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View Full Version : 250R Aluminum Swingarm Extension Project (finished)



Red Rider
08-07-2007, 03:30 AM
I've been wanting a Calfab aluminum swingarm for my '86 250R for quite some time now, and I've all but given up on ever finding one, so I decided to make my own. I bought an '88-89 TRX250R aluminum swingarm on ebay as the donor patient. Since the TRX swingarm is 1" shorter than my stock ATC swingarm, I knew I'd need to lengthen it.

I guess I could have gotten a late model TRX450R cast aluminum swingarm, because from what I understand, they are identical in length to my stock swingarm, but I figure, if I'm changing swingarms, I might as well change to a longer one. And since I'd need to lengthen it, regardless of which one I went with, I decided to go with the TRX250R unit, as it has less cast aluminum in it, which should make for better/stronger welds.

Pics #1 & #2 show the unmolested swingarm.

Pic #3 shows the inside of the front half of the swingarm. While cutting it in half was easy, I had a hard time cutting up a perfectly good swingarm, especially since I had no idea what the inside would look like. Basically, I needed to destroy a good swingarm to figure out if I could actually complete this project. :wondering

Pic #4 shows the inside of the rear carrier. I guess I chose the perfect point to cut it in half. If I had made the cut about 1/16" more to the rear, I would have been cutting through the rear cast aluminum plate, which is solid from top to bottom. It's better to be lucky than good! :w00t:

Pic #5 shows the swingarm pieces layed into the jig that will keep everything straight & true (fingers crossed) while being welded.

Red Rider
08-07-2007, 03:43 AM
I want the lengthened swingarm to be +2" longer than my stocker, so I'm lengthening the TRX unit by +3".

Pics #1 & #2 show the front half of the swingarm, which was split up the middle in order to keep the sides of the swingarm one continuous straight line. This method was inspired by Mr. Sandman's swingarm lengthening project.

Pics #3 & #4 show the rear carrier with slots cut in it to accept the new extensions.

Pics #5 & #6 show the swingarm extensions, which were made by welding 2 pieces of 25x25x3mm square tubing inside the 60x30x3mm rectangular tubing.

Red Rider
08-07-2007, 03:50 AM
All jigged up & nowhere to go!

Pic #1 shows all the major pieces.

Pics #2-4 show everything clamped in place in the jig and waiting to be welded tomorrow morning, which is now today. I better get to bed! More to come in a week or so.

jeffatc250r
08-07-2007, 05:41 PM
Nice jig setup you have there, since you split the swingarm did you have to relocate the linkage mout ears on the swingarm? I have a spare 450r swinger that ive been procrastinating on doing the same to, only instead i want to do a +5 since the 8 over is kind of too much on my 500

Red Rider
08-07-2007, 07:22 PM
...since you split the swingarm did you have to relocate the linkage mout ears on the swingarm?I won't need to relocate them, but I will need to make some plates to put in between them to fill the extra gap that was created when I spread the swingarm apart.

jeffatc250r
08-07-2007, 11:16 PM
Cool, cant wait to see the finished product.

tecat-z
08-07-2007, 11:38 PM
Very nice project you have going on. Never thought of splitting the swingarm to keep the outside straight. Gotta love ingenuity. Keep us posted on progress.

Red Rider
08-20-2007, 01:06 AM
The first stage of welding is finally complete.

Pic #1 shows where I ground away the original factory welds from the cast swingarm pivot/box section tubing, so I could spread the sides of the swingarm apart.

Pics #2-4 show the results of the first trip to the welder.

Red Rider
08-21-2007, 01:34 AM
A lot more progress today & I'm now ready for the second stage of welding.

Pic #1 shows the wedge, which will fill in the gap that was created after splitting the swingarm down the middle & spreading it apart. Also in the first pic is a plate that will return some strength, to the area below the shock linkage mounts, that was lost when the rear carrier was cut off.

Pic #2 shows the wedge & plate installed before welding.

Billy Golightly
08-21-2007, 09:04 AM
This is turning out really well, great work

Kilborg
08-21-2007, 07:24 PM
Nice looking welds, looks like you probably do it for a living like I do...


What are you using as far as welding equipment goes? Iv been wanting to get a welder for the house, but have yet to decide what to do...As of now I use the welders at my shop. Not to hijack..

Red Rider
08-21-2007, 10:27 PM
Nice looking welds, looks like you probably do it for a living like I do...

