That fuel return line crush washer trick is BS

Used to just reuse old copper washers on injector return lines like everyone at my shop in Tulsa did for years, until I had a customer come back with a miss at idle after 3 days. Now I replace every single one and torque to spec instead of just snugging them down, anyone else seen this cause intermittent issues?

3 comments

3 Comments

singh.harper2mo ago

Yeah, you ever check the banjo bolt seating surface with a straightedge? Ive seen guys change the washer but ignore a little burr or groove on the bolt face and it still leaks internally. The intermittent miss is usually from fuel pressure bleeding off just enough to lean out one cylinder at idle. I started lapping the bolt faces with 600 grit on a pane of glass and havent had a comeback in 5 years. You running an O-ring setup or still sticking with the crush washers?

wright.leo2mo ago

You had a crooked banjo bolt and didn't notice, @singh.harper? I've been running crush washers for years and never had a leak unless I reused one too many times. Lapping the bolt face sounds like overkill when a new washer and clean surface does the job. Stop overcomplicating it.

alice9282mo ago

Nah, sorry but this feels like overthinking a simple problem. Half the guys I know run those same crush washers for years without touching them, maybe replace them once every few rebuilds, and their bikes run fine. Lapping the bolt face on glass with 600 grit sounds like something you do when you've got too much time on your hands, not a real fix for a common issue. If fuel pressure bleeding off causes a miss at idle, your pump's probably just getting weak or your filter's clogged, not the banjo bolt face needing to be polished like a mirror. I've seen plenty of crusty banjos with minor scratches seal up fine with a fresh copper washer, no straightedge needed. Stick with the crush washers, torque them properly, move on.