Power valve seals

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drzdude
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Power valve seals

#1 Post by drzdude » Sun Jul 08, 2012 4:20 pm

Mine just started leaking, do the jugs have to come off to replace the power valve seals?
1984 rz350
1987 zx1000r
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ief
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#2 Post by ief » Sun Jul 08, 2012 4:33 pm

Afraid so, one at least. Question is if replacing the seals will be enough tho.

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drzdude
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#3 Post by drzdude » Sun Jul 08, 2012 4:41 pm

Well that sucks, maybe I will do some upgrades while i have it apart.
Thanks for the info
1984 rz350
1987 zx1000r
1993 xr650L
2000 Road King
2006 BMW R1200GS

silverstrom
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#4 Post by silverstrom » Mon Jul 09, 2012 11:00 pm

It's not a big job. The hardest part is cleaning the valves. You can do the whole thing in an afternoon and that's going slow. Order genuine Yamaha oil seals, orings, head and base gaskets. That is not the place to be saving a few bucks and using cheap gaskets and seals. Use the best parts and you only have to do it once.

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drzdude
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#5 Post by drzdude » Mon Jul 09, 2012 11:19 pm

Thanks for the info. So are yamaha oem gaskets considered the best out of all that are availible?
1984 rz350
1987 zx1000r
1993 xr650L
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2006 BMW R1200GS

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jimrd
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#6 Post by jimrd » Mon Jul 09, 2012 11:33 pm

I have the new bushings from steve TS and power valves for the 1UA cylinders

Does any body have the part number for the o rings and seal :smt002
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drzdude
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#7 Post by drzdude » Tue Jul 10, 2012 11:24 am

jimrd wrote: Does any body have the part number for the o rings and seal :smt002

O-ring #93210-30734-00
Power Valve Seal #93108-23010-00

A good site to buy them from cheap is
http://www.ronayers.com/Fiche/TypeID/26 ... p/CYLINDER
1984 rz350
1987 zx1000r
1993 xr650L
2000 Road King
2006 BMW R1200GS

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Chang-Kuao-Lo
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#8 Post by Chang-Kuao-Lo » Tue Jul 10, 2012 3:17 pm

fine steel wool and sea-foam works great to clean the crud off the valves.
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concours
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Re: Power valve seals

#9 Post by concours » Fri Aug 10, 2018 8:12 am

I’ve got both inner seals where the M5 screws loosened & fell out, along with the half moon shaped bushing keepers. Drool on both sides. Exhaust “popping” heard a couple times. Any chance that I can install new keepers & screws, have it seal ok?
WFO for 45 years
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RuZty
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Re: Power valve seals

#10 Post by RuZty » Fri Aug 10, 2018 9:07 am

If it is leaking spooge the seals are probably shot because the valves and bushings are worn. If there is excessive clearance and the valve is no longer running on center with the bushing, new seals won't solve the problem for long (ie. less than one summer, not long enough to be worth the effort). The only way to know is to take it apart and measure, unfortunately the valves wear more than the bushings and all parts are expensive to replace. Fast From the Past has repro valves on their website and I think bushings are still available from Yamaha. Probably $500 to replace everything, but at least it will last another 20 or so years.
The nominal dimension on the bearings is 17.2 mm, with the bushings being 0.02mm above and the valves being 0.02mm below on new parts.

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Re: Power valve seals

#11 Post by concours » Fri Aug 10, 2018 11:01 am

They were in great shape dimensionally (bushings & valves) when I assembled them 3,000 miles ago.. i had used 222 Loctite on the M5 fixing screws.
WFO for 45 years
1984 RZ350
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Hooligan
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Re: Power valve seals

#12 Post by Hooligan » Fri Aug 10, 2018 1:26 pm

The valves are aluminum. Personally I wouldn't use anything highly aggressive to scrub them.

One thing I discovered by accident that works really well to dissolve hardened carbon is gasket remover. It is safe for aluminum cases then it is also safe for aluminum valves. It works really well and I use a plastic or fibre brush to scrub the carbon off. It generally takes multiple applications to remove all the carbon but it really does work well.
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Speed Freak
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Re: Power valve seals

#13 Post by Speed Freak » Sat Aug 11, 2018 4:06 am

I can confirm that gasket remover works well.
The gasket removers are based on ether - would be interesting to have a big glass of this stuff on the shelf for putting pistons, cylinders or valves in.
Only issue... It`s highly flamable, not so easy to get and you should not inhale too much of it because you will fall asleep :smt003
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