Oil-In Frame BSA Design Issues

| 4/10/2020 6:09:00 PM

Motorcycle Classics tech expert Keith Fellenstein
Editor’s note: If you’re having trouble with that old Suzuki, BSA or BMW, Keith Fellenstein is your guy. From motorcycle tuning tips to detailed motorcycle engine repair, he can draw from a wealth of experience to help guide you to success. Send questions to: Keith’s Garage, Motorcycle Classics, 1503 SW 42nd St., Topeka, KS 66609, or send an email with “Keith’s Garage” as the subject.

Oil-in-frame BSA

Q: A friend has an oil-in-frame 1970 BSA. Are there issues related to this design? It hasn’t run in 20 years.

Jerry Gere/via email

A: The only mechanical issues I’ve run into with oil-in-frame (OIF) Triumphs or BSAs were caused by careless sandblasting, leaving sand in the frame oil tank. Having sat that long, the oil left, if any, will be sludgy at the bottom. Best practice would be to first drain the oil, then remove the four bolts holding the bottom cover on the downtube. Thoroughly clean the filter screen, looking for any telltale metal parts, then reassemble with new gaskets.

4/30/2020 1:21:03 PM

These frames have been known to crack, usually where the swing arm mount is welded to the main frame tube. My '71 A65 is still good, my '72 T120 had a small crack there which had to be welded. Most likely culprit is flexing caused by using the center stand. The later T140 frames were reinforced in this area. All the OIF bikes are ridiculously difficult to get onto the center stand. I roll my rear wheel onto a short piece of 2x6 in order to gain some height advantage when deploying the center stand.

4/16/2020 11:43:25 AM

I have a 1971 OIF A70 Lightning with about 47,000 miles (of which 45,500 are mine) which I purchased in 1973. I did have a vertical frame crack just behind the cylinder "jugs" at about 30,000 miles, first identified by unexplained oil leakage. I understand that this has happened before to others. It was a "simple" matter to have it ground and welded (after stripping the entire frame, of course). I then had the frame powder coated, and have not had any problems with the frame since. A70 Rider

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