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Pre Unit to Unit Parts Replacement #231669
01/07/09 5:10 pm
01/07/09 5:10 pm
Joined: Jul 2002
Posts: 59
St. Petersburg Fla
K
Karl Von Offline OP
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Karl Von  Offline OP
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K
Joined: Jul 2002
Posts: 59
St. Petersburg Fla
I am into a 49 speedtwin with a worn out moto. I have alot of unit 500, 650 & 750 parts and am trying to find out if any of the later years rods, cranks, lifters, cam & cam followers might work.

I did a little research in the parts manual and came up with this

Rods 70-2921 1951 to 1954 (500 / 650)
Cams 70-3275 Preunit (500 / 650)
Cam Followers 70-1477 To 1965 Triumph Twins
Lifters 70-3059 (type R)

1st: Since these rods have no rod bearings and are shelless, could you turn down the crank and use later rods & bearings. (I also notoced the crank does not have a sludge trap) Maybe the later 650 rods if they are the same length ?

2nd: Does anyone know the diffrence between a 65 & back Cam Follower and a 66 & On Cam Follower. I assume it had something to do with the pushrod tube flange ?

3rd: Beside the standard preunit E3275 Cam, what other stock cam would be a good canidate to run. The bike is no hot rod and will be in mild tune with the stock cast iron head.

4th: how many diffrent lifters are there and what is the R type ?

thanks

Last edited by Karl Von; 01/08/09 2:44 am.

Karl Von Kologiski

62 BSA Rocket Gold Star Replica
59 BMW R69
62 Triumph TR6SS
54 Triumph Speed Twin
74 Moto Guzzi LAPD
75 Moto Guzzi Sport
96 Moto Guzzi 1100 Sport
98 Moto Guzzi V10 Centauro 4V
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Re: Pre Unit to Unit Parts Replacement [Re: Karl Von] #231679
01/07/09 6:18 pm
01/07/09 6:18 pm
Joined: Aug 2001
Posts: 6,966
Vermont
Jon W. Whitley Offline

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Jon W. Whitley  Offline

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Joined: Aug 2001
Posts: 6,966
Vermont
Some of the later Unit 650 parts will work in those cases. The cranks, rods, cams, tappets, will work. No Unit 500 stuff that I know of will work, except some tappet blocks.

The timing side bearing can be replaced with a bearing from an outlet in Buffalo, NY. The info was discussed about a year ago with bearing number. Try searching the archives for that one.

Otherwise you'll have to turn down the journal to accept the timing side bearing E2877. Still uses an E1591 on the drive side.

beerchug


Jon W.


1957 6T Thunderbird 650
1968 T100R Daytona 500
1971 TR6R Tiger 650
1970 BSA A65F 650
1955 Tiger 100 - Project

Re: Pre Unit to Unit Parts Replacement [Re: Jon W. Whitley] #231690
01/07/09 7:50 pm
01/07/09 7:50 pm
Joined: Jul 2002
Posts: 59
St. Petersburg Fla
K
Karl Von Offline OP
BritBike Forum member
Karl Von  Offline OP
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K
Joined: Jul 2002
Posts: 59
St. Petersburg Fla
I looked up the bore and stroke for the preunit 500 & unit 650. The Preunit 500 had a stroke of 3.15 (80mm) while the unit 650 (1963) had a stroke of 3.228 (82mm)

Since the stoke is diffrent between the 500 & 650, would any of the rods or cranks be innerchangable ? I know on guzzis the rods & bore (cyl) are the same on the 750 & 850. They make up the diffrence in the stoke by the crank journal and location of the wrist pin on the piston.


Karl Von Kologiski

62 BSA Rocket Gold Star Replica
59 BMW R69
62 Triumph TR6SS
54 Triumph Speed Twin
74 Moto Guzzi LAPD
75 Moto Guzzi Sport
96 Moto Guzzi 1100 Sport
98 Moto Guzzi V10 Centauro 4V
Re: Pre Unit to Unit Parts Replacement [Re: Jon W. Whitley] #231725
01/08/09 12:00 am
01/08/09 12:00 am
Joined: Aug 2008
Posts: 66
Monte Nido, CA, USA
C
Chris Kelly Offline
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Chris Kelly  Offline
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C
Joined: Aug 2008
Posts: 66
Monte Nido, CA, USA
Originally Posted By: Jon W. Whitley
The timing side bearing can be replaced with a bearing from an outlet in Buffalo, NY. The info was discussed about a year ago with bearing number. Try searching the archives for that one.


