XS500 - Safe Engine Cylinder Temp - Now 340F then stall at idle.

[SrgtBear]

I was riding my bike around the other day. Thought it was overheating because it was stalling twice out after 10 miles. Needless to say it was actually my carbs falling out of their engine flang, but I felt the engine getting a little hot and smelt the wrinkle paint cooking a bit.

I used an infra-red gun and the cylinder head temp was at 280F. Is this a safe temp for a 4-stroke 500cc air cooled engine? What would be a max temp for this bike? 350F?

 

[crazypj]

Re: XS500 - Safe Engine Cylinder Temp - 280F?

Just about any engine oil made will work as long as temp is below 390~400 F (Pretty sure that is minimum flashpoint?)
220F is a good temp as it will boil out any water vapor, the crankcase should get up around 220~230F on a long (ish) run, the head and cylinder will get over 300F

 

[SrgtBear]

Re: XS500 - Safe Engine Cylinder Temp - 280F?

Just about any engine oil made will work as long as temp is below 390~400 F (Pretty sure that is minimum flashpoint?)
220F is a good temp as it will boil out any water vapor, the crankcase should get up around 220~230F on a long (ish) run, the head and cylinder will get over 300F

thats good to know. im happy that my problem was just the carbs bouncing around.

 

[SrgtBear]

Ran the bike again today. Pulled it into the driveway and let it set for a few minutes to simulate how it handled a long idle. Cylinder head temp kept rising and bike finally stalled at 340F. It seems to run fine and keeps cool if im riding at a decent speed but city stuff stop and go doesnt seem like a good combination at this time.

I am going to try adjusting my valves again with a little more clearance and check timing one more time. Do you think that will help? I heard you could advance the timing to help with overheating. Is that true?

 

[teazer]

Not normally. retarded timing may make the pipes hotter because there is fuel still burning in the pipe. Advancing it may make it run hotter if it's more advance than the motor needs.

340 is pretty hot. I'd be checking anything and everything to see what's going on, but you are right that worst case scenario is slow riding without enough airflow to cool the fins

 

[crazypj]

You want to check the timing marks are accurate and the advancer mechanism is completely free, plus,make sure springs are not weak.
How do the plugs look with extended idling?
They should be pretty dark to black as fuel in carbs (and tank) heats up, evaporation into intake could be whats causing it to cut out?
XS500 had a few problems when new, probably hasn't improved with age

 

[jordy_g_77]

I had the exact same issue with my xs500. Never really did solve it because it would always run awesome again after it sat for a few minutes, but very frustrating indeed.

 

[SrgtBear]

I'll check the plugs next. At one point I only noticed the left cylinder firing harder at idle. Then I sync carbs and both were firing fine but the left cylinder temp was still a little higher.

I am thinking it's valves, timing, or as you mentioned fuel. (which i all checked when putting it back together)

Other than the idle screw which is set at 1,300-1,500 rpm; Would you adjust float bowl level in regards to ammt of fuel for idle?