Mon Jan 03, 2022 1:27 pm

Ossessionato
1979 P150X, 1983 P200E, 1988 T5, 1995 PX200E, 2011 Yamaha Fazer 600 S2
Joined: 02 Aug 2015
Posts: 2909
Location: Veria, Greece
 
Ossessionato
1979 P150X, 1983 P200E, 1988 T5, 1995 PX200E, 2011 Yamaha Fazer 600 S2
Joined: 02 Aug 2015
Posts: 2909
Location: Veria, Greece
Mon Jan 03, 2022 1:27 pm linkquote
chandlerman wrote:
Holy cow, that's some damage right there.

That's not the break-in's fault, that's the tuner's. That thing was waaaay too lean and hard-seized. I've made a variation of that mistake myself mis-reading the main jet size. I got to push it a mile home, and when I realized what I'd done, I ordered a magnifying glass before I ordered the new top end.
Just kidding on the break in. This is four years of constant abuse. Tuner is one of the best guys I know, it was definitely not a lean setup. They went for an MHR this time...
Mon Jan 03, 2022 1:33 pm

Veni, Vidi, Posti
74 Super, 75 Super, PX project, LML off-roader and new to 2018, '66 Blue Badge Smallframe
Joined: 30 Nov 2011
Posts: 8154
Location: Victoria, Australia
 
Veni, Vidi, Posti
74 Super, 75 Super, PX project, LML off-roader and new to 2018, '66 Blue Badge Smallframe
Joined: 30 Nov 2011
Posts: 8154
Location: Victoria, Australia
Mon Jan 03, 2022 1:33 pm linkquote
Fabulous work Charlieman!!!
Mon Jan 03, 2022 1:35 pm

Lucky
76 Sprint V, 63 GL, 62 VBB, 05 Stella, 66 Smallstate, 08 Stella (for now)
Joined: 16 Jun 2011
Posts: 5614
Location: Nashville
 
Lucky
76 Sprint V, 63 GL, 62 VBB, 05 Stella, 66 Smallstate, 08 Stella (for now)
Joined: 16 Jun 2011
Posts: 5614
Location: Nashville
Mon Jan 03, 2022 1:35 pm linkquote
SaFiS wrote:
Just kidding on the break in. This is four years of constant abuse. Tuner is one of the best guys I know, it was definitely not a lean setup. They went for an MHR this time...
Okay...that makes a little more sense. Either way, that was a craptastic ending to that guy's day.
Mon Jan 03, 2022 2:06 pm

Molto Verboso
2006 LX150 (carbed) | 2007 GT200
Joined: 29 Jun 2016
Posts: 1651
Location: Toronto
 
Molto Verboso
2006 LX150 (carbed) | 2007 GT200
Joined: 29 Jun 2016
Posts: 1651
Location: Toronto
Mon Jan 03, 2022 2:06 pm linkquote
charlieman22 wrote:
The Orange Unicorn rides again!


Watching from the sidelines has been very fun! Thanks for sharing as you go.
Mon Jan 03, 2022 2:16 pm

Ossessionato
62 VBB1T Round Tail W/ leaner sidecar
Joined: 26 Jan 2019
Posts: 3123
Location: california
 
Ossessionato
62 VBB1T Round Tail W/ leaner sidecar
Joined: 26 Jan 2019
Posts: 3123
Location: california
Mon Jan 03, 2022 2:16 pm linkquote
Well... she's dead.
Took it out and warmed it up.
Had a chance to run it up through the gears to about 7200 RPM
Ran brilliantly.
Did a few runs.
On the second - with temps near the 230F range - nicely warm but not hot - something bad happened.
Really bad.
Like the sound of shrapnel inside the crankcase.

I'm not certain exactly what - but it looks to me like the butt end of the rod struck the cases at BDC - and might have even scraped through.

Why that happened - is anyone's guess.
Bearing failed?
Case cracked somewhere?
Crank broke?
IDK.

First time it felt like a soft seize - but restarted.
I knew it was over - but thought she might carry me home.
Second time was more like a hard seize - only you can turn the crank a few degrees in either direction.

She's toast - and will have to come apart for a full inspection of what failed.
Pulled jug - rings/piston/cylinder are fine.
Pad also looks fine - from the outside anyway.
What ever is hanging it up is in the bottom of the cases I think.
Looks like the case halves may be damaged at their seam when looking down through the crank.

Appreciate all the encouragement and good words.
Would have liked it to have held up better - but let's take it apart and see what didn't work.
Go from there.

