Glad you posted! Welcome.
Looks like an interesting idea.
Remember to chop safe.
Looks like an interesting idea.
Remember to chop safe.
New Year, Old Bike, New Bobber-
6
-Some Background-
I should introduce myself - I have been a member on this forum since last summer when I purchased a 1986 Rebel 250 as a project. I have been a lurker since then, being on here about every day to keep up on various member projects and absorbing as much information as I can.
This is my bike-
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I bought it from a guy who had already started bobbing it- he had removed the air box, cut the stock rear fender, had a set of bullet signal lights, etc. He ran out of time and I was able to pick it up pretty cheap with a clean title. It had sat for almost a year when I came along so I continue to fight carb issues with it, but it does run.
I had some time off around Christmas & New Year's so I was finally able to spend some time on the bike. I work in a small company's engineering dept. so I have access to the prototype shop which is a huge help.
-The Build-
I wanted to hardtail it, but I wanted to do a bolt-on in order to leave the main frame as "stock" as possible for someone in the future to return it to a standard suspension if they want. After some research I decided to purchase a Honda VLX 600 swing arm since the tire dimensions and mounting system are similar.
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I figured that I could use it with a minimum of modification and make it work as a bolt on... not the case. For the record it flairs to the RH side only, but I didn't really catch on until after I had spent a bit of time cutting and rewelding trying to get it to the same width between the swing arm pivot as the stock arms. Here is a picture of the VLX swing arms in transit-
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Once I realized that it wouldn't work (disappointing is an understatement), I needed to figure out a way to make a tubing bender (cheap) but one that wouldn't crimp the DOM tube I now needed to buy.
I dug around and found some scrap metal from a prototype part we had built last year and it was just enough to turn down into a 3" radius main die for the Rebel's approx. 1.0" DOM tube. The bender I ended up with is not fancy, and the 1.0" x .120" wall DOM tube is easy enough to bend that I can mount the bender in a vise on one of the weld tables at work, which simplified things a lot.
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Another view, this one from the front, showing the tube retainer strap.
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I bent the lower frame tubes first. Here is the RH side clamped to the stock swing arm showing how it will hopefully look.
![]()
I want to extend the rear-end about 4" but keep the standard ride height, so the jig is set up for that. I initially wanted to totally create my own axle mounts and everything, but realized that I would need a much more accurate jig assembly to do that. To be honest I don't have time or focus to do that, so I am going with the new swing arm based off of the stock one. The plan is to use the stock pivot end and the axle mount ends and remove the rest once all the tubing is complete. More to come.
I should introduce myself - I have been a member on this forum since last summer when I purchased a 1986 Rebel 250 as a project. I have been a lurker since then, being on here about every day to keep up on various member projects and absorbing as much information as I can.
This is my bike-
I bought it from a guy who had already started bobbing it- he had removed the air box, cut the stock rear fender, had a set of bullet signal lights, etc. He ran out of time and I was able to pick it up pretty cheap with a clean title. It had sat for almost a year when I came along so I continue to fight carb issues with it, but it does run.
I had some time off around Christmas & New Year's so I was finally able to spend some time on the bike. I work in a small company's engineering dept. so I have access to the prototype shop which is a huge help.
-The Build-
I wanted to hardtail it, but I wanted to do a bolt-on in order to leave the main frame as "stock" as possible for someone in the future to return it to a standard suspension if they want. After some research I decided to purchase a Honda VLX 600 swing arm since the tire dimensions and mounting system are similar.
I figured that I could use it with a minimum of modification and make it work as a bolt on... not the case. For the record it flairs to the RH side only, but I didn't really catch on until after I had spent a bit of time cutting and rewelding trying to get it to the same width between the swing arm pivot as the stock arms. Here is a picture of the VLX swing arms in transit-
Once I realized that it wouldn't work (disappointing is an understatement), I needed to figure out a way to make a tubing bender (cheap) but one that wouldn't crimp the DOM tube I now needed to buy.
I dug around and found some scrap metal from a prototype part we had built last year and it was just enough to turn down into a 3" radius main die for the Rebel's approx. 1.0" DOM tube. The bender I ended up with is not fancy, and the 1.0" x .120" wall DOM tube is easy enough to bend that I can mount the bender in a vise on one of the weld tables at work, which simplified things a lot.
Another view, this one from the front, showing the tube retainer strap.
I bent the lower frame tubes first. Here is the RH side clamped to the stock swing arm showing how it will hopefully look.
I want to extend the rear-end about 4" but keep the standard ride height, so the jig is set up for that. I initially wanted to totally create my own axle mounts and everything, but realized that I would need a much more accurate jig assembly to do that. To be honest I don't have time or focus to do that, so I am going with the new swing arm based off of the stock one. The plan is to use the stock pivot end and the axle mount ends and remove the rest once all the tubing is complete. More to come.
