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Discussion Starter #1
Hello Everyone!

Have been on this forum for a while ever since I picked up my Ace Thruxton back in 2015, lately though I've had the itch to do a complete frame up build, which I was able to kick off this past month!

Thought it might be time to start one of these threads for myself. After on and off searching I found a Featherbed frame in decent condition not too far from me (I'm in metro Detroit, frame was in Imlay city at Fastback_inc about 1.5 hours away). Frame was in decent condition (straight), but does have pitting and actually about 2-3 inch hole on the bottom of the right frame rail. It was spray painted so tough to get an actual idea of real condition until it gets blasted in the next few weeks. Plan will be to fully asses the damage then cut out the 'hole' section and MIG weld in an appropriate size dutchman style patch.

The same place also had a variety of triumph engines available, I found a 1966 T120R that was kindof complete, and in a state of half rebuild. After getting it home and starting the teardown found some interesting things inside...

The good - Pistons are new (60 over... which I didnt even know they did...), as well as freshly bored and honed cylinder. Crank sludge trap had been removed and cleaned, as well as the crank has had some level of balancing done to it.

The less then good - Quite a few parts are missing (read A LOT), I have been following along with the Hughie Hancock DVD for the tear down making a list of parts I need. Turns out I couldn't have picked a better area to move into as British Only (the massive used/new/NOS British parts supplier is about 5 miles away in Garden City. Am able to work on the bike on Wednesday night, put my parts order in Thursday morning, and pick them up on my way home Thursday evening, truly awesome, awesome place. Anyways, the parts missing list or damage beyond repair has been extensive (so far 142 PNs worth about a grand has been ordered). Most of the missing components were external to the engine internals (kickstart assembly, timing cover components, clutch components, etc). Additionally at some point the transmission sat with water in it and destroyed about half the transmission gears. The gears (as well as a couple other bigger items) I was able to source from a gentlemen I met at the Battle of the Brits show in Milford, MI. He happens to have a garage full of vintage parts and is selling at great deals. I wont post his information for his privacy, but if anyone is in need of parts in the metro Detroit area and would like to get in contact, send me a PM and I will facilitate).

Anyways Ill post a couple of photos to get things started, I am currently in the process of setting up my blasting cabinet so I can clean off the parts I have torn down, as well as sourcing the remaining engine parts. Plan is to start with the engine rebuild and hopefully complete over the next few months, while at the same time getting the frame back up to workable condition (as well as source a swing arm and front-end, though I'm not completely decided what front end I want to use). Either way good excuse to spend some time in the garage with a few cold ones. Ill try and update regularly, though life happens so stay tuned!

Thanks for checking out everyone!
 

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A lot to take in, for sure.

Cylinders should have a clean, visible crosshatch final hone, then measure .0045 larger than the pistons. If they already measure larger than that, you may have smoking issues. Maybe won't hurt a thing, maybe a neighborhood mosquito fogger.

That's a 65 or earlier transmission layshaft, with speedometer drive worm gear on the end.

I hate to think of how the frame got a 2" hole in it, but my guess is, it's adjacent to the kickstand lug.

What is the date cast in to the exhaust valve spring pocket on the head, and how many tick marks surrounding it inside the oval?

Love it that you got an extra pushrod!

I sell a swingarm spindle upgrade kit that replaces the infuriating metalastic bushes with sintered bronze units, replaces the 1/2" or 5/8" long bolt with an actual 3/4" high grade steel spindle with bolt-up tab, thrust washers, and o-rings to provide heavy oil lubrication.

Looks like a fun project; I don't want to stomp on it with photos of mine, but you're welcome to search for it in this same section.
 

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Discussion Starter #4
Dave - It was as I was getting ready to drill out the 'punch' mark when I notice it had already been done, spun off the cap and it was nice and clean inside!

GPZ - Pistons are measuring 72.33 mm, cylinders are measuring 72.40 so I do believe (rather hope) they are all set, and I can see the crosshatch from the hone, but it is faint.

Good catch on the layshaft, I hadn't even noticed, the list of inconsistency grows! And speaking of extra parts I actually ordered a new complement of push rods, cant tell from the photos but they all different sizes (length and diameter), and had slight bend on a couple, figured small cost to start fresh in the sense.

As for the frame hole, looks like the frame sat in/near water/dirt/earth at some point and just corroded through.

