[Dr. Zo]

Hi,

Not necessarily? The change was advised by Umberslade Hall mainly because the 'no-hole' rocker was cheaper to make, but is also slightly stronger. Assuming you don't expect to thrash the 'nads off your rebuilt engine at every opportunity, the rockers in your photo. should be fine?

Changing to 'no-hole' rockers is something of a can of worms:-

. the rockers-'n'-washers assembly diagram in the 650 workshop manual becomes wrong, you have to use the one in the triples manuals;

. if you reuse the existing rocker shafts, they need an oil transfer groove or scroll machining along them;

. the lateral position of a shaft within the box and rockers could be a problem when the domed nuts are tightened.


Mmmm ... there's better design, if they're available to fit:-

. In theory, the mushroom head allows for the rocker-arm moving in an arc while the valve stem moves in a straight line. Snag with the mushroom-head is it's still point contact on the end of the valve stem; if the adjuster has to slide across the valve stem during actuation, that force is concentrated in one small area in both adjuster and valve stem tip.

. @DMadigan Dave developed an adjuster nicknamed "elephant's foot" for the triples from those used by Porsche and by Mercedes-Benz on the 190 engine. Each adjuster is in two parts, threaded part in the rocker, circular part covering the entire valve stem top, joint between the two takes care of the difference between rocker arc and valve straight movements. The advantage is, if the rocker arc imparts any sideways force, it's spread over the whole adjuster 'foot' and valve stem tip with the chance an oil film can survive between.

Dave makes his for the triples so they can have a 5/16"-24 thread to match triple rockers - Porsche and MB adjusters are M8 Fine thread, close but no cigar and, rockers being hardened, rethreading triples' rockers for metric adjusters needed two or three taps.

What I don't know is if Dave makes his adjusters to suit the 5/16"-26 thread on pre-'73 twin rockers. However, now I've name-checked him, the Forum software will show him a link next time he checks in.

Or, if you must change the rockers, I don't know whether 750 rockers - with 5/16"-24 adjuster thread - would fit?

Or use the mushroom-head adjusters you've bought, with valve stems shortened for lash caps? Any later wear, the whole valve doesn't have to be changed, only adjuster and/or lash cap.

Hth.

Regards,

OK Stuart - bordering on the esoteric and I think I get some of this. Give me a few more years (if I've got them!).

I’ve another ask. I’ve looked at the ball end of the rocker arms and the ball surfaces seem smooth and polished so I don’t believe I need to attempt to replace them. I am curious as to why the adjuster ends are so gouged up and pitted. It would seem to me that they shouldn’t wear in this manner. I’d appreciate any insights as to why these might be in this condition? Thanks.

 

[Dr. Zo]

What year are my rocker boxes? So, My engine number is EC 19971 T120R. From my look at the engine year data I believe this means it was built in E “May” of “C” 1969, number 19971. Do I have this correct?

If so, I see that my rocker box assemblies are of the older type with the lubrication hole in the ball end. From my reading (in the tech notes from thebonnevilleshop) it reads, “the drilled hole in the rocker arm to supply oil to the ball end was deleted in favor of a notch at each end of the rocker arm bearing,” and that this happened during the later part of 1968, beginning with engine number DU79965. Have I got this right? If so, it appears that while my engine cases are from 1969, my rocker box assembly is from an earlier time, some time later in 1968 or earlier. My frame on this bike is number DU49062, 1967, so I suppose the rocker boxes could have been from the motor original to the frame. Thanks for any comments/insights. I’m trying to get a full idea of what I’ve got here.

Sensitive content, not recommended for those under 18

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[GrandPaulZ]

Oh my, Sensitive Content!

Good thing I'm over 18!!!

 

[Dr. Zo]

Oh my, Sensitive Content!

Good thing I'm over 18!!!

Ha! Yes. Who ever thought an old Triumph tank and frame "member" would be sexy?! Thanks to algorithms our lives are all censored a bit.

 

[broganh]

Greta build thread so far. I’ve learnt a lot from this one thread!

I really wished I’d seen that vid of checking the rotor hub prior to pulling my whole engine and taking it for a rebuild!

vapour blasting looks amazing I kept everything still in serviceable condition as standard/original, I kind of like the Idea of reuse over replace where ever possible. I also kind of like the ratty nature and character of a 50yo bike thats a runner.

