which frame?

[Rasputin]

Which frame will transfer easiest from a 79SF? I have a few frames here that Rooster would like to swap with and his is a 79SF. I have a 78E, an 80G and a 80SG. He is going for the look of the standard. To the best of my knowledge he has a seat and tank from a standard. We have a standard exhaust to fit to the bike as well. I also have the things like footpeg mounts etc to make the swap possible. Any ideas from wiring harness to fitment of parts are very welcome. Thanks guys.

[crazy steve]

Well, to fit the standard exhaust, you need a standard frame, so the '78E and '80G are the best choices there. After that, it gets complicated...

It will depend on what combination of parts he's planning on using. If he's trying to use as many bits off the '79 Special as possible (like sidecovers and seat), the '80G frame will be the best choice as most of those parts will 'cross over' with relatively little work. Wiring harnesses are all more-or-less the same in terms of function (the special harnesses will lack the front running light circuit), but only '78-79 standard harnesses will directly interchange and there's significant differences between '78-79 and '80-81 harnesses (mostly the handlebar controls), enough that a no-mod swap isn't possible.

The other thing to pin down is which 'standard' seat is he planning to use? If it's '78-79 type, you'll need the matching standard harness and rear fender. If it's a '80-81 type, then you can use either the '79 Special harness or the '80 standard harness, depending on which year handlebar controls you use.

If you can tell me more specifically which parts he'd like to salvage off the SF and the 'other' parts he'd like to use, I could give a clearer answer...

[Rasputin]

I guess "Rooster" will have to answer that but he is on the road tonight. I was just wondering which would do the best. There is apparently more options than we have so far thought about. Thanks

[crazy steve]

There's all kinds of weird little differences between the models; some parts will interchange, some won't, and some will but you need all of the assembly to do it...

A lot of it will be determined by what he wants to use and if you have the 'right' combo...

[Schming]

Jat...

...don't forget about the differences in the Standards & Specials forks

[oldnortonrider]

...don't forget about the differences in the Standards & Specials forks

The triple-t's are different also; different lengths or angle(s) or both; had thought in the past about the idea of using Standard triple-t(s) in place of my Special triple-t(s) on my Special, keeping the Special forks. I'm thinking~~would stretch out the wheelbase some; stretch out the trail a bit. Lot of work~~bit of a gamble as to how the geometry change would "be better, or not so better". Fork neck angle is the same; Specials and Standards~~I'm fair sure.............

[crazy steve]

...Fork neck angle is the same; Specials and Standards~~I'm fair sure.............

All the XS frames are very nearly identical; their suspension geometry certainly is. The only reason they're not all interchangable is mother Yamaha changed enough brackets on the various models so that bits that attach to the frame won't interchange...

As far as using standard trees with Special forks, only do that if you're running a sidecar or trike. It will reduce steering effort on those, but the trail number gets too low for high-speed stability if running on only two wheels...

[Rooster]

1979 special with an 80' engine

So the plan is if there ever was one was to make a bike that wasn't what it was bought as. I have 1979 special that came with a seat from likely a 78' standard, it needed an alternator and a right side cover I made from aluminum, replaced the fuse block with fuses not mounted to a block, and have been attempting to get the look I've wanted from an XS of my own. I changed the tank to one from a standard I got from rasputin and I had the bar from a 2001 V-max on it up til recently. Now I have a digital guage set on it and a longer set of bars and bar end mirrors. Also Mikes XS green coils and another ignition box that doesn't look as rough as the one in my bike. I installed short signal markers and am in the process of installing an HID kit as well.

I have to cut off the seat bolt tabs and remount them lower to get the standard seat level on the special frame, and there are the issues of trying to get that under seat exhaust put in. I am going to try to utilize a young mechanic that has access to a computerized exhaust bender to try to match up to a couple of 2 into 1 headers rasputin may be willing to deal on.

[crazy steve]

....I have to cut off the seat bolt tabs and remount them lower to get the standard seat level on the special frame...

The seat mount tabs are in the same place on all the XS frames; if the '78-79 standard seat won't 'fit' down, it's because it's hitting on the ignition box. All models EXCEPT the '78-79 standards mounted the TCI on the plastic inner fender and had a recess in the seat pan to clear the box. You have two choices; cut that recess into the seat pan, or use a '78-79 standard wiring harness, frame, and rear fender to relocate the TCI to the rear fender under the seat tailcone. If you're willing to weld the standard rear fender mount to the Special frame, you don't need the standard frame.

If you have a '80-81 standard seat, then you need to swap to the matching-year standard inner fender for TCI clearance...

[Rooster]

frame

Well I think the seat is older because of the skinny chrome grab rail at the back, but I've been wrong on this bike many times before. Welding is not a problem as I have a skilled welder or 10 at my disposal and some of them like projects like this to get out of the daily monotony of work. I would however like to grab at least the 1980 standard frame as maybe I should build another bike out of it from the different idea's that are out there. I will move the ignition box tonight and see if it helps.