Vintage Dirt Bike Q & A

i need help identifying the rear suspension mods. on the '74 cr125m i'm restoring. the dg swingarm could be extended but i don't have any information on it. i am inclined to remove the forward upper mounts as they prevent the side panels from being used without cutting them. my two questions are; if the swing arm is longer, how will it effect handling with the stock upper mounts. Also..with the forward mounts removed the bike is closer to original and valued more right? anyone seen this kit?

The trouble with the modified travel versions is that they aren't legal for AHRMA competition, so they are relegated to just sitting around and looking pretty. The handeling of the bike would suffer only slightly slower steering and enjoy better high-speed stability with an extended arm. Extended arms were used by some people with the standard travel configuration. This is just a matter of preference, as I haven't heard from my ridding buddy who has one on any headshake or other issues with the regular arm. Full on DG equipped bikes do command a premium, but the optimal bike values will either be seen with pristine OEM reproductions or the full DG bikes. Normal bikes with laydown shocks are too in between to be show pieces, and aren't legal to be raced, so they aren't as desirable.

I am building a full DG racer right now and could use that super early rear-mount-only DG arm you have. I also have a stock swingarm that I won't be using if you want to go the oem route. I also have an original unmodified frame that I don't need either. That frame does have some rust issues, so let me know if there are specific frame sections you need and I'll let you know if they are rusty or not. In the end, if you do keep the DG arm on an otherwise stock bike, it will work just fine. Let me know if you do decide to sell the DG arm. If you'd want to trade for a Redline arm, or a later model DG arm with both front mounts and rear mounts, I should be able to do that too. The older DG would match the other early 74 parts I have on mine more accurately.

Thanks,
Jon

jon,
thanks, thats just the kind of information i was needing. i was sure that i was to "in between" to go either direction. i would like this bike to look and perform as a modified racer of my youth. as one would see at the track. i have a built motor with porcupine head and aftermarket pipe. i dont think i would prefer a stock swingarm so whats the story on the redline. is it longer and does it have both mounts. i need to be AHRMA legal as i've told myself that i at least have to put this on the track once. i am open to options. thanks again


ron

Oops, I haven't checked back in a while.

The Redline has 4 shock mount holes along two parralel plates at the rear of the square section of the swing arm. These had been cut to allow for laydown shock clearance, and I am now in the middle of returning it to its intended configuration. I believe it is the same length as an extended stocker I also have. I should fix this thing up in the next week or so and get you a picture once it is done. I have been less interested in finishing it now that I found the other dual position DG arm that also needs repair. Why can't I ever seem to buy anything that doesn't need fixin?

Really, your arm is pretty cool. If you are planning to keep stock shock positions, it would be an excellent choice to keep. I wouldn't expect you to want to trade for repaired Redline unless you both wanted the Redline specifically and had personally inspected the repaired section. I won't be surprised if you pass-a-roony on it.

Thanks though,
Jon

jon,
your knowledge of this era and expertise on the aftermarket kits is invaluable. even more..your honest responses are greatly respected! this is my first vintage restore and i must admit, it has been a little overwhelming both decision wise and financially. i would probably never b able to afford a "themed" restore such as a dg, muegen or fmf racer. what i would like and am hoping for is a stocker with some goodies. i am a big fmf fan and paid good money for the porcupine head. i wish i had a swingarm and pipe to match but have a dg pipe and probably couldn't afford to replace the dg swingarm. was there a single shock mount fmf arm made for the'74? would it be something i could trade the dg arm for? thank you again for taking the time to help me, i do appreciate it.

ron

Hey Ron, cut that out. I am strictly an intermediate level vintage nut. There are guys who know way more than I ever will. I don't know when that single shock stuff happened, the xr75's and big Yamaha thumpers. I don't know if ksi or dg every did any elsinores. Somebody? The single shock stuff was way more than a swingarm change, they were entirely different chassis. Your arm is probably worth between $200 and $400. The difference will be be between patient and impatient buyers. That might help you judge what you can trade it for.
Patience, time, and regular snooping around CL, vintage web sites, yard sales, and the local channels where old junk is bought and sold; don't be afraid to buy a whole bike and resell it after you've replaced the parts you want with regular parts. Those are the tools that bring us low-dollar folks up to par with the big money crowd. Give yourself a couple of years, and the right parts will come your way. Or, just take a home equity loan and get it all right now. What? Equity? Sorry, four years too late, eh?
Good hunting,

ok jon,
i mistakenly said single shock when i was questioning whether fmf made a arm with a set of single mounts as opposed to the arms with 2 positions (forward mount and laydown). living in a small town in the midwest doesnt seem to offer the same availability of parts bikes. e-bay has been good for the more common things and God, i hope it doesnt take another ten years. i started on the motor almost eight years ago!
thanks again,
ron

Ron,

I saw your 2011 post showing your frame with the DG lay down shock kit welded onto your frame. Do you still have the kit on the frame or did you remove it as you were thinking of doing? I am looking for such a kit or trying to find the dimensions of the kit so that I could duplicate it for my 75 CR125. I could almost guesstimate the measurements from your photos, but would rather do it the correct way. I have the same DG swingarm as you have shown in the photos. Let me know.

Thanks
Vince P