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Re: [ST] Re: Possible bad Triumph valve design



- ----- Original Message -----
From: "Jonathan West" <jwratmaster@xxxxxxxxx>
To: <ST@xxxxxxxxxxxxxx>
Sent: Thursday, May 15, 2003 9:40 AM
Subject: [ST] Re: Possible bad Triumph valve design


> Hi Mike B,
> RE your shop's conclusions about valves:  I think they are feeding you
> one hell of a big bunch of bullshit.

Personally, I don't think they are feeding me anything, I believe them on
this.

 First:  Your leakdown test pretty
> much confirms that your valves were way out of adjustment.  If the
> valves lose all clearance, then they cannot fully seat as they are still
> zeroed out against the heel of the cams.

No, there was still some gap, the valves were not zeroed against the cams.
The leakage could be heard in the exhaust and intake, and I could not hear
anything in the crank case.

 (This assumes you're not
> leaking past the rings or head gasket.)  When that happens, the exhaust
> valves will get scorched as they are constantly getting blow-by from
> combustion, instead of sealing the chamber and getting max compression
> from the ignition, and then expelling the hot gasses.  Second:  The
> blow-by will fry the valve seats as well which in turn will transfer the
> distortion to the valve.

The valves were not burned, however there seemed to be a small amount of
carbon around the valve seat area. The valves are very shiney on the faces
where the cupping is forming.


 Bottom line, valve clearance is important.
> It's better to be loose on the adjustment than too tight (zero lash).
>

You are exactly right, I just kept putting it off because I didn't want to
pay someone to do it and I did not have a tool yet. Not very good reasons.
If I had performed all my valve adjustments properly, and I found this
cupping condition, I would be talking to Triumph  about this. I personally
do not have any evidence this is a problem with anybodies bike besides mine,
but I would like everyone to keep this in mind should this show up on
someone's bike in the future.
I will rebuild my head and hopefully correct this problem.
I spoke with a college instructor today at the race track and asked him what
he knew about valve bounce and if my story sounded valid. He told me he has
seen cupping on valves from weak springs and unsufficient spring dampening.
> I have owned Triumphs since 96 and have been active on the internet
> since then too.  I have NEVER heard the line of crap your shop gave you.
> I don't know how they can claim a world wide problem with Triumph
> valves.  It's the first I've heard of it.

There is no doubt my valves have been badly cupped and cupping is not caused
by any type of valve adjustment settings. It is caused most of the time from
weak springs and bad dampening. The best clue this might be happening to
your bike is indicated by how rapidly your valves continue to need
adjusting. If they require a lot of adjustment, something is wearing and it
might be cupping.

Mike Benzon

>
> Cheers,
> Jonathan West
> 95 Trophy 4
> 96 Super III
> 97 Trophy 900
> 99 ST
> 01 Daytona
>
>
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