Compression/leak down tester

[Johnny K]

I was just wondering what I should buy at Harbor Freight. A compression tester or a leak down tester? I'm not sure which is better as well as there are a couple to choose from and I'm not sure which would be a good buy. Thanks.

[SqDancerLynn1]

You need a good compressor for leakdown tester, I have seen leakdown tester kits that also have compression testers

[silverhorse47]

You can approximate a leakdown tester by gutting an old spark plug and either brazing soldering or using epoxy to stick a fitting to it so you can hook a compressor hose to it. If you want to you can also put a guage inline as all a leak down really does is check where air is leaking from and how fast it's leaking.

I find the guage redundant, as just listening to where the air is hissing from is usually enough to tell you what needs repair. If you have low compression it is impossible to really know if it is rings or worn bores or valves or whatever. It can point you in the right direction, but with the leakdown test you can hear exactly where the leak is, what part of the stroke the leak occurs in and etc.
Both are nice to have, but I suspect lots of mechanics do not bother with the leakdown test. It's a pity though.
S.

[Plooker]

A compression tester is all you need. Leakdown testers are occasionally useful but if I need one I go borrow it from Autozone or one of those places. A compression tester will tell you 90% of what you need to know and they're a lot easier and safer to use. Plug it in, crank the motor, if you get low compression add a little oil and repeat, if you still get no compression you've probably got valve issues end of story. I bought mine at Sears for $20 but if you'r handy/bored/parsimonious you can make one out of an old spark plug, a schreader valve out of a tube and a pressure gauge.
When I worked for the HD dealer the head mechanic was a tool fanatic, he said the only tool he ever regretted buying was his leakdown tester, because he never used it. (and paid snap-on about $300 dollars for it)

[silverhorse47]

the head mechanic was a tool fanatic, he said the only tool he ever regretted buying was his leakdown tester, because he never used it.

Pity.

S.

[Johnny K]

Okay, thanks guys. There are 2 models at Harbor Freight. I'm not sure which one to buy. One is for $19.99, and the other is for $16.99.
Here is the website:

http://search.harborfreight.com/cpisearch/web/search.do?keyword=compression&Submit=Go

[Zook]

I have the $8 one.
Worked great on the GS1000. Those sparky holes are pretty deep in the head and you will appreciate the flexible hose.

[Plooker]

My vote is for the 95187-7VGA
I miss living near a harbor freight....

Pity.

S.

I honestly think he just didn't know how. The first time he saw me balance a wheel on a balancing stand it took me half an hour to explain why it was better than the antique spin balancer everyone else used in the shop. Good skills, but no real education. (AMA Orlando graduate)

[NICK!]

I have and use both. These guys are right, compression tester first, then if you'd like one a leakdown tester is a "nice to have". I really only use the leakdown tester when I'm being picky, like on a race engine or my own bike.

[rudy]

I'm with Nick on this one. I bought a compression tester first, it's useful, quick, easy, and handy. It's a must. The leakdown tester is nice, but not necessary. I bought one because it was on sale, and use it after the compression test every time. It is nice to know if there's anything leaking, and how much.

Though, I always end up rebuilding anyway......