Overheating

[Dagger969]

I have always had a water cooled bike so I know nothing of our air cooled ones. I have a 98 kat 600 and after a lot of driving and lot sitting in traffic and not moving it started to knock. Could this knock be from the bike over heating? I have since driven the bike all over and never heard the knock. I was just curious about this since the bike has never made any noises. Thanks

[paperairplane]

I would check oil level #1....

Bad gas...

I've had mine pretty hot before and not had a knock.... were you in a parade or something?

Is the bike stock?

[KatanaO215]

what did the temp gauge say?

[md86]

what did the temp gauge say?

Uh , seriously ?
Kats don't HAVE a temp gauge

[The CyberPoet]

The knock was probably a combination of super-heated lower-quality motor oil and fuel predetonating as a result of the heat build-up in the cylinders. If you were using a typical car oil and the oil temp was approaching the flash temp of the car oil (which, depending on the brand and type of oil, can be lower than the operating oil temp of the kat under extreme conditions), the oil flashing off may have ignited the gas.

Here's what I would do:
(A) Change oil ASAP to a JASO-MA rated 10w40 or 20w50 (or combination thereof). If you think you're likely to find yourself in this position again, use a 20w50 or at least one-third 20w50 in the oil. Do not use anything thinner than 10w40.
Drain the old oil from the engine and from the oil radiator (remove the oil cooler, drain it, reinstall the cooler). Change the filter. Add the new oil. Do the next oil change after that in about 1500 miles (since a normal oil change only changes 65 to 75% of the oil in the Kat, and draining the oil cooler only ups that to about 85%).

(B) Get some techron fuel system cleaner. Add 1/3 bottle to your gas at the next fill-up. This will help remove sulfated ash and carbon build-ups that may have been left behind by the predetonation and the flashing off of the oil.

(C) If you get any similar symptoms (or other questionable behavior), have a leak-down pressure test performed on all four cylinders -- if it comes back ok, and you still are getting these symptoms, you may need to flush the cooling system (annoying, but effective) to remove oil varnish. After a flush, you'll need to do two to three oil changes back-to-back with draining the oil cooler to get virtually all of it out (i.e. - change oil, run 5 minutes, change again, run 5 minutes, change yet again).

KNOW THIS:
Car oils and API SJ / API SL rated oils are not up to the task of an oil-air cooled motorcycle in hot weather & extreme conditions. Stick to properly rated API SF to SH (SH+SJ if necessary) and look for a JASO-MA rating as well for it to have the ideal qualities for your use. You can learn about everything you need to know here: CyberPoet's "How to understand and choose motorcycle motor oils" at MotorcycleAnchor.com/
At 50 degrees ambient temp, driving 80 mph on the highway gives you a typical oil temp of about 247 - 252 degrees (F). Up the ambient temp to 80 and that oil temp will climb in response as well, to around the 280 - 300 degree point (and possibly higher).
Not all oils shed heat at the same rate. In my experience, Castrol GPS sheds heat extremely well compared to other JASO-MA oils I've tried, so that's what I use.
You can find JASO-MA rated oils from Castrol (ACT/Evo, GPS), RoyalPurple (CycleMax), Mobil (MX4T and VTwin), Valvoline (ATV 10w40 and Cycle 20w50), etc. Know that just because an oil is rated JASO-MA in one country doesn't mean it's rated that in every country (example: Castrol GPS is JASO-MA rated in the USA, but the Australian version is not).
You can install a larger oil cooler on the bike by picking an oil cooler from a larger displacement suzuki air-oil cooled motorcycle of the same general engine type. Some modifications will have to be made to the cooler to have it mount correctly at the existing mounting points.

Cheers
=-= The CyberPoet

[The CyberPoet]

what did the temp gauge say?

Uh , seriously ?
Kats don't HAVE a temp gauge

Mine does
But MD is correct -- stock Kats do not have a temp gauge.

Cheers
=-= The CyberPoet