5 replies to this topic

[fixitsan]

My 900 has started to produce a bit of oil mist/smoke, when idling.

Hopefully nothing more than valve stem seals

 

If the head is coming off, I wondered if there were any known mods for the head which might be worth doing for any benefits.

 

Does anyone know of some mods ? It's a pretty good head design by the looks of it anyway but thought I'ld ask first

 

Dreading the job because the exhaust studs are very well stuck and the nuts holding the headers in have rotted down to about 80% of their original size. Might end up buying a secondhand head ! So because of that I've been looking at some videos showing the seals being replaced with the head in situ. Basically blocking the cylinder up with rag or rope to offer a resistance on the underside of the valves so that the springs can be compressed down from above - does anyone have any experience with doing that ? Any tips ?

Edited by fixitsan, 26 August 2022 - 09:17 am.

[Snowbird]

I've done it with soft rope on 2 valve heads many years ago but would be a bit more wary with the dinky valves of the tdm head.
But if it's going to come off otherwise it's worth a go.
Edit to add: how about a balloon down the plug hole? How strong are the valve springs.

Edited by Snowbird, 26 August 2022 - 09:39 am.

[fixitsan]

I've done it with soft rope on 2 valve heads many years ago but would be a bit more wary with the dinky valves of the tdm head.
But if it's going to come off otherwise it's worth a go.
Edit to add: how about a balloon down the plug hole? How strong are the valve springs.

I don't know the spring's rating but given the potential high revs they must be pretty strong, although the valves are small, being 5 valve heads so maybe they're not as strong as they otherwise might be.

 

My only reservation is the limited working space.

 

I might start off trying to do it with the head in place, with a view to removing it completely should it get too bothersome

Edited by fixitsan, 26 August 2022 - 09:49 am.

[dandywarhol]

I'd be surprised if stem seal would be causing it - stem seal wear is more apparant after closed throttle overrun, then open up again.

 

Check there's not a blocked breather system

[fixitsan]

I'd be surprised if stem seal would be causing it - stem seal wear is more apparant after closed throttle overrun, then open up again.

 

Check there's not a blocked breather system

 

I can't rule it out. It came on pretty quickly over a small number of rides, within about the last 1500miles.

 

I'll check them breathers out !

Edited by fixitsan, 26 August 2022 - 07:29 pm.

[Catteeclan]

I’d prob make an adapter to screw in the spark plug hole and connect to the air line. Done this method on a few cars over the years.