Britbike forum

Classic British SparesKlempf British PartsBaxter CycleBritBike Sponsor SteadfastCyclesThe Bonneville ShopLowbrow CustomsGirling Classic MotorcycleLucas Classic MotorcycleHepolite PistonsIndustrial tec supply

Upgrade Your membership! Premium Membership Gold Membership Vendor Membership

New Sponsor post
5% Off Everything for Brit Bike Users
by The Bonneville Shop - 12/30/21 4:54 pm
New FAQ post
Manuals on DVD - Buy 4 for 3
All 4 DVD Manual
Member Spotlight
Lannis
Lannis
Central Virginia
Posts: 14,120
Joined: July 2001
ShoutChat
Comment Guidelines: Do post respectful and insightful comments. Don't flame, hate, spam.
Top Posters(30 Days)
Cyborg 69
reverb 63
Top Likes Received (30 Days)
Newest Members
DucatiPete, mk31755, MAM, Jonez69, Ian Nash
11,976 Registered Users
Who's Online Now
4 members (Magnetoman, Tridentman, bill50cal, Shane in Oz), 21 guests, and 20 robots.
Key: Admin, Global Mod, Mod
Forum Statistics
Forums35
Topics75,252
Posts757,938
Members11,976
Most Online14,755
May 5th, 2019
Previous Thread
Next Thread
Print Thread
Page 1 of 2 1 2
Joined: Jan 2017
Posts: 1,913
Likes: 107
T
Britbike forum member
OP Offline
Britbike forum member
T
Joined: Jan 2017
Posts: 1,913
Likes: 107
Hi All, Does the main bearings move left to right in the case as your ride & motor is heat soaked?

Specifically on '73 T140 type motor.
Thanks, Don


1973 Tiger 750
Triumphs on eBay
Joined: Dec 2004
Posts: 11,486
Likes: 208
Britbike forum member
Offline
Britbike forum member
Joined: Dec 2004
Posts: 11,486
Likes: 208
The inference fit of 1.5 thou is supposed to prevent that but depending on the crankcase design (Norton twins cases are thin as an example and provide less support) at full working temps and especially on race bikes the bearings can slowly walk. Also if someone in the past has either removed or inserted the bearings cold then the interference fit will be less than 1.5 thou and make walking more likely. The ultimate solution is to pin the bearing in position, Loctite does not work as its bond is broken by the heat cycles.

Joined: Oct 2012
Posts: 6,142
Likes: 210
knuckle head
Offline
knuckle head
Joined: Oct 2012
Posts: 6,142
Likes: 210
I believe Don is using roller bearings on both sides....He mentioned in another about having at least .010 lateral crank thrust so supposedly the bearings don't have to control the thrust..
I have to ask, with about .010 rod to crank side clearance and and several times that for piston to rod side clearance, what keeps the crank from banging back and forth? What about primary chain alignment? Perhaps the primary chain keeps the crank centered between the bearings?..I have used two rollers a few times but shimmed the crank for minimal thrust and called it good........I am no expert with this however..


79 T140D, 89 Honda 650NT ,61 A10 .On a bike you can out run the demons
"I don't know what the world may need
But a V8 engine is a good start for me
Think I'll drive to find a place, to be surly"
Joined: Dec 2004
Posts: 11,486
Likes: 208
Britbike forum member
Offline
Britbike forum member
Joined: Dec 2004
Posts: 11,486
Likes: 208
I fitted twin rollers to my B44, I shimmed the end float to 3 thou as the crank can move from side to side. So I went for the lower end float so the crank cannot build up inertia, that was 6 years ago and no issues but it is a narrow crank that has the bearings closer than on a twin so the crank does not turn into a skipping rope. Norton twin bolted up cranks, from 72 onwards until the last ones in 75, had twin rollers and end float is set larger at 10 to 20 thou as the crank goes like a skipping rope, but the engines do not suffer any affects after the rollers were given an edge treatment now common to all roller bearings. A single piece crank like the Triumph would be stiffer.

