71 OIF Build

[skankr1]

So the frame is square. Neck to axle plates, lower motor mounts crossed to axle plates, basically any points you choose to measure off of are square. The rear wheel and original spacer have the rear wheel perfectly aligned with the front wheel and backbone. It appears that the rear sprocket will end up about 1/4" to the right from the trans sprocket. Has anyone ran into this, and does anyone see an issue with correcting by spacing the engine further to the right? I'm not worried about foot peg clearance issues since I haven't fabbed the new rear plates yet.

[farmall]

A quarter inch offset right won't hurt handling so if ya want to offset the engine as the easiest way, go for it. That's the beauty of chopping!

Easy way to check alignment is with a laser level. My professional machinist bros use Craftsmen levels for setup and they are surprisingly close to their expensive Starrett machinist levels they use to level machine tools.

[Dougtheinternetannoyance123]

Something does not sound right to be that far off. While not unheard of to offset a motor you should NOT have to in this case. Typically when hard tailing a stock frame like you did, You ID where you want the rear wheel to end up relative to the motor and frame. So, you set the jig up like you did. Then set a fixture up on the back end so your rear wheel ends up in the correct location. Then you build the hardtail to line up with everything. While everything is locked down IN the fixture everything stays put.
Does that make sense?
SOME people will hard tail a stock frame by leaving the swing arm in place and locking it in to the fixture on the back end, and cut away the frame rails, then tack in parts of the hard tail so you end up wth your axle plates in the EXACT same spot as the swing arm.
Clearly if doing a stretch or drop that needs to be adjusted accordingly.

Some stock British frames,, you can take 10 of them and line them up and each will vary by a little or sometimes a lot. But you can see how their jigs worked as certain key components all are in the same spot. Featherbed frame Nortons are a prime example. This is the same in many types of fab. In aerospace we welded in tooling points so certain things might be out, But we had consistent references where it counted.

If you like Ill post pix tomorrow of mine. I started mocking up a OIF Bobber for a local guy but appears he changed directions and building something else.I am going to finish the mock up and put it up for sale...

[skankr1]

Here's an update. Chain alignment turned out to be a non issue. I used the smaller engine mount spacers on the left side. I'm not sure if this was how it was mounted from the factory, but it works in this build. I will verify crank, tranny and rear axle alignment later. Next task is to finish rear engine mounts/peg mounts and chain tensioner. They are just kinda mocked up in the pics. I still need to fab the seat mount, fender mounts, battery box, plate bracket and exhaust. I'm probably going to fab some bars also. I'm thinking narrow Pangea Zephyr-ish? If anyone has something along these lines that they want to let go of on the cheap, let me know. They need to mount to a sporty triple tree. Anyway here's some pics...

[skankr1]

[skankr1]

[skankr1]

[skankr1]

It's been a little while. Had some computer issues. The bike is mocked up and tore down for frame paint. I'll post some pics.

[skankr1]

[skankr1]

[tubtub]

A 71-72 bike has a leafspring transmission. Some good some bad. The leafspring setup was a bsa carryover for those two years. And went back to plunger in 73 after sloppy shifts and prone to falling out of gear. Now would be the perfect time to do the leafspring to plunger conversion if needed since motor can still come out fairly easy. You can rent a fixture made for perfect hole drill and alignment. I have a thread on here somewhere explaining it.

[skankr1]

After spending over 20 years in boxes, she finally breathes again. I will post some finished pics soon.

https://youtu.be/w0NnMXEjzQE

[dukerollo]

Congratulations getting it going.

What bearings/stem did you use to mount the sporty front end on the bike? Thanks.

[TriNortchopz]

After spending over 20 years in boxes, she finally breathes again. I will post some finished pics soon.

https://youtu.be/w0NnMXEjzQE

So good, well done on getting it out of the basket and onto the road! Nice job.

[skankr1]

Congratulations getting it going.

What bearings/stem did you use to mount the sporty front end on the bike? Thanks.

The largest center bore from Timkin I could find to fit the triumph neck cup was 7/8". I pressed the sporty stem out of the lower tree and turned it down to fit the new bearings.

[swamptrash]

hey quick question, im in the process of doing the same build on an oif and was just wondering how you went about the sporty front end?
i know the neck bearings are smaller than the sportster steam, did you machine the hd stem down to make fit to the oif neck bearings?

[TriNortchopz]

hey quick question, im in the process of doing the same build on an oif and was just wondering how you went about the sporty front end?
i know the neck bearings are smaller than the sportster steam, did you machine the hd stem down to make fit to the oif neck bearings?

yup, that's what he said...

...I pressed the sporty stem out of the lower tree and turned it down to fit the new bearings.

[swamptrash]

Perfect, that’s what I was thinking of doing to make it easier on my self, and you just went back with oem bearings?