless steel line from one of the members of this site and I also replaced the rear brake shoes. The last thing it could use is a new set of tires, but it is in otherwise great shape mechanically. I did not clean the carbs on this bike as it has always run very nice and smooth.

I did check the float bowl floats for level and the needles & seats looked excellent. The screens were also clear once I put them back in the carbs. I thought between cleaning the mains, pilots, needles/seats/screens that the bike would run at least significantly better but it doesn't.

Any other suggestions???

 

Take a look at your main air jet. It's the small unremovable brass jet located in the side of the intake throat of the carb. I've seen them plug with varnish. Shouldn't have much of an effect on idle, but it will affect drivability at higher throttle positions.

Also, you said that your mains were plugged... Were the pilot jets plugged as well?

 

Ordered every new jet that I could for this bike yesterday. Also ordered fork seals, clutch plates/springs, and new rear brake shoes. Will order another black stainless steel brake line and probably a new set of shocks and fork springs as well.

Will keep you posted whether the bike runs better after the second carb cleaning and jet replacement.

 

Cool. While you wait for the carb parts check your valve clearances.

You can't sync the carbs if the valves aren't in spec first.

Valve clearances: http://xjbikes.com/Forums/viewtopic/t=14827.html
Part Deux: http://xjbikes.com/Forums/viewtopic/t=29209.html

 

Did you replace all of the rubber bits like BigFitz suggested? All of your fuel jets can be cleaned out with carb cleaner and a brass or plastic bristle from a brush (I use .009 guitar wire).If the brass jets aren't damaged, they usually don't need to be replaced.

However, throtte shaft seals, fuel pipe o-rings, pilot mixture screw o-rings and float valve o-rings WILL need to be replaced. Also, check your diaphrams to make sure they don't have any holes and seat properly. Also, don't forget the bench sync, making your slides go clunk, and wet setting the float levels. Complete these tasks (including the throrough carb cleaning), and the requisit running sync and pilot mixture setting, and the ONLY thing that will stop you from running right fuel-wise are air leakes from intake manifolds.