Engine out advice

I guess I already knew the answer to my own question. Thanks anyway guys. Can anyone suggest a place to go who will do a proper job of time certing my studs ?  I am in South East London.
 
Tom, I'm not in South London, but when I was looking into TimeSerting and looking for suppliers/installers I actually contacted TimeSert and found out who their distributors were (there was actually only one), then I contacted the distributor and asked for machine shops near me that were regular customers. They did supply a few names. I never needed to follow up on this but now I have several places I can contact for help if I actually do need it.
One thing to bear in mind with TimeSerts (or similar solid inserts, there's a couple of others around) is that if you have your top crankcase machined out to accept liners for 1200 pistons, the inserts will be VERY close to the big holes in the top case. I'm being very careful inserting the studs in my top case because I don't want this to be an issue.

Ken
 
TheWrongTrousers said:
I guess I already knew the answer to my own question. Thanks anyway guys. Can anyone suggest a place to go who will do a proper job of time certing my studs ?  I am in South East London.
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Ged at GCS Poole. Recommended  ;)
 
CLEMTOG said:
I have bought and fitted new studs as well, because they can lose their ability to clamp, ie linear spring tension.
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I'm not sure that's a real thing that happens to steel. Sure, the steel properties can change due to temperature, fatigue, etc. But I wouldn't have thought that would be likely of Laverda cylinder head studs. They're not in an extreme environment and they're not torque to yield (single use) studs like a lot of engines have these days, so they're pretty much under-stressed.

What sort of change have you observed in the studs and how could you tell? I'm not saying you're wrong. I just don't know what's going on. Always happy to learn something.
 
nothing positive Cam, just a strong feeling that, for the cost of the NOS studs (that I had in stock) I didn't want to put back together an engine that had given me many headaches with blowing gaskets, (pre solid copper days) one of which hit me in the leg and even through leathers was very painful, and then even more pain getting recovered from a very hot French motorway on what is known to be the very busiest traffic day in France,  all the way back to UK, and it seems to me that the emergency services don't increase on the day because of it. It took me years to track the problem which was ignition related and under certain conditions, overheat was the real problem, causing piston and ring damage, on the day that the bit of gasket, the section between the two outer right studs, hit me in the leg, something was happening that I was not working out, I later found that the motor was hydrauliching on oil in the right pot, it had gone onto two cylinders for a few microseconds about five times in 150 very hard and fast miles, and each time on reopening a closed throttle, I didn't know what was going on and hoped to make it home, but didn't, so the right pot had been under a lot of stress, the head was warped and had already been decked too many times, those two studs must have had a hell of a time, the replacement was because I could, the old studs were used to make up blanking plugs to ease crankcase cleaning and blasting by bronze welding 10mm nuts to short thread ends, and they are very useful when that is done here, the welding was trying very hard to tell me that this is by no means "just steal" but something quite special. MMA was just not taking, TIG only slightly better, but oxy acet and bronze weld did the job.

Not very scientific was it? you could easily be right Cam, but everything must surely have a life before death. I don't know if they are available new, I did buy a set from Wolfgang but they went back as the dimensions were wrong and they were plated, I had no confidence in them, and they would not have even fitted! I don't remember the cost of the factory ones I had in stock or the returned ones from Wolfie, but they would not have been very significant as an add on to full engine rebuild. If anyone has a set of NOS 9mm studs then I am a likely buyer!
CLEM
CLEM
 
Dellortoman said:
I'm not sure that's a real thing that happens to steel. Sure, the steel properties can change due to temperature, fatigue, etc. But I wouldn't have thought that would be likely of Laverda cylinder head studs. They're not in an extreme environment and they're not torque to yield (single use) studs like a lot of engines have these days, so they're pretty much under-stressed.

What sort of change have you observed in the studs and how could you tell? I'm not saying you're wrong. I just don't know what's going on. Always happy to learn something.
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They may be under-stressed in use, Cam.  But you'd be surprised what some owners manage... I often replace studs that have had the upper threads stretched!

If the thread in the case isn't damaged, and it really shouldn't be if the engine hasn't been incorrectly re-built, I leave them well alone.  Beginning grief or damage is easily spotted, the alloy around the stud base starts to swell.  If properly fitted, ie, long thread into the case, the thread carries more load than the stud cross-section is able to transmit, the next thing to let go is the upper thread and nut.  The studs are normally a tight fit in the case threads, pointing to fitting with hot cases.  The case threads should not be chased or re-cut.

Things are a bit different on the twins, I find lots of alloy swelling at the stud bases, probably caused by generations of bodgers without torque wrenches, or illiterate bodgers with torque wrenches.  Stretched upper threads are also quite common. 

