Throttle shaft seals installation

Good morning all,

1986 ... XJ700SC ... Hitachi HSC-33.

I am rebuilding my carbs for the third time. I've finished the prep work and am ready to start rebuilding today. I have a quick question.

The throttle shaft seals that I got from Chacal are "grooved" on one side. When I installed them the first time I faced the "groove" outward . Does it matter which side the groove faces?

In fact it would help if I understood the purpose of the seal. Is the seal stopping the vacuum from drawing IN past the seal or is it stopping fuel/air mix from bleeding OUT ?

Any help and all opinions are appreciated.

 

it stops air from being sucked in along with other crud. air leak in will make you run lean possibly holing a piston. there are other problems associated with bad seals too climbing rpms inability to lower rpm to spec ect.

 

frrom xj4ever catalog
These V-shaped seals are installed with their open “face” facing away from the carb throat.

also down load this pdf
http://www.xj4ever.com/hitachi throttle shaft seals.pdf

 

Thanks guys,
I had an idea it was 'groove out' but your verification gives me the green light.
Apparently I didn't check with headquarters and they had me on shopping duty today. I'll see how far I can get tomorrow.
Gotta love the forum.

 

What is the trick on getting those seals to set inside the throats and then install ing the tube?.

 

Throats? Tubes? The seal sits in a recess, groove outward, you slide the throttle spindle, or shaft if you will, into it.
I absolutely disagree with the theory that a tiny amount of air leaking past the throttle spindles is able to burn a piston out - impossible, never happened. Burned pistons need full throttle running with lean mix or too much advance - at those openings any air coming past the seals is negligable.