Scared of engine temp

[xs650newb]

Hello all,
I FINALLY got this bike rideable. What a great feeling. For those of you following my previous posts it turns out my throttle shaft screws and mixture screw o-rings were leaking and had to be replaced. Once that was done the bike fired right up!


Anyways, I have a new issue.

I am using drag pipes with mikes xs pod filters. I have rejetted so I am using a #45 pilot jet and a 135 main jet. I took the bike for a spin today and everything was riding great. There was a slight surging at wide open throttle, but I can deal with that later. My main issue is that I believe the engine is running too hot because the pipes appear blue. I plan on fine tuning the performance by chopping the spark plugs but I am scared to ride the bike if it is running too hot. Am I being overly cautious? Is it okay to ride the bike even though it is running too hot even though I am only riding it to get some color on the plugs?

Thanks,
Adam

 

[5twins]

If you're using aftermarket single wall pipes, they probably will turn colors even with the proper jetting. With straight pipes though, 135s may not be big enough. I'd go bigger. To properly jet a bike, you should go up one size at a time until you're too big, then step back down a size or 2. I think most guys with drag pipes and BS34s run about 140s (I'm assuming you have BS34s?).

 

[xs650newb]

Yes, I am running BS34s. Perhaps the 135 is too small.

Is there a definite way to tell if the engine is running to hot. IF I could an IR thermometer what temperature range would be ok?

I am asking this because I also adjusted the valves and I am a bit paranoid that I did not set the valves properly since it was my first time.

Thanks,
Adam

 

[pyrocentric]

Yes, I have an infrared thermometer. I always measure just behind the sparkplug(like to the rear of the sparkplug). It usually stays below 300F, and that's running so rich the plugs almost foul. I have BS38 carbs so the jetting is entirely different, but I went up several sizes on the jets. The oil temp is usually about 180F. Everyone tells me these numbers are high, but I've been riding two years now and can't seem to get the temps any lower.

 

[rwingsfan]

Hmmmm....180 degree oil temp sounds pretty good to me

 

[XSLeo]

On a stock bike on a 75 degree day oil temps run about 200. Cylinder temps just below the heads can be 290 the heads a bit warmer.
I did some testing as I installed an oil cooler and extra oil filter on my 75.
I modded a right side cover with fittings to plumb in an oil cooler. Before adding the cooler I just linked the oil out to the oil return with hose and a temp senser.
On a 60 mile loop the oil temp held at about 200 degrees. Shot the cylinders and got about 290.
Added the oil filter, ran the loop Oil temp dropped to 195, cylinders to to about 265.
Added the cooler, oil dropped to 150, cylinders to 235.
The heads ran a bit warmer than the cylinders. Stock the left/right temp difference was about 20-25 degrees. With the cooler the difference was less than 5 degrees.
Just a bit of info, use it as you will.
When I get my headpipes built so I can install the modded side cover on the 750 kitted engine I'll redo the testing.
Pyrocentric, how do you read oil temps?
Leo

 

[pyrocentric]

I've just tapped the side cover and added an oil cooler. Now on a 75F day, my heads are running 280F just behind the spark plugs. To measure oil temperature I point my infrared thermometer at the oil cooler or just point it at a low spot on the side cover or filter cover. Oil temp is around 170F. Definitely helped, but I run 20w50 conventional oil: start with 25psi of oil pressure at idle and it drops to 0psi once it warms up.

 

[XSLeo]

I had a 3/4 inch steel tee fitting with 3/8 hose barbs in two of the holes and the temp senser from a car temp gauge in the third hole. I hooked this tee in the oil return line as close to the engine as I could.
I thought getting it there would be most representive of what the engine was getting.
I have thought about drilling and tapping a hole some where on the engine so I could put the temp senser right in the engine to read the temps there. With an electric gauge it will look better than the mechanical gauge I used for the testing.
I think any way you put a cooler on will help. I think modding the cover for the cooler is a better way, it cools all the oil. You can plumb in an external filter too.
Leo