helicoil

campletten

campletten

New member
bugger bugger and triple bugger,
I  have just pulled the second helicoil aut of my 1200 crankcase when refitting the camshaft, after a almost complete rebuild.
Thats it, I will never ever use that produkt again. I know timesert but there is so little meat on a 1200 where a helicoil has been pulled
any thought's ?

Campletten
 
Try a Bigsert.  Not cheap, but it does help you out.  Same method as Timesert, only for fucked up insert attempts.

Never had trouble with Helicoils I fitted myself, only with ones fitted by others... must be a knack to it. :D

piet
 
Campletten, you're pretty new here, if you haven't already looked there's always something in the archives. Just type in a search term in the search bar near the top of the page, select "Entire Forum", and hit "Search". You aren't the first to have this happen. Hopefully you can find an engineering shop with M9 BigSerts, they aren't exactly a common size, you might even need to offer to pay for them to buy a complete reamer/install tool/inserts kit.
Just asking, but since you've pulled one stud already, if you unscrewed the studs, are you positive you're putting them back in the right way up? The thread is longer at one end, that should go at the bottom (into the crankcase hole). A common error. Also, do you have a good torque wrench and are you using the correct settings of all 9mm nuts: 3.5 kg m (25 ft lbs), all 8mm nuts: 2.5 kg m (18 ft lbs). And are you incrementing the torque values as you tighten the head down by about .3 kg m, starting from "snug", tightening in the correct order? Oiled threads?
Good luck anyway, but you won't be the first to deal with these problems. It can be done.

Ken
 
strip the crankcases bare
cut a vee notch in the  stripped threaded hole with a hack saw
get a competent welder to fill the Vee entirely with weld,(trying to fill up a hole that is stripped and still oily is a negative, much easier and better to cut the vee)
fix cases to jig, mount on mill and  rebore the  liner hole(s)
using mill, drill,then countersink and tap the hole(s) for 9mm Timecerts using drill guide bolted to the other three (or even two) existing holes
install Timecerts and your done.
dont torque up the 9mm studs untill you have a ?200 torque wrench.
CLEM

Admin - photos added at Clem's request
 

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Hi thanks for the answers, if the longer threads go in the crankcase even laverda themself got it wrong  are you shure about this Ken ? oiled threads yes, using the correct torque value yes,
and Clem , the first hole I pulled was welded by a skilled welder this spring when the cases was bare !! looks like I have to split them again!
Bugger

Niels, DK
 
They are all the same way around ie the longer threads up but can of course been done by a privius owner I have the bike since 2004

I will turn them !

Niels DK
 
Niels,

One of the threaded ends is rounded, the other chamfered at 45?.  If you look closely, you will find a round indent in the centre on the very end of the stud at the chamfered end.  This indent is made by the inserting tool the factory used when installing the studs. 

So, quite easy.  If unsure of which way round the studs are fitted, just check for the indent.  Tough luck if the studs have been replaced by a previous owner, unlikely to find any installation evidence, rounded end goes into the case.

piet
 
frankly I am confused the roundet end is the short one on my studs Piet says this end in cases
Ken says long end in cases ?

Niels DK
 
The 9mm studs are all with the rounded ends and the short threads up , the 8mm studs are the way as Piet says .Try and look in the original
manuals snd check all the pictures there !!

Regards  Kent
 
hello Niels, I didnt realise Camplettenn was you
think of it this way, the long threads go into the alloy of the cases which "need" a longer thread due to the less load bearing capability OF the alloy, the short thread is at the top which has a much tougher steel nut screwed onto it.
I suspect that your cases were welded just by "filling" the hole, not by actually curtting a big vee shaped wedge out of them, and the other common defect is to fit "short" Timecerts, the longer ones (18mm from memory) are vital.Getting 25 ft/lbs torque is easy, but I recently saw a wrench that when I measured it in a vice at 25 it was not letting go even when my Snap On was was set to 45., but the owner thought that it was OK

the second picture in the post above (pictures posted for me by Bradders ,many thanks) show the "dummy" crank used with bearing "caps" to very quickly and acurately position the jig on a mill at 180 degrees to horizontal,and tilted for the angle of the cylinders (15 degrees?) and quickly get both planes very close to perfect (perfection does not exist) so as to be able to rebore the three holes and correct the cylinder base joint.This dummy crank is also very usefull to have installed in the bolted up cases before any welding takes place,to prevent distortion, especially if the job is close to the crankcase  halving joint, which cannot be machined at all, leave this item bolted up inside untill tempertures are normalised (perferably in an oven with slow decline) keeps everything straight

very willing to help you from her if you can stand the boxing and shipping to UK

you should have been riding your vellocette, much more torquey!

CLEM
 
okay
consensus is short rounded end UP, Clem The weld was done correct ie, wegde shaped cut and thanks for the offer ! Ole thanks great to know that there is a Danish
shop that have this stuff, and Kent you are right all pictures are this way.
Here is the guy thar welded it for me he has restored a yamaha for Agostini. http://www.zaco-classic.dk/

Thanks Niels DK
 
Niels,

Checked today, all 9mm cylinder studs that I found had both ends rounded... my mistake, sorry.

Most other studs in and around the cylinder head are as I described them.

So, yes, short end up!

piet

 
Just be aware that in my case some numb nut put the studs in with the short thread into the case and then when they stick up to high cut them off,so then they appear to have a long thread and a short thread BUT they are now actually shorter than std and have what appears to be the right orientation of threads.Its a lethal trap that results in pulled studs real quick and is really hard to pick up by eye.Be good to have a fitted exposed stud length dimension for an easy check.
 
Had a look at my 1200 crankcase and the amount of metal between stud holes and the opening for the liner doesn't seem sufficient for a helicoil let alone a bigsert. Welding would be my preferred action.

                                                                                                                                    Dave
                                                     
 
DSCF0294.jpg


this is how much room there is on a 1000

Regards, Melle
 
Melle said:
DSCF0294.jpg


this is how much room there is on a 1000

Regards, Melle
Click to expand...

Yes but it's a real bugger trying to fit 1200 barrels to 1000 crankcases.  :D

                                                                    Dave
 
this is how much room there is on a 1000
Click to expand...

Sure evidence of the importance of looking after your engine (or buying triple that's been looked after). Wouldn't want to open out those stud holes, let alone 1200 ones......

Kind of think it might have been a good idea to open up those semi blind holes on the outer studs to protect the cases from heavy handed "fixers"  ::) Having said that, they seem to hold up pretty well....
 
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