Sold / Found / Inactive - Premium leakdown tester, $55 shipped CONUS

[grizld1]

Didn't like commercial leak down testers; they were either grossly overpriced or too cheap to trust, and I didn't care for the lack of filtration on all of them. So I made my own.

The tester is based on a Sears regulator-filter unit. Is it ugly and bulky?Yeah. Does it yield as clean, accurate, repeating comparison of pressure in to pressure retained as anything you can buy? You betcha.

Leakdown testing procedure doesn't involve deep tech knowledge, but even most seasoned owners should do some homework before they attempt it. If your experience with leakdown testing was gained with 4-bangers, be very aware that hitting one cylinder of a twin with standard test pressure of 100 psi is going to move that motorcycle if it isn't locked down tight.

Same conditions as before: payment accepted by mailed check only, reductions down the road won't happen, no trades or "offers" accepted, ad down in 10 days if nobody wants this.

 

[grizld1]

Glad you like the gizmo, Gary. Don't have to be even half bright to spot this as a bargain. The tester can go home with you free in October if a collective cognitive deficit leaves it unsold!.

 

[grizld1]

Maybe some of y'all need a little education here, so here's why I made the thing. Years ago my nice fresh motor developed an idle stumble in the right cylinder. I futzed with ignition. I checked compression; on a 700 cc. motor with streetified Venolia race pistons, I got an exact match at 180 psi cold. Then and only then I started playing with the VM36 carbies on the bike.

Nothing I did made an improvement. The right side idle stumble just got worse with time. There was one test left to apply. When I slowly turned the red lever on the inline valve open, a strong breeze blew out of the carbie. Gauges read 100 psi in, 80 psi retained. (BTW that lever isn't there on the commercial units; if you want to stop the air you have to dial the regulator control, and if something's going FUBAR it's muich faster to move that lever 1/4 turn.) But compression was even!

Yeah. But think this through. A compression tester has a check valve in it. It will tell you the highest pressure a cylinder develops, but it won't tell you if that pressure is retained. The leakdown tester gives much more data on the true condition of the motor.

My biggest mistake was to follow old Joe Minton's authoritatively delivered recommendation to use OE valve springs with a Shell #1 cam. You may get away with that for awhile, but.... Motor out, head off, right intake valve surface was cupped. New intake valve and proper RD valve springs all the way around. Had an SV650 Zook to ride, so the season wasn't lost. I got in the habit of doing a leakdown test at the start of each season.

Don't trust Joe on recurving the advance either, unless you're looking to have an adventure when your bike goes DOR.

 

[jpdevol]

Even on a stock motor, a leak-down tester as Griz is offering, will indicate valve seat/face issues when a compression test will not: carbon build-up, a little melting damage, improper seat cutting....

 

[Jim]

Leakdown test is the ONLY (compression) test used in the airplane world. Done every 100hrs in fact. It's by far the best indicator of top end condition. And bonus... one of the best troubleshooting tools. Hiss out the breather? Worn rings/cracked piston. Hiss out the muffie? Exhaust valve ain't seating properly.
Done annually or on a regular schedule, you can graph out wear on the engine... even down to "predicted" overhaul due date. Yeah, I know... pretty anal that... but it can be done.

If I didn't already have one (and damned expensive Lycoming approved one at that), I'd snag this one in a heartbeat.

 

[grizld1]

Sold. Thanks, Dog Bunny!