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Sep 24, 2024 | 08:37 AM

#21

Racepres

Seasoned HDF Member

Joined: Jul 2014

Posts: 8,565

Likes: 3,318

From: Cental, MI

Quote:

Originally Posted by Abilyeu

Definitely! This is the third old sporty I’ve had they’ve all had issues but never compression

BTW, Oiling for second compression test, is to help Identify Rings vs Valves... betting little to No Difference on yours. As I suspect Valve(s)

Sep 25, 2024 | 02:10 PM

#22

Abilyeu

Thread Starter

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Joined: Aug 2024

Posts: 68

Likes: 5

From: Colorado

Quote:

Originally Posted by Racepres

BTW, Oiling for second compression test, is to help Identify Rings vs Valves... betting little to No Difference on yours. As I suspect Valve(s)

yeah I’m thinking the same but I’ll get it apart soon and figure out what the issue is thanks!

Sep 26, 2024 | 07:51 AM

#23

The Doctor71

Cruiser

Joined: Jul 2008

Posts: 100

Likes: 18

From: '71 XLCH / '74 XLH

A few meaningless

observations, in no particular order:

it's tougher than you think to get a high compression reading on a '71 xlch. Why ? One can only kick so hard / fast. Your leg is not as good as an electric starter.
a 90 PSI reading isn't all that bad on the front cyl, given it's a kicker. If electric start, then 90 is very poor.
a 30 PSI reading is definitely bad on the rear cyl
why have the key "ON" during a compression test ? Just leave it "off". (I think yours is a kick only bike)
thottle & choke BOTH wide open
BOTH plugs should be out when doing a compression test. aka when testing the rear cyl, the plug in the front cyl should be out. Makes kicking easier for you.
a "leak down" test would be good too. But not all of us have the tools to do so. I get it. That said, you'll find it's difficult to get & KEEP both valves closed during a leak down test.... my fix for that is just remove the push rods.

Carry on.

Sep 28, 2024 | 07:30 PM

#24

Abilyeu

Thread Starter

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Joined: Aug 2024

Posts: 68

Likes: 5

From: Colorado

Quote:

Originally Posted by The Doctor71

A few meaningless

observations, in no particular order:

it's tougher than you think to get a high compression reading on a '71 xlch. Why ? One can only kick so hard / fast. Your leg is not as good as an electric starter.
a 90 PSI reading isn't all that bad on the front cyl, given it's a kicker. If electric start, then 90 is very poor.
a 30 PSI reading is definitely bad on the rear cyl
why have the key "ON" during a compression test ? Just leave it "off". (I think yours is a kick only bike)
thottle & choke BOTH wide open
BOTH plugs should be out when doing a compression test. aka when testing the rear cyl, the plug in the front cyl should be out. Makes kicking easier for you.
a "leak down" test would be good too. But not all of us have the tools to do so. I get it. That said, you'll find it's difficult to get & KEEP both valves closed during a leak down test.... my fix for that is just remove the push rods.

Carry on.

for sure! I didn’t do the leak down test but I pulled the heads and put some gas in the valves to see if it leaks and it’s definitely leaking but I think through the guide the springs and stuff were soaked and when I took off the bolts and exhaust on the rear cylinder there was oil all over the gasket was ripped as well