Heat tuning

[d240zx2]

Don't know if that's a good title for this, but anyway...

An old mechanic suggested I try setting my Mikunis via header tube heat differences. I was having a lean condition with spitting back through the carbs at most any rpm level and at any engine temperature. All the plugs displayed a nice, uniform tan color and I was a bit stumped.

Using a touch pyrometer, I discovered vast differences in header tube temps: 385 degrees at the coolest to over 700 at the hottest. Voila! The picturesque "light bulb" cartoonishly drawn over someone's head just lit up. After adjusting the pilots to the same setting as the coolest hole, the problem went away. The subsequent test drive fully confirmed the validity of this method of setting a Mikuni. Next step will be the use of my Unisyn to balance the three carbs a bit closer....

Frank

[steve91tt]

Great tip! Time to get out my pyrometer.

[Zedyone_kenobi]

I have an infrared heat gun that I use to measure, well anything from the temperature of my grill, to the air coming out of my vents.

My question is with your heat shield under those triples is there enough room to touch the pipes. I mean I guess there is since you did it, but VERY cool

Nice use of science. I agree with steve, time to buy another diagnostic tool!

[Travel'n Man]

Very interesting! Thanks for posting.......see, a person never has enough gadgets!

[240260280z]

Pilots can not be wrong:

http://www.aircraftspruce.ca/catalog/inpages/10-01765.php