Author Topic: Valve stem seals  (Read 3741 times)

Offline JustcallmeMrT

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Valve stem seals
« on: February 11, 2015, 07:41:29 PM »
They just push on?  Rebuilding the head tomorrow so tips, tricks and advice always welcome.

Offline mickwinf

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Re: Valve stem seals
« Reply #1 on: February 11, 2015, 07:54:32 PM »
yes they push on, maybe warm them up and lubricate with oil or grease
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Offline Johnwebley

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Re: Valve stem seals
« Reply #2 on: February 11, 2015, 07:55:23 PM »
yes ,locate them on the ridge on the guide,good idea to use plenty of oil on the valve stem,

 and care fitting the collets  !!  little buggers
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Offline bomber

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Re: Valve stem seals
« Reply #3 on: February 11, 2015, 08:38:27 PM »
Which manuals do you have? I found cross referencing helps a lot!
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Offline JustcallmeMrT

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Re: Valve stem seals
« Reply #4 on: February 11, 2015, 09:33:39 PM »
Thanks gents!
I've got the Honda manual and a clymer manual.  I've also found some cross referencing invaluable.

Offline hairygit

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Re: Valve stem seals
« Reply #5 on: February 11, 2015, 09:42:42 PM »
Make sure you put the valve spring seats  on the stems BEFORE putting the stem seals on. The spring seats will not pass over the stem seal, and if you try taking the seal off to fit the seats, you ALWAYS damage it getting it off. Don't ask, seen it happen too many times!:-[
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Offline JustcallmeMrT

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Re: Valve stem seals
« Reply #6 on: February 12, 2015, 03:41:43 PM »
Make sure you put the valve spring seats  on the stems BEFORE putting the stem seals on. The spring seats will not pass over the stem seal, and if you try taking the seal off to fit the seats, you ALWAYS damage it getting it off. Don't ask, seen it happen too many times!:-[
Thanks for that, saved me some swearing. 

Offline JustcallmeMrT

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Re: Valve stem seals
« Reply #7 on: February 12, 2015, 07:02:51 PM »


Job done.  Thanks folks!

Offline bomber

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Re: Valve stem seals
« Reply #8 on: February 14, 2015, 12:51:47 AM »
Sorry for hijacking thread,
Does head need to be assembled to check valves with petrol?
I'm asking as it takes time to put springs and so on, but you need them to hold seal right?

Thanks

Did you remember to tap the top of the springs with a hammer, makes sure the collets are engaged.

I also used to fill the tracts with petrol, if you can see any seepage past the valve seat you've not lapped them enough. Petrol seems to be very effective at finding any imperfections in that area.
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Offline AshimotoK0

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Re: Valve stem seals
« Reply #9 on: February 14, 2015, 07:49:03 AM »
I used to test mine by using a tap wrench, tap as in tap and die set not the kitchen tap  :) I used the chuck type tap wrench, I'd insert the valve with some grinding paste on the seat and then attach the tap wrench to the stem, I found that this way I could pull the valve onto the seat much better than using a good damn awful sucker on a stick. When I wanted to test with petrol I'd just pull hard on the tap wrench, probably less pressure than the springs so if it didn't leak then it was unlikely to leak with the springs on. Similarly I could test the valve seats before removing the springs to see which ones were leaking, if you watch the valve head you can spot the petrol vapour coming out if it was a slight leak or dripping out if the seat was badly burned.

I do the same but with a Jacobs type chuck from a drill. Also use a g clamp witha U shaped bent bit of metal for a valve spring compressor. Soundinga bit 10/- (10 bob) readers  tips from MCM circa 1968!
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Offline JustcallmeMrT

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Re: Valve stem seals
« Reply #10 on: February 14, 2015, 11:30:46 AM »
I did check the valves were sealing - all good, no leaks.

Offline bomber

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Re: Valve stem seals
« Reply #11 on: February 15, 2015, 10:30:11 PM »
Thanks for tips!
One step forward, two steps backward...
Honda CB550F 1976

 

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