Overheating?

[maxherman05]

The other day I was leaving work so I ran outside to start my 1992 Yamaha fj1200 and let it run for a minute. I went back in and got caught up talking to some of my coworkers. I forgot the bike was running and it ended up idling for around 30 minutes. When I went back outside to leave work the bike was smoking a little bit. I rode home like nothing still had the same amount of power and seemed to cool down fine. Do you guys think I did any damage or will It be fine? Also, how do I check to see if my oil cooler is working. My bike doesn't run very hot but I just want to check the oil cooler to see if it's working properly because it's old. Thanks

[Pat Conlon]

Burning your exhaust valves, seats and valve guides can happen.
Do a leak down test or at least, a compression test for damage assessment.
30 minutes is an insane amount of time for a big air cooled 1200cc engine to be idling without airflow.
I'll bet your engine oil is cooked.
Oil coolers only work with airflow. Disconnect the 2 oil lines at the oil pan and blow thru one line...if air and oil comes out the other line, your oil cooler is open to flow oil.

[Old Rider]

Agree with Pat 30 min is a long time. I would have done a oilchange.To check that oil cooler is working you can just after taking a little ride so oil heats up.Stop the engine and wait maybe 10-15
minutes then take your fingers on the right side tube on the copper coming from oilcooler wieved from front of the bike.Both the tubes should have cooled down after 10-15 minutes then start engine
and if the right tube (that is the outflow / Return to oilsump tube) getting hot fast the oil is circulating in the cooler and it is working

[maxherman05]

Ok I will do a compression test on all four cylinders. I don't think their is any damage though I don't hear any ticking in the motor or anything. I'm also using 20w 50 Valvoline motorcycle oil so I'm pretty sure that can withstand the heat. Do you know what psi the compression is supposed to be at?

[Pat Conlon]

128-142 warm engine, throttle wide open.

[T Legg]

 Compression readings are reduced by about 2.7% for every thousand feet of elevation . It doesn't make a lot of difference if you are at a low altitude but it adds up if your live higher up.
        My place is at 4,786 feet . If I read a cylinder value of 120 psi it would be equivalent to 137.8 psi at sea level . It's something to consider when checking compression .
     To figure it out you divide the reading by one minus 2.7 % times your altitude in thousands of feet to get the equivalent value at sea level. I use 4.786 for the value of my altitude .

[maxherman05]

Just did the compression test went like this

Cylinder 1: 136

Cylinder 2: 140

Cylinder 3: 135

Cylinder 4: 134

Seems perfect to me what do you guys think?

[Waiex191]

Am I the only one here who has been stuck in a traffic jam in the summer on an FJ?  Mine still seems fine, and I think that is worse than idling.

[Millietant]

Am I the only one here who has been stuck in a traffic jam in the summer on an FJ?  Mine still seems fine, and I think that is worse than idling.

Nope, I've been stuck in heavy traffic in Italy and Spain in the height of summer many a time, crawling along on tickover at 5-10 mph, in first of second gear for upwards of an hour - the FJ "tick" got louder, but it went back to normal as soon as we got back up to proper running speeds with a bit of air going through the oil cooler fins. Must have happened well over a dozen times and there doesn't seem to have been any long term adverse effects.

[Pat Conlon]

Just did the compression test went like this

Cylinder 1: 136

Cylinder 2: 140

Cylinder 3: 135

Cylinder 4: 134

Seems perfect to me what do you guys think?

Yep, looks good...

[Old Rider]

I have also often got stuck in heavy traffic on hot summer days and as Milletant  mention the engine starts to make more ticking noises the hotter it gets. I investigated this some more and some might desagree on this ,but what i have found is that the ticking from valves gets louder because the valvelash gets bigger when engine gets real hot.Many say the valvelash gets smaller when engine heats up. so i did a test last time i adjusted the valves.I made the test to se if the valvelash gets bigger or smaller when engine is hot.I prepared my garage and took a ride so the engine got real hot
then drove into garage and removed the tank and valvecover as quick as i could manage .By the time i had the valvecover off the engine had got a little cooler of course but it was still hot.
I then measured the valves and the lashes was real lose .then i waited several hours untill engine was cold and measured again then the valvelash had got tighter again.I have written down how much it was but cant find the data now but i think it was 0.03-0.04mm.so the lash gets bigger when engine is hot plus the oil gets thinner

[Bill_Rockoff]

Mine spent a lot of time idling in Atlanta summer rush-hour traffic 20 years ago. It would be too much movement to shut the bike off, but not enough to get any air flow, for 15 or 30 min at a time.

That's probably why mine burns a bunch of oil now and doesn't make the power it used to. It HAS had kind of a long hard life so far, 122,000 miles on the clock.

If it's smoking a bit, you may have cooked the valve cover gasket and/or the valve cover bolt grommets. RPMRacing has them both.
https://rpmracingca.com/proddetail.asp?prod=5WM-11193-00-00&cat=31
https://rpmracingca.com/proddetail.asp?prod=2GH-1111G-00-00 (you need eight of these)

Another thing to expect when your engine has gotten really hot: the clutch slave cylinder seal will get heat-cycled and brittle. This will show up in the clutch fluid slowly leaking out the slave cylinder at the bottom, which will lead to a low fluid level in the master cylinder, which will lead to air in the line, which will lead to the clutch lever getting soft and failing to disengage the clutch fully, making it hard to shift. You fix it with a new slave seal (and dust boot) and by refilling and bleeding the clutch hydraulic system. I had a few summers where I did this either two successive years, or got to skip a summer but did it the following year. I used to commute a lot.
https://rpmracingca.com/proddetail.asp?prod=26H-W0098-00

I've been using Mobil 1 for the entire time. I had to replace the clutch around 80,000 or 90,000 miles, I forget.

[Bones]

Summer in Australia gets very hot and that's when we celebrate Christmas. Every year I do a Toyrun where we travel a route riding mainly in first or second gear for around an hour which gets the engine really hot, there were times I thought it was going to melt going by the heat radiating off it plus I've seen my oil temp gauge up around 135deg C but it hasn't seemed to affect it yet. It's done 125.000km, burns no oil and still has 155psi compression. I also run a thicker 20/60 mineral oil to help protect it in those conditions if that makes any difference.

[FJ1200W]

128-142 warm engine, throttle wide open.

Pat - Do you do anything with the vacuum pistons in the carbs?

[Pat Conlon]

Sure....You can raise the the carb sliders, but I don't...
Other than the first year FJ's that have a flat bottom slider, the later FJ's have curved bottom sliders so plenty of air gets buy....it's the throttle plates that are important to open