Wed Mar 19, 2014 9:04 am

Addicted
64 allstate, 66 sprint, 74 primavera, 79 P125x
Joined: 10 Mar 2013
Posts: 788
Location: Maine
 
Addicted
64 allstate, 66 sprint, 74 primavera, 79 P125x
Joined: 10 Mar 2013
Posts: 788
Location: Maine
Wed Mar 19, 2014 9:04 am linkquote
We are rebuilding a '66 super 125 engine VNC.

When reassembling with new bearings, do the bearings go into the case halves first, then pull the crank into them?

Or do the bearings go on the crank first, then pull the crank into the case? Or a combination of the two?

Thanks!

october
Wed Mar 19, 2014 11:02 am

Veni, Vidi, Posti
1975 Vespa GTR 125, 1976 Vespa V90 (Resto), 2001 Vespa ET4 125 (Sold), 2009 Vespa GTS300 Super
Joined: 05 Sep 2010
Posts: 6063
Location: Northants UK
 
Veni, Vidi, Posti
1975 Vespa GTR 125, 1976 Vespa V90 (Resto), 2001 Vespa ET4 125 (Sold), 2009 Vespa GTS300 Super
Joined: 05 Sep 2010
Posts: 6063
Location: Northants UK
Wed Mar 19, 2014 11:02 am linkquote
Good question. I've got to do that job soon so sticking around to see the posts!

Have picked up from other threads that putting the bearings in the fridge over night (for slight shrink), then heating the cases (for slight expansion) are good moves to help bearing fitting...
Wed Mar 19, 2014 11:33 am

Hooked
'65 Sprint 177
Joined: 28 Oct 2013
Posts: 444
Location: Dorset, UK
 
Hooked
'65 Sprint 177
Joined: 28 Oct 2013
Posts: 444
Location: Dorset, UK
Wed Mar 19, 2014 11:33 am linkquote
OK ...I'll go first.....as Ive just done it albeit on a later Rally

The big bearing on the clutch side should just push in to the case. If it doesn't then heat the area gently and/ or freeze the bearing overnight. Both help

The flywheel side bearing is a different style in so much as the inner ring comes out. This can be slipped nicely over the flywheel side arm of the
crankshaft. The rest of the flyside bearing is put into the case.

You then draw the crank into the case using a crank inserting tool, or a homemade version. I ordered one from Ebay from India for about 12 and it arrived in the UK in 5 days

This video explains it a whole lot better than me....although Im not aware of the subtle differences between the 125 and your Super. Im guessing not a whole lot
Wed Mar 19, 2014 11:39 am

Banned
2:6
Joined: 11 Jan 2007
Posts: 7781
Location: San Francisco
 
Banned
2:6
Joined: 11 Jan 2007
Posts: 7781
Location: San Francisco
Wed Mar 19, 2014 11:39 am linkquote
1. The bearings go onto the crank first (fly side and clutch side).
2. The clutch side case is heated, seal installed, then crank installed. All before it cools down.
3. Fly side case is heated, seal installed, cases closed and center 4 bolts torqued (I use 11ft-lb). Again all before it cools down, this sometimes requires a little bit of added heat to the fly side case but not too much and not too close to the seal.

They are kind of a pain. On the plus side you don't need a puller, on the down side, you can't use a puller as the seal is in the way and a puller would put stress across the bearing.

One thing that can make the job easier is the factory tools that go over the end of the crank to guide the seal into place and keep you from nicking the seal lip with the threads as you rush to get things together.
Wed Mar 19, 2014 1:33 pm

Addicted
Old douglas ..smallie with polini 115..super with nasco 177
Joined: 07 Nov 2013
Posts: 643
Location: New Zealand
 
Addicted
Old douglas ..smallie with polini 115..super with nasco 177
Joined: 07 Nov 2013
Posts: 643
Location: New Zealand
Wed Mar 19, 2014 1:33 pm linkquote
those old vbc don't use the two piece bearing.
I.
Bearings in both case halves first ..works for me....up to you on how you achieve this. I put the bearings in the freezer a couple of hour s before . Hot scalding rags get placed in the bearing area to expand it (doesn't hurt the seals)
Its easier to seat the bearings flat in the cases if they are NOT on the crank.

Some times they need a knock to get them in the cases.... I usually use the old bearing as a drift.
One day Im gonna get an old bearing and grind it down 1 or 2 mm and weld a bar on it use as a bearing installer..still... just the old bearing works.

