My engine sucks a lot of oil down next to the valve stems (backs of intake valves have a lot of oil sludge on them) and I want to change the stem seals. I'm planning on setting the piston to TDC and pressurizing the cylinder then using this tool http://www.uni-max.hu/szeleprugo-szerel ... zam/d/img/ to compress the inner and outer valve springs and remove the cotter then remove the springs and change the seal. Will this work like this, can I do it with the engine in the frame?

Also I'd like to ask, how would you make an oil catch tank?

I cannot see how you do it without taking the heads off?

How are you thinking to pressurise the cylinder if you are taking the valve out to change the seal?

take the heads off mate - if you are going to do a job like this, do it right first time. If you have the heads off and valves out you can also lap the valves in which will also make a decent bit of difference to your compression and the health of the bike.

On a slight thread hi jack, can you take the heads off without fully removing the engine?

I know the engine mounts are on the heads but can you prop the engine under the sump and remove the top engine mounts then remove the heads, or am I talking twaddle?

CMSMJ1 wrote:I cannot see how you do it without taking the heads off?

How are you thinking to pressurise the cylinder if you are taking the valve out to change the seal?

take the heads off mate - if you are going to do a job like this, do it right first time. If you have the heads off and valves out you can also lap the valves in which will also make a decent bit of difference to your compression and the health of the bike.

Easy, I have a leakdown testing setup already, that pressurizes the cylinder. Why would I need to remove the valves, I'm only changing the seals, not valve guides. I know probably I should take the haeads off and lap the valves, but then why not decarb, pull the crancases change main bearings and gearbox, piston rings and so on and so on. Right now I just want to change valve seals.

I can see why you want to just change the seals, save you buying head gaskets n shims if you lap the valves, but i just wondering how good to valve seats will be if the stem seals are going? Have you done compression test just to make sure everything else is ok?
I've always done stem seals the hard way like Mark says, and took the head off. But usually once the valves are out, i end up cleaning the ports out (cos it always seems rude not to) and.........................
Cheers
Ian

Can someone please tell me if it can be done with the heads on?

No it cant, do it the proper way.

That tool will be far too large to compress the springs with the heads in place. NC30 valves are tiny and you would probably have trouble with heads off as well!Just get a G-clamp style valve spring compressor. It is a fairly quick job with the heads on the bench.