Was kinda fun riding while it lasted!
¯\_(ツ)_/¯



Mon Jan 03, 2022 2:20 pm

Lucky
76 Sprint V, 63 GL, 62 VBB, 05 Stella, 66 Smallstate, 08 Stella (for now)
Joined: 16 Jun 2011
Posts: 5614
Location: Nashville
 
Lucky
76 Sprint V, 63 GL, 62 VBB, 05 Stella, 66 Smallstate, 08 Stella (for now)
Joined: 16 Jun 2011
Posts: 5614
Location: Nashville
Mon Jan 03, 2022 2:20 pm linkquote
Noooooooooooooooooooo!

Dude, that's such a bummer, I don't even know where to start. It was sounding *so* good, too.

Mon Jan 03, 2022 2:25 pm

Sergeant at Arms
Weird 80's Vespas & Cool Vintage Lambrettas
Joined: 21 Oct 2005
Posts: 11107
Location: The state of insanity, SoCal
 
Sergeant at Arms
Weird 80's Vespas & Cool Vintage Lambrettas
Joined: 21 Oct 2005
Posts: 11107
Location: The state of insanity, SoCal
Mon Jan 03, 2022 2:25 pm linkquote
SaFiS wrote:
Really glad it all worked out. As for the breaking in period, do what the above Gents suggested. Don't be like a friend of ours...

Old, ported Malossi 210, running on reeds, 33PS on the dyno. He said to the guy that did the engine / tuning, "Hey, I hear something like rattling inside. I'll bring it in next week to get it checked". Day, later...

Happened on 2nd gear while doing wheelies coming off a traffic light. He would always race whatever would stand beside him at the lights...

First pic, reads "rice"...
*kneels*
our lady of blessed acceleration don't fail us now...

*pours 2T over the corpse*
aluminum to shavings, gas to clouds of blue smoke. she lived a wild life.
Mon Jan 03, 2022 2:26 pm

Not So Moderator
VNB vsc o9c VMA vbc VSX
Joined: 28 May 2008
Posts: 6010
Location: Hustletown, TX
 
Not So Moderator
VNB vsc o9c VMA vbc VSX
Joined: 28 May 2008
Posts: 6010
Location: Hustletown, TX
Mon Jan 03, 2022 2:26 pm linkquote
Fuckstockings.

😕
Mon Jan 03, 2022 2:34 pm

bodgemaster
63 GL, 76 Super (x2), 74 Primavera (x2), 79 P200, 06 Fly 150
Joined: 26 Sep 2013
Posts: 6397
Location: So Cal
 
bodgemaster
63 GL, 76 Super (x2), 74 Primavera (x2), 79 P200, 06 Fly 150
Joined: 26 Sep 2013
Posts: 6397
Location: So Cal
Mon Jan 03, 2022 2:34 pm linkquote
Sorry chazman, but still a win … remember Chandler and I had some doubts it would even make it down the block and back to the garage. So we owe you a slice of ham. Watch your mail.
Mon Jan 03, 2022 3:24 pm

Ossessionato
1979 P150X, 1983 P200E, 1988 T5, 1995 PX200E, 2011 Yamaha Fazer 600 S2
Joined: 02 Aug 2015
Posts: 2909
Location: Veria, Greece
 
Ossessionato
1979 P150X, 1983 P200E, 1988 T5, 1995 PX200E, 2011 Yamaha Fazer 600 S2
Joined: 02 Aug 2015
Posts: 2909
Location: Veria, Greece
Mon Jan 03, 2022 3:24 pm linkquote
Noooooooooooo!!!
Mon Jan 03, 2022 3:41 pm

Lucky
76 Sprint V, 63 GL, 62 VBB, 05 Stella, 66 Smallstate, 08 Stella (for now)
Joined: 16 Jun 2011
Posts: 5614
Location: Nashville
 
Lucky
76 Sprint V, 63 GL, 62 VBB, 05 Stella, 66 Smallstate, 08 Stella (for now)
Joined: 16 Jun 2011
Posts: 5614
Location: Nashville
Mon Jan 03, 2022 3:41 pm linkquote
SoCalGuy wrote:
Sorry chazman, but still a win … remember Chandler and I had some doubts it would even make it down the block and back to the garage. So we owe you a slice of ham. Watch your mail.
I'll send you some expired gift cards for my half of the slice of ham.
Mon Jan 03, 2022 4:28 pm

