Old kat running hot

[maikhorma]

I've got a 1990 katana, i do a lot of city driving and a lot of highway driving as well. I understand oil+air cooled can run a little hotter in stop and go, but it seems no matter what type of driving after half an hour it will be running hot. I ride it all year around, and even in 30-40 degree weather after taking a highway trip (about 1hr ~65mpg average) i can tell it's running hot. Now that the weather is getting warmer it's getting pretty bad. I think it has always done it, but it seems like it's getting worse as time goes on. Last weekend i did an oil+filter change (synthetic blend) and maybe helped a little? but not much.

Here is what i mean by "running hot"... well it starts runnign warm by idling high, then when it's hot, it doesn't want to idle. Stopping at a light it will just drop out, must use throttle to keep it running. If it does stall, it'll take a bit of work on the starter to get it going again. Stalled or not, pulling off from a stop, it has NO power unless i've got it going at 7k+ rpms. It'll stall out unless it's runnning that high, or i take my weight off the bike and give it some help.

Any suggestions?

Thanks in advance.

[Suzy750f]

I have had a look in the manual, not for a pre though, so someone else may have to verify, but there is a strainer and and oil pressure regulator in the sump. Sounds like a flow problem if you think it is heat that is the cause of it running the way it does. Download the manual for your bike and have a look through it is all i can suggest

[Wolfe_UK]

Resurrecting the thread due to having similar symptoms.
When riding, does it sound like there's a whine of some kind coming from the engine?
I'm getting basically the same kind of power lack/stopping/running AND SMELLING hot but also there's an engine whine that intensifies with revs and speed that is prevalent even over the exhaust noise.
Riding a '90 Pre 600, and as this is my second pre 600 now, I'm pretty sure I can play spot the difference of normal engine noise and this.