Telltale leaking intake valve symptoms

jamiechapman418
Are there any real significant telltale signs that point to a leaky intake valve? Same question goes for exhaust valve? Or are they the same signs?
|
FGR01
Profile picture for user FGR01
Posts
5112
Joined
10/1/2006
Location
AZ US
Fantasy
1222nd
FGR01 3/9/2021 6:15am
3/9/2021 6:15am
EFI or carb bike? Electric or kick start?

Difficulty starting is usually the first sign. Kick start bike will not want to kick start but will bump start. If they get really bad it won't even want to bump start. E-start bike will crank longer than usually before firing.

You may also hear back firing back through the intake valves into the intake tract. This is where risk of catching your filter on fire comes into play.
jamiechapman418 3/9/2021 7:04am
3/9/2021 7:04am
FGR01 wrote:
EFI or carb bike? Electric or kick start? Difficulty starting is usually the first sign. Kick start bike will not want to kick start but will...
EFI or carb bike? Electric or kick start?

Difficulty starting is usually the first sign. Kick start bike will not want to kick start but will bump start. If they get really bad it won't even want to bump start. E-start bike will crank longer than usually before firing.

You may also hear back firing back through the intake valves into the intake tract. This is where risk of catching your filter on fire comes into play.
EFI with kickstart. Performance wise is there anything that would be a common sign? Flat spots of power? Bogging? Poor throttle response? Etc.
Paw Paw 271
Profile picture for user Paw Paw 271
Posts
3640
Joined
4/3/2013
Location
Benton, LA US
Paw Paw 271 3/9/2021 8:36am
3/9/2021 8:36am Edited Date/Time 3/9/2021 8:37am
Hard to start when engine is cold, but cranks up much easier when the engine is warm or hot even with valves clearances are set correctly.

Paw Paw
2
captain.olives 3/9/2021 11:26pm
3/9/2021 11:26pm
Paw Paw pretty much nailed it. If you suspect valves, check the clearances, adjust if nesc, and do a leak down test on your motor. The leak down will tell if they are leaking and which ones are leaking.

The Shop

See All »
kb228
Profile picture for user kb228
Posts
6161
Joined
1/31/2018
Location
Mansfield, OH US
kb228 3/11/2021 1:37pm
3/11/2021 1:37pm
When you hear excessive air passing through the intake when doing a leak down test...

Post a reply to: Telltale leaking intake valve symptoms