Excessive valve wear (Not for the faint hearted)

Rob Farmer

Rob Farmer

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We whipped the exhaust valves out of RichC's R90 last night. It's only covered around 8k since the heads were overhauled by The Cylinder Head Shop. Unleaded valve seats, new valves and guides along with some porting work all carried out at the same time.

I don't know what valves they fitted but they were as soft as butter. We had to cut the top of the stem off to get one of them out.

R90Valvewear.jpg
 
thats ugly......
Be good to know which Valves were fitted so we can avoid them
 
Thanks once again Rob.:thumb2. You are a true gent. I now have the quietest airhead in the known universe! The transformation is just as startling as the condition of that valve. The one on the other pot had started to go the same way to. Question is..How long will the intake valves last?
 
I've just spoken to The Cylinder head shop Rich. He reckons the valves are Swiss Intervalve but the problem will be caused by the fuelling. When the heads are ported the mixture needs to be leaner otherwise the valves stick causing the stems to get a battering. We need to have a look at your bikes mixture to make sure it doesn't happen again.

Inlets will be fine apparently

I'll speak to you later.
 
I'm certainly no valve expert but i would have thought the valves were case hardened so i'm surprised they would have got hot enough to soften the ends that much?? That metal appears soft, not hard and worn (or broken) away.

Shep
 
Ouch :eek

Nice <strike>rivet</strike> - sorry, valve :D
 
Shep said:
I'm certainly no valve expert but i would have thought the valves were case hardened so i'm surprised they would have got hot enough to soften the ends that much?? That metal appears soft, not hard and worn (or broken) away.

Shep
Click to expand...

I'd go along with that,and their explanation seems a bit limp as well!
 
weather the mixture is lean or rich it will have no effect on the tip of the valve . the excuse is utter rubbish, those valves have a material or heat treatment problem. i gave up with multi piece valves years ago, mind you it makes a change from the head falling off.
 
richie moore said:
weather the mixture is lean or rich it will have no effect on the tip of the valve . the excuse is utter rubbish, those valves have a material or heat treatment problem.
Click to expand...

100% agree.

I'd be asking for a refund.
They aren'y suitable for the job they are supposed to do and haven't lasted a 'reasonable' time that you would normally expect them too.
 
please keep us informed Rob as i was about to rip sorry remove theds:augie
ont my R90 for unleadin, and they were going to go to The cyclinder head shop:blast i think i may try some place else now. Need an airhead for next years Wee-Kend. Pre booking you for carb sync please....:D
Lyn.
 
We have no recourse we the cylinder head shop. The work was carried out before I bought the bike. They did say during a phone conversation yesterday that they do not supply valves for BMW but ask their customers to buy their own valves and send them in with the cylinder heads. I'll be speaking to the chap who had the work done to see if he can shed some light on it.

The main thing is that Rich now has genuine BMW valves fitted.
 
fayeslane said:
Anyone else had a problem with Swiss Intervalves, I am just about to put them in my PD and am now running scared :eek: :eek: :D
Click to expand...

We don't know if they are Intervalve yet, hopefully the guy who bought them will remember where he got them from.
 
richie moore said:
weather the mixture is lean or rich it will have no effect on the tip of the valve . the excuse is utter rubbish, those valves have a material or heat treatment problem.
Click to expand...

I agree completely but being as I wasn't their customer and haven't got the full picture yet in terms of where the valves came from my conversation yesterday was little more than a fact finding call.
 
SED won't use Intervalves for precisely that reason!

cheers,
 
Moto Bins and Motoren Israel have both supplied Intervalves for years , and I cant imagine them doing so if the had ever had problems with them.

But these ones either have not either not been case hardened of someone has shortened them by grinding the case hardening off.

Wouldn't mind a picture of the valve seats - there is a school of thought that recessed exhaust seats work better than level ones - I think Rob has a link to the site - so maybe someone has been doing a bit of, err, inexpert tuning.
 
Interesting point BB, mentioned the valve problem to the mob doing my headwork and they suggested excessively recessed valve seats as a possible cause :confused:
 
Nippy Normans supply Touratech, Wunderlich, Desert Fox and many other makes of accessories.
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