Triumphrat

Pierson

Hello to all. I have been a 'lurker' here since I bought a 1969 TR6R back in June. Many of you have helped me greatly since then.

I have just removed my valve head and will be removing the cylinders soon. When I took off the head the only gaskets on the PRT was one at the top and one inside each of the tubes. There is no 'wedding band' or crush seal. I have purchased a gasket kit for the rebuild from Franz and Grubb Engine in So. California. The kit contains various crush seals, two black o-rings and four red o-rings of the same diameter. So the question is; where do the two black and four red o-rings belong? Do I need the 'wedding bands' or not?

I know this question has been done to death, but I am confused on this issue. I have had oil leaks that I think are from the PRTs, which is why I am rebuilding at this point. Any advice would be greatly appreciated. Thanks. Dave

DAVE M

Hi,.

I don't know the answer to the question, but you do need a service manual and parts book.

They are very useful in figuring out what you need.

That said, sometimes the factory upgraded the next year and the improvement will work for your bike as well.

Snakeoil

Just went thru this a couple of weeks ago. Added an entry to the thread yesterday. Take a look at the responses. They are helpful.

Bottom line is your parts book will tell you what you should have. That does not mean it is what you DO have. There are different PRTs and the seals, o-rings, wedding bands and cups are all meant to work with the other correct parts for that sealing system. So, figure out what you have wrt PRTs first and then that will tell you what you need to use for seals and other hardware like cups.

In my case, somebody had used later model seals on the bottom with the matching wedding rings. I cannot use those rings with the correct seals for my year. My PRTs appear to be correct for my year so I'm going to get the correct cups and use the correct seals, which I already have.

You can also take a look in my restoration thread, "Robs '66 T120 restoration" and I just posted pics of how to measure the proper crush so you are sure not to over-crush and potentially distort the head.

I just took a look at the '69 and '79 parts books on the Big D site. What is interesting is both model years use the same sealing arrangement top and bottom E7310 and same PRT E9349. But in the '69 list they call the seals "rubber washers" and in the '70 list they call them o-rings.

If you have the PRT shown in the parts book, then you should use o-rings top and bottom, part E7310. Cannot speak to the crush required for the o-rings. I think Mr. Pete might have commented on that in my PRT sealing thread. I'd have to go back and look, which you can do, to see if he did.

regards,
Rob

Pierson

Thanks for the responses. I do have the service manual for this bike as well as the parts catalog. It does show the 'rubber washers' part E7310 for what appears to be the top seal and inner seal for the PRT. However, it does not show a crush ring nor wedding band.

So I am assuming (kiss of death) that the four red o-rings (rubber washers) are the ones that should be used for both PRTs. The two black ones may be the o-rings for the tappet blocks. These are listed as part E7563 in my parts book, and appear to be exactly the same diameter as the 'rubber washers'.

So, should the crush rings be used, even though they are not shown in the parts book and not mentioned in the service manual?

Many thanks.
Dave

Snakeoil

The cups or wedding bands are intended to prevent the square section rubber rings from extruding out from under the PRTs and leaking.

Since there is no sealing ring shown on the diagram for your model, I have to assume that the PRT is the correct length to get the proper compression on the top o-ring. If you put a square section sealing ring under your PRT, you will in essence make the PRT/ring assembly longer, making the compression on the top o-ring way outside of spec and will more than likely bend your head.

Use what is shown in your parts book and follow the assembly instructions in the service manual and you should be fine. Do a search here, as there have been many discussions on this topic and perhaps your specific model was subject in one of those.

regards,
Rob

Caulky

One day someone will make a list of the correct tubes and seals for all years.
*Note dont compare 650`s tubes with 73-on 750`s, they are different lengths.
The red O-rings [bottom] are lower temperature spec.
So use the black ones for both top and bottom [high temp]
For `69 to `75 650 engines the tubes are 70-9349 [equivalent for 71-2575].

http://www.tms-motorcycles.co.uk/sto...1.jpg?1.832086

These tubes have 71-1707 sleeves (wedding band)
O-rings 71-1283
Sealing ring 70-4752.
You may need the thin sealing ring 70-3547, if the gap is wide.

All of this stuff can depend on whether you head has been skimmed, and the head gasket thickness.

Also for T120V`s `73 to `75 there`s no spares list...use `72.
NOT the `73 on. (T140)

When ordering parts always quote the engine number.

henryanthony

Pierson,

The change to using the "wedding bands" was communicated to dealers in a November 1969 service bulletin. The bulletin was for 1969 and 1970 models. The wedding band and square cross section seal are NOT shown in repair or parts manuals for these model years. They are however, shown in the 1971 manuals.

Hope this helps,
Henry

Pierson

Thanks again for the responses. It appears that I should get the 'wedding bands' or sleeves and use the crush gaskets that were included in my gasket set in hopes of eliminating any oil leaks.

Since the service bulletin says to use black 'viton' o-rings, I am wondering if any of the o-rings in my set (Emgo) are actually 'viton'. Again, there are two black and four red o-rings. No instructions are included with the kit. Anyone know the answer? Thanks for your time.
Dave

Mr.Pete

Even Viton O-rings come in different colours,depending on the supplier.Viton is fuel resistant.
I suggest you put a black O-ring and a red one in a jar of fuel for a day or so.
If one swells up and goes soft,it's not viton.

The upper pushrod and tappet block O-ring should be Viton.It's really best if they all are,but the one inside the bottom of the tube is least important.

If you have space to fit a square seal under the pushrod tube,fit one with a wedding band.You could even use an O-ring with a wedding band,if it gives the right crush.
Later tubes had this arrangement,and will fit.