1 - 20 of 202 Posts
Being the owner of both Rebels and VLXes and having already attempted cross-swapping Rebel and VLX wheels, I could have told you that "similar" is about as far from the truth as you can possibly get. The VLX rim actually will fit on the Rebel swingarm, but you lose the spacers that keep it centered. Meaning the wheel sits off center and perfectly snug between the Rebel swingarm tubes. Meaning the sprocket sits too far to the left to properly line up with the driven sprocket up front.
But it looks like you're taking the right approach now...a true rigid frame made to spec looks (and works) much better
-Thanks, Buickguy. I will try.
Being the owner of both Rebels and VLXes and having already attempted cross-swapping Rebel and VLX wheels, I could have told you that "similar" is about as far from the truth as you can possibly get. The VLX rim actually will fit on the Rebel swingarm, but you lose the spacers that keep it centered. Meaning the wheel sits off center and perfectly snug between the Rebel swingarm tubes. Meaning the sprocket sits too far to the left to properly line up with the driven sprocket up front.
But it looks like you're taking the right approach now...a true rigid frame made to spec looks (and works) much better
-I appreciate it, Shadow Shack. A great example of "I should have asked". Would have saved some coin... ah well.
4
-Progress-
Well work started back today so I didn't have much time, but here is some progress-
I was initially trying to achieve the swing arm flare (approx 9" width @ pivot to about 9.6" @ the axle slots) by offsetting the front bends on the lower tubes to angle inward. This can seen (sort of) in the picture below.
The inward angle was somewhere around 5-7 degrees mirrored on both sides. The issue came up when I did a test fit of one of the tubes on the bike- the straight tubes interfered with the stock exhaust pipes. Since I haven't decided if I want to bob the exhaust pipes yet or not and the straight tubes with inward angled front ends interfered with the stock exhaust, I decided to try to mimic the flare angles of the stock swing arms. Here is the bender set up to pop the center bend in the RH lower tube. The round bar sitting on top of the follower die slides in and out of the handle tube for more leverage when required.
Here are both lower tubes completed.
It looks a LOT better now. You can see the small bends in the center now with the paint pen marks where I was trying to figure out where to start the bend. The tubes are tacked in place and when viewed above they follow directly below the stock swing arm. I also tacked a temporary crossbar to the two axle end pieces to keep them square to each other once I cut them loose.
Hopefully tomorrow I will get a chance to get some more progress posted.
7
-Progress-
Things are taking shape on the bolt-on hardtail. To make the upper tubes I sheared and bent some 3/8" thick CRS plate into two 1.5" x 3" pieces, formed into "L"s to mount to the upper spring supports. They each were drilled out to 19/32" which fits a M14 bolt shank.
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I notched the upper tubes to match the outer bend radius so that the tubes would lie flush against the back of the two brackets.
![]()
I mounted them in place for the time being with the upper stock spring pivots. I had to order some fine thread M14x1.5 bolts and they are not in yet.
So with the two upper tube assemblies bolted on the bike I marked the lower ends in place and cut them off. The bike was suspended at the ride height during this process. Here is a picture of the swing arm before the upper tubes where in place.
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Here is one with the upper tubes installed. Starting to look like something now. I still have to cut away the rest of the stock swing arm.
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A shot of the rear chamfer on the RH upper tube pre-weld.
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The plan is to gusset this area and fill in the gaps with sheet metal like a member (I can't remember who it was) did with their bike.
Last but not least I couldn't help but set the future seat on there and get an idea of where this is going.
![]()
I am also trying to decide if I want to use the stock rear fender and trim it as required to match the curve of the wheel (previously bobbed by the last owner), or go with something different.
![]()
Things are taking shape on the bolt-on hardtail. To make the upper tubes I sheared and bent some 3/8" thick CRS plate into two 1.5" x 3" pieces, formed into "L"s to mount to the upper spring supports. They each were drilled out to 19/32" which fits a M14 bolt shank.
I notched the upper tubes to match the outer bend radius so that the tubes would lie flush against the back of the two brackets.
I mounted them in place for the time being with the upper stock spring pivots. I had to order some fine thread M14x1.5 bolts and they are not in yet.
So with the two upper tube assemblies bolted on the bike I marked the lower ends in place and cut them off. The bike was suspended at the ride height during this process. Here is a picture of the swing arm before the upper tubes where in place.
Here is one with the upper tubes installed. Starting to look like something now. I still have to cut away the rest of the stock swing arm.
A shot of the rear chamfer on the RH upper tube pre-weld.
The plan is to gusset this area and fill in the gaps with sheet metal like a member (I can't remember who it was) did with their bike.
Last but not least I couldn't help but set the future seat on there and get an idea of where this is going.
I am also trying to decide if I want to use the stock rear fender and trim it as required to match the curve of the wheel (previously bobbed by the last owner), or go with something different.
1 - 20 of 202 Posts
