OP
@xantufrog avatar
UTC

Moderibbit
1980 P200E - "Old Rusty", 1976 ET3 Primavera
Joined: UTC
Posts: 8891
Location: Atlanta, GA
 
Moderibbit
@xantufrog avatar
1980 P200E - "Old Rusty", 1976 ET3 Primavera
Joined: UTC
Posts: 8891
Location: Atlanta, GA
UTC quote
So the previous owner stripped the hell out of the oil drain plug case threads. The plug still stays in, but it does leak a little. I bought a helicoil kit today but the helicoils are larger than the length of the bolt. Thought I could cut them down to a smaller size, but my big concern is how thin the metal layer of the case seems to be.

1) Does the case need to be THICKER than the helicoil, or can the extent of the helicoil be flush with the openings? i.e. how small does the helicoil need to be really.

2) Anyone have another suggestion for how to approach this?

I really want to proceed cautiously before I tap out the helicoil thread
@killo avatar
UTC

Ossessionato
I have a few scooters....
Joined: UTC
Posts: 2229
Location: San Antonio, TX
 
Ossessionato
@killo avatar
I have a few scooters....
Joined: UTC
Posts: 2229
Location: San Antonio, TX
UTC quote
Why a heli-coil? Why don't you just tap it to the next larger bolt size? Taps are very cheap. Get a bolt and put a small o-ring underneath the head and you're golden.
⚠️ Last edited by Killo on UTC; edited 1 time
@caoscape avatar
UTC

Hooked
SS 180
Joined: UTC
Posts: 118
Location: St. Louis, MO
 
Hooked
@caoscape avatar
SS 180
Joined: UTC
Posts: 118
Location: St. Louis, MO
UTC quote
The experienced mechanics will hopefully weigh in on your problem but, I vaguely remember Helicoils from school and from what I remember they weren't very precise and I think in your application it would leak. As a tool engineer we use Key Inserts or Keenserts instead. (but we aren't trying to hold fluid in something...just repeatably build airplanes) We get them from Carr Lane usually but you can get them from McMaster Carr or Grainger. http://www.carrlane.com/Catalog/index.cfm/27825071F0B221118070C1C513E111D081B0006280B1713050245221E0107070F1A3C3B285356445D
http://www.mcmaster.com/#key-locking-inserts/=3g7eq1 You may be able to find them in a GOOD parts store. Hope this helps!
@caoscape avatar
UTC

Hooked
SS 180
Joined: UTC
Posts: 118
Location: St. Louis, MO
 
Hooked
@caoscape avatar
SS 180
Joined: UTC
Posts: 118
Location: St. Louis, MO
UTC quote
Killo Wrote:
Quote:
Why a heli-coil? Why don't you just tap it to the next larger bolt size? Taps are very cheap. Get a bolt and put a small o-ring underneath the head and your golden.
Much better idea!!! I was just thinking of what would replace a helicoil...
@price avatar
UTC

Hooked
74 Rally 200 - 70 Sprint Veloce - 68ish Bajaj VBA - wifes 1970 V90 - 77 NYPD Sprint Veloce
Joined: UTC
Posts: 340
Location: Atlanta
 
Hooked
@price avatar
74 Rally 200 - 70 Sprint Veloce - 68ish Bajaj VBA - wifes 1970 V90 - 77 NYPD Sprint Veloce
Joined: UTC
Posts: 340
Location: Atlanta
UTC quote
Killo wrote:
Why a heli-coil? Why don't you just tap it to the next larger bolt size? Taps are very cheap. Get a bolt and put a small o-ring underneath the head and you're golden.
Why? Because the threads of the heli-coil are harder than the aluminum engine cases. My rally is heli-coiled the first oil change after I got it threads came out when I removed the plug.
@greasy125 avatar
UTC

Sergeant at Arms
Weird 80's Vespas & Cool Vintage Lambrettas
Joined: UTC
Posts: 15080
Location: The state of insanity, SoCal
 
Sergeant at Arms
@greasy125 avatar
Weird 80's Vespas & Cool Vintage Lambrettas
Joined: UTC
Posts: 15080
Location: The state of insanity, SoCal
UTC quote
my suggestion is to tap out to a larger size, 9mm, 5/16", whatever.

a helicoil will leak. because now you're trying to seal two surfaces instead of one...

also, if not installed properly, a helicoil can back out.
imagine losing your drain plug and contents at speed... all over your rear wheel.... not fun.

tap up to the next size.

then when the cases are split for a rebuild, tig then up and retap at the proper size.

best,
-greasy
UTC

Hooked
2006 PX 166 1980 P180X
Joined: UTC
Posts: 124
Location: England, Isle of Wight
 
Hooked
2006 PX 166 1980 P180X
Joined: UTC
Posts: 124
Location: England, Isle of Wight
UTC quote
You could try a copper crush washer if the bolt is secure and is not going anywhere.
@eldorado avatar
UTC

Hooked
1980 Vespa P200E, 1981 Serveta Jet 200, 1982 BMW R100, 2003 BMW F650GS
Joined: UTC
Posts: 153
Location: Chicago
 
Hooked
@eldorado avatar
1980 Vespa P200E, 1981 Serveta Jet 200, 1982 BMW R100, 2003 BMW F650GS
Joined: UTC
Posts: 153
Location: Chicago
UTC quote
That happened to me, I got a 8mm cap screw and cut it down to the right length of the drain plug. Less than a dollar and 10 min of work with a dremel and grinder (to take the sharp edge off the tip.

Screwed right in without forcing, didn't have to tap, sealed nice and dry with the normal drain plug soft washer. Worked like a charm, and now I have a spare.

Never take your drain plug out while the cases are hot, the bolt is more likely to bind and the aluminum is more likely to strip.
UTC

Hooked
Joined: UTC
Posts: 325
 
Hooked
Joined: UTC
Posts: 325
UTC quote
If you don't remove the cover, you might want to run a quart of oil through the the hole to lessen the chance that there are chips in there.
@price avatar
UTC

Hooked
74 Rally 200 - 70 Sprint Veloce - 68ish Bajaj VBA - wifes 1970 V90 - 77 NYPD Sprint Veloce
Joined: UTC
Posts: 340
Location: Atlanta
 
Hooked
@price avatar
74 Rally 200 - 70 Sprint Veloce - 68ish Bajaj VBA - wifes 1970 V90 - 77 NYPD Sprint Veloce
Joined: UTC
Posts: 340
Location: Atlanta
UTC quote
I know a guy that tried to tap is Stella drain plug and messed up a few times and now has a really big oil bolt. For me if I god forbid need to I'll heli-coil again.

Modern Vespa is the premier site for modern Vespa and Piaggio scooters. Vespa GTS300, GTS250, GTV, GT200, LX150, LXS, ET4, ET2, MP3, Fuoco, Elettrica and more.

Buy Me A Coffee
 

Shop on Amazon with Modern Vespa

Modern Vespa is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to amazon.com


All Content Copyright 2005-2025 by Modern Vespa.
All Rights Reserved.


[ Time: 0.0198s ][ Queries: 3 (0.0115s) ][ live ][ 328 ][ ThingOne ]