21-2177 are also four of the barrel base nuts on your bike?
Restoring & Modifying 1971 OIF TR120
- Thread starter NM Bonny
- Start date
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Look like it's got the 12-point nuts...
The point I was trying to make (possibly too subtly) was the stator securing nuts do (should) not need to be locknuts:-
Understood, thank you. I guess that I'm a belt-and-suspenders kind of a guy, so I don't mind having to take the route I took. But, yes, that stator seems to be on there pretty firmly, so I shouldn't worry.
On the earlier discussion re: the axle, my machinist owes me some work, so he's going to machine some circlip grooves in the ends of the shaft I bought. It is extremely hard, Rockwell C60, so he said it'll be a challenge and may require a special cutter. But I'd like the peace of mind that'll come with circlips, and they'll look better than other options we discussed.
Weirdly, the Triumph manual doesn't give you a clutch plate wear spec per se; it requires you to buy new plates and subtract .030". So, um, Triumph's repair manual authors didn't have access to a set of clutch plates...? 
Anyway, so people can annotate their repair manuals, a new Emgo plate measures about .1580", less .030" yields a wear spec of ~.1550". Because of variation among the friction pads, one might want to fudge that a little and say .1540" or even .1535". Mine are .1250"~.1245", or way overdue for replacement. I'll check the springs' length against the general data before reusing them, as the kit I bought included some.
So, I should have the primary buttoned up and be able to wrap up the final few items before the month is out, if my luck holds.
My machinist says he'll have time to machine the grooves in the HTF axle for the stainless circlips soon, and they'll be here before the weekend. He's actually going to do that on the big CNC mill rather than the lathe due to the tooling he found (and I think he just likes using that machine). I'll take a short video if I'm around when he does the job.
I'll post when that job is done for those out there contemplating the DIY 11.5" front disc brake conversion. But it looks like because of the close fit near the outboard/downward-facing fork slider drain screws, one would R&R the clips simply by loosening the cap nuts to drop the axle down a smidge, then use your circlip plier as usual before sliding out the axle and catching the shim(s) in your palm. Pretty straightforward.
Anyway, so people can annotate their repair manuals, a new Emgo plate measures about .1580", less .030" yields a wear spec of ~.1550". Because of variation among the friction pads, one might want to fudge that a little and say .1540" or even .1535". Mine are .1250"~.1245", or way overdue for replacement. I'll check the springs' length against the general data before reusing them, as the kit I bought included some.
So, I should have the primary buttoned up and be able to wrap up the final few items before the month is out, if my luck holds.
My machinist says he'll have time to machine the grooves in the HTF axle for the stainless circlips soon, and they'll be here before the weekend. He's actually going to do that on the big CNC mill rather than the lathe due to the tooling he found (and I think he just likes using that machine). I'll take a short video if I'm around when he does the job.
I'll post when that job is done for those out there contemplating the DIY 11.5" front disc brake conversion. But it looks like because of the close fit near the outboard/downward-facing fork slider drain screws, one would R&R the clips simply by loosening the cap nuts to drop the axle down a smidge, then use your circlip plier as usual before sliding out the axle and catching the shim(s) in your palm. Pretty straightforward.
Attachments
Oh, happy day!
installed the new clutch & Barnett springs (cleaned and greased the cups), filled the tranny (no leaks), installed the new, ultra-slippery Venhill cable, set the pushrod freeplay per the manual (push rod was straight and moved freely in the output shaft), and trued up the pressure plate.
Problem: the clutch effort is significantly higher than before.
I followed the manual's method of screwing in the spring tensioners until their heads were flush with the studs, determining the high spot, and screwing in the nearest tensioner--and an adjacent one which needed far fewer turns--until the pressure plate ran nice and true and the clutch turned easily using the kicker with the clutch held in.
My sense is that two things are contributing to the stiff lever: (i) the old springs were probably weak; and (ii) I should not have started where the manual told me to--with the tensioners turned in until the heads were flush with the stud ends.
Does that analysis sound right...?
However, if no. (ii) is contributing, I cannot simply back off all the tensioners evenly to see if I can achieve good clutch lockup with less tension because I cannot do what the manual suggests--get a screwdriver or knife blade in between the spring cups and the pressure plate to allow the tensioner to get past the springs' outer ends.
Any help would be greatly appreciated.
installed the new clutch & Barnett springs (cleaned and greased the cups), filled the tranny (no leaks), installed the new, ultra-slippery Venhill cable, set the pushrod freeplay per the manual (push rod was straight and moved freely in the output shaft), and trued up the pressure plate.
Problem: the clutch effort is significantly higher than before.
