Aluminum after market swing arms for Penton's

[rob w]

The main reason for using aluminum, to make a swingarm is not solely to lower the weight, but that you can use a larger tube and thicker wall material to achieve a much stronger, more rigid part at the same or lesser weight. The only thing about Dom's swingarms that may not look the era, is the finish (polished aluminum). Change that to some silver/grey paint and no one on the side lines is going to notice. In fact, for a 74 or 75 machine (sportsman class) I think they look very unconspicuous. Now if you were to install one on a 72, that might look a little out of place. What I think is wrong with some of the vintage classes, is that they are letting 76 & 77 bikes run with shock limiters in vintage sportsman. AS for the tracks today, COME ON!, why are people bitching about a jump here and there? I started racing in 71, and there were alot more jumps, and bigger jumps, and big whoops than these lame tracks I'm seeing today. I know we're all getting older, but I thought this was suppose to be moto-cross. Where are the good tracks? I don't see them. Thank you. Bob.

 

[lobo6y]

Hi Larry,
Good points and discussion - the "debate" is one of the best parts of our vintage disease (except when it gets personal).
Here's some more thoughts:
I agree that the forward mounts on many of the ~75-76 bikes need more rigidity for big air in the PV classes.  Unfortunately AHRMA let the camel's nose under the tent in the Vintage classes with some of the like design long travel 75-76 bikes (limited to 4") and moved up aftermarket swingarms on the pre-75s.  I tech them and keep it to 4" but you wouldn't believe some of the stuff guys bring to tech.  At Hollister two years ago, a guy brought a 350 Honda with a 5" extension welded to the swingarm (I saw some of those "in the day"  too.  I made a mistake safety-wise and let him ride (he swore he'd raced it previously).  It folded gracefully in practice with no injuries.  As you remember, even back in the vintage day we used to overtax the bikes and break not only swingarms, but steering heads,  frames and shocks. Remember the famous picture of Doug Grant "wheelbarrowing" his Stormer forks and wheel over the finish line at Indian Dunes?  Point is, reliability vs weight savings has always been an issue in MX bike construction and racing.  How hard you could push a bike has always been part of the equation.
Personal Safety.  Riding gear has come a LONG way.  Any compromise of safety has to be done with full recognition of the tradeoffs.  With the exception of full face helmets, almost all the high tech items you mention can be worn underneath vintage leathers and jerseys (I do this).  Several top quality boots can purchased in all black (or close to it).   I choose to race vintage MX with an open face Shoei with Scotts face protector, but I race vintage Flattrack/TT with a full face.
Tracks:  Lots of variety in opinions  here.  I raced (amateur) all over the country in the '70s and early '80s, and I've raced AHRMA nationally (although primarily in the west) since 1996.  Regarding "Vintage" tracks, we tend to have a lot more man made jumps now than then, but we also tend to have a lot less whoops and rough stuff.  If any of you disagree about the whoops, go get out your copy of "On Any Sunday", most of the MX stuff was filmed in 69-70.  I have to watch it now and then to remind myself how rough it was...  That having been said, realize that in addition to vintage tracks of the '70s and Post Vintage of the '80s,  AHRMA is trying to replicate the tracks of the '60s which were more rough scrambles, but often called MX after ~65.  A heathly mix of tracks is what I really appreciate.  
BTW, for any of you in the west who want to race a real '70s style MX track - try Honey Lake!  Larry Wosick runs it and it'll take you back in time.  I had more/different sore muscles after racing there... Dick Mann told me those were my "motocross muscles!."
Enough for now!
regards, dave

 

[markseals]

Dom, I would be intrested in an aluminum swing arm for my 75 mint 400 penton.      mark.

mark s seals

[markseals]

dom, thanks for returning my email. A 1976 swingarm will fit the 75 frame. Please keep me posted on progress of your product. I would be verry interested in seeing a picture of a finished swingarm, also how much i could get one for.  Thanks mark.

mark s seals

[chris richardson]

VMXpert...so, when are the '73-75 mx swingarms available?
No word since August, any update?

CR

 

[john durrill]

And the swing arm bushing replacements for the 72-74 cmf 100,125,175 frames?
John

 

[Cliff Cook]

I might be interested in a swingarm for a 75 250 Penton.  I agree with Dwight on originality.  The way they were then, they should be now (including tracks): however, if a bike has a deficiency that is going to relegate it back to the shed, I am willing to fudge.  Maybe someone could build an original swingarm with reinforcement like the guys are using for AHRMA motocross now.

 

[chris richardson]

so, how are the swingarms coming?

 

[DKWRACER]

Takes time guys, Dom is an engineer at one of the biggest Aerospace engineering companies in Colorado, one of his biggest challenges is to balance his enormous responsibilities at his job, yet find time for one of his biggest dreams, I have had the opportunity to both meet him and watch him cheer me on at the Nationals, and he has been made aware of what is happening, I believe he has made a commitment, one thing at at time....please!!!

 

[john durrill]

Has anyone heard anything on the new swing arms or the replacement bushing from Dom?
 We have sent three e-mails to them in the last 3 months and no response.
 I would like to replace mine befor the RR and we are building a 72 Six days that needs them now.
John & Peter

 

[frank the welder]

I had contact with Dom some months ago and was under the impression he was going to send me the parts to weld together. We had discussed working together because I am making arms for Hugh's Bulls. I had thought about going into the swingarm business but the tooling cost VS projected short term sales looked like too thin for my small business. I would like to be able to make vintage parts for Penton but I am not at the point yet where I can't afford to do much without someone ordering several pieces of a single item. The vintage market is interesting in that todays cost for prototype parts are way more that the cost of old, used, mass produced parts. Who wants to buy $500.00 swingarms? not me either.

 

[john durrill]

Update on the replacement bushings for the 72-74 cmf 100 , 125, 175 swing arms.
Dom just sent me an E-mail. the Day job     has slowed him don a bit but he is willing to make up the bushings.
 Will let you know when I get the first two sets.
 This is great news. It would take a month in the garage for me to come up with something that might work chuckle chuckle.
 the might being a pivotal part of that statement :>)))
John & Peter

 

[chuck]

Did anything ever happen with Dom making these swingarms?

Chuck

[tlanders]

Spencer Ballentine has been racing AHRMA for years with a trick aluminum fabricated swingarm. I tried to get the guy who built it for him to build me one, but I finally chickened out because of price.

Teddy

[chuck]

How bad was it?

Chuck