high idle when engine gets hot

i, im not sure whats going on here, but when i start my xj550 it will sit on the choke untill warm warm, and then hover at around 900-1000 rpm. but if i go for a ride about 10 miles long, the tick over works its way up to nearly 5000 rpm. once the engine is cold (left over night) it all goes back to normal untill i take it out again. please help.

 

Start by checking your valve clearances.

Check your float levels using clear tubing; you can actually do this on the bike.

Do a vacuum leak test once warmed up, unlit propane torch works well.

Check the condition of the little rubber caps on the intake manifold vacuum spigots. They often LOOK fine while actually being hard as rocks and not sealing well any more.

Check that the enrichment plungers are all completely free when the "choke" (enrichment lever) is all the way off.

Is this a 550 Maxim, or are you in another part of the world where "XJ550" means a bike that looks like a 550 Seca? If the latter, see if you in fact have one of these (you may not) http://xjbikes.com/Forums/viewtopic/t=31872.html If you do, it may need attention.

 

im in the uk, and its a seca model, il have a look for that funny little nossle in the air box. thanks for the tip.

 

Might want to have a look at all the other stuff I mentioned too.

 

what you are experiencing as almost identical to some stuff I was dealing with yesterday.
Follow big fitz to the letter my brother cause Im about to go ride my bike with all those problems gone, yeah gone smooth girl acting like she should and yesterday she had behavoiral issues.
to the T bro, do it all just like he said and youll be thanking him too.
thanks Fitz

 

thanks for the tips, im strugling to find how to do all that in my manual, do you have any previous strings/instructions on how to do these checks. thanks

 

Certainly. There are quite a few articles similar to these in "XJ FAQ Suggestions."

Valve clearances: http://xjbikes.com/Forums/viewtopic/t=14827.html
Part 2: http://xjbikes.com/Forums/viewtopic/t=29209.html

 

thanks so much, very in depth stuff, il take a look at it tonight and see what i find.

 

well, my bike does indeed have that little nozle in the air box. and there is no foam in it. so thats somthing else on the list to repair.

 

and soon. As I pointed out in my article, that is an INTAKE not a vent.