I’m halfway through rebuilding my rocker boxes too. My exhaust side adjusters aren’t lookin too flash, and I forgot to get new o-rings for the shafts… the more I read the more info a (amd opinions) there are on rockers. Changing shafts to grooved, differing washer sequence, etc… are you just rebuilding yours as per manual? Or changing ?

 

[Dr. Zo]

Greta build thread so far. I’ve learnt a lot from this one thread!

I really wished I’d seen that vid of checking the rotor hub prior to pulling my whole engine and taking it for a rebuild!

vapour blasting looks amazing I kept everything still in serviceable condition as standard/original, I kind of like the Idea of reuse over replace where ever possible. I also kind of like the ratty nature and character of a 50yo bike thats a runner.

I’m halfway through rebuilding my rocker boxes too. My exhaust side adjusters aren’t lookin too flash, and I forgot to get new o-rings for the shafts… the more I read the more info a (amd opinions) there are on rockers. Changing shafts to grooved, differing washer sequence, etc… are you just rebuilding yours as per manual? Or changing ?

Broganh nice to hear from you. This is a first build for me on the Triumphs. When I started I thought I'd try to keep it a bit "ratty" too, but as I put more time in it I start thinking about making it a bit "prettier." I'd recommend you also to the forum called, "thetriumphforum.com" in case you are not already on it. I get a lot of good input there, even about the rocker box issues. I wasn't going to vapor blast, but now that I have I am quite pleased with it as the surface of the cases seem much smoother and should resist staining a bit more. I have just changed my rocker arm adjusters as they were looking pretty banged up. I also bought new Thackeray and flat washers to replace the old ones - however I forgot that there are 2 sizes of flat washers, 2 with 3/6 ID and 6 with 1/2 ID, so I'm needing to order new 3/8 ID ones also. There wasn't any problem with my old washers, but I thought why not since it's apart. I'm keeping the spindles as is, and it turns out that my rocker boxes are probably from 1967 while the rest of the motor is 1969. So my rocker arm ball ends have the oil hole in them. They look ok so I'm keeping it as is - just replacing the adjustment ends and washers and the O ring seals also. As for the assembly with my set up the Thackeray washers abut the rocker arms, with the flat washers on the outside of the Thackerays. If my bike had been able to run when I picked it up I would have gone with it but as I looked closer it was obvious it needed a complete re-build. Cheers.

 

[StuartMac]

Hi,

engine number is EC 19971 T120R. From my look at the engine year data I believe this means it was built in E “May” of “C” 1969, number 19971.
frame on this bike is number DU49062, 1967,

rocker box assemblies are of the older type with the lubrication hole in the ball end.
rocker boxes could have been from the motor original to the frame.

Mmmm ... while you couldn't rule out the possibility, iirc earlier in the thread you posted the engine had been swapped into the frame complete (with big-bore kit, etc.)? If so, could be the rocker-boxes were simply what were bolted to the engine, just happened to be the earlier type?

View attachment 774534
curious as to why the adjuster ends are so gouged up and pitted. It would seem to me that they shouldn’t wear in this manner.

Mmmm ... bear in mind:-

. if they're original, they're well over fifty years old;

. however old they are, they've always operated in an environment where oil flow is marginal at best;

. we don't know how good mechanics either the PO of the complete bike or the "PPO" of the engine were - e.g. whether they changed the oil regularly, always used good-quality oil, etc.;

. they're on an engine where other parts (e.g. the big-bore kit) were also knackered ...

However, my experience of how that particular type of tappet adjuster ages is limited (T160's originally had what were known as "captive ball", I swapped mine to mushroom-head many years ago); @GrandPaulZ Paul likely has more relevant experience?

ball surfaces seem smooth and polished so I don’t believe I need to attempt to replace them.

Agree.

Hth.

Regards,

 

[Dr. Zo]

Hi,




Mmmm ... while you couldn't rule out the possibility, iirc earlier in the thread you posted the engine had been swapped into the frame complete (with big-bore kit, etc.)? If so, could be the rocker-boxes were simply what were bolted to the engine, just happened to be the earlier type?


Mmmm ... bear in mind:-

. if they're original, they're well over fifty years old;

. however old they are, they've always operated in an environment where oil flow is marginal at best;

. we don't know how good mechanics either the PO of the complete bike or the "PPO" of the engine were - e.g. whether they changed the oil regularly, always used good-quality oil, etc.;

. they're on an engine where other parts (e.g. the big-bore kit) were also knackered ...