Joined: Aug 2016
Posts: 432
Likes: 39
T
Britbike forum member
Offline
Britbike forum member
T
Joined: Aug 2016
Posts: 432
Likes: 39
I think what Don is getting at is that as the cases expand with heat, the bearings will move apart, and as the crank is located (with 10 thou side to side in Don's case with the timing side roller) at the timing side, the crank will likely move to the right. How much, who knows, but any movement will affect the primary chain alignment, but again, how much matters?

Joined: Oct 2012
Posts: 6,142
Likes: 210
knuckle head
Offline
knuckle head
Joined: Oct 2012
Posts: 6,142
Likes: 210
Three strand chains are not tolerant of misalignment...In a normal situation with the crank located by the timing ball bearing,I believe less than .010 chain misalignment is good?


79 T140D, 89 Honda 650NT ,61 A10 .On a bike you can out run the demons
"I don't know what the world may need
But a V8 engine is a good start for me
Think I'll drive to find a place, to be surly"
Joined: Dec 2004
Posts: 11,486
Likes: 208
Britbike forum member
Offline
Britbike forum member
Joined: Dec 2004
Posts: 11,486
Likes: 208
I use the big pin duplex Mercedes timing chain on all my duplex and triplex engines (just leave one row of teeth free), available from Jason the Chainman. If it can cope with the power output of a Laverda triple it can cope with any Brit bike.

Joined: Oct 2012
Posts: 6,142
Likes: 210
knuckle head
Offline
knuckle head
Joined: Oct 2012
Posts: 6,142
Likes: 210
No matter the type of chain, misalignment is not a good thing....


79 T140D, 89 Honda 650NT ,61 A10 .On a bike you can out run the demons
"I don't know what the world may need
But a V8 engine is a good start for me
Think I'll drive to find a place, to be surly"
Joined: Jan 2017
Posts: 1,913
Likes: 107
T
Britbike forum member
OP Offline
Britbike forum member
T
Joined: Jan 2017
Posts: 1,913
Likes: 107
Hi All, Specifically what I was getting to is does the timing bearing outer race move in its press fit?

I haven’t had all that many cranks out, or replaced many main bearings. Triumph so far as I can tell at the factory, never shimmed the crank bearings. They didn’t center rods. They put both main bearings to bottom of bores in case. Drive roller pressed on crank. Crank drawn tight into timing side ball brg.
That’s it.

Going back last night & calculating end float with ball instead of roller I get the original factory end float of .027.

This morning comparing the relationship between inner & outer races was interesting. Not so simple!

Outer races are basically the same width. However inner races differ in width.

With ball inner race is .001” wider than outer. Roller is same.

Side loading inner/outer race, putting straight edge across inner & using feeler gauges to outer I get .005” on roller, .003 on ball.


So in practice the end limit of float with roller is only .002 different from ball. So roller actually positions crank very closely to the ball even though it has more end float.

Hard to accurately measure some or this & math doesn’t add up perfectly. I get that.

Searching web last night no place could I find any specs on axial clearance of the rollers. Everything else but that!

Thinking of primary chain line. Automotive runs crank end play .004-.010. Ive seen dozens of worn thrust bearings at ,020+. Timing chairs don’t seem to suffer. Most are 2 row or hivo multiple plate.

Triumph installed the 3 piece in ‘81. Not a lot of those bikes, but web search turns up no chain wear problems. I’ve set chain alignment twice on T140s & have shims on hand. If you’ve ever done this kind of tricky. You measure turn crank & clutch, measure in different place it changes. I end up averaging the readings. Any change in thrust washer wear moved basket inwards. Washers can wear fairly quickly.

My hunch is crank will get pulled to one side buy chain & not oscillate side to side in the .010 bearing clearance??

Am I trying to correct problem that doesn’t exist!???

Factory sure never worried about it.
Don


1973 Tiger 750
Joined: Aug 2001
Posts: 8,867
Likes: 116
T
Britbike forum member
Offline
Britbike forum member
T
Joined: Aug 2001
Posts: 8,867
Likes: 116
Bearings fall out when you heat the cases with a blow lamp on the bench.