I followed the manual's method of screwing in the spring tensioners until their heads were flush with the studs, determining the high spot, and screwing in the nearest tensioner--and an adjacent one which needed far fewer turns--until the pressure plate ran nice and true and the clutch turned easily using the kicker with the clutch held in.
My sense is that two things are contributing to the stiff lever: (i) the old springs were probably weak; and (ii) I should not have started where the manual told me to--with the tensioners turned in until the heads were flush with the stud ends.
Does that analysis sound right...?
However, if no. (ii) is contributing, I cannot simply back off all the tensioners evenly to see if I can achieve good clutch lockup with less tension because I cannot do what the manual suggests--get a screwdriver or knife blade in between the spring cups and the pressure plate to allow the tensioner to get past the springs' outer ends.
Any help would be greatly appreciated.
From an old copy of Vintage Bike magazine:-
. New one:-
.. Have you checked everything's been made well?
.. Measure carefully between the lever pivot centre and the nipple centre; Triumph twin levers should be 7/8",
Norton levers are over an inch. 
. Used one, have you checked for wear? Some is likely to be apparent but ime it is a good idea to check movement with pressure applied to the lever parts by pulling on the cable inner.
Springs' wire o.d. and length - ime, whoever makes new springs now is using metric wire, so the o.d. might be slightly different from the quote above, but it should not be significantly different; length should not be different.
As the above shows, the pressure exerted by any of the springs is increased if the spring tensioner is set so the end of the stud is level with the top of the tensioner vs level only with the bottom of the tensioner's slot.
Handlebar lever pivot:-
. New one:-
.. Have you checked everything's been made well?
.. Measure carefully between the lever pivot centre and the nipple centre; Triumph twin levers should be 7/8",
Norton levers are over an inch. . Used one, have you checked for wear? Some is likely to be apparent but ime it is a good idea to check movement with pressure applied to the lever parts by pulling on the cable inner.
Springs' wire o.d. and length - ime, whoever makes new springs now is using metric wire, so the o.d. might be slightly different from the quote above, but it should not be significantly different; length should not be different.
As the above shows, the pressure exerted by any of the springs is increased if the spring tensioner is set so the end of the stud is level with the top of the tensioner vs level only with the bottom of the tensioner's slot.
You have to be quite brutal ...
From an old copy of Vintage Bike magazine:-
Handlebar lever pivot:-
. New one:-
.. Have you checked everything's been made well?
.. Measure carefully between the lever pivot centre and the nipple centre; Triumph twin levers should be 7/8",
. Used one, have you checked for wear? Some is likely to be apparent but ime it is a good idea to check movement with pressure applied to the lever parts by pulling on the cable inner.
Springs' wire o.d. and length - ime, whoever makes new springs now is using metric wire, so the o.d. might be slightly different from the quote above, but it should not be significantly different; length should not be different.
As the above shows, the pressure exerted by any of the springs is increased if the spring tensioner is set so the end of the stud is level with the top of the tensioner vs level only with the bottom of the tensioner's slot.
You have to be quite brutal ...
Okay, so it looks like from the above data (thank you very much - I'll record it in my notes) that indeed I may only need to dial back the tension on the springs.
My old springs look like slightly worn/compressed 57-1830s.
My clutch lever is a stock Triumph twin model which measures as it should per your figures. The hole for the pivot screw is worn a bit, but that's easy to reconcile with a larger pivot. Indeed, I may modify the setup by inserting a bronze bushing to avoid further wear/distortion of the cast part.
I will give your method a try, but generally strive to avoid brutality in my life and work (it sometimes seeps into my art, perhaps unavoidably).
Yup, that was it--thanks Rudie. Remarkable that just a slight amount of preload nets that much more difficulty at the lever... but it does.
Well, the list of 'to do' items until I fire her up is getting shorter. I don't know but it's at least conceivable that I will be giving it a shot this by next weekend--though I do have to sand and polish one... more... cover...
One thing that I'm hoping will work is lifting the fuel tank (a single bolt, after loosening the fuel lines) and simply swiveling the carburetors outward on their threaded manifolds to more easily access the intake valve adjusters. That is, without having to remove the carbs as I've seen people do on later bikes (Lunmad does this on one of his DIY videos).
If that works, it will be a major benefit of the early-style threaded manifolds (see pic). Not that removing the carbs is a huge job, but just loosening that big locknut and tilting them outward would be much quicker--and this is a routine maintenance job I'll be doing regularly...
Well, the list of 'to do' items until I fire her up is getting shorter. I don't know but it's at least conceivable that I will be giving it a shot this by next weekend--though I do have to sand and polish one... more... cover...
One thing that I'm hoping will work is lifting the fuel tank (a single bolt, after loosening the fuel lines) and simply swiveling the carburetors outward on their threaded manifolds to more easily access the intake valve adjusters. That is, without having to remove the carbs as I've seen people do on later bikes (Lunmad does this on one of his DIY videos).
