Stripped out cylinder stud

Hey guys,
While torqueing the cylinder base nuts the front centre stud just kept coming. Almost cried. Been looking at options and have decided to go with time-sert thread repair rather than a helicoil. Have ordered a 3/8" unc kit which contains all the bits and pieces I need to do the repair, also comes with 5 inserts. Will need to drill and tap the stripped out hole deeper ( right through ) leaving the hole non blind. Anyone see any reason not to do this, there is plenty of clearance from moving parts (cam, etc) to do this. Had bad results with helicoils before, that's why I want to go with a time sert.
Thinking I may even do the other 4 studs (4 are 850 style through bolts, this is a 750) in case I go to torque them down and get the same result. I don't want to have to split the cases again, again, again. :shock:
Any thoughts appreciated.
JUG

Re “I don't want to have to split the cases again,”

If you are doing this kind of repair in stiu, metal swarf will get into the engine, so you will need to try to cut the metal swarf getting into the engine to a minimum, and as it’s the camshaft section run a powerful vacuum cleaner down the cam when finished, the run the engine and clean all the oil/ filter/ oil pressure at the timing cover out in case you get any left in there.
Doing this work the lazy man’s way is not all that cracked up it is supposed to be, but it will be at your own ( meaning your engine’s ) risk :!:

Bernhard said:

Re “I don't want to have to split the cases again,”

If you are doing this kind of repair in stiu, metal swarf will get into the engine, so you will need to try to cut the metal swarf getting into the engine to a minimum, and as it’s the camshaft section run a powerful vacuum cleaner down the cam when finished, the run the engine and clean all the oil/ filter/ oil pressure at the timing cover out in case you get any left in there.
Doing this work the lazy man’s way is not all that cracked up it is supposed to be, but it will be at your own ( meaning your engine’s ) risk :!:

Click to expand...

Yeah, I know. I'm not going to do the repair in situ, I'm splitting the cases, AGAIN . What I'm thinking is, while I've got the cases split, again, maybe I should put time serts in the other 4 stud holes so I don't have the same thing happen.
JUG

As long as you have the cases apart, you might as well do the rest of the holes. You can buy more inserts to go with the kit. If you don't want to do the rest of the stud holes, at least do the four side holes if you are using 850 style through bolts. This is a shot of a crankcase with all 9 threaded holes fitted with Timeserts.



Ken

jug said:

Hey guys,
While torqueing the cylinder base nuts the front centre stud just kept coming. Almost cried.
JUG

Click to expand...

Hi Jug

Hope it hasn't done what my front centre stud done, one day I notice my front stud was leaking oil and my motor had a slite rattle when idaling, I found the stud had stripped, I was young and didn't want to pull the motor to fix at the time so I just glued the stud back in (yes I know that is a bit of a ruff job) anyway it stopped the oil leak but the motor still had that rattle noise when idling but went away when the revs picked up, after 12 months of riding it like this I ended up pulling the motor apart for rebuild into my featherbed frame, when I pull the cylinders off I found what the rattle noise was where the stud threated into the front stud hole the peice of crank case had broken away and was sitting on top of the crank, when the motor was idling the broken peice was rolling around the top of the crank which was making the rattle noise but when the motor was reving it flowed in between the cylinders, the peice that broke off couldn't fall into the bottom end and by the time I found the broken peice it was so smooth and polished from rolling around..
I never did weld that peice back on as I didn't want to warp the cases so after the rebuild I just glued the stud back in and never had any problems with it, but I did replace the crank cases many years later after finding hair line fratures around the main oil seal area, I still have that broken peice of crank case somewhere in my collection of parts, I should find it and mount it on my shed wall somewhere.

Ashley

Hi Buddy.
No other damage that I can see, just the pulled stud. I whipped the cylinder straight back off when I realised the stud was pulling out. The front 3 studs only seat into the case about .4 of an inch so there isn't a great deal of metal holding them in, I split the cases and am going with timeserts on all but the 4 through bolt bosses (which are much deeper, maybe an inch) , may even do them as well.
JUG

On the 850 the factory helicoiled the holes for the through bolts in the crankcases, must have been a reason so if you have it apart I would do those as well. Never took the studs out on the others to see if they helicoiled them as well.

this may be too late to help you. Had this problem with mine when it was still brand new. NVT did not take repairs back to the factory -they were done by the supplying dealer. Mine had been bought from a discount source did not fancy their workshop
getting its spanners anywhere near . So what I did was get a plug tap ,cant remember now what size probably UNF . And tapped through the barrel hole into the cases having carefully marked off the depth. Simple matter then to bolt through the barrel into the case. When some years later I took the barrel off the threads were eased out. It has never given any problems. A bodge that
worked.. I suspect my cases were not the only ones to be so affected.

Hi Ashley

Hope it hasn't done what my front centre stud done, one day I notice my front stud was leaking oil and my motor had a slite rattle when idaling, I found the stud had stripped, I was young and didn't want to pull the motor to fix at the time so I just glued the stud back in (yes I know that is a bit of a ruff job) anyway it stopped the oil leak but the motor still had that rattle noise when idling but went away when the revs picked up, after 12 months of riding it like this I ended up pulling the motor apart for rebuild into my featherbed frame, when I pull the cylinders off I found what the rattle noise was where the stud threated into the front stud hole the peice of crank case had broken away and was sitting on top of the crank, when the motor was idling the broken peice was rolling around the top of the crank which was making the rattle noise but when the motor was reving it flowed in between the cylinders, the peice that broke off couldn't fall into the bottom end and by the time I found the broken peice it was so smooth and polished from rolling around..
I never did weld that peice back on as I didn't want to warp the cases so after the rebuild I just glued the stud back in and never had any problems with it, but I did replace the crank cases many years later after finding hair line fratures around the main oil seal area, I still have that broken peice of crank case somewhere in my collection of parts, I should find it and mount it on my shed wall somewhere.



Now I am feeling nervous.