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swing arm extension

Posted: Wed Aug 30, 2017 12:41 am
by Jack Elliott
I am contemplating building a slightly customised Hodaka 125 . My other Hodaka projects (ace 100b , reeded Wombat and Super Combat have stayed pretty close to original but I have assembled quite a few bits and pieces and now want to build a bike for trail riding and Vintage Enduro incorporating the good features of my existing bikes and the good ideas of others.
First thing I am starting with a 74 Dirt Squirt frame adding Thunderdog forks and want to make and fit an extended (1 1/2 inches )wombat swing arm to improve the handling and allow me to run longer shocks . I also want to shift the footpegs to the rear (by cutting the mounts off the originals and welding them to the frame. Also i am thinking of utilizing the air cleaner mount off a spare SC air box and welding two pieces of thin pipe or flatbar/angle to fit it (super Combat style).
I am going to fabricate the pieces and have a go at arc welding them as well.
Was wondering what steel I should use ? just normal mild steel?
Appreciate any ideas.

Re: swing arm extension

Posted: Wed Aug 30, 2017 3:10 am
by olddogs
If you started your project with an 03 Wombat frame you would have most of your wish list already in place. The swing arm is already longer and longer shocks can be fitted, up to 15 inches. The Thunderdog forks are a bolt on using the 03 trees. The foot pegs are frame mounted and much stronger. I did something very similar by welding some round steel tubing to the 03 frame to mimic the SC layout, and used a complete SC air box. The rear fender will have to be modified to clear room for the SC airbox, and I believe I had to cut out all of the 03 gussets under the seat. I used a SC frame to get the measurements and tube locations for the additional brackets and gussets needed. You may be able to make all of these mods to a RT frame as well. The 03 trees and swing arm can be fitted, and they are plentiful used. I am a heavier rider at 260 pounds and this just makes a larger and stronger platform for bigger riders. I love these bikes as they are like a big boys Leggo set. Many combinations can be created using all original Hodaka parts.

Re: swing arm extension

Posted: Wed Aug 30, 2017 6:02 am
by Bill2001
"Big boy's Lego set". I like that. :)

I like these old bikes. Even though they are '60's and '70's technology, they were ahead of their time for the day. And is still a good machine, as well as a blast to ride.

Re: swing arm extension

Posted: Thu Aug 31, 2017 1:25 am
by Jack Elliott
Thanks for your reply. I also love these bikes for the same reasons. Simplicity of design and interchangability of parts plus a lot of shared info to work with.
Its great that 40 plus years on people are still improving these machines....

Re: swing arm extension

Posted: Fri Sep 01, 2017 4:02 pm
by Hydraulic Jack
You can use mild steel tubing for the kicker tubes. There are many sources online for technical tubing, or you may find what you need at the hardware store. I have used chrome moly for this, and didn't have any troubles with MIG welding the tube to frame. But I don't think you really need something as durable as chrome moly for kickers to mount the air cleaner. If you are stick welding and use chrome moly, ask at the welders supply which rods to use. Probably something in the 7012 range but look it up. If using mild steel, the 60-series is fine like 6012.

I have no idea really what steel Hodaka used for their frames, but it is fairly stout so I am thinking mild steel.

Re: swing arm extension

Posted: Sun Sep 03, 2017 12:59 am
by Jack Elliott
Thanks HJ
Mild Steel it is. Will try and post some pics when I make some progress.

Re: swing arm extension

Posted: Sun Sep 03, 2017 4:53 am
by Bullfrog
Confirming - Hodaka frames and swing arms are made of mild steel.
Ed

Re: Hodaka frame material

Posted: Mon Sep 04, 2017 7:49 pm
by Jack Elliott
Thanks for the confirmation Ed
Will work with mild steel ,thats what I was hoping for. Hopefully I can stick weld to Hodaka standard! Must say all the welding I have seen on Hodaka frames seems pretty good.
jack

Re: swing arm extension

Posted: Tue Sep 05, 2017 2:15 pm
by junker2k
I would not say the welding is good that would be a stretch, adequate would be more like it. Some are better than others.
Jack K

Re: swing arm extension

Posted: Tue Sep 05, 2017 2:32 pm
by Hydraulic Jack
If you want gorgeous welds, find someone with a TIG welder to do the work for you.

Re: swing arm extension

Posted: Wed Sep 06, 2017 4:00 pm
by Jack Elliott
Thanks Junker and Jack
Yes adequate is more accurate I was probably being too kind saying "good" . One of my Hodakas has some very Friday afternoon welding on the inside of the stem tube bracing that is well below even adequate!
My "project " has now been delayed a bit due to the failure of the big end in my only recently rebuilt Super Combat . Was going nicely too. I made the mistake of using the "servicable " rod and crank from another engine with new bearings seals rebore piston etc. Probably not a smart move in hindsight! Lots of metal everywhere,hoping the cases are Ok ,havent got that far yet. Had to pack it way and do some meditation...
Another milestone on my Hodaka journey!

Re: swing arm extension

Posted: Wed Sep 06, 2017 4:41 pm
by taber hodaka
I would guess welding would be bad, poor. marginal, good, excellent, professional, perfect. To me the poor weld will not hold. I don't know of welding failures on early hodaka's to me they are good. ------------Clarence