Modern Vespa

A heads-up on the MP3 rear shocks - and other models whose rear shocks have similar adjusting rings.

Just went round to my dealers to get some parts, and he told me how they have so far failed every single one of the '07 MP3s (and a few '08s). All had one particular issue - the adjusting ring on the rear shocks had a crack. We went outside and looked at mine - yup, each adjusting ring had a crack.

We reckon using ACF50 every six months on these unprotected alloy rings should prevent this - as it looks like the cracks are due to corrosion causing a weak point, and bottoming out can then break the ring. With one crack the shocks still work - with two the ring would fly off and the spring would suddenly fully extend.

So as these aren't repairable it's GBP200 for a new pair of shocks. They've done five years heavy duty, so I'm not too disgruntled.

Cheers, Jim. Must check the ones on the (05) X9.

Hmmm. Been out of town and haven't had a chance to really look, but I have a rear shock that failed. Will have to look for cracks.

perfect time to upgrade to the bitubos IMO. a much better shock with ALOT better adjustablity to them in both the preload and shock dampening which you don't have on stock ones.

Thanks for the heads up, Jim. Will be checking this out later on today.

Those are different (although interchangeable) - and should be OK even if seized up. The ones on the '54 X9 250 are fine.

Thanks for the info!
I will check mine!

Don't forget Hagon shocks:

New rear shocks


A cheaper alternative and I'm happy with mine.



Cheers,
Tross

Thanks, Jim.

While good shocks and cheaper, they don't have the adjustment the Bitubos do.

One of these days we should have a shoot/ride out to see if they are worth the $200 extra bucks.

The new replacement shocks (picked up today) have reverted to the old-style adjuster rings, so much sturdier and should last a lot longer.

Last edited by jimc on Wed Jun 13, 2012 4:34 am; edited 1 time in total

post a pic please

Part number 649129







Last edited by jimc on Wed Jun 13, 2012 4:33 am; edited 1 time in total

at least on that new one you can get the wrench in alot easier to adjust it. The top looks different the the original stock ones too.

I'd say different supplier, hopefully they last longer the other/older OEM's. One of mine lasted 6 months before the seal blew. The springs were too soft as well for my ample size, but I can't blame that entirely on the shocks

Cheers,
Tross

A $3 can of dewatering fluid, applied occasionally to the shock spring adjuster, would have stopped it from corroding and ultimately breaking.

If you look carefully at your pic you will see a separate layer of corrosion which has built up inside the ring. The pressure has finally caused the under-engineered ring to break - see how the crack has widened?



$3 of prevention must surely be worth $300 of replacement parts...

I figure all that crack is caused by is corrosion from salt air and not doing something about it periodically, like spraying it with WD40. I never adjust my shocks and they have no corrosion so far because I live in a dry climate, put MP3s inside when I'm not riding them. They spend more time inside than outside. No metal outside here rusts.

I feel a little left out -- our shock rings have no sign of cracks after 12K miles, even here in seaside San Diego. Of course, we keep the scooter in the garage, which may support the corrosion explanation.

Update - the new shock shown above is the *wrong one*. Bloody Fowlers must have had an odd one on a shelf as it arrived in a big Jiffy bag albeit with the right part number written on that. Confirmed by the second shock arriving today which is identical to the original type.

So lots of ACF-50 and grease going on that before fitting.

Last edited by jimc on Wed Jun 13, 2012 4:35 am; edited 1 time in total

well that plain sucks on the not the right one.

Definitely seems to be a humidity/corrosion thing -- I see you were in London and now the Bay Area? My 505-sailing friends in southern UK and in S.F. say a "fine day" is when water's not actually falling, and the other guys w/ring problems seem to be in wet places too. Here on the mesa over San Diego (10 mi inland) we're lucky to get 10" a year, with 6 totally dry months, and our '07 rings still are bright and shiny. Should warn folks not to get any spray-on anti-rust on the rear brake disc, though! (While it might collect dust, no reason one couldn't rub rings with waterproof grease before installing -- also working some under the ring, which seems to be the critical area.)

Has anyone heard a report of a ring failing on the other side and breaking completely, which would be VERY bad for the scooter's handling?

Yikes... thanks for the heads up and hints!

Thanks Jim for the important find. I remember we are supposed to lube and move those to keep them from freezing up. I'll check mine out .