However, my experience of how that particular type of tappet adjuster ages is limited (T160's originally had what were known as "captive ball", I swapped mine to mushroom-head many years ago); @GrandPaulZ Paul likely has more relevant experience?


Agree.

Hth.

Regards,

Thanks Stuart. Yes, I believe the replacement engine could also have come with the older style rocker setup. Since from the history I have found from the PO, when he had the work done that included the engine swap, is when he got the Routt kit (and I think he must have got a used Routt kit since it already must have had the 060 pistons) it seems possible that the "mechanic" may have used his original rocker boxes - but who knows. I also get your point that a lot on this bike is/was knackered so wonder if the person who put this together did it with whatever he had on hand rather than trying to improve it a bit. At this point I'm trying to sort of document it as much as possible so that any future work on this might be sorted a bit better. I've gone ahead and swapped my adjusters with the mushroom type. Apparently the type of adjuster used is a matter of controversy, but so are a lot of items on these bikes - Ha.

 

[GrandPaulZ]

... my experience of how that particular type of tappet adjuster ages is limited (T160's originally had what were known as "captive ball", I swapped mine to mushroom-head many years ago); @GrandPaulZ Paul likely has more relevant experience?

Of all the ones I've seen, the badly gouged ones in these photos are probably as bad as I've ever seen in a big twin.

I'd replace at least the tips. I may have a decent used pair I can offer, but I've been severely under the weather going on a week, and it'll be another week before I can have a look for them (though I know right where they are)

 

[Dr. Zo]

Of all the ones I've seen, the badly gouged ones in these photos are probably as bad as I've ever seen in a big twin.

I'd replace at least the tips. I may have a decent used pair I can offer, but I've been severely under the weather going on a week, and it'll be another week before I can have a look for them (though I know right where they are)

Thanks GrandPaulZ for the offer. I have already gotten a new pair of tips so I'm good. Hope you feel better soon!

 

[Dr. Zo]

I am planning to purchase some new engine case fasteners as well as engine to frame fasteners. It seems that there is a difference in the fasteners kits I see for engine to frame, like on thebonnevilleshop web site. There is a kit for up to 1968 engine to frame, then a kit that is 1969/1970. So my frame is a 1967 and the engine is 1969. Have any of you had this issue before? I’m trying to determine what might be the best kit/solution for my 1969 engine going into my 1967 frame? Thanks again.

 

[GrandPaulZ]

Only issue you will find is in the rare few instances of a threaded boss on either the engine or the frame, in which case you'll have to match that item's year thread form.

 

[StuartMac]

Hi,

purchase some new engine case fasteners as well as engine to frame fasteners. It seems that there is a difference in the fasteners kits I see for engine to frame
There is a kit for up to 1968 engine to frame, then a kit that is 1969/1970.

Hmmm ... you might want to ask detailed questions about what's being offered - "up to 1968 engine to frame" was definitely British Standard Cycle; both '69 and '70 parts books say the same but the offer might be UNF (and bolts, not studs as original)?

Engine case fasteners are by-and-large BSF "up to 1968" and UNC '69-on; however, the head bolts remained (British Standard) Cycle 'til the 76 mm. 750 cylinder block.

trying to determine what might be the best kit/solution for my 1969 engine going into my 1967 frame?

If you want to go (nearly) all Unified, '67 and '69 'oles are the same ID; if the "1969/1970" "engine to frame" offer is UNF, they might all fit, a 19/32" AF socket is a good fit on 3/8" Cycle head bolts' hex. ...

Hth.

Regards,

 

[Dr. Zo]

Hi,

Hmmm ... you might want to ask detailed questions about what's being offered - "up to 1968 engine to frame" was definitely British Standard Cycle; both '69 and '70 parts books say the same but the offer might be UNF (and bolts, not studs as original)?

Engine case fasteners are by-and-large BSF "up to 1968" and UNC '69-on; however, the head bolts remained (British Standard) Cycle 'til the 76 mm. 750 cylinder block.


If you want to go (nearly) all Unified, '67 and '69 'oles are the same ID; if the "1969/1970" "engine to frame" offer is UNF, they might all fit, a 19/32" AF socket is a good fit on 3/8" Cycle head bolts' hex. ...

Hth.

Regards,

Thanks for the insight. I think I'll try with the new fasteners from the 1967 Kit.

