|
Posts: 55
Joined: April 2003
|
|
|
Forums35
Topics76,758
Posts787,766
Members12,432
| |
Most Online230
Mar 11th, 2023
|
|
|
|
Joined: Mar 2011
Posts: 44 Likes: 2
Britbike forum member
|
OP
Britbike forum member
Joined: Mar 2011
Posts: 44 Likes: 2 |
Hello,
I have a 1970 Triumph Bonneville. The stock 1970 head needs to get sent off or have someone install new valve seats in it. While I figure that out I have a 1964 stamped head which is good to go that I would like to install.
Will the stock 1970 pushrod tubes work? As I understand they may be a bit too long. If the stock pushrod tubes wont work can some point me in the right direction of which ones will work?
Thank you in advance for your response.
1960 - BSA Gold Star
1966 - Triumph T120TT
1970 - Triumph T120
1975 - Norton 850 Electric Start
|
|
|
|
|
Joined: Sep 2007
Posts: 1,659 Likes: 37
Britbike forum member
|
|
Britbike forum member
Joined: Sep 2007
Posts: 1,659 Likes: 37 |
No. You will need 68 on back tubes and tappet guide blocks. You need both. Check push rod length. The early head has a much shallower PRT indent than the 69-70 head. FYI A 71-72 head will work with your current prt’s and blocks. Their easy to find.
Last edited by Roadwarrior; 07/31/22 12:50 am.
Who are the Brain Police?
68 B44 Victor
60 MGA
56 Chevy
Bob M.
|
|
|
|
|
Joined: Nov 2008
Posts: 3,823 Likes: 81
Britbike forum member
|
|
Britbike forum member
Joined: Nov 2008
Posts: 3,823 Likes: 81 |
1968 T120R
1972 T120RV
Any advice given is without a warranty expressed or implied.
|
|
|
|
|
Joined: Aug 2016
Posts: 919 Likes: 108
Britbike forum member
|
|
Britbike forum member
Joined: Aug 2016
Posts: 919 Likes: 108 |
The 71/72 will work, but looks silly with the dowels poking out. It is possible to machine the early head for a deeper indent, but it is at an angle, not one for the faint hearted. Also someone, somewhere, will curse you down the line.
|
|
1 member likes this:
kevin |
|
|
|
|
Joined: Mar 2006
Posts: 411 Likes: 18
Britbike forum member
|
|
Britbike forum member
Joined: Mar 2006
Posts: 411 Likes: 18 |
I had a real PIA trying to put a 71/72 head on my 68 bonnie. I could not get the 72 rocker boxes on over the inner head bolts (motor in frame) and didn't want to have to unbolt the motor any time I wanted to pull the rocker boxes. So I pulled the roll pins and went back to 68 boxes only to find the indents in the head under the head bolts were deep enough to have a gap between the early boxes and the head, this connection is imperative as the 68 head bolts clamp the box to the head as a unit to affect proper torque value and clamping ability. So after a bodge with thinning down washers and three bond I didn't even start it up, still sits in my shop looking pretty with a boogered head fitment. If you're lucky enough to find a 72 head with no indentations it would work with early boxes.
'68 Bonnie, '70 TR6r
'74 CL360
trail 70's and minitrails
|
|
|
|
|
Joined: Dec 2013
Posts: 6,713 Likes: 373
DOPE
|
|
DOPE
Joined: Dec 2013
Posts: 6,713 Likes: 373 |
i mix and match al that stuff. i have a 1973 9 and 1/2-bolt head with early boxes on it right now.
how were you planning on adapting the later head steady to your 68?
Last edited by kevin; 07/31/22 2:58 pm.
watermelons, and turnips, and a contaminator
and other stuff
|
|
|
|
|
Joined: Jan 2004
Posts: 5,674 Likes: 236
Britbike forum member
|
|
Britbike forum member
Joined: Jan 2004
Posts: 5,674 Likes: 236 |
Or use adjustable pushrod tubes
|
|
1 member likes this:
kevin |
|
|
|
|
Joined: Aug 2016
Posts: 919 Likes: 108
Britbike forum member
|
|
Britbike forum member
Joined: Aug 2016
Posts: 919 Likes: 108 |
Of course! It could be done by machining alloy tubes, but in no way reversible!
|
|
|
|
|
Joined: Dec 2013
Posts: 6,713 Likes: 373
DOPE
|
|
DOPE
Joined: Dec 2013
Posts: 6,713 Likes: 373 |
i use ^^^daves adjustable tubes. they work fine.
watermelons, and turnips, and a contaminator
and other stuff
|
|
|
|
|
Joined: Mar 2011
Posts: 44 Likes: 2
Britbike forum member
|
|
OP
Britbike forum member
Joined: Mar 2011
Posts: 44 Likes: 2 |
Where does one source these adjustable push rod tubes from?
