Basket case? Runner? Non-runner?

[BigJimmyW13]

Any pics of any general ideas? Of what you're going for?

 

[bobber bill]

spent the better part of my day at the local dmv registering the bike into the modern VIN system. paid $181 in fees and my next stop is the highway patrol in 2 wks to get the bike inspected before registration is complete.

ordered a TC bros hardtail and engine stand. also ordered sump and oil filters from mikesxs, as well as a starter block off. ill be ordering a lot more parts very soon.

as far as the look i have in mind, it will have a cookie cutter bobber start with a sporty tank and minimal rear fender but no front fender. definitely low bars, either drags or clip ons. i plan on hiding the electrics in a dummy oil bag etc... the details will make the difference with this project for sure.

performance and reliability are very important to me so i will address those as the build progresses.

 

[cooltouch]

One thing to keep in mind: the motor on the '72 is the 256 "long rod" motor, and there are not very many performance parts available for it. Check the s/n of your spare motor against the listings that are around the net -- I think MikesXS has a chart. If that motor is the later 447, then that's the one you want to use for performance mods. Probably why the PO had a spare motor, or at least you can hope.

 

[inxs]

- the european 533 rods @ 140mm are 4mm longer than the 256

 

[bobber bill]

One thing to keep in mind: the motor on the '72 is the 256 "long rod" motor, and there are not very many performance parts available for it. Check the s/n of your spare motor against the listings that are around the net -- I think MikesXS has a chart. If that motor is the later 447, then that's the one you want to use for performance mods. Probably why the PO had a spare motor, or at least you can hope.

so i just checked my serials and it looks like ive got a 72 and a 78 motor. the 72 cylinder has a couple of cracked fins so i was hoping to swap with the 78. is this possible? gawd i hope so haha

 

[cooltouch]

so i just checked my serials and it looks like ive got a 72 and a 78 motor. the 72 cylinder has a couple of cracked fins so i was hoping to swap with the 78. is this possible? gawd i hope so haha

You mean cylinders or motors? If cylinders, why? If motors, you bet.

I'm assuming you mean swapping motors, but if you don't, then the problem is that the cylinders have to be within pretty tight tolerances to match the pistons. And the 72's pistons are different from the 78's. I'd be surprised if the 78's bores were within spec for the 72's pistons.

As I mentioned previously, it sounded to me like the previous owner was aware of the limitations of the 72 motor and picked up the 78 to have more options. That's what I'd do. If you plan on doing any performance enhancements to your bike's motor, you'll be much better off doing them to the 78.

 

[pumps]

Seems like to me that parts for a 78 motor are in general easier to get.

 

[bobber bill]

bummer. i was hoping to keep the 72 motor so that id have matching numbers with the frame. oh well

 

[cooltouch]

There's no reason not to keep the 72 motor, unless you're in desperate need of the funds that you can get from selling it. That way, if you ever sell the bike, you've got a motor with matching numbers to include in the sale, which will enhance its value somewhat.

 

[XSLeo]

One option is to use the crank with rods from the 78 in the 72 engine.
Bore the 72 jugs to the next oversize, fit 477 pistons.
Press the sprocket off the 72 cam, press the sprocket off the 78 cam, press the 78 sprocket on the 72 cam.
The 72 cam has a different profile than the later cams. A bit more power overall. The head is ported different, again a bit more power.
Converting the internals to the later 477 parts will make future repairs easier.
It will also allow you to keep matching numbers.