Author Topic: Harley XR750 (Read 35373 times)

Bob3050 · « **Reply #75 on:** May 18, 2014, 04:18:28 PM »

I put the bare cases and top end in the frame to check the fit and I've found a few minor problems. The motor mounts are all the same as the XR but there is a relief cut in the backside of the primary to accommodate the swing arm pivot bolt that doesn't line up with this frame. I had to enlarge the relief in order to get the motor mount bolts installed. Next thing was the front rocker box was slightly larger than the distance between the frame front down tubes and had to be trimmed for clearance. That only required a small amount of grinding on the front corners of the rocker box. Because the exhaust on an XR exits on the left and this engine exits on the right the thing that I have to address now is the front cylinder exhaust is pointing straight at the right down tube. There is some room for the pipe but it's going to have to bend a lot quicker than the sportster front pipe normally does. So far none of this is insurmountable but it's going to take some work to get it right. Here are some pictures that may help to see what I'm talking about.
Bob

Old Scrambler · « **Reply #76 on:** May 19, 2014, 06:36:19 PM »

That is looking real sweet

Not much of a HD fan.............back in the '50s they sued my father over an accident that unfortunately killed one of their test-riders..........got thrown out of court because the rider was on his own time...........AND IT WAS HIS OWN FAULT.

A good friend is now retired from HD as an engineer. His first project was assembling and testing the XR before they were made ready for production..............he has XR frame and motor #1 in his garage. He is now assembling the motor to spec and will offer it for sale.............part of his retirement plan.

I don't look at this page very often...............but your project looks interesting.

Prospect · « **Reply #77 on:** May 19, 2014, 08:23:09 PM »

Quote from: Bob3050 on December 05, 2013, 11:53:55 AM

Quote from: dusterdude on December 05, 2013, 10:33:37 AM
Dont be skeered,right side shift is a mans bike

Sent from my iPhone using Tapatalk
Many years ago(early seventies) the bike shop that my brother and I owned carried Honda, Triumph and Norton. Honda was left side shift, Triumph and Norton were right side and to complicate it Triumph was first gear down and the rest up while Norton was first gear up and then rest down. I once wound a Norton up in second gear and then proceeded to stuff it back in first when I went looking for third. I caught it quick enough that it didn't do any damage but it sure got my attention in a hurry. So I think I'll stay out of trouble rather than have to get out. I hope to be able to jump back and forth between my Honda CB500 an the Harley with no confusion. But if I don't find a more suitable donor I will use the right side shift.
Bob

I have a 74 sportster with right side shift and a cb750. I switch between the two all the time. No issues. The only difference I notice is the extreme difference in performance between the two. It's no wonder the cb750 killed Harley.

Terry in Australia · « **Reply #78 on:** May 21, 2014, 02:07:22 AM »

That looks sweet Bob, that is gonna be one tasty bike!

mrbreeze · « **Reply #79 on:** May 21, 2014, 03:58:41 AM »

I don't remember if I already said this but a few years back I was at Corbins in Hollister, Ca. getting my seat done on my 750 and they have a little bike museum there. Its been a few years so I don't recall exactly how many bikes they had but I remember my most favorite was an XR-750 owned by Steve McQueen. I wish I had pics. Don't plan to go anytime soon but next time I will take some pics. Another cool place to drool is at Arlen-Ness's new (er) shop in Dublin, Ca.

Bob3050 · « **Reply #80 on:** April 11, 2017, 06:29:26 PM »

I haven't been very active on the XR750 project for quite awhile. I had some health problems (prostate cancer) but that's all good now. The other thing that was in my way was employment so I gave that up the first of the year. I figure that at 75 years old I need to be doing what I want to do. Anyway I'm back working on the bike again. I've made peg mounts for both sides and I mounted the rear brake master cylinder on the left side. I've gotten both front and rear brakes working like they are supposed to. The rear disc was drilled but the front is not. I haven't ever tried to do that but I think I will. Has anybody out there got any experience with this? The fuel tank had no mounts either on the tank or on the frame, so I got an old Honda SL175 tank that was in terrible shape and cut the front mounts out of it. Then I installed two pins in the frame to hold the rubber biscuits. Works just great. I've made a set of pipes out of old ones that
I cut up and pieced together. I think I'm going to use them as patterns and have my buddy weld a set of stainless ones. That's all for now but I'll post more if anyone is interested or not.
Bob

754 · « **Reply #81 on:** April 11, 2017, 06:45:42 PM »

Very cool..

