BannedCR500Riders.com

I have a cylinder head temp monitor for the 480.
I noticed that the head temp hovers around 320* while trail riding and in town cruising. Sustained higher speeds brings the head temp up to 350*+.

What is considered normal operating temps for an air cooled engine???

Wow, that seems hot! I shot my wife's 300ex with an infrared thermometer once and got 225 degrees, then again, it's a 4 stroke with an oil cooler mod. Interesting question.

I don't know for sure, but I would have to think an air cooled 2 stroke would run on the pretty warm side.

If you have it idling and not moving it will be on the hot side for sure. When you are riding down the road it is probably alot cooler. Hence the term air cooled.

I just think it's odd it runs hotter even at higher speeds. Generally there is no substatute for air when passed through a radiator or accross fins. I guess those air cooled bikes don't really have a way of channeling air to the cylinder. The fins may not see more air at higher speeds than they do lower because the engine sits in a pocket behind the front wheel and forks...I don't know? Just thinking...

Well it is certainly not the best design or they would have made all the bikes air cooled.

Joshwfl wrote:Wow, that seems hot! I shot my wife's 300ex with an infrared thermometer once and got 225 degrees, then again, it's a 4 stroke with an oil cooler mod. Interesting question.

How did you do the mod?I honestly thought 4 strokes run hotter than 2's,I own a Polaris Hawkeye and ride alot of different 4 stroke quads all the time and the heat is pretty intense sometimes

This is the same cooler it had:

http://cgi.ebay.com/ebaymotors/TRX-300e ... 0147308350

Now she has a newer 300ex and it does seem to get very hot.

I know that timing, fuel mixture and oil content plays a role in EGTs (combustion temps).
Timing is in the stock position.
The clip on the slide needle is in the top groove. I placed it in the center position and it was so blubbery it wouldn't run, I put it in the #2 slot and took it on a high spped run and it didn't change the #s one bit. I can feel that the power fell off, so it is indeed running richer.
I might run a slightly richer oil mix (maybe also some race fuel?) and see what it does.
I heard it detonate one time when it approahed 350. I pulled over and let it idle....it actually cooled down.
I don't know what's in the engine, the head could have been milled at one point.

Seems that could have been an issue....the old 500 has a shroud.

What fuel, jetting and carb are you running? How long are your trail rides? Are you riding in stop/start traffic for protracted periods of time? IMHO, I think you are sweating the small stuff on this one.

On this board or http://www.cr500riders.com you'll find a post about a Klemm Research (?) mod to the 1984 CR500R cylinder head to stip it pinging. The CR480R can ping and I ran 50/50 race gas to avoid this - probably not practical for you though. You might want to see what these folks can do for the 480.

BTW, stock jetting is way off - but on the rich side which will help with the temperature factor. A high-speed run is not going to be significantly impacted by the needle. Run a 70 (72) pilot and a 152 (172) main as a test as see if you like it.

I figured I'd pull the bowl and see what #s it has.
Whoever owned the bike in the past did a great job of taking care of it. It has an aftermarket pipe/silencer kit on it, so I would guess it might have been tuned also.
I was going to look back in my prior thread and see what the jet sizes you mentioned were, so thanks for resubmitting those #s.
Changing the needle did make a big difference in the low/mid throttle openings. It blubbered terrible and never would clear up, and even changing to 1 groove richer made a big difference...It was way less snappy and killed the off-idle power.
I figured I'd put the needle back where it was and document the pilot jet.
High speed doesn't mean large throttle openings. 65/70MPH is only 1/4 throttle.
I can trail ride/hit side streets/play around all day long w/temps at 300+/-. I can get on the highway and within 2 miles it'll be inching up/past 350. Steady RPMs @1/4 throttle = 350*+. It's not the temps that I mind, it's the detonation that comes with it.
The head could have been milled down at one time, I figured I mix in some race fuel and see what it does.

You can listen to the engine and see that I don't rev it hard (I take care of my shit), even on the highway I keep the RPMs comfortable. Maybe I am a worry-wort.I guess if I didn't have a temp monitor it'd be "outta sight, outta mind".

Thanks for the advice....and I realize what people are thinking. It's a racing machine, not a fucking street bike.


You've probably seen the vid (I'll post it in case you haven't).

i wouldnt worry much about the temp unless you ride sand dunes. it will let you know when its to hot

redrocket190 wrote:Run a 70 (72) pilot and a 152 (172) main as a test as see if you like it.

I just checked the jets in mine. It has a 72 and a 162, clip in top groove. I might try the 152, just to see how it would run. It's crazy fun now, leaning it down will make it even more so???

Great advice....Thanks.

Wheelie-Gene wrote:[ It's crazy fun now, leaning it down will make it even more so???

until you squeek the piston.

I'll probably leave it as is.
Slightly rich is better than slightly lean.

Wheelie-Gene wrote:I'll probably leave it as is.
Slightly rich is better than slightly lean.

Air cooled..... even more so....