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Hey, I got a question for you. If you were trying to build the perfect 1975 Honda XL350 Vintage Motocross Bike, what type of suspension would you use? Lets say we already have a C&J frame and swingarm. We're using Works Performance shocks on the rear. Our motor and carb work has already be done and the bikereally hauls ass. What type of front end are we going to install? Any pair of 35mm forks off of any dirt bike made back in 1975 or before. What would you want to install? Who has the best vintage forks for this bike within 7 inches of travel?

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Personally I'd go for a triangulated swingarm with twin inboard mounted Fox Shocks, and Simons forks up front. Wrapped in a chrome plated Cheney frame.

But I'm a little biased...

Ceraini MX front forks were the ones that I first put on my 403 back in '75.  A year or two later the Marzocchi were lighter and better.  Over the eraly years I switched to early CR125 35mm forks and then the Suzuki 36mm 125 forks.  Early Maico or Bultaco forks would work.  They were better than the early Honda stuff.

Swiss

I have heard recently of forks modified with cartridge internals etc...  But don't know of anyone specifically doing the mods.  The real catch is you can get better dampning and fluid control, but you aren't increasing the strength of the old small 35mm tubes beyond what they were 30 years ago.  the design flaw is in the tubing diameter and strength compared to what has been designed in the years since.  The older tubes will flex more and bend much easier than any of the newer tubes of larger diameter.  Funny thing is that due to better design, the new forks weigh just about what the old tubes did but are MUCH stronger.  When you get to the tubes designed after the '75 year, you are generally talking about offset axle forks with the axle in front of the center of the tubes.  MANY of the vintage clubs are not going to allow this.  The straight leg tubes were the prevalent tubes in the early years.  Maico was probably the first manufacturer to use the offset tubes on their MX bikes.  Another problem is travel, the later forks all started to go to longer travel, also not allowed in the early vintage classes.  IF you shorten the internal rods or increase the top-out spring, then you can limit the travel AND pick up extra strength due to the increased overlap inside the lower tubes.  But the 35mm fork tubes will mostly bend at the lower clamp and not at the top of the lower tube, so that won't keep the tubes from bending.  The steeper head angles from the newer models if you should decide to go with that design change put more stress on the tubes than the older forward rake angles of the early bikes.  Again, more stress and more flex/bending.  Don't misunderstand me, you CAN make better 35mm tubes out of the old parts, but they will NOT come even close to the newer forks.  You also have to look at the weight that you are going to throw at those skinny forks compared to what a 100cc or 200cc bike weighs.  Good luck and although you can build them better than they were, they will have their limitations.

Swiss

If you look at the XL Page, you can find the University Honda bike.  I watched them race this bike and take big air flying 40-50' and beyond at the Puyallup track back in '75.  Those are CR250 front forks and I am sure that they had a fork kit and springs in them.  But they were vintage and worked with under 7" of travel.  Not saying that this is your best option, as the Maico forks were ahead of their time.  I just always upgraded the bike as things came available on the used part market.  Didn't worry about vintage, as I was running the desert and mountain enduros.  So I ended up with 43mm TT600 front forks and disk brake.  I did run 36mm Suzuki 125 forks for years with a kit and for several years an anti-dive system.  See my pictures on the web site.

Swiss

(see photo below)

Check out some of these other trick features: Wide modern foot pegs, C&J frame or some type of custom built frame, aluminum swingarm that looks almost modern like that's used today. Custom sprocket and chain guide, trick parts on motor, like gear shifter and black painted engine side covers. Special hoses hanging down from gas tank, not sure what that is ??? Custom aluminum air box, Looks like he might be using Ohlins rear shocks ??? Also looks like maybe taller seat foam ??? That's a very tricked out bike...for sure. I'd be lucky to get half that close.

(see photo below)

If this bike was being raced back in 1975, it's probably safe to say that everyone saw this as a bike from the future or some type of cheater bike. Can't think of any other stock '75 that looked like this. By today's standards however, this is a common tricked out vintage bike. Must of been really something to see this bike race back in the day......very nice!!!

Since University Honda was also a Bultaco dealer, and since the Bul wheels weighed about 7-8 lbs lighter than the CR Honda stuff, they ran Bultaco wheels front and rear.  The frame and swingarm were both custom and built from Chrome-moly tubing.  Yes, it was impressive to watch kick ass on the 400 Maicos and other 2-strokes that it ran against.  It just THUNDERED around the track!  Buck Murphy used to pick it up in his arms at the starting line to show the 2-strokers how light it was.  Its big debut race was to have been at the Puyallup Trans-AMA race with Murphy riding it, but they broke the tranny gears the week before and couldn't get it fixed in time!  I don't remember if the trick racing 3rd and 4th gearsets were available at the time.  Honda hadn't even released the Centerport engine yet, but they had center-port cut this head from an early head.  I had an article on it that was printed in one of the early Washington Moto papers, but somehow I lost it over the years.  They claimed 222 lbs or less for it, but since I built a comparable bike I don't see how they were quite this light.  I would have said about 228-230.  That was still 15 lbs or more lighter than the C&J bikes that were being built and the Knobby Shop bikes weren't being built yet.  Yes they are CR250 forks, but if I remember, they were machined lowers for lighter weight.  That would explain why you can't spot the drain screw like stock.  Sorry the picture was taken with an old camera which was all that I had back then.  Many considered it a "cheater" bike after they saw it run.  The frame was custom designed and built by Al Oppie.  He was their "engineer" and designer.  Used to work on Indy cars in the old days and did the centerport change for the head as well as adapting over the small magneto ignition.  I believe that they ran the 90cc magneto from the day.  I adapted the XL125 '75 magneto when I built mine, using their adapter plate. 

