Typical Operating Temp of Cylinder & Heads?

[wideglide38]

Has anyone ever measured the temperatures of their VL Cylinder/heads after (motor thoroughly broken in) warm-up and/or short ride? I’m breaking in a ’35 VLD and wondered what normal operating temps will be. Thanks

[mark59]

William, i have a U model, temps on cylinder at exhaust range from 350 to 375, cylinder base about 300 to 315. these temps are the hottest part of the top end. on a run in july there were 5 other BT flatheads in the group, my bike ran a bit cooler than the others on average, one bike was almost a 100 degrees hotter, these were taken at gas stops and done very quickly. the bikes had been shut down and the exact time they sat till i checked them could have affected the results. i do have alum heads. the temps i stated on my bike were always after a good heat soak, 30 mile plus, i don;t have a reference on break in temps.

[wideglide38]

Mark, Thanks for the info! I had heard those temp ranges and just wanted to see what others had experienced. My builder discussed with me a break in cycle (basically: run +/- 10 mins up to 200-225 Degs, shutdown, cool for 2-3 hrs., change crankcase oil, check torque on head bolts, repeat for 3-4 times; then set-up run length & temp, and so on....). So I have this squared away. Are you running straight 60 weight oil or something different? Any additives? Thanks

[Steve Slocombe]

Dear Bill, Terry Richardson has done some measurements on his 32 VL and should now be running a set of my 7-bolt aluminum heads on this bike in the Cannonball. Ask him for more info when he finishes. With new, cheaper, technology around more people are checking cylinder temperatures these days.

[wideglide38]

Thank you Steve. Sent you a PM. William

[mark59]

i had run 20/50 synthetic for more than 20k miles, just switched over to standard 50wt last oil change. no noticeable temp change. on my ohv bikes a temp difference of about 20 degrees between syn and standard oils. i can not find an answer to whether syn oils reduce friction or reject heat being carried back to the oil tank.
i know you have a V model without returning oil or tank, but my u oil temps range from 115 to 145 degrees.....much cooler than an ohv.

[wideglide38]

I run 50 & 60 wt oils in my pan & shovel and will in my VLD. I do run 20W50 regular and syn in my Twin Cams. When Syn is installed, the motor seems to get hotter even though the Syn is suppose to cling to the metal (especially on my '10 Ultra where the MoCo has leaned the engine out so much to meet EPA regs. ). Also, the motor sounds noisier when running Syn. Sounds like your alum heads are giving you greater heat dissipation!