Was wondering what temperature the zenoah motors should run??? Thanks...David

Hotter than you might think :diablo: , the internal clearances are for air cooled type motors and they have been adapted to water cooling..anything less than steam on the water outlet is OK and temp stick readig on the cylinder is near 180 --these are what I would consider as MAX temps in HOT weather..

Scott will probaly chime in on this with some min. temps as He lives in a cooler place...:beach:

Ed Sidders wrote:
Cooler my arse !! ... Been 102-104 all week :diablo:

Ed pretty much has the idea down :dance2:
Internal combustion engines operate at better efficiency when above 200* .... But being water cooled with steam at 212* we can't run that close to the edge, so we try and get the cylinder area at least 170/180, the cases will be much hotter by as much as +30/50*

Water cooling allows greater heat absorption that in turn allows for more radical engine tuning producing greater heat as a by product.

If you DON'T have a way too measure heat, do the "Old School" finger test placing a finger tip on the cases under the carb ... HOLD finger on case for ONE ... TWO ... THREE seconds which should be a resounding, DAMN that is uncomfortable .... Perfect temp

That is providing you are getting a GOOD solid stream of water outflow while running :beach:

* It is better to have a very warm engine than one running too cool

So if my on board temp gauge maxs at 180* wrapped around the water jacket i'm good???

If your saturation temp of the water jacket while running is 180 .... that's just right !

Thanks Scott, I also have a set of Tempilstiks, maybe check case at 225* or would you go higher??

Being your able to see what the water jacket is doing, case I would not even worry about.
So long as your not blowing steam and staying @30* under the boil point, your good to go.

On that note, if the exhaust is smoking and crackling...is that normal. The cooling head is unbelievably hot. Is the engine much cooler dowm low?

Pipes normally don't pop and crackle unless they get water inside.
That said ...
If the engine is hot as you say, a steel pipe will be really hot and in such states of tune ( Which is Good have little to no carbon & oil build up inside them. An Aluminum pipe running cooler can at times if getting oily inside do some crackling.

Again, if engine is running with a solid stream of water at discharge outlet .. your OK