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Doc, I want to mount a Mooneyes oil tank forward of the downtube on my custom pro-street. My powerplant is a TP 121 with a Baker 6-speed open primary. I’ve seen many customs with the oil bag mounted up front and it looks ol’ school cool. Are there any issues with the oil flow to the motor using this configuration? I will be installing a pressure gauge/temperature gauge where the usual oil pressure switch is located. The bottom of the oil tank is slightly higher than the bottom rails of my pro-street frame. TP has said that its proprietary smart pump is not self-priming. Do you know of anyone who has successfully mounted an oil bag for this motor? I’m running ⅜in oil lines.

– Russell

To answer your questions Russell, I contacted Andy at Hyperformance Cycles/SA Choppers. He’s built many a ground-up custom, including some with this configuration. Frankly, it concerns him that you need to ask these questions as it indicates that you may be out of your depth with this aspect of your custom bike. It is not his intention to be rude but, if you get it wrong, you will lunch a very expensive motor. He suggests you take it to a shop where an experienced technician can check your set-up. Essentially, the oil tank has to be somewhat higher than the oil pump. As far as self-priming goes, none of the oil pumps are self-priming, which again is something that a person playing around with them should know. I also don’t mean to be unhelpful but destroying a motor is easily done if the setup is not correct. That said, good luck and thanks for your query.

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