What are you using as far as welding equipment goes? Iv been wanting to get a welder for the house, but have yet to decide what to do...As of now I use the welders at my shop. Not to hijack..I only wish I could weld like that! I take my stuff to Dave @ Precision Welding of Rialto to be welded. While he was doing some more welding on the swingarm today, I glanced at the name on his TIG welder, and now I can't remember what brand it was. I'll try and remember to make a note of it next time I'm there, which will be in a few weeks.

Red Rider
09-25-2007, 04:21 AM
After about a month of not working on this project, I finally made some more progress on it. I got the center section welded back together and have already ground & smoothed the welds in that area. I also cut out the top & bottom plates that will enclose the open box section at the rear of the swingarm. I've also cut out the spacer plates that will be welded onto the insides of the "dogears" (where the shock linkage bolts to the swingarm). If all goes well, 1 more trip to the welder tomorrow morning, and I'll have a finished product to show off!

Kilborg, Dave uses an ESAB Heliarc 252 welder. I'm no welder, but I have a hunch it's the man operating the welder that makes such nice welds, rather than the welder itself. :D

Red Rider
09-26-2007, 02:50 AM
As planned, I got the rest of the welding on the swingarm done today, as well as the 2 new engine motor mount tabs that were added to the frame. After several months of work, I've finally got an aluminum swingarm for my machine!

BigGreenMachine
09-26-2007, 06:46 PM
Very nice! I mean wow, another great addition to your sweet R.

cheers

Black86tri-z
09-26-2007, 07:02 PM
super nice job tere, what did all the welding cost if you dont mind telling?

Red Rider
09-26-2007, 08:08 PM
Thanks guys. The wallet's about $160 lighter now.

NE250r
09-28-2007, 04:29 PM
That swinger looks great man.. I'm planning to do this myself, but without the extension since I want a -1 swinger anyway... I have a few questions, I saw that you had to spread the pivot tubes apart and cut away the center it looks like, will it work if i cut away the center and use washers to make up the difference on the outer? or does it need to be spread apart, im just trying to figure a way to do it quickly this weekend. And my last question.. Does the carrier and axle and all that jazz fit the aluminum carrier? Thanks

Red Rider
09-28-2007, 04:55 PM
That swinger looks great man.. I'm planning to do this myself, but without the extension since I want a -1 swinger anyway... I have a few questions, I saw that you had to spread the pivot tubes apart and cut away the center it looks like, will it work if i cut away the center and use washers to make up the difference on the outer? or does it need to be spread apart, im just trying to figure a way to do it quickly this weekend. And my last question.. Does the carrier and axle and all that jazz fit the aluminum carrier? ThanksThanks. If you're wanting a -1" swingarm, the 88-89 TRX swingarms (which is what I used) are already -1", so no modifications are necessary to the swingarm, but you'll want to have the same motor mounts welded to your frame that I did because you need to remove the stock, rear motor mount/swingarm pivot mount to install the TRX swingarm. All of ATC bearing carrier, brake hardware should work fine if your ATC is an '86.

Red Rider
10-06-2007, 12:53 AM
I finally found the time to mount up the new swingarm. Before mounting it though, she went on the scale to see how much weight she gained from the lengthening process. She plumped up 2 pounds, but still weighs 1.5 pounds less than the stock steel swingarm. I've already lengthened the chain, but I still need to get a longer rear brakeline, and that will have to be ordered it looks like.

bigpimpin
12-15-2007, 11:46 PM
how much lighter is the swing arm than stock?

Red Rider
12-16-2007, 04:24 AM
how much lighter is the swing arm than stock?1.5 pounds.

edog
12-16-2007, 09:35 AM
I must say this...I am not a big fan of making the swing arm longer.But that does look really good on there.I thought about putting the 88 TRX swing arm on my mine!

Very nice work!!!!!!

Red Rider
12-17-2007, 03:18 AM
I must say this...I am not a big fan of making the swing arm longer.But that does look really good on there.I thought about putting the 88 TRX swing arm on my mine!

Very nice work!!!!!!Thanks edog. I never really liked the look extended swingarms either, but things change with time.

JethrowMan
12-23-2007, 01:58 PM
wow! i have to say that is one of the nicest extended swingers i have seen! what are your rear hubs and wheels they look a little different

tecat-z
12-23-2007, 02:58 PM
Definately one heck of a job. i hope it works well for you. Your R looks even more like a 88 model.