Ossessionato
79 P200E (Ruby), 62 Allstate (B-62), 2008 Stella (Olive)
Joined: 11 Jan 2006
Posts: 2959
Location: Florence, OR
 
Ossessionato
79 P200E (Ruby), 62 Allstate (B-62), 2008 Stella (Olive)
Joined: 11 Jan 2006
Posts: 2959
Location: Florence, OR
Mon Jan 03, 2022 4:28 pm linkquote




Mon Jan 03, 2022 4:28 pm

Sergeant at Arms
Weird 80's Vespas & Cool Vintage Lambrettas
Joined: 21 Oct 2005
Posts: 11107
Location: The state of insanity, SoCal
 
Sergeant at Arms
Weird 80's Vespas & Cool Vintage Lambrettas
Joined: 21 Oct 2005
Posts: 11107
Location: The state of insanity, SoCal
Mon Jan 03, 2022 4:28 pm linkquote
SoCalGuy wrote:
Sorry chazman, but still a win … remember Chandler and I had some doubts it would even make it down the block and back to the garage. So we owe you a slice of ham. Watch your mail.
and thus the new currency of NSM was born...
Mon Jan 03, 2022 4:35 pm

Ossessionato
VSX, Stella 177, Stella 150, VNX1T, V9A1T, V9B1T
Joined: 20 Jul 2018
Posts: 3710
Location: Staten Island, NY
 
Ossessionato
VSX, Stella 177, Stella 150, VNX1T, V9A1T, V9B1T
Joined: 20 Jul 2018
Posts: 3710
Location: Staten Island, NY
Mon Jan 03, 2022 4:35 pm linkquote
charlieman22 wrote:
Well... she's dead.

Was kinda fun riding while it lasted!
¯\_(ツ)_/¯
oh shit. this would have driven me to quit permanently. I'm losing hair just following along. You'll be back on the road in about 4 days! You have the patience of a saint.
SoCalGuy wrote:
So we owe you a slice of ham. Watch your mail.
greasy125 wrote:
and thus the new currency of NSM was born...
https://www.myinstants.com/instant/ham/

Last edited by swiss1939 on Mon Jan 03, 2022 4:41 pm; edited 1 time in total
Mon Jan 03, 2022 4:38 pm

Sergeant at Arms
Weird 80's Vespas & Cool Vintage Lambrettas
Joined: 21 Oct 2005
Posts: 11107
Location: The state of insanity, SoCal
 
Sergeant at Arms
Weird 80's Vespas & Cool Vintage Lambrettas
Joined: 21 Oct 2005
Posts: 11107
Location: The state of insanity, SoCal
Mon Jan 03, 2022 4:38 pm linkquote
charlieman22 wrote:
Well... she's dead.
Took it out and warmed it up.
Had a chance to run it up through the gears to about 7200 RPM
Ran brilliantly.
Did a few runs.
On the second - with temps near the 230F range - nicely warm but not hot - something bad happened.
Really bad.
Like the sound of shrapnel inside the crankcase.

I'm not certain exactly what - but it looks to me like the butt end of the rod struck the cases at BDC - and might have even scraped through.

Why that happened - is anyone's guess.
Bearing failed?
Case cracked somewhere?
Crank broke?
IDK.

First time it felt like a soft seize - but restarted.
I knew it was over - but thought she might carry me home.
Second time was more like a hard seize - only you can turn the crank a few degrees in either direction.

She's toast - and will have to come apart for a full inspection of what failed.
Pulled jug - rings/piston/cylinder are fine.
Pad also looks fine - from the outside anyway.
What ever is hanging it up is in the bottom of the cases I think.
Looks like the case halves may be damaged at their seam when looking down through the crank.

Appreciate all the encouragement and good words.
Would have liked it to have held up better - but let's take it apart and see what didn't work.
Go from there.

Was kinda fun riding while it lasted!
¯\_(ツ)_/¯
boosville on that shizz. nothing is sadder than seeing your rig on the back of a truck.

