78 XS750 chop first bike build

[Rjcinelli]

Carry on...Good luck with your build.
Don't forget to research and plan.

Don't forget to research and plan.[/QUOTE]

I put a bid in on eBay for a 750 neck with paperwork, if I win it I will be doing what you suggested, thanks for that tip!

[Rjcinelli]

Okay so I won the bid on the neck & title, so now I should have no issues getting the bike registered in MA, and can use the method that TriNortchopz recommended to fit my Harley frontend. I also just ordered some foot pegs, 5/8" steel rod for the sissy bar, LED blinkers (trying to look somewhat legal since I'm not running a front brake), bungs to mount tank and seat pan, foam for the seat pan, a front tire, and a few other things I'm already forgetting.

Forgot my buddy has a ton of leather from when we did upholstery so I'll be wrapping the seat pan in that, hopefully I should have the neck Saturday or so. I sandblasted my engine covers, now I'm working on getting rid of all the sand... Any good recommendations?

[Rjcinelli]

[Rjcinelli]

Could somebody help me out here, probably a dumb question but I can't figure this out. I got my neck in the mail, stock xs750 upper bearing and race fit on my Harley stem. The stem is larger diameter at the top (see attached picture) so how do I get a 7/8" bearing down over the stem when it's 1" diameter at the top? Am I missing something? bearing on bottom of stem in picture is a 1" bearing, which is too loose on the long portion of stem, fits snug on the larger part up top*

[TriNortchopz]

That is an excellent question, because you asked...I believe you have a piece of collectable history there - from the photo I recognize the bottom tree, the conical (barrel-shaped) spring and the rectangular linkage - I believe you have a Durfee girder - not Harley specific - I have a Durfee girder on my rigid Triumph.

There is a set screw I see that holds the neck post into the bottom of the tree. On top of that is a spacer someone made - probably to set the distance between the upper and lower pivot points on the trees the same distance apart as the pivot points on the legs - which is the ideal setup.
Durfee also had the pivot rod on the bottom tree a one-piece rod, which went through the bottom of the neckpost,so it may need to be lubricated and pressed out to remove the neck - depending on what the previous owner did, there may also be a nut on the bottom holding the neck post into the lower tree. Those top threads don't look great, but might be saved with a thread file of the proper pitch...depending if it will fit your frame...

It is time to get a good measuring tool, like a dial caliper,vernier caliper or a digital caliper - to measure what you have to determine what you need - may need to machine a new neck depending on the distance between the tapered bearing cones in your 750 neck, and measure the bores of the upper and lower trees, they need to be perfectly round - top one is often out of round due to assembler having threaded portion through the top tree - the Durfee top nut and crown nut was not designed like a typical springer top and crown nut(think Jammer - see spigot on nut in Yamaha springer pic above) - Durfee did not machine a step into those nuts, so a precise size-on-size fit of the neck post needs to assured into both the top and bottom tree.

[TriNortchopz]

Look on the bottom of that lower tree for a 5 digit serial number - I can tell you what year and month it was made. Post more photos of it. Measure the leg from the center of the axle hole to the center of the top pivot hole on the top of the leg - stock length is 24".
Here is my +12 square Durfee girder:

Girders are one of the finest handling front ends and the Durfee is one of the strongest.
Read this from the Durfee site:
It all started back in 1968 when Earl Durfee picked up an old Indian Scout Girder and knew he could do better. You see the better part was easy for Earl because of two big factors.

(1.) By 1968 the popular girder design which was used by Indian Motorcycle Company and was the preferred front suspension design used by the majority of the European motorcycle makers had seen a lot of bad roads (or in some cases, no roads and even bomb craters, motorcycles were used extensively in both WW-1 & 2) and many, many years of hard use. Earl saw that “Road” and “Stress” tests on these old girders pointed out the strengths and weaknesses of the designs. (2.) Earl had spent the last 15 years working in the R&D labs for two well known aircraft and defense contractors, building by hand, the prototypes for the Polaris and Minute-Man missiles. The Metallurgy and welding processes fields in which he had studied, worked-in and knew, had supplied him with the knowledge and tools to bring the girder design up-to-date. Some of the old girders had flaws from the limits of materials and processes available in the 1920’s, 30’s, and 40’s, but by 1968 things had changed and we where in the middle of the “space race”, with all the knowledge and new materials that brought.

