Long term Triumph Chopper project

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Prof
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Re: Long term Triumph Chopper project

Post by Prof » Tue Aug 07, 2018 11:19 am

Just looking back at your original photo of the frame on the table.

Frame is level. Girder touches the table top. Distance of rear axle plates to table top (less distance of girder axle hole from table top) is basically the amount you will need to raise the steering head if you keep the same rake and use a 19" front wheel with a 3.25 tyre on it... Less about an inch of sag in the girder you will get with the weight of the bike on it.
Chopit'nrideit... Prof

TriNortchopz
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Re: Long term Triumph Chopper project

Post by TriNortchopz » Wed Aug 08, 2018 2:49 pm

This Thread: P&P girder from a month ago on Chop Cult may be of interest; the original poster needed a new shock as the original by P&P was rusted beyond repair, and interestingly, the spring was interfering with the upper cross link spacer. Measurement information is posted, with options for replacement shocks.
http://www.chopcult.com/forum/showthread.php?t=51863

El Skitzo
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Re: Long term Triumph Chopper project

Post by El Skitzo » Thu Aug 09, 2018 9:56 am

Wow some brilliant information there TriNortcopz! I'll keep that handy when it comes time to go through the front end.

Thank you!
65 Triumph Chopper (project)

El Skitzo
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Re: Long term Triumph Chopper project

Post by El Skitzo » Fri Aug 31, 2018 12:15 pm

We have some progress!

Tom Sharman at Sideshow Cycles is transforming my pile of parts into a roller at the moment, and it's looking real slick so far.

We can see a fair few repairs the front loop will need going forward, but some of those issues might disappear if we get the go ahead to chop and stretch the frame. The girder front end needs a complete rebuild as the studs and bushes are pretty flogged out, so that's next on the list.

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65 Triumph Chopper (project)

TriNortchopz
Posts: 55
Joined: Sat Feb 24, 2018 5:41 pm
Location: Haines Junction,Yukon, Canada
Interests: Choppers, nature, learning more about choppers

Re: Long term Triumph Chopper project

Post by TriNortchopz » Fri Aug 31, 2018 11:19 pm

Progress is good. Those rear engine mount/footpeg mount plates are nice.
Have you determined what the stretch and rake will be for the frame chop?
Took a visit to Sideshow Cycles facebook page and saw your machine in an Aug. 21 post"
https://www.facebook.com/Sideshow-Cycle ... 953986494/
and added your CA build link and another comment.

El Skitzo
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Re: Long term Triumph Chopper project

Post by El Skitzo » Mon Sep 03, 2018 10:33 am

No we haven't thought about the rake and stretch required for this front end yet. We'll get it sitting on the ground and rolling first, then we'll be able to take 100% accurate measurements of what we have, and then determine what we think we need to do. Then I can start to talking to an Engineer...
65 Triumph Chopper (project)

El Skitzo
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Re: Long term Triumph Chopper project

Post by El Skitzo » Thu Sep 06, 2018 10:08 am

Well the first little snag has been found.

Tom was aligning the rear wheel in the frame yesterday and making up the spacers, and had it to the point where he was happy. He then gave the rear wheel a bit of a spin and the wheel was tracking true, but the drum brake wasn't and appeared to be wobbling around like it was warped or something, which would be weird given it's cast.

So he pulled the rear drum assembly apart and found the problem. A dodgy spacing job by someone in the past to space the drum out further from the hub, probably to help the chain clear a wider tire, they've used 3 washers per wheel stud. Obviously garden variety washers are not very precise in thickness, hence why the drum was not spinning true like the rest of the wheel.

Unfortunately this assembly was in place when I had the rim re-spoked and offset, so if we remove this spacing the chain may not clear the tyre any more. We could pull the tyre off the rim and have the rim offset adjusted again, or what we're probably going to do is replace the washers with a custom CNC made spacer plate to keep the drum where it was in relation to the hub, but be perfectly precise and aligned.

This is my fault really. Having received an old rear wheel which I was told was rebuilt, I should not have believed the seller and stripped it down myself to check everything before proceeding with any further work with it. Lesson learned for future!

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65 Triumph Chopper (project)

Prof
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Re: Long term Triumph Chopper project

Post by Prof » Thu Sep 06, 2018 1:09 pm

Two things one learns early on; Bolt on ain't bolt on, and if the bike/parts are second hand they have been messed with! Like you I have learnt the hard way and a couple of times had to redo jobs on customer's bike at my own expense. Sure pays to triple check everything.
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El Skitzo
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Re: Long term Triumph Chopper project

Post by El Skitzo » Tue Sep 11, 2018 10:09 am

Well while the rear wheel issues are being sorted out, Tom is pushing ahead with rebuilding the girder front end with plans for improving the fork pivoting assembly.