As for the date on the head, it does have a 66 with 6 ticks marks. (case number is DU29814)

And absolutely, Ill keep that in mind when I get to the swingarm. And I actually have spent quite a bit of time looking through your build and comments/tips on other builds, has already been a major help haha. Side note, where can I pick up a copy of your book?
 

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Discussion Starter #6
More Hidden Findings

Starting to truly understand the fun of picking up on what was somebody else's project. With the cases now split I have been checking everything over and getting ready to prep for media blasting (have heard good results with walnut shell media on the aluminum).

However I have found marks where the previous builder used a center punch (I'm guessing) to hold in the outer race of the left side main bearing (photo). Which tells me it is a new bearing which makes me happy, but leads to another concern...

On the cam gear side there are the same markings around one of the cam bushings... As I understand when the bushings are replaced they need to be line reamed. I don't want to assume anything, is there a check or spec for fitment to determine if line reaming is necessary or has been done?

And lastly on the opposing side one of the cam bushings has a visible groove, not sure what would cause this, but does seem odd.

As always thanks for any insight guys.
 

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Discussion Starter #7
Inner crankcase screw/thread issue

Had a couple big milestones recently, was able to get the cam bushings replaced (and sized), and get the cases back together!

well almost...

Have hit a brick wall with the 2 inner crankcase screws (photo below). Was putting the cases together and the last two screws to put in where these two. While they started threading fine, about 7 mm from fully seating the screws feel like they hit a wall. I am confident these are the correct screws (ordered directly from British Only), and I have tried to ensure the threads are clean (look good visually), they simply will just not get past a certain point (and its the same on both sides). I have tried comparing the threads, trying to see if the previous owner might have crossed with something similar (like an M7x1), but still is off.

Hoping to see if anyone has had any similar issues or has a recommendation. My only thought at this point is I will have to split the cases again and re-tap with the correct threads?

Thanks again in advanced guys
 

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I agree with Paul, Triumph found them unnecessary, so they deleted them after 70. Pull them out and put a probe in the holes to see how deep they are, if they are shallow for the bolt, do as Paul recommended. Remember that if they did happen to loosen, they can't go anywhere as the sleeve prevents them from dropping into the motor. I would recommend to anyone replacing them to use an allen bolt instead, much easier to use an allen wrench than a screwdriver at odd angles trying to get the torque correct.
 

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Discussion Starter #12
Progress Update

Hey Everyone!

Wanted to post a quick update on the engine progress. Has been a good few weeks (with some mixed in tough nights) but I have the gearbox inner and outer cover assembled as well as the timing side put together.

*Side question - the shift quadrant when installed with the springed plunger in the track is nearly impossible to shift, even with the use of a screw driver as in the Hughie Hancox DVD. He does it with relative ease, but I had to unscrew the plunger completely just to make sure there wasn't a bind somewhere else. Anyone care to chime in on if this is normal?

Couple things I learned; focus on cleaning internal threads!!! Thought I gave them good attention while blasting the cases but they have been the biggest pain thus far. I imagine this isnt an issue if you are doing the disassembly, but seeing as these parts where sitting there was corrosion and gunk in most threads. Had to resort to a few cleaning methods but turns out a gun cleaning kit (very thin and long wire brush - just watch out for stray bristles that fall off and stick in threads!) and dental picks.

Another quick note, keep and eye out for close ratio gears... I assumed the gears that I had in my pile of parts were original, well turns out a close ratio gear snuck in that I didn't notice and caused a few curse words when I couldn't get it to assemble correctly. Moral of the story trying to finish someone else's project (read: fix there errors) can be a major pain and ASSUME NOTHING ha.

Along that same line of possible incorrect parts I found tonight that my cover plate (behind the clutch basket) may be incorrect. I am unable to fit the seal into the ID, the cover ID is 30mm, while the seal OD is 35mm. I know its supposed to be a press fit but I'm fairly certain this isn't correct (and I know the seal is correct as I bought it new). Anyway I am going to head to British Only tomorrow and compare parts and get the correct plate.

Issues coming up to tackle, exhaust pipe adapter threads on the head are toast. I read around and apparently this is pretty common, so I am going to try for oversized adapters and see if I can get them to bite enough.

Couple photos below while I enjoy this glass of Papa's Pilar, Cheers Everyone!
 

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Discussion Starter #13
Hey Everyone, quick Sunday morning update with a (mostly) finished engine!!!

