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· Polini Boy
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Discussion Starter · #1 ·
Hello there - Any idea what the running temperature in Farenheit for a water/coolant. I finally installed the GPT tach/liquid digital reader....this thing has a cool feature/alarm when you program it to set the high temperature reading....

Thanks:confused
 

· Polini Boy
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172 Posts
Discussion Starter · #3 ·
Thanks Vince - now when you said "try keeping it" you meant - adjusting the oil/gas mixture, jetting, etc or do you mean percentage of waterweter mixture to distilled water - by the way what the mixture ratio on waterwetter/distilled water?

mucho gracias senior:clap
 

· Dorkus Maximus
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2,763 Posts
so what do you see?

brown plugs dont mean anything...other than that you remembered to put oil in your premix. ;)

take a look at my bit on reading plugs for the rationale on the subject - gained largely from the moto guru, the legend himself (RIP) gordon jennings...

vince
:D
 

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Vince_24X said:
so what do you see?

brown plugs dont mean anything...other than that you remembered to put oil in your premix. ;)

take a look at my bit on reading plugs for the rationale on the subject - gained largely from the moto guru, the legend himself (RIP) gordon jennings...

vince
:D

Dude I was trying to shortcircuit that whole discussion, sorry if it created confusion. What I'm saying is that if all the indicators are great, jetting is correct, even slightly rich, plugs look great, engine is pulling strong, oil/fuel mix is right, and yet the engine is running well above the 75C ideal and the internals (piston, ring, cylinder) all look great, then what would you say is the downside and what would I look to change?
 

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As I stated in another thread before,everyones temp readings are going to be different,unless you use a controlled enviorment.

If you are measuring your temp under the plug,you will get higher readings,more in line with most 2 stroke tuning books because that is the best way to measure combustion chamber temp.but it is not very accurate for water temp.

I think that is where most peoples confusion comes from when someone states an "ideal" temp,it all bs,just a ball park figure,if your motor is screaming and making power than alls well.

Internal inspection is the best way to tell what your motor is doing,yes you can tell if it is running too hot.Ie look in the water jacket around the cylinder,(if not using distilled water)look for scale buildup or mineral deposits,well if you have an abundance of them you are running well above 180 F,how do I know that,the minerals will sart to "drop" out of the water the closer you get to boiling 212F,you system is under some pressure so the boiling point is raised ,slightly.Now if you run distilled water it is harder to see whats going on,because the mineral and impurities have been removed during the distilling process,you have to rely more on the color of the aluminium in the water jacket,it changes color,grey scale,with heat,very hard to tell but it is possible.

This is just what I have learned building other aluminium motors,albiet much much larger.


Tom
 

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in my "non-expert" opinion,water temps on our bikes runs 165 - 180 ish

Vince,

I think you are more an expert than myself ,I've only been fooling with 2t for 2 or so years,big

block chevys and rodecks for 10 or so.

I'm the original king of afro-engineering.

Tom
 

· Dorkus Maximus
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ha! :laughing

nah dude, i just type well. ;) truth be told, my forte was never w/ motors. im an electronics nerd that is too poor to pay someone else to work on my bikes, so its 'knowledge by force', so to speak.

(not)coincidentally, your numbers are in the same general range (74 - 82C). tks for the info!

vince
:D
 

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Right on about the water temps.

But the bad thing is most of these temp gauges /data logger deals measure the temp under the plug,that's why most people say that the numbers are too low,but as you and I both know if you want to measure water temp then you need to measure on the inlet side of the rad. or exit side of motor,not under the plug.

Electronics nerd ? never would have guessed. You should be working on some kind of cd ignition system w/variable timing curves for these things.hahahahahaha

Tom
 

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Well for me, just an observation not opinion, 82C is a noticeable 13 fahrenheit degrees above the proposed max limit of 75C and I'm seeing more like 86C in the coolant with 139C at the head.... so I seem to be missing it on both ends... with no noticeable ill effects... thats why I asked. So either the 75C ceiling is non-existent or there must be a very great deal of flexibility in it.

