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Would like to try syn oil in FLH but all I find is really light weight, like car oil. I cannot seem to find anyone making a good syn replacement oil for HD super heavy.

Honda sent me these coupons, offering a free filter if I buy their new synt. I searched high and low, no one has that oil in stock, well the coupon is good through Dec. hopefully the dealers around here will start caring it before the offer expires. (Or maybe they just hide it when they see me coming? )

slimcolo wrote:Would like to try syn oil in FLH but all I find is really light weight, like car oil. I cannot seem to find anyone making a good syn replacement oil for HD super heavy.

You mean the synthetic oil designed specifically for Diesal engines isnt gonna work? Walmart sells it.

I cant seem to find any heavy weight syn oil, the closest I can find is BEL RAY semi syn but its only 50 wt.

slimcolo wrote:I cant seem to find any heavy weight syn oil, the closest I can find is BEL RAY semi syn but its only 50 wt.

hmm have you tried online?

slimcolo wrote:I cant seem to find any heavy weight syn oil, the closest I can find is BEL RAY semi syn but its only 50 wt.

What weight is "heavy weight"? I run into 20w-50 synthetic a lot. But sounds like you need heavier.

Shorts

I run Harley grade 105 which is the same as 70wt in summer. This is on the old FLH. I run 20w50 in bmw, no problem there.

slimcolo wrote:Shorts

I run Harley grade 105 which is the same as 70wt in summer. This is on the old FLH. I run 20w50 in bmw, no problem there.

Oh ok.

slimcolo wrote:Shorts

I run Harley grade 105 which is the same as 70wt in summer. This is on the old FLH. I run 20w50 in bmw, no problem there.

I see AmsOil carries an SAE 60 wt heavy racing oil, but that's the heaviest I could find.

Heavier weight oil may degrade lubrication and cooling. The oil passages in a motor are made for the weight oil the mfg. recommends. Heavier oil will cause higher pressure at the oil pump (the bypass opens, so less oil circulates). The thicker oil travels through oil pipes and passages design for lighter oil. This causes a higher pressure drop. So while pressure at the oil pump is higher, pressure at the end of the oil passage is usually lower. This means less oil and less pressure at the bearings, which is what you were hoping to avoid. In addition, oil is an important ccolant in an engine. It reaches where air or antifreeze can't. Like the pistons and crank bearings. The thicker, slower moving oil does not carry as much heat away, and the lower flow through the oil cooler means the oil isn't cooled as much.

Bearing clearances are designed around the weight oil expected. Heavier oil may lubricate less than the design weight oil.

Now going up a weight won't cause the motor to blow up instantly, it will actually degrade the life of the motor and lower performance. If your engine calls for 10W-40, and you put 15W-50 in it, you are reducing lubrication at startup (the cold 15W rating) and using more HP in the oil pump to move the thicker oil.

Arguments that viscosity degrades in a motorcycle so a higher visc. oil will shear down to a lower visc, while true, don't take into account that the motor was designed for the lower weight oil and the accompany loss of viscosity over time. If not for the loss, the mfg. would probably recommend 10w/30, like the autos.

Use the proper grade and rating oil on your engine, and you will get the best life out of it. Go lower or higher, and your engine life will suffer. Over time, the wear will be higher than normal...