cylinder compression or leakdown tester

[RandyR]

There have been a couple threads recently about potential valve or ring damaged engines (yet to be verified).

 

Harbor Freight has a Cylinder leak-down tester for $35

 

http://www.harborfreight.com/cylinder-leak-down-tester-94190.html

 

or a simpler compression tester for $20.

 

http://www.harborfreight.com/compression-test-kit-66216.html

 

Would these be worth while to buy for local maintenance days, or for Freebird's MD?

 

Who has used these devices, and how long does it take to test all 4 cylinders with one?

 

Is there enough need or interest in testing compression to make this worthwhile?

 

http://www.harborfreight.com/media/catalog/product/cache/1/image/370x/9df78eab33525d08d6e5fb8d27136e95/i/m/image_6165.jpg

[V7Goose]

The HF Leakdown tester is NOT a good tool. The manual says it can handle anything up to 100 lbs input pressure, but this is a flat lie. The second gauge is only a 15 lb max gauge, so if you use anything over 15 lbs input, you destroy it. In addition, I could not find any restriction orifice between the two gauges - this seems to explain the dishonest use of the low pressure gauge on the cylinder side (it makes it LOOK like it is working like a real leakdown tester instead of just a cheap gauge connected to a hose).

 

Although the tool DOES work if you keep the pressure down, I do not feel a max 15 lbs is appropriate, as I suspect it will not properly diagnose some issues, and the low air flow volume will make it more difficult to identify where it is escaping.

 

The HF tool is $40 - you can buy a good tool for $80. I do buy a lot of HF stuff, but this tool went back!

Goose

Edited December 7, 2010 by V7Goose

[RandyR]

Goose,

 

Any thoughts on the $20 compression tester for doing quick checks?

 

Am I right to assume that if one sees the Yamaha specified PSI and it only slowly leaks off, that the upper cyclinder walls, rings and valve seats are going to be ok? This presumes turning the engine by hand, and stopping at TDC.

 

Found a link for a do-it-yourself leakdown tester.... Its a good storry even if someone doesn't want to make one.

 

http://www.motorcycleproject.com/motorcycle/text/Leakdown.html

Edited December 7, 2010 by RandyR

[mbrood]

A good compression check would involve a wide open throttle and a "quick" turn over of the engine with the starter for three of four compression strokes. Trying to hold any "rubber tipped" tool down into a DEEP recessed plug hole and firmly against the seal for all of that is near impossible if not just awkward as heck. A screw in connection is THE standard... same for a quality leak-down tester.

[mbrood]

A good compression check would involve a wide open throttle and a "quick" turn over of the engine with the starter for three of four compression strokes. Trying to hold any "rubber tipped" tool down into a DEEP recessed plug hole and firmly against the seal for all of that is near impossible if not just awkward as heck. A screw in connection is THE standard... same for a quality leak-down tester.

[dingy]

Below is a link to one I have from Auto Zone. I have been satisfied with it. It is easy to screw into plug holes on my 1st gen.

 

$39.99, it doesn't have a case, but comes with a pouch.

 

It does not have the rubber tipped adapters, but as mentioned these are of little use.

 

Hose has a disconnect fitting from gauge which makes it easier to screw into holes.

 

It has 10 mm, 12mm, 14mm, 18mm and a 14mm long reach adapters.

 

The gauge is wrapped in heavy rubber, so it seems durable.

 

http://www.autozone.com/autozone/accessories/Actron-2-1-2-in-standard-and-metric-professional-compression-tester-kit/_/N-25j0?counter=3&filterByKeyWord=compression&fromString=search&itemIdentifier=347021_0_0_

 

Gary

[MikeWa]

Either gauge from Harbor Freight will work just fine. While they are not professional quality they are fine for occasional use. At work I used Snap-On. At home I have these. Just make sure they have the adaptor that will screw into your spark plug holes.

Mike