I'd be interesting in the post autopsy findings. if the top end looks okay then betting odds are downtown. doesn't sound like over-rev thus blowing out the bottom end, so that leaves the maybes of sucking a seal or a main bearing. possibly the pad peeled down a bit and got caught?

anyway, condolences. I know that you had a metric ass ton of work on that.
Mon Jan 03, 2022 4:55 pm

Ossessionato
Joined: 22 Oct 2011
Posts: 4863
Location: Tega Cay, SC
 
Ossessionato
Joined: 22 Oct 2011
Posts: 4863
Location: Tega Cay, SC
Mon Jan 03, 2022 4:55 pm linkquote
Damn, just Damn.
Mon Jan 03, 2022 8:46 pm

Ossessionato
62 VBB1T Round Tail W/ leaner sidecar
Joined: 26 Jan 2019
Posts: 3123
Location: california
 
Ossessionato
62 VBB1T Round Tail W/ leaner sidecar
Joined: 26 Jan 2019
Posts: 3123
Location: california
Mon Jan 03, 2022 8:46 pm linkquote
My best guess was that it was producing low 20's in HP with the box.
Based on not much.
Maybe it would have hit the magical 25 with the pipe.
IDK.
I just liked the smooth big curve.
Wholly cow 3rd gear was so much fun!

I travel tomorrow - on a 5:45 am take off.
I can't spend all my time working on scooters.
There are other things in life I have to focus on.

Which is to say - I just went to the garage pulled the lump & tore it down.
🙂

Ok - let's talk turkey.
Here's what I found.
1. Crank didn't contact cases. All good.
2. All my patches held/were fine - they are ugly but effort made them solid.
3. Seals were all good. Narry a scrape or nick.

So what went wrong?!?!
Well - the main bearing on the clutch side is toast.
Shrapnel everywhere.

The autopsy (pics below) showed that the main bearing cage was rubbing on the case on fly side.
That was probably okay at 5000 RPM.
Not so much at 7000 RPM.

I am also going to guess that the crank moved axially towards the fly side adding pressure to the contact point.
But it wasn't the bearings moving on the crank.
In fact - the bearings remain on the crank exactly where I pressed them.

The bearing itself is probably moving in the bronze seat.
All the pics show the retaining compound still on the bearings - but not so much on the bronze.
I suspect the failure mode was like this:
- Fly side bearing was already touching fly side case ever so lightly.
- As I heated it up - and depressed the clutch - it pressed the bearing harder on the cases
- The bearing cage rubbed the cases and exploded.

I could solve this pretty easily - using a bearing shim.
In fact - some came with my DRT seals - see pic below.
They just sit on the outer ring of the bearing.
Would create an air gap for the race area not to hit the cases.

However - need to think this through.
The bearings on a Vespa aren't really made for axial load.
They will handle some of course - but not like a thrust bearing.
These big clutches we put in load them hard axially.
That said - not sure a thrust bearing can handle 9000RPM.
That's a question for my bearing specialists down the street.

I'll contact them this week to better understand options.
Meanwhile - remarkably - other than the bent cylinder stud of my own hackery when moving the motor - everything else is pretty much recoverable.

Will have a closer look on return - but bottom line appears to be - fly side bearing was in contact with fly side cases - and it caused failure.


The carnage. That bearing got a little toasty.


Commensurate mating surface. Who needs a mill - when you can just shave the stuff off in situ? (note my little custom oil channel) 🙂 You can see where bearing cage scrubbed


It's ugly - but effective. The seal has no evidence of scrubbing - think I am ok on the clutch side - thrust washer is doing it's job.


Epoxy has turned brown - but no less solid. This fooled me - I thought it was crank case oil. Instead - its just absorbing some of the fuel color. Note how clean the bronze is.


Pad took a little beating from some of the shrapnel. It could be repaired... but I will likely fail the bond with heat - and replace.


These align with the outer ring of the bearing. They would create an air gap to keep the spiny bits from touching the cases. I may utilize

Mon Jan 03, 2022 9:07 pm

Ossessionato
Joined: 26 Oct 2015
Posts: 3528

 
Ossessionato
Joined: 26 Oct 2015
Posts: 3528

Mon Jan 03, 2022 9:07 pm linkquote
"Hello, United Towing?...It's me, Ned. Can you send over a flatbed truck"?

(gruff voice from the other end of the line)..."Yup, we have one on standby especially for you. We've been following your build thread all along."
Mon Jan 03, 2022 9:45 pm

Veni, Vidi, Posti
74 Super, 75 Super, PX project, LML off-roader and new to 2018, '66 Blue Badge Smallframe
Joined: 30 Nov 2011
Posts: 8154
Location: Victoria, Australia
 
Veni, Vidi, Posti
74 Super, 75 Super, PX project, LML off-roader and new to 2018, '66 Blue Badge Smallframe
Joined: 30 Nov 2011
Posts: 8154
Location: Victoria, Australia
Mon Jan 03, 2022 9:45 pm linkquote
Sucks. But as this is more experimentation than riding, I guess it's all ok?

