Topic: 1974 Rickman-Honda 750 CR replica/tribute

[slikwilli420]

For the frame, definitely stick with 0.065 DOM tubing. DOM is substantially stronger than regular ERW steel, and approaches non-normalized chromoly for strength. Its not quite there but closer to CrMo than it is to ERW. Its a solid choice for strength and ease of welding.

Not sure what diameter your swingarm tubing is, but on a Seeley swinger for instance, the tubing is pretty thin wall (like an 0.085-ish), but is like 1-3/8" or so, making it light and strong. The 0.120 is probably overkill, but you likely won't notice a real weight penalty, only a bit more stiffness, which isn't a bad thing.

[kosmjon]

The .120 DOM for the swingarm will be plenty strong without added bracing, unless, you are going nuts on the HP. 0.120 walled tubing is about 2x thicker than stock and the modern steels are far stronger than 40 year old stuff.

For the frame, definitely stick with 0.065 DOM tubing. DOM is substantially stronger than regular ERW steel, and approaches non-normalized chromoly for strength. Its not quite there but closer to CrMo than it is to ERW. Its a solid choice for strength and ease of welding.

Not sure what diameter your swingarm tubing is, but on a Seeley swinger for instance, the tubing is pretty thin wall (like an 0.085-ish), but is like 1-3/8" or so, making it light and strong. The 0.120 is probably overkill, but you likely won't notice a real weight penalty, only a bit more stiffness, which isn't a bad thing.

I really appreciate these recommendations guys!  I was mainly guessing on wall-thickness and erring on the overkill side. 

[754]

 I would not use that fixture for a swingarm, looks flimsy, lke stuff can move and pull.
Do you have a buddy with, or access to a milling machine ?

[kosmjon]

I would not use that fixture for a swingarm, looks flimsy, lke stuff can move and pull.
Do you have a buddy with, or access to a milling machine ?

I might.  Assuming yes, and we could machine up some kind of fixture -- what should it look like ?

[kosmjon]

Getting ready to pull trigger on tires. Someone mentioned the 4.10 Dunlops would be a tight fit in front and they are a bit wide for a WM2 rim.  One source I have says the front was a 3.50x18.  Can anyone confirm if the front was 3.50 or 4.10 ?

[calj737]

I would not use that fixture for a swingarm, looks flimsy, lke stuff can move and pull.
Do you have a buddy with, or access to a milling machine ?

I might.  Assuming yes, and we could machine up some kind of fixture -- what should it look like ?

For best results, you'd want the legs of the swing arm clamped down, and the joint of the leg/pivot locked in. The more you securely clamp steel while welding, the less the distortion and movement. Pay close attention to heating areas extensively and allow proper cooling.

Since the part appears to be tacked to the pivot, for final welding of that coped joint, I'd want the legs locked together and locked to the table to prevent movement away from each other. Weld 1 leg at a time, let cool, unclamp, then flip and do the other side.

[754]

I like to see something more positive to locate the parts and prevent movement.
Fist off determine if you wil, use the fixture again for another arm or different arm, then you want length/width adjustability.
 The pivot tube, i would probably use blocks that are bored to fit the pivot bolt, then fit to a keyway or pinned in place with dowels., try to prevent movement while welding.
 The way it is in the pics, it looks like the pivot tube can get pulled over while tacking.
 I am not a welder, but i would tack everything first, then wel part of the tube to pivot,then jump to the other side..alternate back and forth.
If you have the elements of the fixture high enough like 1.5 inches of the plate, or cutouts in the plate...you can probably weld 3/4 of the weld before, turning the part over to finish

[calj737]

If you have the elements of the fixture high enough like 1.5 inches of the plate, or cutouts in the plate...you can probably weld 3/4 of the weld before, turning the part over to finish

Frank, when welding tubes (as the arms are) that are closed at either end, you either need a vent hole, or you can not finish weld them in a single, continuous pass. The gas and pressure from the heat will blow out the weld. To avoid this, you drill a small hole in the pivot tube where the arm connects, or, you weld 3/4 of the tube, wait for it to cool, then weld it closed quickly. 1-1/2" of space above the plate won't let a TIG torch underneath, even close to getting 3/4" around.

[754]

I did say stitch weld.. I am aware of the gas issues.
 If the fixture element are say 3 inches above plate, you can get pretty far around, but sometimes cutouts will help.

In the pic he shows, I am thinking they tacked heavily..everywhere, then removed arm to finish weld (probably. Kept a tube and bolts between axle plates). This then is followed, by checking and probably a straightening operation......its probably most time effective if only doing one or two pieces.

[Steve_K]

I am not a welder, but I have made fixtures that needed welding to complete.  That said, the shop I was working at had several welders,  but only one who knew how to weld with minimal distortion.  That man made my job much easier to get the fixture so it was straight.   A good welder is a good thing.
Steve

[754]

I hung around a few expert welders heavy on the tig, that passed on a lot of tips..
 I always try to suck up some knowledge so to speak..
 Some pretty cool stuff people are building out there...