Once both bearings are in the cases ....use a very hot scalding rag and roll /twost it up and stick it in the inside of the fly side bearing race so just the inside heats up and expands
The main trick is to install the fly side case half as far as it wil go and then press the kick start for the final 3cm.

I love that feeling as the two halves meet nicely
good luck
Wed Mar 19, 2014 2:24 pm

Banned
2:6
Joined: 11 Jan 2007
Posts: 7781
Location: San Francisco
 
Banned
2:6
Joined: 11 Jan 2007
Posts: 7781
Location: San Francisco
Wed Mar 19, 2014 2:24 pm linkquote
Also see:

The correct way to build VBB engine
Wed Mar 19, 2014 6:08 pm

Ossessionato
a lambretta or two
Joined: 31 Mar 2012
Posts: 3726
Location: San Francisco
 
Ossessionato
a lambretta or two
Joined: 31 Mar 2012
Posts: 3726
Location: San Francisco
Wed Mar 19, 2014 6:08 pm linkquote
oopsclunkthud wrote:
1. The bearings go onto the crank first (fly side and clutch side).
2. The clutch side case is heated, seal installed, then crank installed. All before it cools down.
3. Fly side case is heated, seal installed, cases closed and center 4 bolts torqued (I use 11ft-lb). Again all before it cools down, this sometimes requires a little bit of added heat to the fly side case but not too much and not too close to the seal.

They are kind of a pain. On the plus side you don't need a puller, on the down side, you can't use a puller as the seal is in the way and a puller would put stress across the bearing.

One thing that can make the job easier is the factory tools that go over the end of the crank to guide the seal into place and keep you from nicking the seal lip with the threads as you rush to get things together.
Patrick, don't you get tired of telling people this? I do. I'm getting old. I'm working on my last Vespa right now. Afer this one, I'm closing my shop. I hope someone else has the patience that I don't seem to have.
Wed Mar 19, 2014 6:28 pm

Ossessionato
2015 GTS300, 1974 Primavera, 04 Ninja 250
Joined: 04 Apr 2013
Posts: 4653
Location: San Diego, CA
 
Ossessionato
2015 GTS300, 1974 Primavera, 04 Ninja 250
Joined: 04 Apr 2013
Posts: 4653
Location: San Diego, CA
Wed Mar 19, 2014 6:28 pm linkquote
SFvsr San Fran will be losing a good resource if you do. I know people on here get touchy with your replies but you've been a good help to lots of folks.

I'm not totally sure why Vespas exasperate you more than Lambrettas but I hope you're staying active with the Lammy crowd on LCUSA.
Wed Mar 19, 2014 8:39 pm

Addicted
64 allstate, 66 sprint, 74 primavera, 79 P125x
Joined: 10 Mar 2013
Posts: 788
Location: Maine
 
Addicted
64 allstate, 66 sprint, 74 primavera, 79 P125x
Joined: 10 Mar 2013
Posts: 788
Location: Maine
Wed Mar 19, 2014 8:39 pm linkquote
Thank you for your help. I do appreciate the time you took to reply to my questions. It's nice to know that there are a few people out there that aren't too old or too tired to take a few minutes to help someone out.

Thank you.

oct
Thu Mar 20, 2014 8:05 am

Banned
2:6
Joined: 11 Jan 2007
Posts: 7781
Location: San Francisco
 
Banned
2:6
Joined: 11 Jan 2007
Posts: 7781
Location: San Francisco
Thu Mar 20, 2014 8:05 am linkquote
Bearings 101
Spent some time this morning doing some drawings to help some basics in dealing with bearings. Been meaning to do this for a while.


When installing a bearing with an interference fit you must only apply force to the race you are trying to move.

Thu Mar 20, 2014 8:26 am

Banned
2:6
Joined: 11 Jan 2007
Posts: 7781
Location: San Francisco
 
Banned
2:6
Joined: 11 Jan 2007
Posts: 7781
Location: San Francisco
Thu Mar 20, 2014 8:26 am linkquote
With that basic knowledge, lets look at the install steps for the VBB/Sprint.

First some facts.
1. There is a strong interference fit between the bearing and the crank. These are also both steel so expansion between them will not make much difference.
2. There is a small interference fit between the bearing and the case. By warming the case this becomes a slip fit.