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65 Triumph Chopper (project)

TriNortchopz
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Re: Long term Triumph Chopper project

Post by TriNortchopz » Tue Sep 11, 2018 11:23 pm

The shouldered bushings will be a big improvement over the straight bushing with flat bronze bushings on each side.
It looks like the plan is to lock the shafts in one side of the leg (9/16" thread) by threading the holes, while the rest of the shaft is still 1/2". Then using 1/4" setscrews to lock the triple tree shafts it in place - any reason why you want to lock all the shafts in place?

Have you considered just using 9/16" shafts? You can still thread and lock it in the one side(not sure why), then just bore out the long spacers to fit the shaft, the ends of the linkage arms, change the lower shock bushing, and use larger diameter bushings. This will also provide the chance of boring out the holes on each leg at the same time, in a milling machine, with an axle bolt in place, to ensure all of the holes are in perfect alignment at each location - that may be worth considering before threading the holes on one side - confirming alignment of all holes.

This is also the time to consider the width of the girder, as it can be made wider or narrower by cutting the spacers shorter, or adding spacers to make it wider. Do you know the width of your wheel, and will you be running a drum, singe or dual disc brakes?
You can also consider boring the axle hole from original 5/8" to 3/4", which is more common with new springers and girders, and stronger.

Also, when you make the neck post , measure the neck of the bike with bearings installed,to ensure the neck post is the right length, so that the distance between the upper and lower shafts on the legs are the same distance apart as the ones on the 'triple trees' when mounted - parallel pivot arms will help prevent binding and wear.

As you know, I have the same girder, so curious what your plan is, as I have been planning a rebuild for some time, which included larger diameter shafts to increase the strength.

Prof
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Re: Long term Triumph Chopper project

Post by Prof » Wed Sep 12, 2018 9:31 pm

Girders on British factory bikes in the 30's and 40's had arms on both sides fixed to the shafts by serrations so they were locked together, making both sides of the girder a solid unit.
Chopit'nrideit... Prof

TriNortchopz
Posts: 55
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Re: Long term Triumph Chopper project

Post by TriNortchopz » Wed Sep 12, 2018 11:07 pm

Thanks, I see the Webb design here with just one side threaded:
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"As you can see the right link has the spindle threaded into it while the left one is plain and locks up against a shoulder on the spindle, adjustment is by threading the spindle further into or out off the right link."

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http://drewgrant.info/blog/?p=476

El Skitzo
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Re: Long term Triumph Chopper project

Post by El Skitzo » Thu Sep 13, 2018 9:40 am

Yeah Tom's thinking to improve the design by locking the spindles so only the bush area moves and wears, which as Prof has said is how it was done on old British bikes and old Indians. At the moment the P&P is a very crude design, and by having the spindles able to move, you could eventually wear out the spindle holes in the legs and the triple trees, which would be far more difficult to repair in future than the smaller easily replaced parts like pivots arms, spacers and bushes.
65 Triumph Chopper (project)

TriNortchopz
Posts: 55
Joined: Sat Feb 24, 2018 5:41 pm
Location: Haines Junction,Yukon, Canada
Interests: Choppers, nature, learning more about choppers

Re: Long term Triumph Chopper project

Post by TriNortchopz » Thu Sep 13, 2018 10:51 pm

Good stuff, I like it. Using an older design to update something that's not as old! Instead of threading the hole in the leg, I guess the shaft could also be locked on one side by having a lock nut on the inside of the arm and a cap nut on the outside and locking them together...if the section of the shaft that went through the leg was not threaded.

El Skitzo
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Joined: Wed Sep 30, 2009 6:40 pm
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Re: Long term Triumph Chopper project

Post by El Skitzo » Tue Oct 02, 2018 9:46 am

This week I've had a bit of a win and a bit of a kick in the face with wheels.

I've been lucky enough to have a front wheel donated to the project for FREE, with a friend giving me a narrow glide Sportster front wheel to try out. Yes is needs new bearings, disk, spokes and outer rim, and the hub could do with a polish, but that's all easily done and what you'd expect of an old wheel. The overall width of the hub is just 4.5" so should definitely fit in the narrow girder front end. Whether that leaves any space for a disk brake bracket to slide in on the front axle as well we don't know yet. Perhaps calliper mounts would have to be welded directly to one of the girder legs. At least we have something to play around with now and see if a disk brake is an option.

The bad news is after finding the rear drum had been spaced off the hub with washers and most likely causing the drum/sprocket to appear to wobble when the wheel was spinning, on closer inspection that wasn't the cause and the drum probably isn't warped either. It turns out the mounting surface of the hub itself is not completely flat/square. So I'm going to need to talk to a machinist to see about skimming the hub face down flat, or making a thin spacer that can be machine to flatten it all out. The big question is, can this be done with the wheel complete like it is, or will we have to strip the rim and spokes off the hub to get it into a lathe...

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65 Triumph Chopper (project)

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