Been working on converting my mill over to CNC.
I wasn't really sure why - until I cut my first part.
More on that soon, over on my shop thread.
I'm well outside LA now - much more rugged California coast and less gridded valley with stop lights.
The run to my shop on the scoot is a killer stress test for the motor, with the penultimate portion being a 65MPH, WOT, up hill run, for 4.3 miles, no letting off.
The motor now has about 4K miles (best guess) - and its running great.
The hill is such a stressor, I've used it to experiment a bit with the Smart Carb's rods (jetting).
But in my never ending commitment to providing entertainment - thought I would test something near and dear to my heart:
temperature senders.
Now, I know what you're thinking - and it's true - you will never get these few minutes of your life back - but stick with me here for a sec - 'cause I have something you might find interesting.
First - some background:
The BGM was the first head I used that had a place to screw in a temp sensor.
When I ran it originally - I kept my under plug unit - 'cause that's what I had.
But at some point - feelin' fancy - I plonked down $20 of my hard earned money and installed the in-head version.
I was kinda shocked.
Damn thing started "over-heating" right away.
I knew I should have just left well enough alone!
But then it dawned on me - that perhaps reading in head was different.
So I did some quick testing - where I would have both an under plug and in head sender on the scoot - and would unplug one and plug in the other on the run.
This was no easy feat - as those plugs are designed to confound humans.
My results as best I could tell showed about a 50 degree difference.
Regular readers of this thread may recall - I postulated that the difference would grow as the temp went up.
Which brings us to today, the 4.3mile uphill run, and the purpose of this post.
For fun (ik, ik), I put the old under plug sensor in today, and did runs up the 4.3 miles first using the in-head feed, then swapping to the under plug feed.
Settings:
65MPH.
4th gear.
3/4-7/8 throttle.
Tool bag and 1 gallon of extra petrol in the sidecar for weight.
Sitting up straight (no tuck)
Leather coat
Air in the tires (though I have no idea how much).
Using the in head sender - temps climbed to a "whopping" 393° by the top of the hill.
When I reached the top, I unplugged the in-head and swapped to the under-plug - ran down the hill - U turned - and did it again.
This time - I noticed the temps were kinda slow to register.
But sure enough - they started to climb.
When I reached the top after ~4 minutes of just sitting on the throttle under load - temps hit... wait for it... 283°.
Not a typo.
Now some of you may be spitting and cussing at this point - and postulating all kinds of uncharitable thoughts about my honesty - but those are the numbers.
>100° difference.
Prologue:
There may be more to the story.
I made this run with the scooter's side cover (cowl) off the scoot.
And I suspect that the under plug is far more affected by external conditions than in head.
- does it touch a fin?
- is it in the path of the fan blown air?
- Etc.
Tomorrow - I'll make the exact same run again - with the cowl on the scoot.
Let's see if its a little warmer.
In the mean time - consider what a difference the readings for VMC/BMG/MMW heads that utilize screw in type senders vs under plug.
For me, it was more than 100°
The run. 4+ minutes at near WOT under load
The scoot - exposed to outside for both runs
The set up: both senders in place. Just plug/unplug between runs.
I only saw this after the event - about a month ago. No seize - no unhappiness.
Suspect I was just ranking on the throttle into the wind. (note: 433°...)
I need a Seventies with Sidecar sticker.