PX clutch cover bolt threads stripped
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Enthusiast
1959 Allstate w P125x Engine
Joined: 29 Nov 2020
Posts: 74
Location: Los Angeles
Thu Apr 29, 2021 6:57 pm quote
Hey guys,
Replaced my clutch in-frame. All went well until the top left cover bolt would hardly catch.
Put it back in with blue thread locker and got some bite. Not a lot at all but it didn't spin freely. Other two bolts are solid.
I'd like to ride it. I have everything ready to pull the engine to replace oil seals, etc. Repair those threads...
Just want to ride it for a while before then.
What do you guys think?
Sergeant at Arms
Weird 80's Vespas & Cool Vintage Lambrettas
Joined: 21 Oct 2005
Posts: 8701
Location: The state of insanity, SoCal
Thu Apr 29, 2021 7:14 pm quote
If itís snug? Then roll.

If it starts to leak or the clutch gets wonky then pull the whole thing out and while rebuilding drop a helicoil or timesert in there.

My $0.02 on it

-g
Ossessionato
76 Sprint V, 63 GL, 62 VBB, 05 Stella
Joined: 16 Jun 2011
Posts: 3201
Location: Nashville
Thu Apr 29, 2021 7:15 pm quote
You can fix it with a time-sert or a helicoil. It's not a bad job, can probably do it with the motor in the bike if you swing the motor down on the swingarm.
Hooked
Vespa PX200
Joined: 27 Jun 2010
Posts: 430
Location: Belgrade
Thu Apr 29, 2021 7:33 pm quote
I've run for tens of thousands of kms with only one properly threaded hole out of the three. Just try not no think about it and ride!
Ossessionato
62 VBB1T Round Tail W/ leaner sidecar
Joined: 26 Jan 2019
Posts: 2241
Location: california
Thu Apr 29, 2021 7:34 pm quote
Ray - here is how I would treat:
1. Get a 7mmx1 tap and run it in - use plenty of oil. Get the type of tap that is made for a 'blind hole" since your hole has a bottom.
2. Use a caliper and measure depth - then use a longer bolt than stock. There will be some good thread that you are not utilizing - and it may save your bacon.

Be gentle - it might work.
Molto Verboso
One or two fun scoots....nothing too precious
Joined: 17 Jul 2013
Posts: 1678
Location: UK (South East)
Thu Apr 29, 2021 11:45 pm quote
^^ +1. I've found this with the screw that holds the cylinder cowl through the flywheel cover and onto the casing. I lost some thread at the top, but found good thread further in when I sourced a longer screw.

I typically replace all my clutch cover bolts with slightly longer flanged bolts of much better quality than the Piaggio ones, and then use 5 or 6 foot pounds to tighten
Jet Eye Master
PX221 MHR, O tuned PX200, PX125 and some motorbikes
Joined: 14 Jun 2017
Posts: 2755
Location: London UK
Fri Apr 30, 2021 12:42 am quote
^^ me too

If this doesn't work. The next step is a helicoil. This is normally great forever but if installed badly then still enough meat to put a timesert in.
Molto Verboso
2007 Stella 225
Joined: 02 Nov 2019
Posts: 1683
Location: Rochester, Minnesota
Fri Apr 30, 2021 2:35 am quote
charlieman22 wrote:
Ray - here is how I would treat:
1. Get a 7mmx1 tap and run it in - use plenty of oil. Get the type of tap that is made for a 'blind hole" since your hole has a bottom.
2. Use a caliper and measure depth - then use a longer bolt than stock. There will be some good thread that you are not utilizing - and it may save your bacon.

Be gentle - it might work.
Bottoming tap, here is an M7 x 1

https://www.mcmaster.com/taps/thread-size~m7/individual-set~individual/for-use-on~aluminum/thread-direction~right-hand/application~closed-end-hole-threading/
Molto Verboso
2007 Stella 225
Joined: 02 Nov 2019
Posts: 1683
Location: Rochester, Minnesota
Fri Apr 30, 2021 4:39 am quote
M8 Tap ?
With a 1mm diameter difference, would drilling for an M8 tap be an option? I was thinking since you have to drill an oversized hole for a tap anyway. Would an M8 bolt fit through the clutch cover holes? Would the M8 be a big enough difference to get good threads? If it didn't work you would still be able to drill for a thread repair kit.
Ossessionato
76 Sprint V, 63 GL, 62 VBB, 05 Stella
Joined: 16 Jun 2011
Posts: 3201
Location: Nashville
Fri Apr 30, 2021 4:53 am quote
It's an M6 to start with, so M7 is already effectively "first oversize"
Enthusiast
1959 Allstate w P125x Engine
Joined: 29 Nov 2020
Posts: 74
Location: Los Angeles
Fri Apr 30, 2021 6:18 pm quote
Took several rides today. New clutch feels great (will make a new thread for that one--px engine on 8's solved).
No leaks.
Now I remember, there was one bolt longer than the other two. Pretty sure I put them back where they came out of, but it's possible that was the bolt that went there. Looked like it was around 10mm longer than the other two.
Really appreciate all your advice, guys. Enjoy your weekends!
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