Red Rider
12-23-2007, 03:41 PM
wow! i have to say that is one of the nicest extended swingers i have seen! what are your rear hubs and wheels they look a little differentThanks Jethrow & Tecat-z. Jethrow, the wheels are from an '89 Banshee that have the BIG bolt pattern (4 on 156mm). The rear hubs are the stock ones, with some adapters that I made to run the bigger bolt pattern, bolted on. The hub adapters were the very first thing I fabricated for my bike, all because I couldn't find the product I needed from an aftermarket company. I originally made the adapters so I could bolt up some stock 87 Tecate rear wheels, with the rolled lip. Those things are basically indestructable. If you're hauling ass through the desert with those wheels wrapped in 18" low profile rubber, and you here that nasty BUUUUNNNNNNNGGGG, which means you just fricken nailed a rock with your wheel, don't even worry about. Just keep on riding, and then wipe the dust off the wheels when you get home, because there won't be a dent, or even a scratch, on them. I switched to Banshee wheels a few years later, because they had a nicer anodized finish on them and looked a lot better, and are just as strong. ;)

JethrowMan
12-24-2007, 02:08 PM
wow that awesome! you think that you could make another set? ;)

Red Rider
12-24-2007, 02:53 PM
Jethrow, unfortunately, I hand made those a long time ago, and the templates are long gone. Who knew 19 years ago, when I made them, that someone would be interested in them, or that I'd still have the same bike? I've had others ask me about reproducing some custom parts for their bikes as well, but I just don't have the time. :( I wish all of the fabricated stuff on my bike was made on a CNC machine, and the programs saved. Then, if someone was interested, I could just clamp a chunk of metal down, load the program, & hit the start button. :D

JethrowMan
12-25-2007, 04:46 AM
awe!:( thanks anyway for the info

FPMXer
01-17-2008, 09:25 AM
Good job on the swinger. I want to know how different the ride is with the extension. I want to add some inches to mine to keep the front end down when blazing the dunes. But I want to know if it's really worth the trouble.

Red Rider
01-18-2008, 03:44 AM
Good job on the swinger. I want to know how different the ride is with the extension. I want to add some inches to mine to keep the front end down when blazing the dunes. But I want to know if it's really worth the trouble.Thanks. I'll get you a ride report as soon as I get to ride. Since I finished the swingarm, I've only been on 1 ride, and that only lasted 12-15 minutes until my motor seized, due to a failed waterpump. :cry: For some reason, no waterpump = no coolant flow, which = no motor worky. :confused: I'm now in the process of completely rebuilding the entire bottom end, new crank/rod, seals & bearings.

FPMXer
01-18-2008, 03:58 AM
Thanks. I'll get you a ride report as soon as I get to ride. Since I finished the swingarm, I've only been on 1 ride, and that only lasted 12-15 minutes until my motor seized, due to a failed waterpump. :cry: For some reason, no waterpump = no coolant flow, which = no motor worky. :confused: I'm now in the process of completely rebuilding the entire bottom end, new crank/rod, seals & bearings.

That sucks to hear.

Red Rider
02-29-2008, 09:36 PM
While I'm waiting on some parts to complete the engine rebuild, I began searching for a longer skidplate to fit my lengthened swingarm. I called all of the aftermarket skidplate manufacturers, whose work & products I like, and none of them offered longer skidplates for lengthened swingarms, nor are they interested in making 1. So, I decided to get a new skidplate and lengthen it myself. I settled on a unit from XFR (www.xfrproatv.com) as they offer an excellent product for a decent price.

Once I was back into fabrication mode, I began to cut up a perfectly good, brand new plate, that I'd just shelled out $72 for. I completely forgot about taking pics of the whole process, but I think I can explain it fairly clearly. I cut the skidplate into 2 pieces, front & rear. The front piece contained the forward mounting tabs & the shock linkage protection. The rear piece contained the rear mounts & the sprocket/chain & disc brake guards. I cut out a 2" wide piece of 3/16" thick 6061 plate aluminum, as the spacer, for in between the front & rear skidplate halves, clamped everything in place, and then had it all welded back together. I also bent a piece of aluminum plate into a "U" shape, and had that welded to the front to better protect the lower shock-to-frame linkage.

Red Rider
03-17-2008, 02:10 AM
I finally got around to installing the new skidplate & Pro-Link stickers. Now my bike is really looking like the '88 ATC250R that Honda never built.