I wonder with all the emphasis on eliminating axial movement, why do the modern cases (Malossi, Pinasco) make them with roller bearings on the flywheel side? If you turned up a bearing holder and bonded/welded it into the case you could use one of the nice T5 roller bearings. Let it be held in tight on the clutch side only? Also has the bonus of ditching the brass ring. Just a thought.
Mon Jan 03, 2022 10:27 pm

Ossessionato
62 VBB1T Round Tail W/ leaner sidecar
Joined: 26 Jan 2019
Posts: 3123
Location: california
 
Ossessionato
62 VBB1T Round Tail W/ leaner sidecar
Joined: 26 Jan 2019
Posts: 3123
Location: california
Mon Jan 03, 2022 10:27 pm linkquote
Ginch,
Your often insightful with ideas.
Not sure I fully followed - but one thing you identify correctly - it's the clutch side you really want to hold in place.

Can you post an image of the bearing set up you were referring to?
Mon Jan 03, 2022 10:35 pm

Molto Verboso
bare metal cafe racer
Joined: 01 Sep 2017
Posts: 1379
Location: Aotearoa (New Zealand)
 
Molto Verboso
bare metal cafe racer
Joined: 01 Sep 2017
Posts: 1379
Location: Aotearoa (New Zealand)
Mon Jan 03, 2022 10:35 pm linkquote
Since I have never even split any cases (the secret is a stock PX200EFL with sfa on the clock in case you are wondering…) can someone explain what would normally stop axial movement? I woulda thought there is a step in the shaft preventing any movement. Does the fly side bearing end up taking the axial pressure from the clutch because of this tho?
Tue Jan 04, 2022 12:07 am

Veni, Vidi, Posti
74 Super, 75 Super, PX project, LML off-roader and new to 2018, '66 Blue Badge Smallframe
Joined: 30 Nov 2011
Posts: 8154
Location: Victoria, Australia
 
Veni, Vidi, Posti
74 Super, 75 Super, PX project, LML off-roader and new to 2018, '66 Blue Badge Smallframe
Joined: 30 Nov 2011
Posts: 8154
Location: Victoria, Australia
Tue Jan 04, 2022 12:07 am linkquote
charlieman22 wrote:
Ginch,
Your often insightful with ideas.
Not sure I fully followed - but one thing you identify correctly - it's the clutch side you really want to hold in place.

Can you post an image of the bearing set up you were referring to?
P series motors all have the roller bearings on the flywheel side, they have pretty fine needles. The T5 had the much chunkier needles and this is what is being used on all the aftermarket cases afaik. I couldn't find a picture of one in place but here's the bearing from sip, and a youtube video of a PX motor assembly (at 2.10). The inner race is pressed onto your crank and then just slides into the flyside case on assembly.




https://youtu.be/R2vTsiKUBmc?t=130
Tue Jan 04, 2022 12:54 am

Jet Eye Master
PX221 MHR, O tuned PX200, PX172 Quattrini and some motorbikes
Joined: 14 Jun 2017
Posts: 3206
Location: London UK
 
Jet Eye Master
PX221 MHR, O tuned PX200, PX172 Quattrini and some motorbikes
Joined: 14 Jun 2017
Posts: 3206
Location: London UK
Tue Jan 04, 2022 12:54 am linkquote
So sad. We're all feeling it. Come too far not to live again. Struggling to comprehend this much failure in such a short amount of time. Any picture of the clutch side bearing?

One major difference between VBB cases and PX is that the clutch side bearing is axially retained on both sides (inner circip, outer either casting shoulder, another circip or bolts) and uses a roller fly side as ginch stated to allow axial float, unstressing the crank pin. The VBB does axial retention via the crank pin using the outer edge of both bearings. Helical primary gear puts a heavy axial load on the bearings. Obviously worse with increasing torque and never dreamed of bhp. With all the casing work, were the oil ways to the bearing outers still functional? Can't understand what failed the clutch side bearing. It all looks a mess but you can fix it.
Tue Jan 04, 2022 1:06 am

Addicted
PX 200
Joined: 25 May 2016
Posts: 668

 
Addicted
PX 200
Joined: 25 May 2016
Posts: 668

Tue Jan 04, 2022 1:06 am linkquote
Wow.... the bearing explosion sucks ass...

Super sad after spending so much time on it...

