Topic: AN-8 vs AN-10 oil lines

[DougB]

Based on my measurements of the oil take off fittings at .365" ID and a very restrictive washer  coming from the stock oil tank which measures .341" ID, I went ahead and bought an oil cooler and Mocal oil thermostat with AN-8 (.375" ID) fittings and braided lines to plumb my CR750 replica. However, all the pictures I look at of the CR750 bike's oil lines look like they're 3/4" to 7/8"OD. WhenI  see them against the frame tubes which are about 1 1/8" diameter. I didn't have the stock oil lines (I bought a a basket case) when I made this decision. Now that I see the stock oil lines are huge, similar to AN-10, and I am wondering if my AN-8 investments are all wrong. 
I'm making the oil tank now, but I'm second guessing myself now that I'm using too small diameter oil lines. AN-8 hose can't be crimped onto the stock oil pickups. I've made new pickups using a CNC'd plates with 3/8"NPT to an-8 fittings but I'm all afeared this diameter won't refeed the oil back to the engine, even though that stock washer was more restrictive than the hose i am using.
Someone please tell me 3/8" is an OK line to use.

[WHALEMAN]

I can not answer your question directly. There are websites out there about CR750 builds and restorations. I bet someone there would know the answer. One factor in the flow rate of a fluid through a pipe is size and length. The amount of oil that could flow through the short stock lines would be greater than could flow through almost the same size line up to a cooler. Do a search for Carpy, he makes oil line sets and could at least tell you what size he uses.

[Terry in Australia]

Someone please tell me 3/8" is an OK line to use.

I think you've answered your own question mate, the stock lines are larger than 3/8" ID, probably more like 1/2" or even larger, regardless of that washer. (the washers in my spare lines were much larger, so maybe yours was added by another owner?) All the CB750 based race bikes I've seen use similar to OEM size feed and return pipes, so I wouldn't mess with them. Cheers, Terry.