Honda CB750 Sandcast

Synthetic oil and our KO clutch???

nmbr12 · 11 · 3373

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Synthetic oil and our KO clutch???

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nmbr12

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Greetings!  When synthetic oil became available in the early 70s,I tried it  in my sandcast crankcase and it fried my clutch.I was told then that it wasnt compatible with our wet sump clutches.Has anything changed or do I just stick to my more slippery than snot Valvoline racing 20/50...thanx,   _Tim


markb

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I personally don't use synthetic oil in anything, especially the old bikes.  Just my opinion.  I 've heard these old engines don't like the synthetics.  You might be opening up a can of worms with this question.  I've seen heated debates about oil on other forums.
Mark
Mark B
1969 CB750 sandcast #97 restored - Sold Restoration thread link
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Wayne

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To answer your question specifically nmbr12, if it's meant for a motorcycle, it shouldn't slip. If the oil has a friction reducer (dino or syn) your clutch will slip. There are companies that make Motorcycle specific synthetic and they should be fine. (Amsoil comes to mind)

Now, would I use synthetic in my engine?? No sir. Too many first hand experiences both personally and professionally to take me there. EVERYTHING I drive now gets Kendall GT Motor Oil in the crankcase. Why? Kendall sourced their crude from the Bradford PA oil fields and at that time used only the sweet (low sulphur) Bradford oil making it probably one of the best on the market. I don't think they get it there now but it is still formulated to the same high standard. We used this stuff in fleet and I could not believe how some beat up old engines would just keep going and going.

But!...its like everything else, ask 10 people and you will get 10 answers. Everybody is passionate about their oil. My sandy will run Kendall GT 20-W-50 as will by T120 Triumph and Harley. I like Royal Purple 75-W-90 in my Harley trans. (makes a huge difference in shifting) I also run Amsoil 20-W-50  in the primary as it hasn't eaten an inner primary bearing since I switched. I have never tried a synthetic in the Triumph trans but I may. Can't experiment with the primary as it's belt drive and dry.

So I'm with Mark on this one, just a bit more long winded!  ;) Being that the oil compartments aren't self contained I would stick with a good high quality dino oil.
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CB750faces.com (Lecram)

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I have heard that synthetic oil will solve the dirt in your engine and block the oil canals. Why should you not use just mineral oil? That's always good




markb

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By the way, I'm not sure I understand what we're voting for.
Mark
Mark B
1969 CB750 sandcast #97 restored - Sold Restoration thread link
1969 CB750 sandcaxt #576 - Sold
1969 CB750 sandcast #1553 - Sold
1969 CB750 sandcast #1990 - Sold
1969 CB750 sandcast #5383 restored - Sold Restoration thread link
1970 CB750 K0 restored - Sold
2010 H-D Tri Glide Ultra Classic (Huh?)


Steve Swan

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Wayne is exactly "on the dot," about Kendall oils.  My son road raced Yamaha R6's four seasons, we ran 5 - 8 classes, including 3 heats for each class plus the race.  We ran Kendall "R" straight wt.30, absolutely NO cam wear.  We had "A" and "B" bikes, neither experienced malfunction or breakdown.  We ran in extreme ambient temps, our hottest day was 114 degrees F in the shade and out coldest day was 35 degrees.

i had an early vin K1, reluctantly followed a friend's (who is decades in the industry) suggestion of using synthetic motorcycle designed oil.  The K1 WAS relatively oil leak free b4 switching to synth.........  it began weeping, seeping and leaking within 1000 miles from anywhere there was a joint.  I am pretty sure the coefficient of friction is less w/ synth which translates, as i understand it, to, strange as it sounds, increased operating temps and decreased heat dissipation.  

Anyone, correct me if i am wrong or have misundertanding.......  ;D


nmbr12

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Markb,Thanx for responding;Im still a skeptic re synth.too for my oldie but goodies!  I will be using the Kendal GT-20/50 that Wayne+Steve recommend as soon as I can find it!  Im already happily using Royal Purple Products.  Lecram,I used Castrol Oil for years and was quite happy untill my good Friend&Mechanic,that I still respect,reassured me I had to swtch to Valvoline Racing...     Four cabbage heads are always better than one!  Thanx   _Tim



Steve Swan

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In the CB750, i use Castrol "Actevo" 20/50 motorcycle oil from motorcycle dealer.  Motorcycle oils have a "J" rating on the back label.  I use different oils in my different bikes.  Quite a number of new bikes, the mfg'r recc's synth.oil ONLY.   Autmotive grade oil is not "J" rated. 

Did a little web surf, here is a simple yet very good and unbiased article as i have seen in a long time -

http://www.motorcycleanchor.com/motorcycle/how_to/mc_oil.html


Wayne

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Good article Steve. Oil has changed a lot over the years. Or has it really?? nmbr12 since a single oil lubricates everything in your bike including the clutches you will need to get the motorcycle version of the oil you choose and it will be without friction modifiers. I can get away with the "car" version on Brit bikes and Harley's as they have engine, primary and trans oils all compartmentalized. Here's the link to Kendall's Motorcycle Oil.

http://www.conocophillipslubricants.com/brands-products/Single.aspx?pid=232&brand=Kendall+Motor+Oil

You can find a retailer on the site as well.

It's all about good oil and keeping it serviced. It kills me when I see people with expensive vehicles and toys dumping in some garbage oil made from recycled oil, chemicals wax and who know what the heck else. Some of it is even labeled as "Synthetic"!  :o
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nmbr12

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  Time well spent reading the oil article on the web.Thanx for sharing,Steve! I learned much,easy to understand...