If that works, it will be a major benefit of the early-style threaded manifolds (see pic). Not that removing the carbs is a huge job, but just loosening that big locknut and tilting them outward would be much quicker--and this is a routine maintenance job I'll be doing regularly...
Attachments
I'm attaching a screenshot of a '73 service bulletin that I'm definitely going to follow before running through the usual carb-tuning procedure in the Amal manual.
I note that the inside of the L/H cylinder is sooty (not oily), as was the outlet of the corresponding muffler. These are brand new carbs bought by the PO or broker from whom I got the bike. But no reason not to pull the bowls and see if the float level is correct to avoid overly rich running.
This, especially at my daily operating altitude, which ranges from 5,000 ft. (city) to 6,000 ft. (home). I've set the needles in the middle groove to begin with, in lieu of any input from folks who may be running a Unit 650 at this altitude.
I note that the inside of the L/H cylinder is sooty (not oily), as was the outlet of the corresponding muffler. These are brand new carbs bought by the PO or broker from whom I got the bike. But no reason not to pull the bowls and see if the float level is correct to avoid overly rich running.
This, especially at my daily operating altitude, which ranges from 5,000 ft. (city) to 6,000 ft. (home). I've set the needles in the middle groove to begin with, in lieu of any input from folks who may be running a Unit 650 at this altitude.
Attachments
That Service Bulletin is out of date, it applies only to the hollow white plastic floats; however, they are affected by ethanol, they should have been replaced with current Amal solid black plastic "Stay Up" floats (with black Viton tipped aluminium needles).
Just setting the float height, top of a StayUp should be parallel with the top of the bowl, level or just above the top of the bowl. However, Amal recommends against just setting the float height, instead setting the fuel level - Optimising Amal Mark 1 Concentric Fuel Levels | AMAL Carburetters
Btw, just checking float heights, there is a better way than in that service bulletin - bowl with float, needle, pivot pin fitted, trap ends of pin in bowl with thumbs, turn the whole assembly upside down, gravity mimics what the fuel does to the float when the assembly is the right way up, observe float height relative to bowl.
Finally here, while StayUp float heights can be changed as in that Service Bulletin, StayUp height can also be changed simply by bending the tangs that fit around the the pivot pin; they might open up when bending, close again by squeezing carefully with pliers.
I agree with your sentiments on ethanol.
Excellent, thank you! I hope this thread, with all the tips people have provided, has helped others as much as it has helped me in getting familiar with these vintage Unit 650s.
BTW some of the mods I've chosen have made the bike even easier to work on. For instance, the DIY rear-sets have eliminate the need to R&R the L/H foot peg in order to service the clutch (a benefit of the stock-pattern exhaust, too, which doesn't have to be disturbed). Front brake linings are of course far simpler to inspect and replace with the disc setup.
The PO installed the Boyer Bransden pointless ignition, so I can't take credit for that. But I'm hoping the 3-phase alternator and rectifier, together with LED lighting, will keep the battery healthy longer--as well as improving visibility.
All in all, routine maintenance is going to be a breeze.
Your point about this thread helping others was 100% on the mark.
It's a "must read" for anyone else here who may be working on a similar restoration.
It's a "must read" for anyone else here who may be working on a similar restoration.
I wholeheartedly agree with Rocky.
Thank you, Sir.
I hope a corollary benefit is 'demystifying' these bikes for younger riders, who may feel intimidated by the prospect of owning a Meriden machine. We'll see, but my hope is to begin logging enough miles--and recording the more interesting rides--to put such would-be owners 'in the driver's seat' as it were, so they might feel confident enough to dive in.
BTW - I am perusing camping tents (one of REI's offerings looks like a good balance of cost to features) and about to start looking at tank bags. When combined with the soft tail trunk I've already got, that should provide me with enough stowage to start some backroads interstate jaunts. Per another thread, first is likely out to Ashland, Oregon to visit some longtime motorcycling friends.
If I'm just not satisfied with backroads touring on this bike (I hate the interstate, regardless of a bike's abilities) and decide to relegate it to rides within NM, I may be selling the '51 FL to buy a '70s or '80s airhead BMW. But we shall see...
If I'm just not satisfied with backroads touring on this bike (I hate the interstate, regardless of a bike's abilities) and decide to relegate it to rides within NM, I may be selling the '51 FL to buy a '70s or '80s airhead BMW. But we shall see...
I'm pretty much a teetotaler but won't turn my nose up at a good glass of red wine with supper...
Sounds just like meI'm pretty much a teetotaler but won't turn my nose up at a good glass of red wine with supper...
