BritBike Forum logo
BritBike Sponsor BritBike Sponsor BritBike Sponsor
BritBike Sponsor

BritBike Sponsor

BritBike Sponsor
BritBike Sponsor BritBike Sponsor BritBike Sponsor
JWood Auction JRC Engineering dealers JWood Auction
Home | Sponsors, Newsletter | Regalia | Calendar | Bike Project | BritBike Museum | Spiders Cartoons, "OLD" BritBike Forum | DVD- Manuals & Parts books | BritBike Stickers & Decals
Upgrade to: Premium Membership | Premium Life Membership | Vendor Membership | Site Sponsor Membership
Photo posting tutorial

Member Spotlight
MikeTRP
MikeTRP
Melbourne, Australia
Posts: 69
Joined: September 2001
Show All Member Profiles 
Shout Box
Search eBay for motorcycle parts in following countries
Australia, Canada, France, Holland, Italy, United Kingdom, USA
Random Gallery photo
Who's Online Now
188 registered members (1xfatboy), 1,750 guests, and 605 spiders.
Key: Admin, Global Mod, Mod
Newest Members
iansouthoz, Lightning Sim, Simon.Holyfield, Bushcreature, Gary Shackleton
10035 Registered Users
Top Posters(30 Days)
Lannis 144
kommando 105
Stuart 67
Popular Topics(Views)
476,705 mail-order LSR
Forum Statistics
Forums33
Topics65,721
Posts635,225
Members10,035
Most Online3,995
Feb 13th, 2017
Like BritBike.com on Facebook

Previous Thread
Next Thread
Print Thread
Rate Thread
Carb Manifold Question 67 Bonneville #548496
06/14/14 6:52 pm
06/14/14 6:52 pm
Joined: Aug 2001
Posts: 745
USA
Dave M Offline OP
BritBike Forum member
Dave M  Offline OP
BritBike Forum member
Joined: Aug 2001
Posts: 745
USA
I am assembling the carb manifolds, 67 Bonneville. Both refuse to go farther than 1,1/2 turns and are far from seating against the shoulder to the rear of the head. There is no evidence of cross threading.

How far into the head must these travel? If too shallow might there be a clearance issue with the tanks' petcocks?

Wrong part? Did threads change by year?

I lack a thread gauge which might answer my question.

I'm usure how to solve this, appreciate any help. eek Thanks! dave


This shows 1,1/2 turns in, will travel no farther.


The threads of each.


66 TR6R Trophy
67 T120R Bonneville
68 BMW R60/US
69 T100R Daytona

Support Your #1 BritBike Forum!
Membership Type! Free
Member
Premium
Member
Premium Life
Member
Vendor
Member
Site
Sponsor
Recognition No Premium Member Premium Life member (5 years) Vendor Member Site Sponsor Membership
Post commercial threads No No No Yes Yes
Custom title No Yes Yes Yes Yes
Upload avatar & photos No Yes Yes Yes Yes
Link avatar & photos Yes Yes Yes Yes Yes
Private Message Storage: 10 100 100 100 100
Length of signatures 255 600 600 600 600
Removes this very advert island between post 1&2 No Yes Yes Yes Yes
Price Free $12.90/year $105.00 No End
$55.00/5 years
$210.00/year
($17.50/month)
Email
Click on button >>
  Premium Member Premium Life member Vendor Member Site Sponsor Membership
Re: Carb Manifold Question 67 Bonneville [Re: Dave M] #548508
06/14/14 7:33 pm
06/14/14 7:33 pm
Joined: Jul 2006
Posts: 361
Kent, UK
N
Nick_Smith Offline
BritBike Forum member
Nick_Smith  Offline
BritBike Forum member
N
Joined: Jul 2006
Posts: 361
Kent, UK
The threads in the head look finer than those on the stubs.

Rather than trying to force them in, I'd invest in a thread gauge and see what you've got.

Nick


"1967 TR6R"
Re: Carb Manifold Question 67 Bonneville [Re: Dave M] #548516
06/14/14 8:02 pm
06/14/14 8:02 pm
Joined: Sep 2011
Posts: 944
New Zealand
Excalibur Online content
BritBike Forum member
Excalibur  Online Content
BritBike Forum member
Joined: Sep 2011
Posts: 944
New Zealand
Yes, the threads changed somewhere around '69 at a guess.

Re: Carb Manifold Question 67 Bonneville [Re: Dave M] #548544
06/14/14 11:22 pm
06/14/14 11:22 pm
Joined: Jul 2009
Posts: 3,549
Vic. Australia
P
Pete R - R.I.P. Offline
In Remembrance
Pete R - R.I.P.  Offline
In Remembrance
P
Joined: Jul 2009
Posts: 3,549
Vic. Australia
From about '64 until mid '72,the thread was 1-3/8" x 16 tpi.It would have been a BSC thread up until '68 model.Your manifolds look right for '67.'69-onward manifolds have brazed-in studs.

The threads would have been UNF form from '69 onward.Even though it's the same pitch and thread angle,a UNF thread is effectively smaller than a BSC thread because of the different nose radius.On a thread with that pitch (16 tpi),it amounts to a little over 0.007" difference.

The '67 manifolds would probably have trouble screwing into a '69-onward head,unless you ran a BSC tap into the head first.

Re: Carb Manifold Question 67 Bonneville [Re: Dave M] #548553
06/15/14 12:09 am
06/15/14 12:09 am
Joined: Nov 2002
Posts: 404
australia
T
tiger_cub Offline
BritBike Forum member
tiger_cub  Offline
BritBike Forum member
T
Joined: Nov 2002
Posts: 404
australia
Is there a set distance that the flange sits away from the head? On my T120C I got replacement manifolds & I am struggling to fit the unified airfilter in (actually it won't go in due to the carb float chamber on the right side even though there is a cutout in the filter plate there!)


1970 TR6C
1972 TR6C
Re: Carb Manifold Question 67 Bonneville [Re: Pete R - R.I.P.] #548581
06/15/14 7:56 am
06/15/14 7:56 am
Joined: Aug 2001
Posts: 745
USA
Dave M Offline OP
BritBike Forum member
Dave M  Offline OP
BritBike Forum member
Joined: Aug 2001
Posts: 745
USA
Originally Posted By: Pete R
From about '64 until mid '72,the thread was 1-3/8" x 16 tpi.It would have been a BSC thread up until '68 model.Your manifolds look right for '67.'69-onward manifolds have brazed-in studs.

The threads would have been UNF form from '69 onward.Even though it's the same pitch and thread angle,a UNF thread is effectively smaller than a BSC thread because of the different nose radius.On a thread with that pitch (16 tpi),it amounts to a little over 0.007" difference.

The '67 manifolds would probably have trouble screwing into a '69-onward head,unless you ran a BSC tap into the head first.


I'm reasonably certain the head is original to the engine, it is stamped 66.
Printing your reply Pete, and will buy a thread gauge. Most helpful, thanks to all. bigt dave


66 TR6R Trophy
67 T120R Bonneville
68 BMW R60/US
69 T100R Daytona


Moderated by  John Healy 


Home | Sponsors | Newsletter | Regalia | Calendar | Bike Project | BritBike Museum | Spiders Cartoons | "OLD" BritBike Forum | DVD- Manuals & Parts books | BritBike Stickers & Decals
Upgrade to: Premium Membership | Premium Life Membership | Vendor Membership | Site Sponsor Membership
Powered by UBB.threads™ PHP Forum Software 7.6.1.1