Inconsistant Idle/Bogs down

Ive had an 82 XJ550 Seca for a month now and am having troubles with it. It seems to idle fine much of the time but often the idle speed starts to slow and it starts to try and cut out. Also [and more annoyingly] it bogs down when moving off at the lights and doesnt realy gain any speed at all even at full throttle. Then after 5 or so seconds pulls away normally. Again this seems to happen about half the time. It seems to run fine at motorway speeds.
Ive had the carbs cleaned and balanced by a bike shop and this seems to have made little if any difference to this problem.

This is killing me as other than this im loving the bike. Any help would be great.

Thanks, James.

 

Welcome to the site.

Have the carbs been cleaned by you or someone you trust to do it properly with no shortcuts? That's the first step.

Then you can get it tuned up and running good.

You'll also need to check the rear brakes for delamination.

The valve shims should be checked and changed as well.

Instructions of all of these and much more can be found by searching this site.

 

I suspect that even though the shop "cleaned and balanced" them, they didn't get the float levels right. Your symptoms tend to point in that direction.

The Mikunis on the 550s seem to be really sensitive to float height, at least that's been my experience.

They need to be checked using fuel and the "clear tube method."

 

mine was a combination of carbs AND igniter box.

cleaned and set the carbs. that helped a little. the igniter took care of the rest of the problem.

the timing was stuck at a certain degree. it was too far advanced to run at the lower rpm range. about 4000 rpms she ran like a champ. the igniter wasn't retarding the timing like it was supposed too at the lower rpm range.

 

How does your oil smell James?
Pull the cap and take a big whiff.

 

Check the carb to engine boots,some call them joints. If it will not idle but does great after 2000 rpm you may have a cracked boot.Years and heat do great damage to these parts. There is a test for this but if you are not very careful you could torch your bike. Use a can of spray carb cleaner or something similar, start your bike and try to get it to idle evenly. Use the straw on the spray can to spritz around the carb to engine joints. They are made of rubber and can crack where you cant see it. If it smooths out for a second after the SHORT spray then you have a leak. Please spray this stuff in very short bursts as it is flamable.These boots/joints are under alot of vacuum so it will pull the spray into the crack and seal it for a moment which will even the idle out,for that same moment. I dont know of a fix for a cracked boot other than smearing RVT sealant on the area until you can get a replacement. RVT will not last long so start looking for these parts now. Drew36

 

Will wd40 work for the spray test drew36?

 

WD40 does work.

An unlit propane torch works best because you get a constant flow of fuel out of it to move around and find the leak if it's there.

I wouldn't spray any more carb cleaner than necessary on rubber parts.