Glad nothing happened to you when riding though
Tue Jan 04, 2022 4:18 am

Hooked
Bodgerific 150 Super, PX200(ish...), US 50 Special in progress
Joined: 18 Aug 2016
Posts: 475
Location: Melbourne, Way Downunder
 
Hooked
Bodgerific 150 Super, PX200(ish...), US 50 Special in progress
Joined: 18 Aug 2016
Posts: 475
Location: Melbourne, Way Downunder
Tue Jan 04, 2022 4:18 am linkquote
Well that all sucks.

Is there space in the cases to cut a groove to circlip in the bearing?
Tue Jan 04, 2022 4:52 am

Ossessionato
62 VBB1T Round Tail W/ leaner sidecar
Joined: 26 Jan 2019
Posts: 3123
Location: california
 
Ossessionato
62 VBB1T Round Tail W/ leaner sidecar
Joined: 26 Jan 2019
Posts: 3123
Location: california
Tue Jan 04, 2022 4:52 am linkquote
Quote:
P series motors all have the roller bearings on the flywheel side, they have pretty fine needles. The T5 had the much chunkier needles and this is what is being used on all the aftermarket cases afaik. I couldn't find a picture of one in place but here's the bearing from sip, and a youtube video of a PX motor assembly (at 2.10). The inner race is pressed onto your crank and then just slides into the flyside case on assembly.
Ok - helpful.
So those bigger thicker rollers don't aid in axial load - but are beefier for what ever you call the load perpendicular to axial. 🙂
Quote:
and uses a roller fly side as ginch stated to allow axial float, unstressing the crank pin
Right - so this is the issue - and good explanation.
I've noted previously - the reason I think the factory manual calls for putting the bearings on the crank (seating them completely) then putting the crank in the cases, is it traps the crank axially.
That said - with our heavier clutches - a lot of force is passed through the crank pin as the fly side can't move.

Pull clutch - pushes on clutch side crank web - pushes on crank pin - pushes on fly side crank web - pushes on bearing shoulder.

Take apart VBB cases, and you will find your connecting rod with a lot of lateral float - that wasn't there when it was built. The crank is getting compressed at the middle - but held at the edge by the pin.
Causes webs to be pried apart at pin.

I attempted to only bond the crank side - allowing the fly side to be pressed in.
My thinking was - fly side would have some give.
But in the end - realizing that stock motors already do the same thing - I decided to allow my fly side to be bonded also.
Quote:
Any picture of the clutch side bearing?
sure. see below. its in prime shape. Came out on the crank - bonded there.
** the retaining compound holds steel on steel completely. Crank is NOT going to move in bearing**
Quote:
Is there space in the cases to cut a groove to circlip in the bearing?
Good thinking - Some mechanical form of fly side bearing retention is on my mind.
I don't think there is room for a circlip - but their is some space to work with.
Have a few ideas on retaining wings that might work.
See image below.

BTW - 'Pheas - I think these guys answered the question better than I could have...

Bottom line - If I can hold the crank side bearing stable - then the retaining compound should hold the crank in that bearing.

Thanks all.


Clutch side bearing - happy as a lark.


That gap could allow some form of mechanical ears to hold the bearing in without needing to be completely counter sunk

Tue Jan 04, 2022 6:38 am

Lucky
76 Sprint V, 63 GL, 62 VBB, 05 Stella, 66 Smallstate, 08 Stella (for now)
Joined: 16 Jun 2011
Posts: 5614
Location: Nashville
 
Lucky
76 Sprint V, 63 GL, 62 VBB, 05 Stella, 66 Smallstate, 08 Stella (for now)
Joined: 16 Jun 2011
Posts: 5614
Location: Nashville
Tue Jan 04, 2022 6:38 am linkquote
Assuming you have your in-flight wifi going, CM2, here's my thoughts on your post-mortem after I've had a little time to chew on it...
charlieman22 wrote:
Ok - helpful.
So those bigger thicker rollers don't aid in axial load - but are beefier for what ever you call the load perpendicular to axial. 🙂
Roller bearings help with *managing* axial load, but they do so not by containing it but by allowing it to pass through. It protects the bearing by allowing the axial pressure to bypass the crank, as you already worked out. That's also why the flywheel moving in & out when the clutch is pressed and released is a good diagnostic of bearing wear on P motors that use the two-part bearing. Plus, they make (dis)assembly a breeze compared to the older design.

