1981 XJ 550 Temp/Start Trouble

I have a1981 XJ550 that I have owned for about six years. It has always had this problem but it has gotten worse in the past few years. It will fire right up if it is hot, it takes a few tries if I let it cool for about 30min, it will fire right off if I let it cool for about an hour or more, and if I let it sit for more than two days I have to jump it off. The temp related starting tells me it is the valves, they are all within spec but they are all on the tight end. Is anyone familiar with this problem on this model?

 

Be more specific about valves "in spec but on the tight side."

"if I let it sit for more than two days I have to jump it off" sounds to me like a battery that is beginning to go flat and won't hold a strong enough charge to start the bike if it sits idle for too long.

THAT one happened to me last summer, and it was time for new battery.

Keep in mind it is possible for the battery to have enough "juice" to spin the motor very vigorously, but not have enough left over to actually fire the ignition.

 

my 83 XJ does not like to start either when night time temps start getting below 45 degrees farenheit. It has been professionally tuned and carbs professionaly cleaned. I ran into this problem last year in mid September. I had ridden my bike over to my gf's house the previous night and had just got up to go to school. I went out to start it up and the starter spun normally but the bike wouldnt start. Had my dad bring me back to her house later that day and held the starter for like 3 seconds and it started right up. These bikes are very cold blooded and they even seem to resist starting when the air temp gets that cold.

I have the same problem with mine also when it sits for around 30 mins. I found that if i give it between half to full choke it will crank for 5-10 seconds and then fire a couple of times and then start right up.

You can also buy yourself a battery tender to keep the battery charged. By using a battery tender you can increase the life of your battery dramatically.

 

Thanks for the info. On the valves I meant that they are dead on on the tight end of the tolerance I do not remember the exact specs but if they where allowed .002-.004 they where .002.