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General Topics/Tech TipsDiscussion on break in periods, rider comfort, seats and pad suggestions. Tech tips as they become available will be posted here.
I need some advice from an experienced Shovelhead rider.
I am getting closer to returning my new (to me) Pan-Shovel ('51 bottom, '66 top) to service after going over it stem to stern. It has an SS Super E carb that I've rebuilt (easiest carb I've ever worked on), and I ordered a master jet kit because the carb was evidently set up at sea level, but I run between 5,000 and 6,000 ft. Also, I am fitting different pipes (it had a single fishtail exhaust and I'm fitting side-by-side shotguns with old-school Sporty mufflers, similar to the attached photo. The engine has stock 74" Shovelhead pistons, reportedly, though I'll be pulling the heads shortly to reseal and inspect the rockers and valves, so we'll confirm that.
Anyway, here's my question: should I be using premium or regular gas with this engine? I've always run premium in my bikes, but then I've never had an engine with this modest of a compression level.
Here's my bike...
Last edited by NM Pan-shovel; Oct 6, 2021 at 09:48 PM.
I was in Montana and Idaho this summer they had the choice of leaded or unleaded premium gas, I think the octane was 91, I put the leaded in ran Great.
I was in Montana and Idaho this summer they had the choice of leaded or unleaded premium gas, I think the octane was 91, I put the leaded in ran Great.
Leaded or Un-leaded? Did you mean Ethanol or Ethanol free? As far as I know no Refinery has made leaded gas for about 25 years now.
Leaded or Un-leaded? Did you mean Ethanol or Ethanol free? As far as I know no Refinery has made leaded gas for about 25 years now.
I thought for sure it said Leaded or unleaded , They did stop making it a while ago you might be right, may be it was Ethanol Free Gas, the station was on Hwy 93, Salmon, Idaho. my ride sure did run better I even got a speeding ticket in Custer county ID,
the ole saying "fly it and watch it"
the compression ratio is in the 7> to a tad over 8 range and hardly required premium fuel.
these are slugs when it comes to performance as the head flow is shinola.
but your ride and your money!
octane has nothing to do with power unless your are in detonation. gasoline is generic and has the same BTU content, only additives to control ignition flash point.
with proper tune, i see no issue running 87. i run 87 in my tricked out 01 sport with 10:1+ static ratio with no issues and flog it regularly, my dynamic ratio allows for this. this machine redlines @ 7.5k and runs the speedo out dropping out of 3rd to 4th.
91 premium no alcohol is what I would run through it.
Are the valve seats hardened? If not, you should add a lead additive to every tankful.
Okay, sounds good. That was my suspicion--thanks very much.
I will find out in a week or two whether the exhaust seats are hardened. I'm pretty sure Shovelheads have valve seat inserts, so easy-peasy to have them replaced and then hand cut the seats with my carbide set, as shown in the attached pics of the head on my 1275cc A-Series (powered the MG Midget, Austin Healey sprite, Morris Minor, Mini Cooper, et al). All you need to do is make sure your guides are good to go (easy to knock out and replace with a cheap impact driver from Scamazon or Harbor Freight), and the cutters do an excellent job.
On the lead, while I genuinely appreciate you are trying to offer helpful suggestions (thank you), I won't run leaded gas in light of the extensive, decades-old research showing developmental problems in young children--learning disorders, behavioral problems, etc. Among other things, it interferes with the interaction between glial cells (which to oversimplify form the superstructure of the cerebrum) and neurons as young children grow, and the effects are heartbreaking. Most people are more familiar with the effect of a mother's alcohol consumption on glial cell migration and other issues, which can manifest in Down Syndrome, but the effects of lead are relatively unknown to people who aren't old enough to remember the Congressional hearings in the '70s on lead in paint and gas. I will never forget the testimony about refinery workers dying (15 of them, I think) in New Jersey and Ohio from lead poisoning.
Anyway, for those reasons, it's hardened seats or the paint-shaker sits in the garage.
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Octane recommendation
