Working on cil.head - Your thoughts

[Mincehead]

Quote from Tarwetijger:

Doesn't the engine case need to be split in two, to change the chain?

Nope,just removal of the oil pump,hmmm from a quick search you might find this thread interesting:

http://trx850.motomaniac.net/forum/view ... ain#p40556

[Tarwetijger]

Interesting stuff to read. But ... 8< 8<
edit: never mind.

[HansJ]

...
I didn't know that the cam chain was such a weak point? The marks on the cam lined up nicely with the cil.head though!
Will have a closer look on the cam chain then. Doesn't the engine case need to be split in two, to change the chain?
...

It's not that weak point, actually never heard of any TRX engine failure because of broken cam-chain. (Check that your cams rotate freely, too tight cams seem to be the biggest culprit...)
I just noticed the timing was off, and since I had spent a fortune already on other parts, I thought the few extra bucks wouldn't harm anything but my already empty monetal reserves... Since Your timimg is OK, i wouldn't worry!

[Tarwetijger]

Sigh. This weekend I installed the valves back into the cil.head. One of the tiny wedges got stuck in a wrong way. Don't now how to explain in english but what it comes down to: I damaged one of the valve stems. The scratch is just at the level of the seal. So I have to replace the valve, as I wanted to reduce oil consumption...

[Mincehead]

Sigh. This weekend I installed the valves back into the cil.head. One of the tiny wedges got stuck in a wrong way. Don't now how to explain in english but what it comes down to: I damaged one of the valve stems. The scratch is just at the level of the seal. So I have to replace the valve, as I wanted to reduce oil consumption...

Those wedges are called collets Tarwetijger.
You won`t have to replace the valve,you can use a carborundum stone to dress the valve stem smooth.Unless the damage is severe as long as the valve stem is smooth to touch you`ll be ok.

[Tarwetijger]

Okay so one of those collets came into the valve spring quite deeply. I thought it would get in place more or less automatically so I removed the valve compression tool. Stupid action! Instead of getting in to place, the collet was pressed by the spring on the valve stem, very hard and in a wrong way, and left a mark/scratch on the stem. The scratch will just pass the stemseal, every time the valve is actuated. If I polish the sratch out, the stem will get thinner just at the level of the stem seal, I don't want that. So I decided to replace the valve anyway.
It's a real shame because the whole inlet side of the cilinderhead was just perfect, with smooth contact faces and even the valve clearance needed no adjustment at all - the bike did 39.000 km.

[Mincehead]

Hmmm,I see your point it would allow a tiny amount of oil to be burnt past the guide and stem seal.
Was the stem damaged THAT badly,got a picture of it?

[Tarwetijger]

Before:


After:


The exhaust valves could have been better, but it's alright to me.
Yes, I know there's a valve missing. Here it is.


A real beauty, isn't it? But here the top side.


I sanded it very gently to get the valve out without damaging the cilinderhead.

[Tarwetijger]

Oh by the way, the Haynes book states that the sprockets of the cams have to be taken off, to get the cams out. I didn't do that, just got the cams out including the sprockets! What is that all about?

[JL]

Sorry to hear about scratching the valve! Have been following this thread as I am still waiting for parts to do my head & cylinders too, and those valves aren't cheap I haven't removed my head yet, or even the cams - it's interesting that you could remove the cams leaving the sprockets on - is that after you remove the cam chain tensioner and guide?

[Tarwetijger]

Sorry to hear about scratching the valve! Have been following this thread as I am still waiting for parts to do my head & cylinders too, and those valves aren't cheap I haven't removed my head yet, or even the cams - it's interesting that you could remove the cams leaving the sprockets on - is that after you remove the cam chain tensioner and guide?

I will get a valve from a guy who trades in TDM's and TRX's. I've some old exhausts laying around which will be traded in (left one damaged, he has an set of which the right one is damaged). He 's quite an expert in overhauling those engines. Good to know such addresses!
Yes, I removed the cams with the sprockets on, indeed after removing the tensioner and guide. I did it like this with my other bikes I've had before and I couldn't figure out why it wouldn't happen like that with the TRX.

And don't let my stupid mistake hold you down. Now I'm actually getting the bike back together again, it's kinda cool to do this stuff all by myself.

[bobtrx]

JL I will chase you up for info once you get your parts ( prices and where from etc ) as I'm going to do the same with valves etc now that the speedo has clocked over to the start again . Oil consumption is another reason and I want to have a look at the bore . Lucky for me my riding style doesn't include reving past red line so the internals should look like new . May be I could sell it , I can see it now
FOR SALE
TRX 1996 model 1508 genuine kilometres on the clock ,( forgot about the other 100,000 )
41 mm FCR , over pipe never reved over red line ( waste of time )
Only ridden on weekends at specially prepared road surfaces by old turd ( lost count of the track days )
Been known to beat young turds on 1000cc sports bikes who couldn't ride ( but they look good in the pits )

[Tarwetijger]

How did you that Bob; start with talking about valves and end up trying to sell your bike?!

[bobtrx]

It's called a joke , bike has small speedo reading must be new so sell it for more money. It's not really for sale

[Trixz]

What a story so far Tarwe, keeps us all busy in our heads

Greetz
Gerben