If the intention was to capture that load (as it was de facto the case with the early (i.e. VBB) design), I'd expect they would have gone to a tapered rather than a roller bearing when they redesigned the motor for the P.
charlieman22 wrote:
I've noted previously - the reason I think the factory manual calls for putting the bearings on the crank (seating them completely) then putting the crank in the cases, is it traps the crank axially.
That said - with our heavier clutches - a lot of force is passed through the crank pin as the fly side can't move.
Those forces may have been tolerable with low horsepower, but once power crosses some threshold, the press fit of the main bearing into the bushing is no longer adequate. Again, something they specifically addressed by capturing the bearing with a circlip when they redesigned the motor for the P.

Which is going to generate more axial pressure, both in the moment and, especially, over time? A clutch that's engaged for under a second, or maybe a minute if you're sitting at a light and keeping it in gear, or 20+ HP of power being partially vectored into the crank and bearings?

I couldn't be bothered to do the math, but I don't think the clutch pressure is the problem. It has to be pretty nominal compared to the axial force of 20+ HP (and accompanying torque) with helical gears.

Which brings us to straight gears...the reason that people (and engineers) don't like straight cut gears isn't that they don't work well. They're arguably superior at getting the power where it's wanted with less heat, no axial load, and simpler, lighter gearbox designs. It's that they're *really* noisy.

They also increase the separation forces between the two gears, so the gearbox may need some additional reinforcement, like a plate welded between the output shaft and main shaft (sound familiar?).
charlieman22 wrote:
Bottom line - If I can hold the crank side bearing stable - then the retaining compound should hold the crank in that bearing.
Sadly, I think you've already crossed the point of diminishing returns on this design, if not into a full-on evolutionary dead end. You're bringing a tube of glue to a circlip fight.

You could use one of the DRT bearing spacers to prevent a re-play of the current explosion, but then you're just trapping the axial force in the crank, and you already observed what that does to crank play over time. If you welded the webs onto the pin, that might work to absorb it, but it's still a sub-optimal solution, IMO.

I'd bet a slice of ham (double or nothin'?) that straight cut gears, combined with current mitigations, would solve the problem, albeit noisily.
Tue Jan 04, 2022 6:59 am

Jet Eye Master
PX221 MHR, O tuned PX200, PX172 Quattrini and some motorbikes
Joined: 14 Jun 2017
Posts: 3206
Location: London UK
 
Jet Eye Master
PX221 MHR, O tuned PX200, PX172 Quattrini and some motorbikes
Joined: 14 Jun 2017
Posts: 3206
Location: London UK
Tue Jan 04, 2022 6:59 am linkquote
Although disappointing, it's not so bad now I think I understand why it failed. Seems really unlucky. If ever you need a longer primary, get a straight cut version.
When you get back home: Ears sunk in on the clutch side main will fix the axial float.
Mill out the rubbed area on the fly side case.
Re-assemble with more new seals and gaskets (and new cylinder stud?). Loctite 603 is like 638 but thinner. Timing 24@4000 is good.
Tue Jan 04, 2022 6:59 am

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Tue Jan 04, 2022 6:59 am linkquote
does the oil seal have the same ID as the bearing? If so you could put the seal on the crank side of the bearing and then hold that plate down with some countersink bolts (kind of like a lambretta does)
Tue Jan 04, 2022 7:13 am

Lucky
76 Sprint V, 63 GL, 62 VBB, 05 Stella, 66 Smallstate, 08 Stella (for now)
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Lucky
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Location: Nashville
Tue Jan 04, 2022 7:13 am linkquote
He welded a DRT seal adapter onto the clutch side, so no good options there.

CM1 is more clever than I am about this stuff, so he'll figure out a way to mechanically fix that bearing in place, I just think it's not necessary if he avoids the axial load of the helical gears entirely.

And if you believe Scooter Center, their BGM Superstrong/COSA2 straight cut gear sets are as quiet as helical, but the lowest ratio they have is 23/63 (2.74), which probably isn't ideal for a hack.
Tue Jan 04, 2022 7:20 am

Jet Eye Master
PX221 MHR, O tuned PX200, PX172 Quattrini and some motorbikes
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Jet Eye Master
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Joined: 14 Jun 2017
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Tue Jan 04, 2022 7:20 am linkquote
chandlerman wrote:
He welded a DRT seal adapter onto the clutch side, so no good options there.

CM1 is more clever than I am about this stuff, so he'll figure out a way to mechanically fix that bearing in place, I just think it's not necessary if he avoids the axial load of the helical gears entirely.

