Oil cooler or Not

[jayteenz]

I'm reassembling my engine and it was fitted with an oil cooler by the previous owner. I know it was a modification to fix the many oil related issues but I'm wondering whether it's really necessary ?

I like the cleaner lines of not having one so does any run a bike without a cooler ?

Cheers = John

[retromech]

Hi John, For what it is worth my experience here in the uk over the summer months is that an oil cooler (although mine is of an xs850) is not needed, I found that even after a 100 mile non-stop run at often 70 mph my oil cooler was overcooling the oil resulting in condensation in the oil tank, even after taping over the cooler this problem persisted, I may install an oil temp. gauge to check properly, or fit an oil thermostat in the cooler lines, or simply remove the cooler !!,clearly the above applies to my bike , ridden in the uk at the sort of speeds I ride at, other people may have different experiences, I would not suggest that others should do the same, just going on my experiences.
Regards Paul

 P.S. forgot to say my bike has extended factory sump

[jayteenz]

Thanks for the reply Paul. I'm in New Zealand and although our summers are warm that aren't really hot.
Mine also has the upgraded crankcases including the extended sump and I don't intend to work it really hard (too old for that now !).

Cheers - John

[bigskyforever]

Some comments I picked up on different forums, is the secondary benefit of the sump is that the airflow around it does assist in cooling the engine and engine oil. I do not remember where I read it though.

[farmrjohn]

I don't know if it is here, but the Toby Folwick site had a service news bulletin from Yamaha on oil temperatures.  tinyurl.com/h5wqp75  I was able to find a cooler on ebay that didn't have the piping but was able to connect it with flexible hoses.  It does make a big difference in the oil temperature, and I have a '74 with the deep sump.

[bigskyforever]

Farmjohn

Can you post a picture of your cooler and fittings.

Thanks

[farmrjohn]

The oil cooler is the one supplied by Yamaha back in the day so it fits right on at the side reflectors.  I took the hose off of  the crankcase fitting for one of the cooler lines, and the other cooler line goes to the oil tank.  It's necessary to use a small clamp on the crank case hose connection otherwise the clamp will interfere with the air box.  I think I also turned the fitting around, but don't recall for sure. 

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[pewe]

I believe the deep sump is all you need. You can find the background here www.classicyams.com/4-stroke/4-stroke/yamaha-tx750-story.html
I'm not quite sure if Ludy remembers right... I have a '74 which was directly imported Form Japan by a Honda (!) dealer. As one of the latest sold in Europe it has a small cooler and the hidden hoses under the tank.
Cheers
Peter

[royb]

Mine doesn't have a deep sump (& even if one could be found they are very expensive), so I'm in the process of retro fitting an oil cooler.....just wanted to double check before cutting the line, that the return pipe is the left hand one (showing #17 in parts book) when facing forward on the bike? cheers

[bigskyforever]

jayteenz

I would think there are a few things you should consider IMHO

Climate average temp during riding season

Touring or using as daily rider in urban traffic

Weight of engine oil you plan on using 

Exhaust link between cylinders (removal or leaving stock)


Removal of exhaust tube between cylinder will allow considerably more air flow it should not need a cooler

If you live in a Nordic climate and use for touring no cooler is required with stock exhaust tube

Average temp over 30 degrees celsius and use as daily rider cooler required especially if stock exhaust tube is not removed

I know that vintage  h.d. Sportster had a thermostatic valve built in, that would be a good fix for this application

High temp climate should use heavier weight synthetic oil