Board index Flathead Power-Technical Questions, Answers, and Suggestions Big Twin Flatties Has anyone measured BTSV temperatures?

Has anyone measured BTSV temperatures?

Post Thu Mar 17, 2022 6:47 pm

Posts: 41
Just wondering what other people have found in this regard.

Here's mine: https://www.youtube.com/watch?v=mi3sdvztWV4


Posts: 14
I was at a swap meet last summer and someone who also rode a VL had a temp reader like you use he shot the jugs on my bike while it was running I don’t remember the temperature but I was surprised how high it was I believe around 400 and like 360 there was a difference between the cylinders the bike was running very well that day . There are people with the information you are looking for hopefully they see this ,nice bike enjoy.

Post Mon Mar 21, 2022 11:25 am

Posts: 41
Thanks Shovelhead,

Your bike is a VL? What year? It's good to know that the temperatures I'm seeing are typical. I figured they would be, but just wanted to ask anyways.

Thanks for the compliment.


Posts: 3552
Location: Central Illinois, USA
Flattys are supposed to be 100F hotter than an OHV, Folks!

HEATCHRT1.jpg


Or else they ain't warmed up.

....Cotten


Posts: 41
Cotten! What a gem there! Where is that image from? It's good to know that what I've seen is normal. I just didn't know which is why I was asking :D

Thanks!


Posts: 3552
Location: Central Illinois, USA
Its from the 1942 Fort Knox Armored School Handbook, WildOne,...

I took my IR thermometer to Davenport one year, and read machines as they would pull by the booth.

Nothing made much sense to me.

....Cotten


Posts: 41
Cotten,

I have searched and can't find that handbook. Might you know where I could find a copy for my collection?


Posts: 27
Location: Snohomish Co., WA
THEWILDONE wrote:
Cotten,

I have searched and can't find that handbook. Might you know where I could find a copy for my collection?

My edition of the manual that Cotten cited had a green cover, but I gave it away when I sold my WL. Here are two links to outfits where you can get a reprint of the Ft. Knox manual:
https://www.45restoration.com/Products/ ... -1943.aspx
https://aaok.com/index.php/books-shop-m ... la-xa.html


Posts: 2665
Location: Los Angeles, CA
The demise of the U series was because H-D had tried many different cylinder designs to reduce heat they simply couldn't do it. My old time H-D dealer, Andy Verrone, once told me that the ULH Big Twin Side valves usually tapered the cylinder .001 every thousand miles. So after 10,000 miles it was time for new pistons or at least expand the old pistons.


Posts: 3552
Location: Central Illinois, USA
Chris Haynes wrote:
The demise of the U series was because H-D had tried many different cylinder designs to reduce heat they simply couldn't do it. My old time H-D dealer, Andy Verrone, once told me that the ULH Big Twin Side valves usually tapered the cylinder .001 every thousand miles. So after 10,000 miles it was time for new pistons or at least expand the old pistons.

I suspect it wasn't the heat they were fighting, Chris,..

They were designed for peak efficiency to run in the same heat range as 45s, which were a phenomenal success. The problem with larger bores is heat distortion.

The bigger the bore, the more it goes out-of-round, particularly close to the valves. (The squirrely barrel spigots were their own issue!)

There's only so big a 'Ricardo' motor can be, and survive.

....Cotten


Return to Big Twin Flatties

cron