Is it this thread? http://www.britbike.com/forums/ubbthreads.php?ubb=showflat&Number=131123&page=1

It's interesting.


1952 Triumph 6T
Re: Pre Unit to Unit Parts Replacement [Re: Chris Kelly] #231752
01/08/09 1:51 am
01/08/09 1:51 am
Joined: Nov 2008
Posts: 22
hamilton, va
pittss1s Offline
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pittss1s  Offline
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Joined: Nov 2008
Posts: 22
hamilton, va
And They have a website...sales@buffalobearings.com. 1-800 669-8019 they were very helpful, even supplied me with a copy of a bearing industry reference that crossed almost all brg. manufacture #'s! I spoke with the son named John, he works with his dad in their bearing shop/dist. I highly recommend them.

Cliff


57 T110
62 T120 project
77 T140 J
07 Bonneville
Re: Pre Unit to Unit Parts Replacement [Re: pittss1s] #231807
01/08/09 12:32 pm
01/08/09 12:32 pm
Joined: Feb 2006
Posts: 221
Greenock, Scotland
G
gearhead1951 Offline
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gearhead1951  Offline
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G
Joined: Feb 2006
Posts: 221
Greenock, Scotland
Iknow someone is gonna throw down the"BULLSHIT" flag on this , but I had a '67 T100R that needed a new cylinder set.

The shop I had to use(no-one else in Charleston SC at that time wanted any thing to do with it)used a set of 650 barrels, modified by reducing the circumferance of the part of the cylinders that entered the cases by grinding with a belt sander!!

IT WORKED!! I rode that little beast for 2 yrs before a transfer to Britain made me have to sell it 'cause the Navy would not ship it for me!!

Re: Pre Unit to Unit Parts Replacement [Re: gearhead1951] #231810
01/08/09 1:29 pm
01/08/09 1:29 pm
Joined: Sep 2008
Posts: 768
Skudeneshavn Norway
S
Stein Roger Offline

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Stein Roger  Offline

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S
Joined: Sep 2008
Posts: 768
Skudeneshavn Norway
Gearhead, that's interesting. I guess you had to shorten the barrel to make it work, or did you use longer rods? Did you use the T100 head or a 650? The T100 bolt pattern is closer to the 8 bolt barrel, but not identical. I've got a 500 engine and might want to try it just for fun.

SR

Re: Pre Unit to Unit Parts Replacement [Re: Stein Roger] #231818
01/08/09 2:18 pm
01/08/09 2:18 pm
Joined: Jul 2002
Posts: 59
St. Petersburg Fla
K
Karl Von Offline OP
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Karl Von  Offline OP
BritBike Forum member
K
Joined: Jul 2002
Posts: 59
St. Petersburg Fla
Well did some more digging and found that the 500 & 650 twins up to 1954, did not use rod bearings. So if you have bad wear, you have to replace the rods and maybe the crank. I may have access to a 1950 T-bird lower end, but it has the same rod & crank issue.

Would it be possible to use a later 650 crank w/ bearing rods, into a 1950 preunit 650 case. If so I may bench the orginal 500 motor and use a 65o engine.


Karl Von Kologiski

62 BSA Rocket Gold Star Replica
59 BMW R69
62 Triumph TR6SS
54 Triumph Speed Twin
74 Moto Guzzi LAPD
75 Moto Guzzi Sport
96 Moto Guzzi 1100 Sport
98 Moto Guzzi V10 Centauro 4V
Re: Pre Unit to Unit Parts Replacement [Re: Karl Von] #231843
01/08/09 5:19 pm
01/08/09 5:19 pm
Joined: Aug 2001
Posts: 7,419
scotland
triton thrasher Offline
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triton thrasher  Offline
BritBike Forum member
Joined: Aug 2001
Posts: 7,419
scotland
You can put a 650 Pre-unit crank into a 500 Pre-unit crankcase. You can use a Unit 650 crank if you modify the oil feed nose and/or the timing case. There is a bearing size issue on the timing side if you have pre-1954 cases, I think.

