R1100 valve repair

[GORILA]

I had a recent breakdown/ loss of power on my 98 R1100GS. I would appreciate any advise with my repairs.
I carried out a compression test and found very low compression on the right cylinder. I took the head apart today and found that one of the exhaust valves is damaged/ burned out.
A leak test showed the other exhaust valve as well as one of the inlet valves were also leaking slightly.
I am intending to replace all four valves on that cylinder. Not having done this repair before can anyone tell me if I can just do a clean and straight replacement or will the valve seats require repairing?

 

[jaak]

Hi,

I'm in the middle of that myself right now. Bike's a R1150GS with 130000km. I bought new exhaust valves and new seats as well (+valve seal rings of course). Took the parts for a refurb to the local valve specialists. They said the seats are just fine but VALVE GUIDEs need replacement. First I waited for the valves for 7 days. Now I'm waiting for the guides for 10 days.
So my suggestion is to get it all appart and order everything you need at once!

PS! Why are you changing the inlet valves?

Br,
Jaak

 

[GORILA]

Thank you for getting back to me Jaak. I originally spoke to my local independent mechanic, hoping he could carry out a cheap valve repair. However he cautioned against this as in his experience repaired valves would not last long. He recommended replacing with new valves and also said that it would only be a matter of time before the others failed. Indeed when I carried out a leak test, I found two other valves slightly leaked.
The valves seem to slide ok in their guides/ bores. It seems a bit of a fuff taking them out or just measuring their width in situ. I don't have the necessary measuring tools!
In the end I think I'll replace the valves myself and check for leaks. I can't believe the cost. Cheapest price for an exhaust valve seems to be £90 at Motobins, that is for a 4.5 inch piece of metal!!!!!!!!

regards,

Mario.

 

[uncle dick]

When it's fixed, I'd recommend fitting one of John's chips. It'll run cooler and go better.

 

[GORILA]

I already have one of those. The bike was running fine until it started to run rough and lost power in very short time. Not sure why the valve has burned out, I can't see any bits missing/ broken off...

 

[GORILA]

In the end I have decided to try and repair my valves. The valves and the seats are coked up but otherwise complete. I am hoping that a careful rubdown and valve grind will do the trick. My friendly local bike mechanic suggested I use a wire brush on a drill to slowly and carefully clean up the valve seats, then use a valve grind tool by hand to apply the paste to the valves. I'll be interested to see how it all works out........

 

[mikeyboy]

Am I missing something?
You say a valve has burnt out,then state that,"i can't see any bits missing/ broken off"
Can you post up some photos of the valves and seats?

 

[GORILA]

Hi Mike, I've cleaned it up pretty well now so there is nothing to see. The face and stem of the valve were burned/ coked up a nasty tan brown whilst the others were a dark black and when I carried out a leak test, fluid poured through so there was no seal. I am hoping that if I regrind it I may get a proper seal and that will resolve my lack of compression...

 

[mikeyboy]

Sounds to me like your valve clearances were too tight,
If nothing's damaged I would give them a quick relap with some fine grinding paste and recheck for a good seal.
Don't go mad with the regrind, and look for a nice even seat all the way around the valve and the seat,it will soon be obvious if you have a bent valve.

 

[GORILA]

Thank you, I'll give it all a go as soon as the new seals arrive.