Swiss  

You have to remind us what bike/engine you have.

Swiss

Oh, sorry....It's a 1974 XL350 side port. It's all stock right now. Has everything still on it...lights, blinkers, the battery, key ignition switch, tail light, horn, on/off switch at the handlebars. Has all the stock parts. I want to do away with all of the above parts and turn it into a vintage motocross race bike, or VMX bike. I futured I'll need some kind of new ignition source once I remove the battery and key switch. I need to know what to buy and how to hook it up? Thanks.

The XL250 and 350 have stand alone magneto ignition systems that do not need the charging/battery system for running.  I will email the pages on converting the 250 to MX use that Honda had in their shop manuals to Geoff.  Just need him to post them on the web site with the other new stuff that he has.

Swiss

OK, we already have an article on the web page for weight reduction and it got an Enduro version down to 261 lbs.  Considering the weight of the lights and the heavier big tank, you could probably pull at least another 7 lbs from this, and the CR wheels should be a little lighter than the XL wheels.  I would either go with the Yamaha or the Suzuki wheels, both were lighter than any of the Honda wheels back then.  So you could get the stock frame built and down to about 254 lbs with Honda wheels and lighter by a couple of lbs with other wheels.  I wouldn't worry about the welds unless you are already seeing cracks.  A built up C&J framed Honda 350 with the CR pieces weighed about 245-249 lbs sitting on the showroom, so there isn't a really large savings with the C&J.  The handling and strength are much better with the C&J.  The CR or some of the Yamaha or Suzuki seats should have a plastic base on them.  I used a 175 Yamaha on my enduro bike, but that was in the early '80s.  The stock seat is WAY wide and might be hard to find a plastic base seat big enough to replace it in the scrap yards.  You could pound out an aluminum base, I did that in '75 for mine.  The early seat with the rise in the rear used the aluminum base and was pretty light considering the amount of foam that I used. 

Don't know the dimensions of the CR arm but I KNOW that is not the same as the XL. 

No one was selling aluminum arms back then except for ONE company, and they were expensive and hard to come by.  The technology just wasn't there yet.   A good Chrome-moly arm is as light as any aluminum arm especially the early ones.  The C&J arm wasn't that heavy, but the Bronze bushings were really heavy compared to a bearing set-up.

All of the side panels were custom for the aftermarket frames.  If you want something you will have to pound them out yourself.  I made the ones that are shown on the C&J frame bike of Scott Steger's. 

Most down pipes are going to give ground clearance problems with MX racing.  A crushed pipe won't give very good power.  Most all aftermarket pipes are lighter than the stock pipe because the stock mufflers are anchors.  Powroll made up pipes for the early side port bike.  EBay would be a source or you can fabricate one yourself.

Pat would be a possibility for building, or Powroll.  Pat will make more power than anything except the most radical stuff that Powroll would put out.  Powroll CAN build anything that you want.  Money is the key.

Swiss

The Bill Bell Honda article says that there is a 20 lb difference in the two complete frame/swingarms.  Don't think it is quite that high, but have never weighed a stock frame. 

Swiss

I have a bare C&J MX frame in the garage along with the swingarm.  I can weigh them but we need someone to weigh a bare Honda frame, both early and late versions.

Swiss

My bike is still completely together, so there's not much I can do right now. We'll need someone else to help us out.

Hey Swiss,...Check out this photo. This is a 1974 Champion framed XL350. This is one of the best looking XL-CR VMX bikes I've ever seen; ...next to that Buck Murphy "Works bike". The black rims makes this one look more modern....Same for the aluminum handlebars. I like the heat wrap around the exhaust too. Plus, he's painted the motor black as well. Very trick !!! Check out the black custom made air box. Looks like he's even polished for lower fork legs. Also uses a CR Elsinore gas tank and a different breaking bar on the rear hub.

Here's another nice bike...Not sure of the year but it looks like a center port. It uses a C&J frame with C&J swingarm. It's XL250 with a (290 kit). Has a long travel suspension for EVO class racing. Has an Elsinore gas tank, forks, and wheels. The black paint has been removed from the hubs...Renthal handlebars, Ohlins shocks, and a YZ125 seat, plus much more. The bike was missing its exhaust at photo time. Very nice !!!

Mark,

Have you got larger pics of those two XLs?  Send them to Geoff so that he can get them on the web site in larger images under misc. C&J etc...  Hard to see the detail in small photos.  Both of them look good.  The 350 with the wrapped pipe would be better off running either a stainless pipe or ceramic coated.  Will be intersting to see how the pipe runs on the 250.  You can see on the 350 that it was run through a cut in the side plate.  Both side plates look the same which leads me to believe that they might be C&J plates.  C&J will sometimes make up replacement parts for the older frames, so you might check with them about some side plates when you find a rolling chassis to work with.

The 250 looks really clean and I would just trim the back fender sides a bit.  The seat fits well and works with it.  The 350 looks more like a hard working bike.  A little rough but sorted out.

Swiss

Mark,

A friend of mine lives in Austin and has a side port engine that is a little rough.  I can send you his email if you are interested in working with a second engine rather than tearing yours apart.  You should run the later model 3rd and 4th gear sets at a minimum, but the Websters would be the best regardless of the year.

Swiss