Wrapped up the engine the past few weeks (still couple items to revisit, like a stripped center bolt, need a few more beers before I can swallow the $90 helicoil kit for these 26TPI threads). But anyways have started to move on to other sub-assemblies, have most of the fork parts. Only change from the original forks is using commando sliders so I can run a single disk brake set-up. Tried finding a used fork set to salvage on ebay, but after comparing costs and usability of components, decided to essentially start from scratch and build from the ground up. At least I know I have the right parts this way!

Next big item to tackle is getting the engine to frame to mock-up some mounting plates, but first I need to restore the frame, which brings me to my big question. What would be the best way to repair the pitted holes in the frame (photo below). My current thought is to use steel pipe of the same OD, cut out a 180 degree section of the affected area (the top half of the tube is fine) and MIG weld in a matching patch. But before I start making cuts into the frame wanted to ask for everyone's opinions.

Thanks as always!!!
 

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That corroded frame is VERY worrisome. You need to strip it and test it every inch or so for a nice "ting" sound when tapped with a small spanner. Adjacent to that rust-thru, you are sure to get more of a "thunk" sound.

It will need to be addressed for structural integrity. I'd replace the damaged section entirely, rather than patching over it.
 

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... but first I need to restore the frame, which brings me to my big question. What would be the best way to repair the pitted holes in the frame (photo below)....
That corroded frame is VERY worrisome. You need to strip it and test it every inch or so for a nice "ting" sound when tapped with a small spanner. Adjacent to that rust-thru, you are sure to get more of a "thunk" sound.

It will need to be addressed for structural integrity. I'd replace the damaged section entirely, rather than patching over it.
I agree, I would definitely not patch up the frame. I would call Brit bike shops to see if anyone has a damaged featherbed frame that you can buy. Then you can cut out the complete lower section of the frame and partly up the vertical tubes. Replace it with the section from the damaged frame. You should not rely on butt welds alone. Insert tubing inside the frame tubes in the weld areas. Drill and plug weld the tubes, as well as butt welding the splice.

If you don't find a damaged frame, you may need to locate a good fabricator that can bend tubing and make new lower frame tubes.
 

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Discussion Starter #16
Frame and Fork Progress!

Hey Folks!

First a stupid question I have searched around and haven't found a definitive answer for. The atlas rear wheel drive sprocket and the T120 engine final drive sprocket are not the same size (width). I have heard people said it is not and issue and run them together, I have hear people grinding down one to match the other, and I have heard people replacing one sprocket to match the other... does anyone have any input on this??? Feel dumb for getting this hung up on a sprocket question ha.

On to the frame, using the forums advice I had the frame blasted to review and check for pitting. There are definitely concern spots, but I thought I would try and tackle the biggest issue first (where it was completely rusted through). I cut out the effected area and after many many many hours on the pipe bender and grinder made a suitable patch, sprayed the inside of the frame with a rust neutralizer and got to welding. I'm fairly happy with how it came out. I still have other areas to look at, though the pitting is fairly concentrated in a couple areas (all on bottom of lower tubes) so I think I should be ok. As a reinforcement I had the idea if I still feel I need to add strength could either do what was suggested and replace the bottom section entirely, or weld in a third tube between the two existing and brace them in, just thinking out loud.

As for a glamour shot, I was able to wrap up the front forks with the latest delivery from AN. After rebuilding my Thruxton shocks with a full Ohlins cartridge kit, I couldnt believe the simplicity of these roadholders, truly beautiful. The forks are primarily made of new stock components, but I was able to get a set of original commando sliders for a disk and polish them up decently.


CHEERS!!
:beerchug
 

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The last pic in the previous post actually is the welded area, it was after sanding the area to be flush. I can take some more photos when I get back stateside (currently in Korea for work).
 

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Had to make out but your crank seal, primary side appears to be the wrong way round. The garter spring should face outwards.

Rod
 

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Hey Fellas!

It has been a very busy few months (sadly was getting so wrapped up in the build forgot to post some photos!). Since the last update I have fabricated a set of engine mounts, fabricated the exhaust, mounted the oil tank, got the basic layout for the rearset controls, set up a sub-frame to mount the battery and tail light. Picked up a tank from Tab Classics in the UK as well as a seat pan from legendary cycles in Florida! (its been a very expensive couple of months haha)

Have been trying to up the pace of the build such that it is finished in time to show the bike at the annual Battle of the Brits show in September in Milford MI. Next big steps are getting the hubs/wheels/tires set-up. Getting the front end mounted, getting the mess of electrical sorted out, and finalizing the rear end suspension!
 

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