 

[Dr. Zo]

Since I got my new cams, I thought I would do a dry run assembly making sure they had enough clearance in my bushings - as I had to to some trimming of the timing side bushes. So, the exhaust side was fine, however the intake side could rotate but I could tell it was binding, I believe on the inside part of the bushing on the timing side. So, I am going to need to remove this bushing. I think I know the answer to this, but is it possible to reuse the bushing even though it has been installed once? I would think it is not worth the risk of having a bushing spin so I’d need to get a new one and trim it as needed. Thank for your comments.

 

[GrandPaulZ]

Since I got my new cams, I thought I would do a dry run assembly making sure they had enough clearance in my bushings - as I had to to some trimming of the timing side bushes. So, the exhaust side was fine, however the intake side could rotate but I could tell it was binding,..

Were the cams lubed?

 

[Dr. Zo]

Were the cams lubed?

Yes, I made sure to do this.

 

[Dr. Zo]

Looking for Help with Pushrod Tubes. I’ve taken a good look at the 69 parts book regarding this, as well as the page on JRC Engineering that has a great description (Understanding Triumph Tappet Blocks and Pushrod Tubes | JRC Engineering, Inc.) . However I am still a bit uncertain how to proceed with my rebuild.

My pushrod tubes align with the one in the 69 parts book, it is castellated at the top (part number E9349). When disassembling it had an O ring inside a cutout on the bottom of the tube, as well as an O ring at the top (E7310), fitting over the castellated part (just like in the parts book). It also had a white rubber washer that was sealing the bottom of the tube - however this is not represented in the parts book. So I suppose what this means, from what I’ve read, is you use whatever size of washer(s) you need on the base of the tube to insure a good seal when assembling.

When looking at the JRC Engineering diagram for 69-73 650 Twins, it seems to identify another component of this assembly (that was not found when I disassembled my motor). So I am wondering if this is the “wedding band” part that I have heard mentioned at times? This being the case, would it be good for me to include this wedding band when I put my engine together? - Seems so if it will fit.

The length of my tubes from the top shoulder to the base is about 4.87 inches. The diameter of the base of my pushrod tube is about 1.24 inches, and the diameter of the cut out on the base of my new Aerco Cylinder for the rod tube base is 1.36 inches. So it seems there is some room for something here around the base of the tube - like the wedding band item.

I see the wedding band listed on the JRC Engineering site as part numbers 71-1707, 71-1707C, and 17-7107S (also on thebonnevilleshop site). So it this is a good idea to fit this band, how does one determine which pf the 71-1707’s to use? I would imagine it depends on the clearances, however I have not been able to find the measurements of any of these bands.

OK - well while writing this I found Service Bulletin No. 324, which seems to indicate the wedding band was a fix, and that it is something I can add to my re-build. Again, if this is the case, which band is the correct one? Are they different sizes? Once again further looking I find that the size must be the same, the C version being chromed and the S version being stainless.

So I think I may have answered my own question while writing this - but if there are any comments that might assist me I will greatly appreciate it!

Thanks.

 

[Dr. Zo]

Well, I’m quite busy today on the forum - result of finally getting the flu. So here goes some more questions.

Regarding tappets. Those from my bike need replacement, There was some chipping on the edges of a couple and uneven wearing so I need 4 more. I’ve been advised to beware of those manufactured in China as they have had some failures.

My bike had the oil driveway plugged for the exhaust tappets - The Routt barrel that was on it wasn’t drilled. The new Aerco barrel I have is drilled, however I am going to keep the case plugged as I’ll be having new tappets and cams (nitrided).

Please take a look at the photo of my cams, they all look the same, with a smaller diameter section in the middle of the tappet rod So, do I need to find tappets with the same smaller diameter middle section? For example see the photo from thebonnevilleshop of intake R tappets that are the same diameter the whole length of the shaft. Would there be any problem with these? Also, since I am not running with an open oilway for the lube to the exhaust cam, is it OK, fine, advisable to use 4 tappets which are the same - as was in my old motor. So could I just purchase 4 of these R inlet tappets and be good? The other tappets I see for sale that are exhaust tappets have the oil hole, is there any benefit running those on the exhaust side when the oil driveway is plugged? Thanks again

 

[Dr. Zo]

I also note that the exhaust tappets I see for sale have the oil hole in the rod, an oil hole on the tappet bearing surface, and the head of the tappet has 2 cutouts on either side. I am curious how this affects the engine in view of my previous query?