And if you believe Scooter Center, their BGM Superstrong/COSA2 straight cut gear sets are as quiet as helical, but the lowest ratio they have is 23/63 (2.74), which probably isn't ideal for a hack.
DRT do a 22/64. Probably ok. Not sure what CM22 is running on helical
https://www.sip-scootershop.com/en/product/clutch-gear-cog-22-teeth-primary-polini-64-teeth-drt-cosa-2-clutch_87474000?q=64%20gear
Tue Jan 04, 2022 8:03 pm

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Tue Jan 04, 2022 8:03 pm linkquote
Guys.
Like this discussion.
Only a moment but quick response.
- interesting point on helical gears. Insightful
- I don't think I've exhausted the clutch side bearing options for halting movement. More on that to come
- Floating fly side/ locked clutch side is most durable/ effective if I can. Locked both sides second best option/ like a std vbb build.
- I welded the DRT seal holder on the FLY side rather then clutch. I can do what I please on clutch side.

OTC - any picture to show what you referred to?


All - thanks a ton For the input/ ideas
Fri Jan 07, 2022 9:06 am

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Fri Jan 07, 2022 9:06 am linkquote
Gents - can anyone confirm my understanding on the following?
I see a few fly side roller pin type bearings on SIP.
T5 style has the larger rollers rather than pins - as noted by CM1.
When assembling this type of motor - does the inner sleeve press fit on to the crank - but then only slip fit into the fly side bearing?

Thanks in advance.
CM


A few examples - different motors - of the roller pin style bearing

Fri Jan 07, 2022 9:22 am

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1979 P150X, 1983 P200E, 1988 T5, 1995 PX200E, 2011 Yamaha Fazer 600 S2
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Ossessionato
1979 P150X, 1983 P200E, 1988 T5, 1995 PX200E, 2011 Yamaha Fazer 600 S2
Joined: 02 Aug 2015
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Location: Veria, Greece
Fri Jan 07, 2022 9:22 am linkquote
Yes, inner race fits on crank. NU205 is the one you want. NJ is for smallies and lammies…
Fri Jan 07, 2022 9:25 am

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Fri Jan 07, 2022 9:25 am linkquote
SaFiS wrote:
Yes, inner race fits on crank. NU205 is the one you want. NJ is for smallies and lammies…
Thanks!
Fri Jan 07, 2022 9:36 am

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Fri Jan 07, 2022 9:36 am linkquote
interesting!

I looked at using the NJ type on both sides of the crank for my smallframe, since it has straight cut gears and the clutch sits on the layshaft, so no thrust loads.

Ditched the idea when I could not find one of high quality. in the end a ballbearing on one side and roller on the other really is the ideal.
Fri Jan 07, 2022 10:12 am

Jet Eye Master
PX221 MHR, O tuned PX200, PX172 Quattrini and some motorbikes
Joined: 14 Jun 2017
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Location: London UK
 
Jet Eye Master
PX221 MHR, O tuned PX200, PX172 Quattrini and some motorbikes
Joined: 14 Jun 2017
Posts: 3206
Location: London UK
Fri Jan 07, 2022 10:12 am linkquote
charlieman22 wrote:
Gents - can anyone confirm my understanding on the following?
I see a few fly side roller pin type bearings on SIP.
T5 style has the larger rollers rather than pins - as noted by CM1.
When assembling this type of motor - does the inner sleeve press fit on to the crank - but then only slip fit into the fly side bearing?

Thanks in advance.
CM
Yes.
If you turn up some adapter, the T5 bearing should/could fit your VBB case. Like it.
Fri Jan 07, 2022 10:13 am

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Fri Jan 07, 2022 10:13 am linkquote
Quote:
If you turn up some adapter,
Yup - where my mind is on this.
Fri Jan 07, 2022 10:55 am

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Fri Jan 07, 2022 10:55 am linkquote
Hey - one other.
I think I recall that when mounting the P200/T5 style bearing race - it should be gapped from crank shaft in some manner.
That may or may not be true.
If tru - can someone explain why this is done/ how much it should be gapped?
Fri Jan 07, 2022 11:09 am

Lucky
76 Sprint V, 63 GL, 62 VBB, 05 Stella, 66 Smallstate, 08 Stella (for now)
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Posts: 5614
Location: Nashville
 
Lucky
76 Sprint V, 63 GL, 62 VBB, 05 Stella, 66 Smallstate, 08 Stella (for now)
Joined: 16 Jun 2011
Posts: 5614
Location: Nashville
Fri Jan 07, 2022 11:09 am linkquote
It's done so you can get it off again with a puller rather than doing something that might damage the crank.

The spacing is pretty small. I have a spacer, which SM says is 1mm thick.
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