New pushrod tube grommets leaking

[montmil]

...Hi Monte - Hanging with the Britbikers.  Seeing what it takes to get BMW reliability out of a BSA...  I got the long distance riding award for driving my Thunderbolt from Atlanta to Petaluma CA and back again May 2014.  It was quite an adventure.   8-)

Stop teasing us. There's a spot her in the R65 NutHouse for your Beezer's dbl x-cty ride report and... PICS. The inmates demand pics.

[Ed Miller]

Semper Gumby hangs out here:

http://www.britbike.com/forum/

Next time I have my heads off I'll have to search for shim material like he suggests, as my push rod tubes always seem to seep a little.  So do the ones on my Triumph, now that I think about it.  

Mine have moved in the head before, so I don't know if they are even in right.  I think they're supposed to be fixed in place with green Loctite.  If somebody does get an exact measurement for an R65 please post it.

[Barry]

I checked the BMW repair manual and there is no mention of installed depth for the pushrod tubes.  Tom Cutter says there is no BMW specification. Snowbum suggests the rings should be 5mm below the base of the cylinder.

There was this though which suggests the rings are not fixed on the early models. The repair manual I have is the original 1978 version and I believe this is not be applicable to 81 on model years.

[Tony Smith]

The later model (post 1981 I *think*) and all R65 tubes do not "feature" friction fitted rings, attempting to use the "adjustment" procedure that worked on the older models will not work and may prove expensive.
 
For what it is worth, I purchased after market stainless steel pushrods for my R100RS, fortunately I took the salesperson's advice "you need 4 so buy 6" because I did bugger up two of them - put heads in oven (at some risk of discovery by the doemestic Goddess) put rear axle and pushrod tubes in dry ice, try to drive tubes accurately and as quickly as possible for the heat transfers tot he tubes and they do not want to move anymore, or crease before doing so - this is NOT a job I ever intend to do again!.

Anyway, long story short, I messed up the installed depth a little on a couple of tubes, or perhaps they were just dimensionally different, in any event they leaked after a relatively short period of time. When they annoyed me enough I pulled the cylinders and removed the grommets and put them back with stainless steel packing washers carefully selected by the TLAR (that looks about right) method. Interestingly, amongst the various ills my poor worn out R100 engine suffers from, pushrod grommet leaks is not amongst them.

[dziadzu42]

I had already tapped the ring before the question of it being brazed arose and I had seen oil squish out of the space between  case and grommet so some movement occurred. Nathan of Boxerworks said it was brazed and either the ring moved, or the entire tube moved. Either way was an acceptable temporary fix. Thanks all for your input.

[Barry]

The later model (post 1981 I *think*) and all R65 tubes do not "feature" friction fitted rings,  

Tony,

The pic I posted above is from a 1978 R65 repair manual so it may be that some R65's don't have brazed rings.  Whether that's just 78's or all R65's up to the model change in 81 I don't know.  

[Tony Smith]

The pic I posted above is from a 1978 R65 repair manual so it may be that some R65's don't have brazed rings.  Whether that's just 78's or all R65's up to the model change in 81 I don't know.  

Barry

The hard way I found out about the R65 fixed rings was working on my (now wife, then fellow member of riding group( wife's R65 in 1979. Her nearly new R65 had a weep from a pushrod seal and I had just recently made my handy-dandy pushrod grommet re-seating tool for my R100.
 
The results were "bad", due to the fixed rings. it's a wonder she ever spoke to me again, especially as for my next trick when she seized her nearly new Honda XL125 (who sets out on a 300 mile ride on an XL125 fer Chrissake!) another friend and I volunteered to fix it for her.

Instead of putting it back together stock, we "improved" it, a power-oll storked crank and a Henry Abe over sized piston turned the docile little 125 into a fire breathing 185cc monster. The other really clever thing was that we obtained a brand new XL175 front end from the local wrecker and fitted that to it.

We were so proud, it went like a cut cat and the frotn end from the 175 gave it a lot more ground clearance, so much in fact that we had to make an extension for the side stand.
 
Pity that a relatively petite female had immense trouble straddling it and even more trouble starting it, and it was prone to biting back.


In retrospect is is amazing that she ever spoke to me again. Although it must be said that after we did get together and she bought a lovely little XR200 (two valve) to go trail riding on I was forbidden to undertake any modifications.

'nother story but she sold the XR only a year or so back and the guy who bought it paid her more than she paid for it in 1983, I couldn't figure that out until I spoke with another friend who pointed out that the XR200 was a honda factory bored and stroked honda 100 - his theory that the internals of the XR were now inside a "cheater" 100cc bucket racer, a trick that was popular a few years back but which had all but died out due to the very, very few XR200 2 valves that were ever sold, friend reckoned that it was now so long that the cheater would probably get away with it for a while as nobody would be looking for that trick anymore.

[dziadzu42]

Tony, you wrote;

"The hard way I found out about the R65 fixed rings was working on my (now wife, then fellow member of riding group( wife's R65 in 1979. Her nearly new R65 had a weep from a pushrod seal and I had just recently made my handy-dandy pushrod grommet re-seating tool for my R100.
The results were "bad",


Could you tell in greater detail what you did (like how hard you tapped it etc.) what happened to the tubes, and how you ultimately corrected the damage. I may be in the same boat.

[Tony Smith]

Could you tell in greater detail what you did (like how hard you tapped it etc.) what happened to the tubes, and how you ultimately corrected the damage. I may be in the same boat.

That's just plain nasty making someone fess up to something dumb.

The first one looked like it worked, sadly what had really happened was that the entire tube had moved. Emboldened by my "success" I tried the next leaky grommet and when no movement was apparent I hit it progressively harder until it did, the tube had a crease and a tear in it needing pretty much immediate replacement although I was able to institute a temporary fix with a bandage and epoxy.
 
The first tube I "moved" was thereafter a loose fit and had to be removed, which destroyed it and a new one refitted using a loctite preparation to both holdit in place and seal it.

[dziadzu42]

One final comment.   I tapped the rings on all 4 push rod tubes and could see the rubber gromets compress slightly.  Nathan at boxer works  said the tubes pulled slightly out of the heads and that this was an acceptable TEMPORARY fix.  To make it a more permanent one, I put a small gob of epoxy on the tube that would prevent the tube from sliding back to its old position.  I can scratch away this epoxy if the need arises.  I don't know if the epoxy is doing anything constructive or not, but after about 1K miles, no oil leeks, weeps, etc.   8-)