Compression Test '90 FLHS

Reply Subscribe

Thread Tools

Search this Thread

Sep 23, 2007 | 04:13 PM

DarkKnight1963

Thread Starter

Cruiser

Joined: Jul 2007

Posts: 132

Likes: 1

From: Connecticut

Compression Test '90 FLHS

Opening this question to all. I've got a '90 FLHS, and I'm going to be doing a compression test on her.

16K miles, engine is in good shape, so I'm curious. What should I be looking for numbers?

Thanks in advance!

Sep 25, 2007 | 02:00 PM

iclick

Extreme HDF Member

Joined: Sep 2005

Posts: 11,615

Likes: 50

From: Baton Rouge, LA

RE: Compression Test '90 FLHS

Quote:

ORIGINAL: DarkKnight1963

Opening this question to all. I've got a '90 FLHS, and I'm going to be doing a compression test on her.

16K miles, engine is in good shape, so I'm curious. What should I be looking for numbers?

Thanks in advance!

My '96 RK ran 160Â±3 PSI on both cylinders from 1998 'til 2006 (106k miles). It had an Andrews EV13 cam, which increased static compession over stock. I believe stock is around 135-145 PSI, but I never found a spec in the service manual. It only said the two cylinders must be within 10% of each other with a minimum of 90 PSI, IIRC. Check with engine warm and at full-throttle, cranking over 5-6 times to get a good reading.