To my tiny mind, the safest assumption is that they are not held tightly when the running engine is fully hot.


Amateur Loctite enthusiast.
1 member likes this: Gordon Gray
Joined: Oct 2012
Posts: 6,142
Likes: 210
knuckle head
Offline
knuckle head
Joined: Oct 2012
Posts: 6,142
Likes: 210
Don, if the ball bearing outer race is a decent fit in the cases, the crank is held tight and any end float is just the clearance of the balls in the race.. Maybe .001 at most?
Are you sure the crank isn't going to bang from side to side? Ever hear those loose automotive thrust surfaces make noise? Are you falling down the rabbit hole?


79 T140D, 89 Honda 650NT ,61 A10 .On a bike you can out run the demons
"I don't know what the world may need
But a V8 engine is a good start for me
Think I'll drive to find a place, to be surly"
Joined: Feb 2014
Posts: 1,480
Likes: 45
Parts Dealer
Offline
Parts Dealer
Joined: Feb 2014
Posts: 1,480
Likes: 45
When rebuilding a motor, I always check every single bushing or bearing bore before installing any component

Use your new bearings (or old) bearing that you will be using for its given application and use the OD as a master

Measure the ID of the bore and compare with the OD of the bearing to calculate the fit

Most Triumph cases I have measured are .001" or a bit over in terms of press fit

Could the bearing walk out? - yes

Why?

Lack of press fit or bearing housing out of round, damaged or worn

Last edited by C.B.S; 09/14/21 11:42 pm.
Joined: Feb 2008
Posts: 5,855
Likes: 341
Britbike forum member
Online Content
Britbike forum member
Joined: Feb 2008
Posts: 5,855
Likes: 341
It was a pretty well known "secret" back in the day that bearing outers moved in crankcase bores when the engine was running.
This was particularly so at high revs in high ambient temperatures.
There were two cures:
a) Stake the bearing outer so that it could not move in the case. This was what Norton did with the Manx racing engine
b) Pretend it doesn't happen because most people get away with the movement for most of the time. And it normally goes back to the assembled condition when it cools so nobody knows it happened anyway.
Certainly Loctite does not survive. It is not just the heat that causes Loctite to fail but of course that does not help.
Rather it is the tremendous forces involved when two metals expand or contract at different rates.
So the message is clear---mechanically stake the bearing outer or use the standard interference fit and convince yourself that you have done a good job----which you have--or certainly as good a job that the factory did when the engine was new.
Just my two cents worth of course.

Joined: Jan 2004
Posts: 5,247
Likes: 132
D
Britbike forum member
Offline
Britbike forum member
D
Joined: Jan 2004
Posts: 5,247
Likes: 132
Charlie said he puts a steel insert in the triple cases to house the ball bearing to keep it from moving. Presumably this has more interference so the walk does not move to the insert.

Joined: Feb 2014
Posts: 1,480
Likes: 45
Parts Dealer
Offline
Parts Dealer
Joined: Feb 2014
Posts: 1,480
Likes: 45
Originally Posted by DMadigan
Charlie said he puts a steel insert in the triple cases to house the ball bearing to keep it from moving. Presumably this has more interference so the walk does not move to the insert.

This is interesting

Joined: Jan 2017
Posts: 1,913
Likes: 107
T
Britbike forum member
OP Offline
Britbike forum member
T
Joined: Jan 2017
Posts: 1,913
Likes: 107
Hi Hillbilly, I was quite surprised at the .010 side clearance. I expected more like .003”.