But even with the flaws, the good, far outweighed the bad because there are so many great things about girders, some ahead of their time, which convinced him that this was the way to go if you were after a good looking, incredibly strong, light weight and smooth riding motorcycle suspension...
See the rest of the story here:

http://durfeegirder.com/about.html

See more on Chop Cult here; Thread: Picture Thread: Girder Front Ends

http://www.chopcult.com/forum/showthread.php?t=27119

[Rjcinelli]

Thanks for the info TriNortchopz! I believe somebody a few years back told me that girder was a Durfee, I will take some pictures when I get to my buddy's place. As for now, yesterday I got my sleeve fixed up at the machinist and he sent me on my way, 30 mins that's it. Worked on getting the front entrance mounted today, rough idea of what the trail numbers would be and see what I need to do. Back to work today hopefully get some more work done on the frame. that's my buddy Dave who's doing the welding for me.

[Rjcinelli]

Got some more work done, doesn't look like much but it seemed like it's moving along now. Ended up welding the new (clean titled) neck on, had to rake it a bit to get a better trail number. Right now with the current setup I have 6" for trail. From what I read that's about the most you'd want to be at for "safe riding"? Anybody feel free to chime in and tell me otherwise, any info about that is appreciated.

[Rjcinelli]

Go a little more work done yesterday after class, up next I need to put the motor in the frame and make sure it fits before it really gets welded.

[datadavid]

This is just going to be awesome��

[TriNortchopz]

Got some more work done, doesn't look like much but it seemed like it's moving along now. Ended up welding the new (clean titled) neck on, had to rake it a bit to get a better trail number. Right now with the current setup I have 6" for trail. From what I read that's about the most you'd want to be at for "safe riding"? Anybody feel free to chime in and tell me otherwise, any info about that is appreciated. [ATTACH=CONFIG]83483[/ATTACH]
[ATTACH=CONFIG]83484[/ATTACH]

Great to hear that the other neck ya got worked out - which includes title!
Now that you posted a few more pics, gonna say that is not a Durfee - curve of legs at the bottom and the lower pivot points on the lower tree do not go through the neck post at the bottom.
How are you ensuring alignment?

[Rjcinelli]

Great to hear that the other neck ya got worked out - which includes title!
Now that you posted a few more pics, gonna say that is not a Durfee - curve of legs at the bottom and the lower pivot points on the lower tree do not go through the neck post at the bottom.
How are you ensuring alignment?

Yeah I'm real glad I got the neck and title, a lot less stress now that I know I can register the bike no problem. Hmm I wonder what the girder is if not a Durfee. I set up a home made jig using some square tube and angle iron, it wasn't the prettiest setup but it seemed to have gotten the job done. Didn't take any pictures of that as I was too focused on working on the bike at that point.

I checked the fitment for the motor last night and she will fit right into the frame with oil filter housing removed and then installed before actually bolting the motor in.

[Rjcinelli]

This is just going to be awesome��

Thanks man, a little bit of a slow down on progress since I'm low on cash, but working all day Saturday should help with that. Need to pick up some more 1/8" metal for gussets, and sheet metal for the seat pan. Still not sure what I'm doing about rear fender, maybe a trailer fender from tractor supply that I could modify. I do have a Sportster front fender but I don't see how I could modify that to fit well around the rear tire.

[Rjcinelli]

If anybody has tips on size or placement of gussets, I'm all ears. I was thinking from top tube to each down tube, and maybe a small one on each side of rear hardtail. Does anyone see any strength issues with the design of this frame? First frame build I just want to make sure I am building it strong enough I won't have any issues, a lot of the xs750's I've seen built have bars going down slightly angled on each side of the hardtail portion... Not sure if it's necessary or not but if not I'd rather not do that because I feel like it ruins the clean look.

[TriNortchopz]

Yeah I'm real glad I got the neck and title, a lot less stress now that I know I can register the bike no problem. Hmm I wonder what the girder is if not a Durfee. [ATTACH=CONFIG]83572[/ATTACH]

Not sure of the girder make...yet, but here are a couple pics of what looks to be the same girder on a '64 Sporty: