Boxerworks.com

my bike is a 1977 75/7 and i found a 1975 r90/6 frame will it go together as a direct fit ?

Yes.
But as I have not swapped these 2 specific frames –
I will add the caution that some minor bits & brackets may vary.

The 1977 /7 frame introduced these changes:
A double-wall backbone
An additional transverse frame member at the front down-tubes
Additional gusseting around the steering head.
... the '75 frame will not have these improvements.
ie, the '77 is a more robust frame.

"The various frame tubes' placement and external dimensions are as before;
the tubes do have thicker walls, and thus greater rigidity,
and though you can't see this difference the change in feel is unmistakable."
~ Cycle Magazine Road Test Reprint - May 1977

THANKS ..Vanzen... i found the correct frame now for 400 bones and shipping ..or a torn apart R90/6 title there and sitting outside under a half a shed for 15 years missing a few parts but mortor has 15,000 miles on it motor did run - was told for 550 bones .motor is in the frame .
So now i need to make a choice here.........

How old is your motor????

The bike is all ORG. and a 1977 75/7 so the motor is 54,000 miles with no oil leaks ,runs fine with a dyna ing.

so cal charlie wrote:The bike is all ORG. and a 1977 75/7 so the motor is 54,000 miles with no oil leaks ,runs fine with a dyna ing.

And I'd bet it would run just as fine with points, too ...
How's the valve guides and exhaust valves doin' ?
Done a compression or leak-down ?

NO leak down test here the possible doner bike i might grab.

"SO CAL. WE RIDE ALL YEAR LONG"

I do that in the Motor City Mi, too –
Only we got Mutha Nature to cull the poseurs, don't you know.

Parts is parts, if the price is right - jump on it !

I would always want to consider the issue of registration. I've heard that it has become harder to register bikes that are not in the system. I have a couple frames that have fallen out of the system by not having been registered for more than five or six years. That's got me worried that I won't be able to register them after I put a whole bike together on them.

When I replaced the frame on my R90S after it had been "totaled" by the insurance company after having been hit in the rear, they required paperwork with frame numbers for all parts that were replaced. In other words, "where did that rear fender come from?" The folder I gave the CHP officer was a good half inch thick.

so cal charlie, where do you live? I'm in Vista, Ca.

Chuey

I assembled my /6 Hot Rod from several bikes, all of which were out of the Cali system.

To get a title, I took the frame to the CHP Inspection station, explained that: "I want to build a bike using my components, on an old frame that I found in a barn. Heres the frame. can you check the numbers for me real quick?" The officer checked the numbers, confirming that they were out of the system.

Later, when the bike was together, I took it back for another scheduled inspection and they gave me the paperwork to get a new title.

It's not that big a deal! Just be careful.