I don’t if it will rattle or not. Triumph factory installed the roller in ‘81 on. I didn’t find any complaints of noise from play on line. Several have converted to roller. No complaints that they speak of.
I don’t know what play was on factory bearing. The NSK Japan bearing has same end play as the ones commonly sold from the parts places. As I understand imported, distributed by Coventry Spares. I purchased from Steadfast Cycles. Quality can’t get better than that.
Had I purchased a ball bearing I would have just put it in without a thought. I’ve never looked at crank position, rod centering, end play before. Just installed bearings & it worked good.
The bore in right case feels plenty tight. At 300f it wouldn’t slam out as others did. Even at 330f it came out harder than normal back it harder than normal.
I’ll seep on this a day or two.
Staking the bearing might be possible. I’ll have to go look. Crank is out now.
Should I fall down the rabbit hole…. I put ball back in. At least I’m watching where I’m walking. So if I go down the hole it’s mot an accident or stupid.
The working load of the roller is about double the ball. I was surprised at how much more working load it has.
Don


1973 Tiger 750
Joined: Sep 2013
Posts: 3,501
Likes: 167
Q
Britbike forum member
Offline
Britbike forum member
Q
Joined: Sep 2013
Posts: 3,501
Likes: 167
the DS outer race may move when heat soaked and interference fit is lost or minimized ... but there's no thrust pulling
it out

the TS ball handles the thrust and so does a 3 piece roller.

if the , as supplied , TS roller float is more than desired
the DS crank race can be shimmed out . ( the float is between the 2 inside crank race shoulders/lips )
or the TS thrust washer can shimmed out
and the whole crank mored to the drive side .
( whatever better centers the conrods and minimizes cold float )

Last edited by quinten; 09/15/21 7:19 am.
Joined: Dec 2004
Posts: 11,486
Likes: 208
Britbike forum member
Offline
Britbike forum member
Joined: Dec 2004
Posts: 11,486
Likes: 208
Originally Posted by DMadigan
Charlie said he puts a steel insert in the triple cases to house the ball bearing to keep it from moving. Presumably this has more interference so the walk does not move to the insert.

The steel insert has the same expansion rate as the steel bearing, so whatever the interference fit is cold its much the same when hot. With Aluminium crankcases the crankcase expands more than the steel bearing as the temperature raises. So with a steel insert you can get away with a smaller interference fit than a plain aluminium alloy case housing. The steel insert also has the same issue with the aluminium alloy case but can be physically locked in easier than a bearing by milling flats on the OD of a flange as per BSA timing side bushes.

Joined: Oct 2012
Posts: 6,142
Likes: 210
knuckle head
Offline
knuckle head
Joined: Oct 2012
Posts: 6,142
Likes: 210
" the TS ball handles the thrust and so does a 3 piece roller". . How does a timing side roller control thrust like a ball bearing? The crank is free to float between the two roller bearings, not clamped to a ball bearing,Yes?


79 T140D, 89 Honda 650NT ,61 A10 .On a bike you can out run the demons
"I don't know what the world may need
But a V8 engine is a good start for me
Think I'll drive to find a place, to be surly"
1 member likes this: kommando
Joined: Jan 2004
Posts: 5,247
Likes: 132
D
Britbike forum member
Offline
Britbike forum member
D
Joined: Jan 2004
Posts: 5,247
Likes: 132
Roller bearings are available with no lip or one lip on the inner race. A separate guide ring is available to make a second lip for the inner race so the rollers take some thrust in both directions. Not as much as a ball bearing though.

Joined: Mar 2005
Posts: 10,778
Likes: 145
J
Britbike forum member
Offline
Britbike forum member
J
Joined: Mar 2005
Posts: 10,778
Likes: 145
Quote
Staking the bearing might be possible.

Not the best idea, or solution.

You can get a very good idea if the previous bearing was spinning in the case. The outer bearing contact surface of the bearing housing in aluminum crankcase will appear polished. If it doesn't there is a very good chance that the bearing never spun in the crankcase.

Also you mentioned that you had to throw a lot of heat at it the remove the original ball. This alone would give me a good idea that the bearing hadn't spun in the case.

If you have access to inside, and outside micrometers, measure the i.d. of the crankcase bearing housing and the o.d. of the bearing. Also compare the o.d. of the new roller with the original ball.

