BritBike Forum logo
BritBike SponsorBritBike SponsorBritBike SponsorBritBike SponsorBritBike SponsorBritBike SponsorBritBike SponsorThe Bonneville ShopBritBike Sponsor
Upgrade to: Premium Membership | Premium Life Membership | Vendor Membership | Site Sponsor Membership
ShoutChat Box
Comment Guidelines: Do post respectful and insightful comments.
Buy BritBike staff a coffee
Buy BritBike's staff a coffeeStill here since 1996 serving BritBike enthusiasts..
Search eBay for motorcycle parts in following countries
Australia, Canada, France, Holland, Italy, United Kingdom, USA
Random Gallery photo
Member Spotlight
Mikethebike
Mikethebike
Washington, USA
Posts: 24
Joined: August 2012
Show All Member Profiles 
Newest Members
JM Ahumada, Michael nelson, [email protected], Bryan Holmes, TODD CHILD
10822 Registered Users
Top Posters(30 Days)
franko 148
NickL 76
DavidP 70
reverb 54
Popular Topics(Views)
972,208 mail-order LSR
a word from..
Forum Statistics
Forums34
Topics67,357
Posts677,127
Members10,822
Most Online14,755
May 5th, 2019
Who's Online Now
66 registered members (Al Eckstadt), 416 guests, and 759 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
Oil Pump Confusion Unit 650cc SOLVED! #699783 06/27/17 10:45 am
Joined: Apr 2015
Posts: 429
P
Peter Gee Offline OP
BritBike Forum member
OP Offline
BritBike Forum member
P
Joined: Apr 2015
Posts: 429
In pre Unit days it was real simple, now from 63-72 there seem to be a bewildering variety of oil pumps. I have a DU 33XXX series 1966.

My parts book says my pump should be E3878, then in 1968 it's E6928, in 1970 E9421 and so on. Which models will fit my 1966? Can't find E3878 new or second hand for the life of me..the others, yes.

I have unit oil pumps with the "offset" mounting holes..the pre- units were 180 in line. . I have pump plungers (a) Scavenge 0.487/ Feed 0 .374 and another pump (b) scavenge 0.436 /feed 0.374---this seems to be correct for my year 1966 according to the Workshop manual 650's up to 1970 and must be the mysterious E3878?.

What on earth is the other pump for? A T100 Unit as I also had parts for that lying about? It would seem odd to have a bigger scavenge diameter (0.487 vs 0.436) on a smaller engine, or did Triumph get it wrong in the literature and actually (a) is correct for my 650 since it scavenges faster but delivers the same , both feed plungers being 0.374

Don't want to blow up my rebuild, so it helps to know. Am using the factory 63-70 edition of Workshop manual.

Last edited by Peter Gee; 06/27/17 3:48 pm.
Support Your #1 BritBike Forum!

Check out British motorcycles for sale:
British Motorcycles on e-Bay UK
British motorcycles on e-Bay North America
Re: Oil Pump Confusion Unit 650cc [Re: Peter Gee] #699798 06/27/17 1:52 pm
Joined: Mar 2006
Posts: 4,078
L.A.B. Online Content
BritBike Forum member
Online Content
BritBike Forum member
Joined: Mar 2006
Posts: 4,078
Originally Posted by Peter Gee

My parts book says my pump should be E3878, then in 1968 it's E6928, in 1970 E9421 and so on. Which models will fit my 1966? Can't find E3878 new or second hand for the life of me..the others, yes.

I have pump plungers (a) Scavenge 0.487/ Feed 0 .374 and another pump (b) scavenge 0.436 /feed 0.374---this seems to be correct for my year 1966 according to the Workshop Manual 650's up to 1970 and must be the mysterious E3878?


650/750

'63 - '66, E3878 (Scavenge 0.437"/ Feed 0.374")

'67 - 'early' '69, E6928 (Scavenge enlarged to 0.487"/ Feed 0.374")

Late '69 - '79, E9421/ 70-9421 (Scavenge 0.487"/ Feed enlarged to 0.406")

'80 ->, 71-7317 'double check-valve' pump (same 0.487"/ 0.406").







Re: Oil Pump Confusion Unit 650cc [Re: Peter Gee] #699808 06/27/17 3:37 pm
Joined: Mar 2005
Posts: 10,245
J
John Healy Offline
BritBike Forum member
Offline
BritBike Forum member
J
Joined: Mar 2005
Posts: 10,245
And they are interchangeable...


Re: Oil Pump Confusion Unit 650cc [Re: John Healy] #699809 06/27/17 3:47 pm
Joined: Apr 2015
Posts: 429
P
Peter Gee Offline OP
BritBike Forum member
OP Offline
BritBike Forum member
P
Joined: Apr 2015
Posts: 429
Many thanks in that case...... great.....

Re: Oil Pump Confusion Unit 650cc [Re: Peter Gee] #699853 06/27/17 9:13 pm
Joined: Feb 2012
Posts: 133
D
DUHC Offline
BritBike Forum member
Offline
BritBike Forum member
D
Joined: Feb 2012
Posts: 133
Fascinating! Never knew that. A lot of suppliers just say 'oil pump suitable for 350, 500 & 650 unit construction' which aligns with JH's comment.

Re: Oil Pump Confusion Unit 650cc [Re: Peter Gee] #699860 06/27/17 11:01 pm
Joined: Jul 2011
Posts: 114
F
fried okra Offline
BritBike Forum member
Offline
BritBike Forum member
F
Joined: Jul 2011
Posts: 114
Yes, Peter, I gather the oil pumps are interchangeable but gotta believe the latest two valve pump, or using the four valve pump by maybe grinding the timing cover to allow a proper fit, has to be the best way to go.

Not sure the four valve pump will fit the unit 500cc bikes though.

But what do I know.

fried okra

Re: Oil Pump Confusion Unit 650cc [Re: Peter Gee] #699911 06/28/17 12:18 pm
Joined: Oct 2006
Posts: 3,138
I
Irish Swede Offline
BritBike Forum member
Offline
BritBike Forum member
I
Joined: Oct 2006
Posts: 3,138
Any modifications needed to the crankcase to allow for the larger scavenge and feed ports of the later pumps?

Re: Oil Pump Confusion Unit 650cc [Re: Irish Swede] #699957 06/28/17 9:49 pm
Joined: Apr 2015
Posts: 429
P
Peter Gee Offline OP
BritBike Forum member
OP Offline
BritBike Forum member
P
Joined: Apr 2015
Posts: 429
As far as I know Irish Swede, no, none... enlarging the feed holes would reduce the pressure when the pump plunger was enlarged to increase it......

Re: Oil Pump Confusion Unit 650cc [Re: DUHC] #699958 06/28/17 9:50 pm
Joined: Apr 2015
Posts: 429
P
Peter Gee Offline OP
BritBike Forum member
OP Offline
BritBike Forum member
P
Joined: Apr 2015
Posts: 429
Yeah like a lot of Britbike things, there is a ton of subtly and I thought the same till I started measuring pump plungers!


Moderated by  John Healy 

Home | Sponsors | Newsletter | Regalia | Calendar | Bike Project | BritBike Museum | Spiders Cartoons | DVD- Manuals & Parts books
Upgrade to: Premium Membership | Premium Life Membership | Vendor Membership | Site Sponsor Membership
BritBike Sponsor
Powered by UBB.threads™ PHP Forum Software 7.7.3