Ok, so I'm writing this more as a sanity check than anything--I'm trying to decide how much of what I think I'm experiencing with this change is real, as opposed to in my head.
I drained the SYN3 out of my bike yesterday and replaced it with Mobil 1 V-Twin. Also replaced the filter, although both oil and filter had been changed 1500 miles earlier at the first service. My SEEG now has 2600 miles on it. I went on a 100 mile ride last night between about 9:30 and midnight--the first time it was cool enough all day to ride, as it's been over 100 degrees in Northern California most of this week. Here is what I think I observed:
Mechanical Noise: Harley engines always have had what I can best describe as an "agricultural" type sound. Without water jackets to muffle it, seems like you can hear most of the internal pieces doing their things, from the whirring of the cams to the individual valve train components. One of the things I noticed when I got my SEEG was that the motor noise seemed even louder with the 103 than it had on my '91 Evo motor. I recently replaced the stock short windshield with a 12" Memphis Shades one, and with my head now out of the windblast, the engine noise was much more noticeable at any speed.
With the Mobil 1, it is very much quieter. The "individual piece" sound I described above is reduced to the point, both at idle and at highway speeds, that I don't feel like I'm listing to parts rubbing on each other--that's about the best way I can describe it. Perhaps if I put the stock exhaust back on I'd hear more, but this motor is definitely quieter now.
Temperature: I installed the oil temperature gauge last month and have since noted that on 80-90 degree days at highway speeds the gauge tends to stay between 180 and 190. In traffic, if I sit for a while it will creep up to about 220-230. On hotter days in traffic it has hit 240.
Last night, with the temperature between 85-90 at 11 p.m., it stayed right at 180 at highway speeds. I'm sure being out of the sun had an impact, and I don't think the gauge is reading much different now than with SYN 3. When I came into town and idled around for a bit, it crept up to 220 or so. It did seem to take a bit longer to hit 180 in the first instance, though--longer warmup time?
Oil Pressure: The best way I can describe my impression here is that the gauge, while reading within the same ranges with M1 as SYN3, seems to be less sensitive to temperature and rpm changes. When the bike was cold with SYN3, the pressure at idle was up at 20-30, and would eventually settle down to 10-12 as it got hot. At highway speeds, it would hang at least above 32, and seemed like it would immediately move to 45 or so when I got it to 4500 rpm and higher.
Now, as soon as I start the bike, even cold, it seems to idle at about 16 and on the highway hangs right in the middle of the gauge (about 32) whether it's completely warmed up or not. When I jump on it, it will slowly work its way up to 40+ (at 4500-5000 rpm), and then slowly settle back down to about 32 at 2800 rpm. Small changes in engine speed don't seem to affect it much. In town, with the bike thoroughly warm, it will idle right at the 16 mark, and as the oil temperature slowly comes up, pressure will drop to maybe 12 (just on the high side of the small mark, one below the 16). Never went any lower than that, no matter how long I idled--it was still at least 85 degrees ambient when I was doing this last night. In short, oil pressure just seems less sensitive to temperature and rpm (not completely independent, just less sensitive), but the operating range seems about the same as with SYN3.
Vibration: This is where I'm ready for y'all to tell me I'm nuts. At highway speeds the quieter engine gives a sensation of less vibration, although it's hard to tell whether it's just that I'm listening to less noise so that it "feels smoother". Of course, one of the advantages of the "A" engines is that they are less vibration-prone at highway speeds because of the rubber mounting.
But around town with the engine thoroughly heat-soaked, it feels like a different bike. The vibration/rocking I had gotten used to with the rubber mounted engine is greatly reduced, almost to the point of elimination. I had to put my hand on the horn bell sitting at a stoplight because I thought I was seeing things--it wasn't rocking back and forth much, if at all--just a slight vibration. I'm used to seeing (and feeling) it bounce around at idle. Between the noise reduction and the vibration reduction, the engine "just feels like it is not working as hard" when sitting at idle--seems like it's easier for it to keep itself going. Don't know how else to describe it.
I've worked on and around internal combustion engines my whole life. Built 2 stroke 250 Grand Prix road race engines for the AMA 250 GP National series for 7 years, and won two national championships along the way. We tried many different types of 2 stroke oils (sponsored by several manufacturers over the years), and each one had its own fingerprint--particularly in how it affected reading spark plugs and piston crowns--perhaps the most critical skill a 2 stroke mechanic needs to develop in order to get the bike jetted correctly. So I feel like I'm really well aware of the impact different lubricants can make. I've got to say though, I wouldn't have guessed I'd see, hear and feel such a difference in going from one synthetic oil to another.
So please, tell me I must be imagining it. I've half-way convinced myself most of this is in my head anyway.
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Topic: SYN3 Out--Mobil 1 V-Twin In (Read 24002 times)