Last edited by MaaseyRacer; 07/31/22 10:36 pm.
1960 - BSA Gold Star
1966 - Triumph T120TT
1970 - Triumph T120
1975 - Norton 850 Electric Start
|
|
|
|
|
Joined: Nov 2008
Posts: 3,823 Likes: 81
Britbike forum member
|
|
Britbike forum member
Joined: Nov 2008
Posts: 3,823 Likes: 81 |
DMadigan
See 4 posts above here.
1968 T120R
1972 T120RV
Any advice given is without a warranty expressed or implied.
|
|
|
|
|
Joined: Jan 2014
Posts: 2,469 Likes: 463
Britbike forum member
|
|
Britbike forum member
Joined: Jan 2014
Posts: 2,469 Likes: 463 |
I had a real PIA trying to put a 71/72 head on my 68 bonnie. I could not get the 72 rocker boxes on over the inner head bolts (motor in frame) and didn't want to have to unbolt the motor any time I wanted to pull the rocker boxes. So I pulled the roll pins and went back to 68 boxes only to find the indents in the head under the head bolts were deep enough to have a gap between the early boxes and the head, this connection is imperative as the 68 head bolts clamp the box to the head as a unit to affect proper torque value and clamping ability. So after a bodge with thinning down washers and three bond I didn't even start it up, still sits in my shop looking pretty with a boogered head fitment. If you're lucky enough to find a 72 head with no indentations it would work with early boxes. my old '70 had a later head and rocker boxes, just used the later two part fixings with hex's on on the inside and short bolts for the covers. It was tight getting the covers on and off but was ok. Fabricated a head steady to suit. Dave Madigan does adjustable pushrod tubes if needed.
|
|
|
|
|
Joined: Mar 2011
Posts: 44 Likes: 2
Britbike forum member
|
|
OP
Britbike forum member
Joined: Mar 2011
Posts: 44 Likes: 2 |
DMadigan, sent you an email.
1960 - BSA Gold Star
1966 - Triumph T120TT
1970 - Triumph T120
1975 - Norton 850 Electric Start
|
|
|
|
|
Joined: Sep 2007
Posts: 1,659 Likes: 37
Britbike forum member
|
|
Britbike forum member
Joined: Sep 2007
Posts: 1,659 Likes: 37 |
The 71-72 head works with a 69-70 motor with the eailier rocker boxes just fine using the earlier rocker box gaskets. Pull the locator pins. The 71-72 head will not work with a 68 or earlier motor unless you also change out the tappet guide blocks and PRT tubes. I’ve done this at least 8 times with complete success.
Who are the Brain Police?
68 B44 Victor
60 MGA
56 Chevy
Bob M.
|
|
|
|
|
Joined: Aug 2016
Posts: 919 Likes: 108
Britbike forum member
|
|
Britbike forum member
Joined: Aug 2016
Posts: 919 Likes: 108 |
Or Dave's adjustable PRT's?
|
|
|
|
|
Joined: Mar 2011
Posts: 44 Likes: 2
Britbike forum member
|
|
OP
Britbike forum member
Joined: Mar 2011
Posts: 44 Likes: 2 |
I ended up checking in with a friend on this issue and he referred me to MAP. I purchased a set of their alloy machineable pushrod tubes, they arrived cross country two days after I ordered them. Installed them on the bike, took my measurements and turned them down for a perfect fit.
I am sure an adjustable tube would be better for exact fitment, but this was a one click purchase solution that does not look completely out of the ordinary.
1960 - BSA Gold Star
1966 - Triumph T120TT
1970 - Triumph T120
1975 - Norton 850 Electric Start
|
|
|
|
|
Joined: Jan 2014
Posts: 2,469 Likes: 463
Britbike forum member
|
|
Britbike forum member
Joined: Jan 2014
Posts: 2,469 Likes: 463 |
|
|
|
|
|
or 