Factory stock studs came both plated and un-plated.

piet

piet
 
mcnicol said:
One thing to bear in mind with TimeSerts (or similar solid inserts, there's a couple of others around) is that if you have your top crankcase machined out to accept liners for 1200 pistons, the inserts will be VERY close to the big holes in the top case. I'm being very careful inserting the studs in my top case because I don't want this to be an issue.
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Timeserts are actually the same diameter as a helicoil, so there is no difference in that regard.  It's why they're so clever, the inner and outer thread helixes are indexed so they can achieve this.  With a timesert you do have to make the upper counterbore which IS larger than a helicoil but it is only 2mm deep so has no great effect.
You're right about being careful fitting these things in any case though, I've seen many a bad situation made very much worse by someone whose ambition outweighed their ability - as someone once said.  :)
 
Re Piets post pertaining to 750 studs.

The Wagner kit that went boom into mine had to have the studs wasted, as per directions. Surely this wasting would be the weak spot in this case?
 
750 uses M10 studs, you knew that, and a repair is sometimes made by opening the M9 triple cases thread to M10, and then using 750 studs, turned down to M9 over the length and a new thread at the top, and maybe change the length, or so I have heard, but it would be too much bother for me and I don't think effective, mainly because the stud threads are rolled not cut and accurately taking .5mm off the stud length would be less than easy, without using a cylindrical grinder, which is not by any means a common machine in most workshops. I could be wrong but maybe this is what was meant when the term "wasted" was used.
CLEM
Clem  Clemo, Clemo, Clemo, Clemoooohh
 
chrisk said:
Re Piets post pertaining to 750 studs.
The Wagner kit that went boom into mine had to have the studs wasted, as per directions. Surely this wasting would be the weak spot in this case?
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Super-duper head studs are waisted to the minor diameter of the thread anyway, it provides a better stress distribution.
The 10mm shank on the Laverda studs is just some extra weight to carry around.

As to waisted vs wasted... no comment at all!  :D
 
Waisted implies thinned in the middle, hourglass-like. Maybe I am not seeing it, but where is this required to achieve a clearance. The barrels need to slide past the threaded bit up top, why would they need more clearance lower? Just read Steves post, I think Red went to stronger studs a while back, so no stress raisers in this waisting?
 
CLEMTOG said:
750 uses M10 studs, you knew that, and a repair is sometimes made by opening the M9 triple cases thread to M10, and then using 750 studs, turned down to M9 over the length and a new thread at the top, and maybe change the length, or so I have heard, but it would be too much bother for me and I don't think effective, mainly because the stud threads are rolled not cut and accurately taking .5mm off the stud length would be less than easy, without using a cylindrical grinder, which is not by any means a common machine in most workshops. I could be wrong but maybe this is what was meant when the term "wasted" was used.
CLEM
Clem  Clemo, Clemo, Clemo, Clemoooohh
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Except the 73 SFCs which had 12mm studs.

Paul
 
chrisk said:
Re Piets post pertaining to 750 studs.

The Wagner kit that went boom into mine had to have the studs wasted, as per directions. Surely this wasting would be the weak spot in this case?
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I heard this from Red when going the OS sleeve size to give adequate clearance for oil to get to the rocker spindles but couldn't really understand why it would be any different to a std sleeve. Looks to me that even tho the sleeve is closer to the stud it wouldn't limit oil supply.
 
Paul Marx said:
Except the 73 SFCs which had 12mm studs.

Paul
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And these are waisted.  At least the inner four, so oil can travel to the head.  Guess the race shop didn't want to drill out the stud bores in the barrel any further.

Triple studs have rolled threads, stud diametre is around 8.5mm.

Quentin, some OS sleeves actually reach into the stud bores in the barrel, creating a slit along the liner bores of the barrel.  I'm not a great fan of this, heat transfer can get dodgy in stock form, having a line the length of the liner at a different temperature can cause problems.

piet

 
"Quentin, some OS sleeves actually reach into the stud bores in the barrel, creating a slit along the liner bores of the barrel.  I'm not a great fan of this, heat transfer can get dodgy in stock form, having a line the length of the liner at a different temperature can cause problems."

you are seriously not wrong there Red, I once (as a spanner) dealt with a TZ700 that repeatedly seized all four pistons in varying degrees where it was super dooper before under the same conditions, the fault was traced to the cylinder sleeve nuts which were a pattern part,  changed as they were getting a but ragged from repeated engine strips, but sold as genuine Yamaha, and the seizures were apparent in four points close to the stud bores on all four pistons, the worst ones being those that were furthest away from the radiator hose connection exiting from the heads.

three sets of pistons later, genuine sleeve bolts and all good again, the best part of a season lost.
CLEM
 
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