1. The bearing is installed on the crank with a drift that rests on the inner race of the bearing.


2. The bearing is fully seated on the crank.

Thu Mar 20, 2014 10:42 am

Banned
2:6
Joined: 11 Jan 2007
Posts: 7781
Location: San Francisco
 
Banned
2:6
Joined: 11 Jan 2007
Posts: 7781
Location: San Francisco
Thu Mar 20, 2014 10:42 am linkquote
Installing the crank into the clutch side:


3. The case is heated and the seal is placed on the punch


4. The seal is seated in the case.


5. The crank/bearing is seated by hand into the still heated case.




7. When the case cools the bearing becomes an interference fit in the case.

Thu Mar 20, 2014 5:42 pm

Banned
2:6
Joined: 11 Jan 2007
Posts: 7781
Location: San Francisco
 
Banned
2:6
Joined: 11 Jan 2007
Posts: 7781
Location: San Francisco
Thu Mar 20, 2014 5:42 pm linkquote
Now for the fly side:


8. The crank is in the clutch side of the case, both bearings are on the crank, and the cases are ready to be closed up.


9. The fly side case is heated and the seal and drift are ready to go in


10. The seal is seated into the fly side case


11. The, still hot, fly side case is then assembled onto the crank, bearing, and clutch side case.




12. When the case cools the fly side bearing has an interference fit.

Thu Mar 20, 2014 11:45 pm

Banned
62vnb , 71 sprint ,1974 vespa90
Joined: 31 May 2013
Posts: 650
Location: Idaho falls
 
Banned
62vnb , 71 sprint ,1974 vespa90
Joined: 31 May 2013
Posts: 650
Location: Idaho falls
Thu Mar 20, 2014 11:45 pm linkquote
Also compress on the kick start at the same time when the halves together . If it wont go on easy all the way on heat it up a little more around the bearing .
Mon Aug 31, 2015 4:51 am

Member
Vespa Touring 1959 (VGLA1T)
Joined: 14 Apr 2015
Posts: 16
Location: Oslo, Norway
 
Member
Vespa Touring 1959 (VGLA1T)
Joined: 14 Apr 2015
Posts: 16
Location: Oslo, Norway
Mon Aug 31, 2015 4:51 am linkquote
Hi everyone,

I'm doing a full restoration of a Vespa 150 from 1959. I bought a new crank and took it to a mechanic along with the engine cases for him to install BOTH bearings on the crank, and then install the crank on the clutch side case - as advised above.

What he did instead is to install only ONE bearing on the crank (clutch side), and the other bearing on the flywheel side case. I think this is not the way it should be done. The crank is already installed on the clutch side case.

Now, do you think I'll have trouble when putting the cases together? Will the crank sit well on the inner ring of the bearing that is already installed on the flywheel case? Any tips on how to make the process easier?

Thanks!
Francisco
Mon Aug 31, 2015 5:16 am

Molto Verboso
2005 PX150 In a Love-Hate Relationship with a 2-Stroke Vespa Since 2007
Joined: 01 Sep 2007
Posts: 1853

 
Molto Verboso
2005 PX150 In a Love-Hate Relationship with a 2-Stroke Vespa Since 2007
Joined: 01 Sep 2007
Posts: 1853

Mon Aug 31, 2015 5:16 am linkquote
Nice drawings, Patrick!
Makes sense to me if you don't want to stress the bearings.
Also looks like a PITA.
Tue Sep 15, 2015 7:10 pm

Addicted
Old douglas ..smallie with polini 115..super with nasco 177
Joined: 07 Nov 2013
Posts: 643
Location: New Zealand
 
Addicted
Old douglas ..smallie with polini 115..super with nasco 177
Joined: 07 Nov 2013
Posts: 643
Location: New Zealand
Tue Sep 15, 2015 7:10 pm linkquote
Yo francisco
Did you sort it out. FYI....I put a very hot rag inside the bearing (that accepts the crank) for two minutes.....By hot I mean it has to be boiling in a pot of water second before you......put some gloves on ..lift with tongs and twist the rag up inside the bearing race....this way only the race heats up and as you offer up the case half it slips on nice.

Remember the last 3 to 4mm of closing will require the kick start to be depressed.

The hot rag trick means you can do the job in you bed room /apartment with zero fumes
  DoubleGood Vespa Scarves  

All Content Copyright 2005-2021 by Modern Vespa. All Rights Reserved.

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.

Shop on Amazon Smile with Modern Vespa
[ Time: 0.1489s ][ Queries: 46 (0.1195s) ][ Debug on ][ 156 ][ Thing Two ]