few more questions on my 81 seca 550

So i found an airbox on ebay, put it in, and started it up. RPM's went straight to 5k and stay there.

I tried turning the idle adjustment knob, no change. Any common causes of this? Will syncing the carbs fix the problem?

And secondly i was hoping i could get a PDF of the manual?

Thanks guys!

 

If you PM me your email, I can send you a copy. I did eventually buy a copy though, it's nice to have pages when you have greasy hands. It'll get you through in the meantime.

 

If you PM me your email, I can send you a copy. I did eventually buy a copy though, it's nice to have pages when you have greasy hands. It'll get you through in the meantime.

 

Sounds like you didnt properly seat the throttle cable in its seat. Pull the tank and make sure that the throttle cable housing is properly seated in its seat on the carbs. Either that or you might have routed and pinched the cable when you put the tank back on.

Sean

 

the cable is fine

 

It sounds like it is time to do a carb cleaning and full adjustment. Also, make sure your throttle is completely closing when at idle. I had a gummed up throttle cable that stuck just enough to cause the same problem.

 

I had i similar issue and it was the throttle cable... you wouldn't believe how much a tiny little tug or pinch on that cable will do...Hope you get tyour prob taken care of..

 

I cleaned the carbs and made sure everything was in working order. I'll check later and see if pulling the cable down changes anything, but im fairly sure that the throttle is fully closed.

I think my mixture screws may be set wrong though, could that be the cause?

 

Actually, just pull the throttle linkage at the carbs up all the way, and disengage the cable from it completely...see if it drops to a proper base idle then...then you'll know if it's got anything to do with the cable or not...

mine did that one time when I took the carbs off and put them back on, had the screaming idle at 5K...I was convinced the carbs were at idle rest, but apparently not, after removing them a second time and replacing, all went back to normal...so I had something narfed, but never figured out exactly what...

 

For starters: fintip, the guy has a 550, it's not the same as the 650s. Unless you have an actual 550 book, don't bother.

On to the original questions:

-Just installing a stock airbox will not magically "fix" everything.

The 550s are Mikuni equipped; the Mik's have even tinier and more convoluted passages than the more often-discussed Hitachis.

You need to do ALL of the following and in order:

FIRST: Check and adjust the valve clearances. Trying to sync with out of spec valves is an exercise in frustration, especially with the smaller-displacement motors. Here's how: http://xjbikes.com/Forums/viewtopic/t=14827.html and Part Deux: http://xjbikes.com/Forums/viewtopic/t=29209.html

NEXT: CLEAN those Mikunis, here's how they come apart: http://xjbikes.com/Forums/viewtopic/t=31061.html

THEN: Wet-set the float levels. The more accurately you set them, the more evenly the bike will run and the easier it will be to get it in tune. http://www.xj4ever.com/setting%20fuel%20levels.pdf

Then you do an accurate bench sync, and set the mixture screws at 2 3/4 turns out.

Check THIS thing, be sure it's not running wide open: http://xjbikes.com/Forums/viewtopic/t=31872.html

After returning the carbs to the bike, you do your running vacuum sync with the YICS properly blocked off.

Then you can fine-tune the mixtures if needed.

Be sure to fit a new set of NGK D8EA plugs, correctly gapped for the 550s: http://xjbikes.com/Forums/viewtopic/t=34431.html

Do what I've told you, in order, don't take any shortcuts, and your '81 550 Seca will run like mine:

 

fitz-- i gotta say that is one pretty bike... i just love the white and red together.

 

Thanks.

Those are the stock colors for an '81 Seca 550. (Original paint and graphics, truth be told.) Actually the whole bike is largely original; just lovingly resurrected from a hard previous life.

The original fairing was "removable" and only offered here in the USA, as far as I know. I removed mine; I feel it really detracts from the lines of the bike (plus it screws up the handling.)

 

yes. i remember the 81. I was considering it but opted to purchase new a GS650 G in 82. That was back in the day of the heyday of the STANDARD motorcycle... those days are kinda gone... Anyway.
I am considering a white an red paint scheme using the new R1 Graphics possibly to pull it off for my XJ 650 Seca. Still considering options since i really need to tear it down and again and rebuild the carbs right this time but start with a valve adjustment. With 6500 miles they areTIGHT!
All this plus rebuild by 85K100 that is my daily driver this winter. Ill be busy this winter. How is your 650 rebuild going?