09-13-2021, 02:52 PM
(09-13-2021, 12:43 PM)tod.branko_imp Wrote:It makes sense on a Softail to a certain extent if we are talking about a twin-cam because there is a design flaw with the oil pump for the rear cylinder. From what I remember it wouldn't create enough pressure on idle so in stop and go traffic the cylinder would dry up and seize. HD have since implemented the system where the rear cylinder shuts down completely on idle and it's a system they are utilizing on the M8 even though it's water-cooled.(09-13-2021, 10:12 AM)furious_blue_imp Wrote: Probably not relevant here but I'll mention it.It makes sense on a Softail to a certain extent if we are talking about a twin-cam because there is a design flaw with the oil pump for the rear cylinder. From what I remember it wouldn't create enough pressure on idle so in stop and go traffic the cylinder would dry up and seize. HD have since implemented the system where the rear cylinder shuts down completely on idle and it's a system they are utilizing on the M8 even though it's water-cooled.
My long gone Harley Softail was programmed to kick into high idle if the oil temperature got above a preset limit. The idea is that with the engine on the brink of overheating they want oil circulating faster to cool the engine. Given that I'm sure that they've tested this thoroughly and it works as an emergency measure, it kind of surprised me to read about this in the manual because I would have just assumed that higher rpms automatically meant higher temps, but then this is the idle speed and the engine isn't running under a real load when this happens so I guess it makes sense. It had happened to me a few times on that bike and once traffic got moving and the engine cooled down the idle speed would go back to normal.
There is no system of that kind on the CB1100 (not officially anyways)
I heard a YouTuber once talk about a system on the CB1100 that allegedly skips a spark on random cylinders when the temperature goes too high, and I tried to find any official information on this, I even hit up a guy I know here who is a regional manager for Honda motorcycles here in the ME, and he told me that that's not the case, only cooling technology Honda is utilizing is the machining tech that allows them to cut the cooling fins thinner and longer (deeper) and that supposedly dissipates heat better.
'14 CB1100 STD 5 speed
There is no system of that kind on the CB1100 (not officially anyways)
I heard a YouTuber once talk about a system on the CB1100 that allegedly skips a spark on random cylinders when the temperature goes too high, and I tried to find any official information on this, I even hit up a guy I know here who is a regional manager for Honda motorcycles here in the ME, and he told me that that's not the case, only cooling technology Honda is utilizing is the machining tech that allows them to cut the cooling fins thinner and longer (deeper) and that supposedly dissipates heat better.
'14 CB1100 STD 5 speed
Very interesting, I hadn't heard that about the Softail. One other major change that happened on that engine was tighter bearing clearances necessitating specs for a new oil filter for finer filtration AND a boost of the idle speed to bring up the oil pressure, which I understood was intended to provide sufficient pressure to keep the tighter bearings happy. I have seen numerous youtube videos of people doing 'cool mods' to their later model Softails which include turning down the idle speed to barely sustainable, which of course will not be good for the engine because the bearings will suffer... I wonder if the problems tended to occur with bikes that had been modified like this and Harley realized that they could change 'the culture' so they had to upgrade the pump, which they actually should have done in the first place instead of just raising the idle speed and counting on that to keep the pressure at minimum. Maybe, maybe not. It sounds more likely that the reasons you give for the new pump are true. Glad I never had THAT problem with mine !
For the 1100 cooling, don't the spark plug oil cooling circuits also help with additional engine cooling > (extremely targeted cooling for sure !).