Valve stem seals?

Rocket tests · 05-15-2020, 07:10 PM

Around 400 miles ago I did a head swap on my TBR7. The project went off without a hitch and I've been loving the performance gains of the extra compression and port work.

Today I was sorting thru some of the spare parts i have and noticed I still have a set of spare valve stem seals. ??? I thought back but can't remember ever installing them on the new head. So I pulled the valve cover off and sure enough, NO SEALS!

I inspected everything else, adjusted the valve lash and closed everything back up. It's odd that the guides don't seem to be blowing by at all, oil consumption is non existant and it seems no worse for the wear. The only problem is that now I know and it is going to bug me until I finally break down and do the job rite.

I assume the lack of blowby on the exhaust valve is a result of my modifications to the exhaust, the low backpressure seems to help.

mtiberio · 05-15-2020, 07:43 PM

I have owned many bike without valve stem seals.

Rocket tests · 05-15-2020, 09:42 PM

I bet you have. Wouldn't be a necessary item for a race motor.
If I don't install them then I probably shouldn't ever use synthetic oil. I had a truck once with leaking seals, it would foul the plugs if I tried running synthetic. Made an awesomely dense white cloud in intersections.

Megadan · 05-15-2020, 10:45 PM

Eventually you will start seeing some start up smoking, and you may see an increase in oil consumption, so keep a closer eye on your oil levels. It won't really hurt much. If it does bug you then you can always tear it down again lol

05-15-2020, 07:10 PM	#1
Rocket tests Join Date: Mar 2020 Location: Pennsylvania Posts: 87	Valve stem seals? Around 400 miles ago I did a head swap on my TBR7. The project went off without a hitch and I've been loving the performance gains of the extra compression and port work. Today I was sorting thru some of the spare parts i have and noticed I still have a set of spare valve stem seals. ??? I thought back but can't remember ever installing them on the new head. So I pulled the valve cover off and sure enough, NO SEALS! I inspected everything else, adjusted the valve lash and closed everything back up. It's odd that the guides don't seem to be blowing by at all, oil consumption is non existant and it seems no worse for the wear. The only problem is that now I know and it is going to bug me until I finally break down and do the job rite. I assume the lack of blowby on the exhaust valve is a result of my modifications to the exhaust, the low backpressure seems to help.
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05-15-2020, 07:43 PM	#2
mtiberio Join Date: Jun 2016 Location: Arlington, VA Posts: 258	I have owned many bike without valve stem seals. __________________ 4 time WERA SuperVintage Roadracing National Champion, SCTA Land Speed Record Holder, 3rd AMA Motorcycle GP of Miami
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05-15-2020, 10:45 PM	#4
Megadan Join Date: Apr 2017 Location: Omaha, NE Posts: 8,061	Eventually you will start seeing some start up smoking, and you may see an increase in oil consumption, so keep a closer eye on your oil levels. It won't really hurt much. If it does bug you then you can always tear it down again lol __________________ Hawk Information and Resource guide: http://www.chinariders.net/showthread.php?t=20331 2018 Hawk 250 - Full Mod list here. http://www.chinariders.net/showpost....62&postcount=1 2024 Royal Enfield Shotgun 650 https://chinariders.net/showthread.php?t=34124
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05-15-2020, 09:42 PM	#3
Rocket tests Join Date: Mar 2020 Location: Pennsylvania Posts: 87	I bet you have. Wouldn't be a necessary item for a race motor. If I don't install them then I probably shouldn't ever use synthetic oil. I had a truck once with leaking seals, it would foul the plugs if I tried running synthetic. Made an awesomely dense white cloud in intersections.
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