People used to convert the metalled rods for shells, but nowadays you would use later rods.

Any Pre-unit cams will fit. Unit 650 inlet cams will fit inlet or exhaust on a Pre-unit. A pair of 1970 Bonneville inlet camshafts will go well.

66-on tappet blocks might be the oil fed exhaust type. R followers have alarger radius foot but it's not all that important.


Amateur Loctite enthusiast.
Re: Pre Unit to Unit Parts Replacement [Re: triton thrasher] #231872
01/08/09 7:42 pm
01/08/09 7:42 pm
Joined: Jul 2002
Posts: 59
St. Petersburg Fla
K
Karl Von Offline OP
BritBike Forum member
Karl Von  Offline OP
BritBike Forum member
K
Joined: Jul 2002
Posts: 59
St. Petersburg Fla
How about a set of 650 shell-rods on the orginal 49 speedtwin crank. Since the 500 & 650 rods are the same length, that would solve a bunch of issues I am having. I have also talked to some old hot rodders who are into flat head V8's. They have babbet rods with no shells and they mill down the rod caps on the rods and use plastic gauge to get the right clearance. Sounds a little riskey. I would rather just put on the later rods & bearings on the stock crank, if I can

Last edited by Karl Von; 01/09/09 8:53 pm.

Karl Von Kologiski

62 BSA Rocket Gold Star Replica
59 BMW R69
62 Triumph TR6SS
54 Triumph Speed Twin
74 Moto Guzzi LAPD
75 Moto Guzzi Sport
96 Moto Guzzi 1100 Sport
98 Moto Guzzi V10 Centauro 4V
Re: Pre Unit to Unit Parts Replacement [Re: Karl Von] #231913
01/09/09 1:41 am
01/09/09 1:41 am
Joined: Apr 2004
Posts: 1,093
somewhere in the UK
Mike Muir Offline

Life member
Mike Muir  Offline

Life member
Joined: Apr 2004
Posts: 1,093
somewhere in the UK
Karl, you may want to check the manual ref the sludge trap. My TRW (plain rod bearings, not even a split eye) has a trap, but you have to separate the crank shaft to get at it, no external plug.


Mike, home is where we moor it.
Re: Pre Unit to Unit Parts Replacement [Re: Mike Muir] #232025
01/09/09 8:55 pm
01/09/09 8:55 pm
Joined: Jul 2002
Posts: 59
St. Petersburg Fla
K
Karl Von Offline OP
BritBike Forum member
Karl Von  Offline OP
BritBike Forum member
K
Joined: Jul 2002
Posts: 59
St. Petersburg Fla
The motor is at my pals house, but I will look in the manual and check it out. This project is getting to be quite the mess. To bad the bike is very correct or I would just make custom out of it.


Karl Von Kologiski

62 BSA Rocket Gold Star Replica
59 BMW R69
62 Triumph TR6SS
54 Triumph Speed Twin
74 Moto Guzzi LAPD
75 Moto Guzzi Sport
96 Moto Guzzi 1100 Sport
98 Moto Guzzi V10 Centauro 4V
Re: Pre Unit to Unit Parts Replacement [Re: Stein Roger] #232095
01/10/09 12:08 pm
01/10/09 12:08 pm
Joined: Feb 2006
Posts: 221
Greenock, Scotland
G
gearhead1951 Offline
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G
Joined: Feb 2006
Posts: 221
Greenock, Scotland
the mechanic was chris hall, it was 1975 in north charleston sc and i watched him grinding the outer circumferance of the skirts to make the barrels fit the cases!

i cannot say for sure if the were 650's or not, but that is what he told me. as to the rods, i don't think he changed them, but at that time i was an e5 in the us navy on board a VERY busy submarine tender and had no time to do any extracurricular wrench turning! i was forced to rely on my mechanic!

the bike ran well and handling was excellent, whatever th' bugger done, he done it right!!!


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