Busted valve stem seal because of guide installed wrong??

[BigBoreSwede]

Hello.

Okay, so I´m tearing apart my top end and this is what I found. 2 busted valve stem seals. Nothing funny about that. The engine is old

But there is 2 things that does´nt seem right!

1. The seal at the pic looks funny. It totally broken and I have found pieces from it all over in the engine. Springs and a piece that seems to be the metal shell that wraps around the acctual seal itself.....hope you know what I mean

2. The valve guide where the broken seal is does´nt flush against the casing. You can barely see it......but it´s there. Hard to get a pic of that.
So the question is.....is it possible that the guide has something to do with the broken seal??

Maybe the bottom of the spring cap can break the seal when the guide is set a little higher?

Thanks/BigBoreSwede

 

[grizld1]

Old valve stem seals are prone to leakage, but they don't tend to break as a result of wear and age. The seals may have been incorrectly installed at the outset, or your engine may have a high-lift camshaft that's incompatible with the seals that were installed, so that the collets interfered with the seals and smashed them. From your photos it looks like the exhaust valve seals survived and both intake valve seals were trashed.

 

[BigBoreSwede]

Grizld1.....it´s the opposite. Both exhaust seals are more or less broken. The one at the pic is the most damage. The other seal looks like this (pic)

I don´t really know how to tell the difference between a stock and high-lifting camshaft.

Tearing the engine apart tells me it´s a 3L1 bottom with 750 barrels, 447 rods and camshaft.

/BigBoreSwede

 

[grizld1]

Ain't it grand when you think you've bought a motorcycle, then find out you've just paid tuition for a learning experience?

Here's what ya do. Go to www.biker.net . Use the 78 and after factory manual's engine section and appendix; there's no significant difference among 447 cams. You'll find the measurements for the OEM cam, the procedure for degreeing the cam, and the lift and valve event specs if you take your time, read, and look for them. You'll need a micrometer, a degree wheel, and a dial indicator. Zero the degree wheel while you have the head off so you can locate TDC accurately. If your cam doesn't match OEM specs things could get interesting for you, since different makers have different inspection specifications. For example, most performance cams are degreed with valves at zero clearance and the valve event read at either .050" or .040" lift. Yamaha has their own inspection valve lash (see the manual), and valve events are read at zero lift (the point at which the valve begins to open or closes fully).

You may find Yamaha markings on the camshaft, but that doesn't help; most performance cams are regrinds or weld-ups on OEM cores.

 

[Jack]

Looking at those valve springs posted,they appear to have a progressiveness wound to them like stockers,most aftermarket springs aren't wound that way.Those type of guide seals are cheap,regardless who sells them,what automotive overhaul kit you got'em from,etc,try and find some Viton replacements.

 

[BigBoreSwede]

Ohh my......

I did´nt know it was common OEM camshafts are regrinded or welded. PO told me about the 750 barrels only, I think a high-perf. cam should be intresting to me.....as a buyer but not a word about the camshaft. But a closer look tells the truth.

Thing is I don´t have the tools.....yet, neither the knowledge. But as you wrote "Grizld1", maybe a bought myself a training-course instead of a bike

I drove the bike last summer and it peformed VERY!!! well. No smoke.....no nothing! Only thing was the metalshaving in both the filters. This was the reson for me to tear it down.

Now, if the camshaft is OEM is it still possible for me to install high-lifting stem seals. Would not make a diffrence, right? Then I will not risk breaking the seals again IF!! the cam is a high-lifting one.

"Jack", all parts are home and I´m ready to start the re-build. I bought it all from Heiden tuning and all gaskets come from Athena. But you´re saying the quality is´nt top of the line?? It will serve this time, I guess


/BigBoreSwede

 

[grizld1]

Yep, XS Performance seals from Heiden Tuning are made to allow higher lift and may take care of things, but as Jack says, find out whether they're made of Viton or recycled Chinese condoms. I can't see much in your photos, but I don't see any impact dings on the tops of the seals. Jack is probably right that they're substandard seals that just didn't hold up.

 

[BigBoreSwede]

Well, both intake seals are OK and there´s no impact dings. That should tell me the camshaft is stock.

On the homepage of Heiden Tuning this is the info about the stem seals:
"Valve Stem Seals - Fits: All 650's 1970-84 Made in Japan - OEM Ref.# 341-12119-00/02"

This means either the seals are good or they are made out of Japanese condoms.......better then Chinese?? Same shit, I guess

Anyhow, tomorrow I´ll put the head in the owen. I´m going to replace the guide seals because of the one guide who is installed wrong and also I´ve been using alot of gasket remover when cleaning the head. Big risk the guide seals are broken by now.

/BigBoreSwede

 

[BigBoreSwede]

Hello.

Since PO had the 750 setup done I asume he got a 750 gasket kit. These kits comes with high-lift valve stem seals. Today I noticed my old stem seals are high-lift version.

(On pic you´ll see from left to right: old one // new high-lift // new stock)

Now.....I do have a set of stock seals and they look more ridgid, so to speak. Don´t know if it matters but I would like to use the stock ones just because the look better

To do that I MUST know if the camshaft is stock or a high-lift one.
"Grizld1" gave us a good tip with biker.net but can you tell by mesuring with a slide caliper on the cam nock (is that the right word??) or is the difference so small I´ll need a micrometer to tell?

Thanks for all the help

/BigBoreSwede

 

[BigBoreSwede]

Today I continued my re-build of my top end. I put the head in the oven for about 15-20 min. and then got crazy with the hammer and the driver tool.

The exhaust guide oil seals where really bad so I guess I was right about replacing them. Now I´m going to clean the head really good and put it all back together.

Seems that the guides tend got "mushroom" a little. A very, very gentle touch with the dremel took care of that but I cant figure out how you´re suppose to do installing new guides? Maybe pressure is the way instead of pounding the shit out of it


/BigBoreSwede

 

[Jack]

That what she said also

Just heat the head for about 30 to 45 minutes, bath the guide with oil,slip a thick washer on the stem of the driver that inserts in the guide to prevent mushrooming the seal end and drive her home.

 

[grizld1]

Hope you cleaned up the carbon really well before you knocked that valve guide out and didn't move any metal in the head. If you did you may need an oversized guide. Refer to the factory manual at www.biker.net for installation procedures and specs on minimum and maximum interference fit between head and guide. You'll need a valve guide installation tool. You'll also need to check the valve and seat after installation; seats usually need to be recut and valves lapped in. Again, that's in the manual, and it's no harder to read it there than here.