Power valve seals
Moderator: rztom
Power valve seals
Mine just started leaking, do the jugs have to come off to replace the power valve seals?
1984 rz350
1987 zx1000r
1993 xr650L
2000 Road King
2006 BMW R1200GS
1987 zx1000r
1993 xr650L
2000 Road King
2006 BMW R1200GS
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- Moderator
- Posts: 7038
- Joined: Wed Mar 24, 2010 2:20 am
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.
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
Does any body have the part number for the o rings and seal
1964 Austin Cooper S 1071cc
1967 Austin Cooper S vintage race car
1999 Ducati ST 4
1981 RD350LC , R1 Front,toomey pipes, Barnet Clutch, ported , PJ carbs, R1 Speedo 01
1983 RZ 350 - stroker bike,R6 rear shock,tapered stem bearings,progressive springs,
1967 Austin Cooper S vintage race car
1999 Ducati ST 4
1981 RD350LC , R1 Front,toomey pipes, Barnet Clutch, ported , PJ carbs, R1 Speedo 01
1983 RZ 350 - stroker bike,R6 rear shock,tapered stem bearings,progressive springs,
jimrd wrote: Does any body have the part number for the o rings and seal
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
1987 zx1000r
1993 xr650L
2000 Road King
2006 BMW R1200GS
- Chang-Kuao-Lo
- Posts: 381
- Joined: Sun Aug 16, 2009 7:02 pm
fine steel wool and sea-foam works great to clean the crud off the valves.
'84 RZ350
4mm stroke, wickedatv stroker chambers and torque head 20cc
VM30 carburetors (270 main, 3/4 turn air screw), 2-in-1 Y intake
stg. II porting
"have a crappy weekend, i hope your house burns down." -carl brutananadilewski
4mm stroke, wickedatv stroker chambers and torque head 20cc
VM30 carburetors (270 main, 3/4 turn air screw), 2-in-1 Y intake
stg. II porting
"have a crappy weekend, i hope your house burns down." -carl brutananadilewski
Re: Power valve seals
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
1984 RZ350
1973 Yamaha TX750
1975 Yamaha DT400
1974 Norton Commando 850
Triumph Tiger 1050
Triumph Rocket III
1984 RZ350
1973 Yamaha TX750
1975 Yamaha DT400
1974 Norton Commando 850
Triumph Tiger 1050
Triumph Rocket III
Re: Power valve seals
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.
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.
Re: Power valve seals
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
1973 Yamaha TX750
1975 Yamaha DT400
1974 Norton Commando 850
Triumph Tiger 1050
Triumph Rocket III
1984 RZ350
1973 Yamaha TX750
1975 Yamaha DT400
1974 Norton Commando 850
Triumph Tiger 1050
Triumph Rocket III
Re: Power valve seals
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.
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.
'82 RD350LC in '81 colours, OEM pipes, UNI filters
'85 FZ750
'85 FZ750
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- Location: Spielberg (Austria)
Re: Power valve seals
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
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
My Bikes:
Yamaha RD500 1985
Yamaha RD350 1985
Yamaha R1 2001
Honda CBR 1000 2006
Yamaha RD500 1985
Yamaha RD350 1985
Yamaha R1 2001
Honda CBR 1000 2006