Modern Vespa

Hey guys,

I'm having a mare!

I have stripped the thread off a couple of cylinder bolts and also from some engine case bolts. I was just trying to torque them to the right level but the nut just destroys the bolt. I had the same problem when re-fitting a mallosi kit but just put it down to old bolts and perhaps being taken off and put on too many times. However I have split the engine, fitted a new DR cylinder kit and replaced the engine casing bolts and the cylinder bolts with new ones but they are doing the same thing.

This was my first time re-building a Vespa engine. Is this a common problem. Have I just been sent rubbish bolts? Can you buy reinforced ones?

As always, any help is greatly appreciated.

Thanks

Hello
Welcome to the world of aftermarket parts,they are made in bulk with pisspoor quality testing and shite material.
You also need to check that the torque wrench is in calibration and the figures you are given are for a clean dry new thread unless otherwise stated.

The figures given for Vespas are plus or minus and not a range, for instance. 20 to 25 nm. Is 22.5 nm. So take the lower figure from higher figure and divide by 2.
Bear in mind that an old thread may have been deformed past its parameters and be waisted and will strip as you look at it.

Regards you are not alone

Grumpy

The nut should always strip before the stud. This is to insure that you don't carelessly strip the case itself.

The studs are a harder steel than the nuts.

You need to buy quality studs.

I bought P200 studs from a very reputable dealer. They stripped at 14 ft/lbs. Even the good guys are getting stuck with some shit from their suppliers. I bought first oversized hardened studs from SIP. I haven't had a problem with case bolts.

I didn't realise such a thing exists. Do you have a link?

there's 2 sizes.. for 2 mounts of strippedness!

http://www.sip-scootershop.com/en/products/cylinder+stud+kit+m8x162mm+_87128000

Cool thanks! Don't need it right now but there will be a day.

make sure your reading the torque wrench with the correct settings man.

If youre using a break back type make sure it operates correctly by setting it on a low setting and testing it. mine sometimes locks off and wont break torque

Here go!
http://www.sip-scootershop.com/en/products/cylinder+stud+kit+m8x162mm+_87128000

Sip description

MJ9 Cyl. stud kit M8x162mm



With special threads, that are milled by hand, the studs are made of high quality tool-steel. They possess an extremely high tensile strength and hardness, while remaining flexible at all engine temperatures. The threads were modified to make to studs sit firmly in the engine case, once they are screwed in. This solves the problem of old engines that have an unduly high thread play. 'MJ9+' studs are suitable for slightly, 'MJ9++' studs for extremely worn out threads.

M8x162mm: for Vespa 160 GS/180SS/Rally/PX200/PE/Lusso/Cosa 200

Conclusion: Top quality and new grip for your worn out threads. Ideal for tinkers who are good friends with their cylinder.



Silver steel / M8x162mm

Silver steel with chrome / vanadium alloy, 162mm, 4 pcs.

Just saw that Vader beat me to it!

Some pics


New stud that was torqued to 14 ft/lbs. Two of them stripped



SIP studs





Being first oversize they were tight going in. I used some anti seize and went slow installing them.

It's great that they have that flat, makes it much easier.

7mm open end fits right in but I needed to double wrench to set them in.