Bob3050 · « **Reply #82 on:** April 12, 2017, 04:56:12 PM »

Here are a couple more pics of the rear brake master cylinder set-up and the pipes. Like I said I hope to get some stainless pipes made but if I have to I guess I could use these in a pinch. You can see howI had to wind that front pipe around the right downtube. This motor is a tight fit in this frame.
Bob

MoMo · « **Reply #83 on:** April 12, 2017, 05:35:09 PM »

Good to hear the cancer is over. Also good to finally quit and do what you want. I'm a tad behind at 70 and thinking of following your lead. Bit late on the thread but bike is looking good. Stay well...Larry

Terry in Australia · « **Reply #84 on:** April 12, 2017, 07:43:05 PM »

Looking good Bob, I wonder if the tight fit is because the race bikes had reversed heads and ran the exhausts out of the other side? Cheers, Terry.

Bob3050 · « **Reply #85 on:** April 17, 2017, 01:36:14 PM »

I took my seat to my upholstery buddy last week and I got it back today. I had him do it in the original Harley style with the snaps. I'm still going to use some velcro on it but I really wanted that original look even though the velcro is a better way to attach the seat to the pan. Here are a couple of pics to show the difference between the original style and the later aftermarket style.
Bob

Bob3050 · « **Reply #86 on:** April 24, 2017, 03:54:08 PM »

The front disc on this bike had no holes drilled in it so I thought I would do something about it.I transferred the pattern of the rear disc onto the front then I center punched all the proposed holes, eighty of them. First I drilled them to 3/16 and then a second round to 9/32 which is the size of the rear disc holes. It took awhile to do but it came out looking like I wanted and I think it's a big improvement. Here are some pictures of the job.
Bob

Terry in Australia · « **Reply #87 on:** April 24, 2017, 04:27:23 PM »

That looks great Bob, well done! Cheers, Terry.

Bob3050 · « **Reply #88 on:** May 04, 2017, 09:27:15 AM »

I got the frame and swing arm back from powder coating yesterday. Now I have to get back to trying to assemble the chassis and then build the engine. Actually it's lots of fun.
Bob

Bob3050 · « **Reply #89 on:** May 14, 2017, 03:37:14 PM »

Now that the powder coating is finished I'm starting to assemble the chassis.

mrbreeze · « **Reply #90 on:** May 14, 2017, 03:50:07 PM »

This is gonna be a sweet ride!!

Bob3050 · « **Reply #91 on:** May 25, 2017, 01:35:20 PM »

I went to a swap meet last weekend and found some pieces for the XR. The handlebars fit great and I like the chrome finish better than the painted because the tie downs I use to hold the bike on my hoist mark the paint after just a few uses. The air cleaner is all there and I got an extra cover also. I do need a new element for it. I bought the sprocket cover in the picture but it turned out to be wrong for my engine. Anyway things are moving ahead, slowly but surely.
Bob

Bob3050 · « **Reply #92 on:** June 07, 2017, 02:19:44 PM »

I started actual re-assembly today by putting the engine cases together. The rods had been replaced and checked out very good, but I did put both main bearings in new. I painted the inside of the crankcase and transmission cavity with sealer as was recommended to me. I'm really glad that I have gotten back into this project and I hope I will have some good progress to post.
Bob

754 · « **Reply #93 on:** June 07, 2017, 06:16:30 PM »

Very good, do you think you can ride it this summer ?

MoMo · « **Reply #94 on:** June 07, 2017, 09:11:32 PM »

progress is a good thing

...Larry

Terry in Australia · « **Reply #95 on:** June 08, 2017, 01:03:19 AM »

Good work Bob, I watched a you tube vid of a guy treating his car engine with that stuff, looks like a lot of work to do it properly, but if it does the job, then well worth the effort. Cheers, Terry.

Bob3050 · « **Reply #96 on:** June 08, 2017, 01:49:34 PM »

Quote from: 754 on June 07, 2017, 06:16:30 PM

Very good, do you think you can ride it this summer ?

I don't really know yet, but I am hoping to. The actual deadline that I've set for myself is the middle of October so that I can take it to San Luis Obispo for the Central Coast Classic M/C Club's annual vintage and classic show and rally. I've taken my CB500 and my little Honda P50 to it several times and its always a great show. Some of the grand marshals they have had in the past were Craig Vetter, Gene Romero, Mert Lawwill and others.
Bob

Bob3050 · « **Reply #97 on:** June 10, 2017, 08:45:21 PM »

I got the lower end in the frame, the cams in and timed and the cam cover installed. I may have to order a couple of transmission parts before I can continue but I will have to to check closer to see if I need them or not. Basically it's moving right along.
Bob

Bob3050 · « **Reply #98 on:** June 23, 2017, 03:49:24 PM »

I made a little more progress on my Harley in the last week or so. I got the transmission, clutch, primary and kick starter all installed and buttoned up. It's moving along and I'm getting ready to put the top end together.
Bob

754 · « **Reply #99 on:** June 23, 2017, 03:52:53 PM »

Did you put a bent spoke in the mainshafrt and set endplay ?

Been a long time since I put one of them together.. Lookng good.

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Author Topic: Harley XR750 (Read 35373 times)