Joined: Sep 2013
Posts: 3,501
Likes: 167
Q
Britbike forum member
Offline
Britbike forum member
Q
Joined: Sep 2013
Posts: 3,501
Likes: 167
Originally Posted by Hillbilly bike
" the TS ball handles the thrust and so does a 3 piece roller". . How does a timing side roller control thrust like a ball bearing? The crank is free to float between the two roller bearings, not clamped to a ball bearing,Yes?
no .
the 3 piece roller , used on the timing side has a lipped race on the crank , lip goes to inside of crank .
and theres a thrust washer ... and race with rollers ... that are shrunk fit into the TS case

[img]https:/
[Linked Image from 8.cdn.ekm.net]


when the crank race is slid into the roller race and nutted down
"a float" is established between outer thrust washer and inside lip .

ive never played with this roller set up , so dont the "captured roller float"
the roller float of the single timing-side roller may need to be tightened up with a shim inside the DS roller
so that the 2 inside lips of both roller bearing control total float
Crank can't move left ...because of the inside lip on right bearing
Crank can't move right... because of the inside lip on left bearing
( the thrust face on the outside of the TS roller get shimmed out of play
by the inside DS lip )

[Linked Image from skf.com]

Last edited by quinten; 09/15/21 7:51 pm.
Joined: Jan 2017
Posts: 1,913
Likes: 107
T
Britbike forum member
OP Offline
Britbike forum member
T
Joined: Jan 2017
Posts: 1,913
Likes: 107
Hi John, I specifically looked for signs of spinning is case. None. Old bearing was fully seated in the case tight against its back side.
I do mot have bore gauge. I have inside mic.

I didn’t think about out measuring case bore at the time.
I heated case to 300f in kitchen oven (had wife’s permission).
Bearing still had to knocked out with drift.

2nd go round I used 330f. Bearing fell out on 3rd hard slam on bench. So bore in case is not loose.

I’ll check my notes on brg OD.
Don


1973 Tiger 750
Joined: Oct 2012
Posts: 6,142
Likes: 210
knuckle head
Offline
knuckle head
Joined: Oct 2012
Posts: 6,142
Likes: 210
Well, we know the ball bearing has more or less zero float when the crank is clamped by the pinion nut., The bearings you are showing must take into account the tolerances of the Triumph crankcases . So they must require shimming or the tolerances could stack up wrong with the crank "jammed" between the bearings...so it goes back to my previous posts, the crank lateral play is dependent on shims...At least this is how I see it....
On my 650 racer, I used two the the older style rollers with just the single lip outer race, lip facing outward, away from the crank. Shims between the crank and inner race control the end play..I don't know if this is the best way but it hasn't caused any problem yet....


79 T140D, 89 Honda 650NT ,61 A10 .On a bike you can out run the demons
"I don't know what the world may need
But a V8 engine is a good start for me
Think I'll drive to find a place, to be surly"
Joined: Jan 2017
Posts: 1,913
Likes: 107
T
Britbike forum member
OP Offline
Britbike forum member
T
Joined: Jan 2017
Posts: 1,913
Likes: 107
Hi All, Regarding using DS roller lip to reduce end play of 3 piece takes some serious thought.

Bearing tutorials state end play of rollers is critical on the 3 piece type brg. It is designed in. Nowhere do they give a spec.

Reducing the .010 to say .003-4” by shimming/grinding the race end etc modifies factory clearance.

What is the ramifications of this? I don’t t know.

Moving crank to left is easy. Moving to right is hard. You must remove metal from crank, bearing, or case.

Not a lot of wiggle room to move sprocket to inwards without grinding spacer next to bearing.

Setting chain line on T140 is a pain. Seems nothing runs true. I measure 5 places. Make a spreadsheet & average it.

Repro clutch hubs with the taper & baskets can change chain line by .020-.030+. Thrust washer thickness is part of this.

Still the T140 primary chain is not a big source of problems or seem to wear faster than 2 row.

All I want to do is ride around & have long service life.
Don


1973 Tiger 750
Page 1 of 2 1 2

Moderated by  John Healy 

Link Copied to Clipboard
British Cycle SupplyMorries PlaceKlempf British PartsBSA Unit SinglesPodtronicVintage MagazineBritBike SponsorBritish Tools & FastenersBritBike Sponsor






© 1996-2022 britbike.com
Powered by UBB.threads™ PHP Forum Software 7.7.5