Oh and the better data loggers will log both, not just one. They even do EGT!

212C = 413.6F is that safe for a 40cc Polini engine?

;)
 

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You can get variances just by where you locate your thermal couple to measure the temp of the water.If you are reading 86 C and the theoretical ceiling is 75C than actually you are not to far off,11C is peanuts,you are running in the same areas I am water temp wise.


head temp has so many variables it's not funny,you can have a casting flaw,air pocket ,that will screw with your temp readings .How tight the contact to the head is ,corrosion under the sensor,if the aluminium is not shiny it's got corrosion.Is the head got some kind of coating on the outside,anodize or hard coat. 139C is probably correct given the weather on the east coast,Bell's optimal temp is probably under ideal conditions,but to answer your question about the 212C its temp at plug,I measured with a laser temp gun 400F,It's safe I've had one of our motors that hot,lean and mean,run at Starke for practice and heat races and never changed the color of the plug at the tip,under a spark plug reader,the base of the plug,up inside,it was just a light shade change.Ran the same way at Palmetto,When I rebuilt the motor before this season ,it still looked new inside.

If you want to run at the edge you will need to do some serious blue print work on the motor,clearances have to be perfect ,measurements precise.

I wouldn't recommend doing it though,running that hot,I am sure it's gonna take a shit on me.

Exhaust temp determines how well the pipe works and mixture leaness/richness

head temp how well your combustion process is going

Tom
 

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while all three temp sources (water, head , egt) can tell you to a point whats going on . i feel egt simply for the time factor is most beneficial . you can stick a ring or piston long before you even hit 120F on your water reading . head temp is not as slow but if a problem comes up it may not be quick enough . egt is the most real time of the three . you could see a change (if temp reading units resolution is quick enough ) with as little as 100 engine cycles .

karters use egt to keep their 2-stroke engines dialed in(carb adjustments) between turns . attention to this during a race i feel isnt practical for a pocketbiker ,but for tuning you have to as yourself if you can do better ..............2 cents..........j
 

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"72" said:
while all three temp sources (water, head , egt) can tell you to a point whats going on . i feel egt simply for the time factor is most beneficial . you can stick a ring or piston long before you even hit 120F on your water reading . head temp is not as slow but if a problem comes up it may not be quick enough . egt is the most real time of the three . you could see a change (if temp reading units resolution is quick enough ) with as little as 100 engine cycles .

karters use egt to keep their 2-stroke engines dialed in(carb adjustments) between turns . attention to this during a race i feel isnt practical for a pocketbiker ,but for tuning you have to as yourself if you can do better ..............2 cents..........j
The only reason I asked is because I was considering getting the Mychron. If you get the H2O guage you have to buy the $26 coupler. I understand that you need to drill a hole in your pipe for the EGT. So it seemed easier to just use the head temp guage. It is just a ring that goes under the plug.
 

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bulldawg racing said:
....139C is probably correct given the weather on the east coast, Bell's optimal temp is probably under ideal conditions,but to answer your question about the 212C its temp at plug,I measured with a laser temp gun 400F,It's safe I've had one of our motors that hot,lean and mean,run at Starke for practice and heat races and never changed the color of the plug at the tip,under a spark plug reader,the base of the plug,up inside,it was just a light shade change.Ran the same way at Palmetto,When I rebuilt the motor before this season ,it still looked new inside.

.....I wouldn't recommend doing it though,running that hot,I am sure it's gonna take a shit on me.

Tom

That describes pretty well where I'm at with the 139C (the head was shiny and new when sensor was installed).... I wouldn't be comfortable at 212C either.... thanks Tom...


bulldawg racing said:
.....If you want to run at the edge you will need to do some serious blue print work on the motor,clearances have to be perfect ,measurements precise....
That also pretty much describes where I'm at with these engines.... perfectly matched and tuned by a master.... ;)
 
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