carbs

[alanr]

Cleaned carbs after sick of seeing them leak all the time,all new internals.turned tap on,started second kick,went for ride ,no missing, no backfire,no leaks even with leaving tap on,really confident Ive done something right on the first try,Question,how do I know if the engine is overheating,may not be,just seems hotter than l remember,dont want to go too far in case l cook something,motor runs well,sounds good,may be worrying about nothing,thanks

[GTandcbr]

Hi
Best way to check if your engine is overheating is to check your spark plugs. If the plugs show any trace of white deposits or electrode damage that usually is a sign. Just make sure your exhaust baffles are clean and clear and that the aircrews are adjusted properly (petrol also cools the cylinder) and you should be okay.

[jabcb]

Don’t think I’ve seen it discussed here, but an infrared thermometer could give you temperature readings.
I don’t know what correct or good readings would be. Perhaps a forum member can provide some insight.

I used it a triple & found out the carbs weren’t balanced. Balanced the carbs & the bike ran much better.

[GTandcbr]

The infra red gun is a good tool to check all cylinders are firing the same i.e. they all have similar temperature readings. I dont think there is a bench mark reading anywhere.
These old machines are very well cooled and there shouldn't be a problem there.

[sportston]

Three ways to overheat an air-cooled engine. Clogged pipes, lean mixture or clogged cooling fins.
As already mentioned above, Check your baffles.
Are the carbs already definitely set up correctly?
Unlikely you use the bike off road, but if so, make sure the cooling fins ain't mud-plugged (have once read about a guy who had an air-cooled Norton that was overheating due to very, very thick layers of black paint on cooling fins. Amusing I thought).

[Zunspec4]

On my race engines I have under-the-plug Cylinder Head Temperature (CHT) sensors. Mine are made by TTO but there are others. In general race running we have seen 165 degrees C, and last time out they were only getting to 135 degrees. On the cool side if anything but in terms of C/R, jetting, ign. curve we are quite conservative for reliability/consistency reasons. My rider (Gary May) has been briefed to get nervous if he sees the gauges hit +190 degrees C. It would be interesting to see how an Infra-red device would compare to the TTO readings though. We use these readings as an indication only but more so to see if both cylinders are operating in sync. A more pertinent parameter would be Exhaust Gas Temperature (EGT) gauges as this give a better insight into how the engine is running.

Cheers Geoff

[jabcb]

I used the infrared thermometer on the exhaust headers something like 2 inches away from the cylinders. One was a lot cooler than the others. After balancing the carbs they were a lot closer. Don't remember the readings, but it was a good bit lower than 135 degrees C.