[kosmjon]

I appreciate all the great tips guys.  I surely would've missed the vent holes.  I have seen them my stock frames and swingarms over the years and never really thought about what they were for. 

Tips on securing the parts during the entire welding process make a lot of sense as well. 

I have only 4 years of on-and-off welding experience using my Eastwood Mig 175.  I feel I've gotten better over time, but this will be a real test.  I would love to use this project as a reason to add a Tig welder, but I've not sure my budget will allow it plus I'd be starting over my welding learning curve all over again.  I will take my time and I think all will turn out OK.

[kosmjon]

My copy of the Rickman assembly manual has arrived. As I suspected it has lots of great exploded parts diagrams and parts lists which will help a lot.

[slikwilli420]

That may be the best road map for this project you can get. Which one do you have? Honda or Kaw? Which forks are shown on the cover and on the front end section?

[kosmjon]

That may be the best road map for this project you can get. Which one do you have? Honda or Kaw? Which forks are shown on the cover and on the front end section?

It is the Honda one and it also looks like it covers triumph is well


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[calj737]

If you are going to MIG that swing arm, might I suggest you weld the pivot tube/arms first, and do so in 4 1/4s. 12:00-9:00, then 12:00-3:00. Do the other arm while the first cools, same 2 steps. Let cool, flip over, and repeat. MIG welding downhill is far better for penetration than welding uphill with MIG.

[Stev-o]

Which one do you have? Honda or Kaw?

Theadjack: here is a Rickman Kawasaki project bike for sale:

http://www.ebay.com/itm/1974-Other-Makes-CR-/222371975969?forcerrptr=true&hash=item33c6671321:g:QoQAAOSwa~BYcvUf&item=222371975969

[SOHC4 Cafe Racer Fan]

Love that Rickman bodywork.

[754]

Looks like its got the 1 5/8 fork on it, as did the OP,s bike...... Hard to find

[slikwilli420]

Yeah I noticed that to frank. Remember there were 4 versions of front ends. The 38mm and 1-5/8 forks with single and dual disc. Either dual disc front seems far rarer. Wonder the cost difference?

[Scott]

Hello

When it comes time to buy body work, I have used airtech and was very happy with them.  The guy is very easy to talk to and really wants to help.  He goes through it carefully with you on the phone and then gave me little discounts from their listed price.  I think he even sold me the pingle fuel taps for half price. I think I saved about $200

He also put me in contact with the screen manufacturer and organised it to come in the one delivery from air tech

I haven't fitted the body work yet but it all looks good.

Scott

[kosmjon]

Hello, When it comes time to buy body work, I have used airtech and was very happy with them.  The guy is very easy to talk to and really wants to help.  He goes through it carefully with you on the phone and then gave me little discounts from their listed price.  I think he even sold me the pingle fuel taps for half price. I think I saved about $200
He also put me in contact with the screen manufacturer and organised it to come in the one delivery from air tech I haven't fitted the body work yet but it all looks good.
Scott

  Wow, thanks this is great news. I was hoping that since the total was gonna be ~$1500 they'd work with you a bit.  About how much was shipping (for my budget planning purposes.) You have a thread going on this build, I presume?  I will seek it out.  Buying of all this will have to wait until I sell another bike.  Actually, this one to be specific.  After I give the wife her cut to help pay for my shop, I should have enough to pull the trigger on these parts.

[slikwilli420]

Airtech makes some nice stuff. I bought the full fairing, seat and inner fender for mine. I think I might cut down the full fairing to be more of a half fairing style, but that is yet to be determined. I personally like the steel tank with cover model of tank, which is what I have.

[kosmjon]

Airtech makes some nice stuff. I bought the full fairing, seat and inner fender for mine. I think I might cut down the full fairing to be more of a half fairing style, but that is yet to be determined. I personally like the steel tank with cover model of tank, which is what I have.

I didn't know they offered a inner metal tank with cover option. That does sound like a safer way to go for the street.

Do you happen to have a  link? 

And also I thinking ahead to ordering some aluminum plate.  Can you tell me the width of the following parts (if you have them):
Rear brake bracket: looks to be 5/16 or 3/8
Front brake bracket (welded? bolted? to front fork)
Speedo / tach bracket: looks to be 1/4 or so
Taillight / License plate bracket: looks to be 3/16 or so.

Thank you!

[754]

The front brake bracket is cast into the fork, they are very scarce. Betor made them for Rickman .
 I lusted after that fork since 72 , i finally started to build a sort of replica, using 41 mm leg assemblies.
 That would be ok if you build trees to suit..but, I got lucky and found Rickman trees, and fit the 41 mm to it but had to use shims . Rickman is 1 5/8 which is about 13 thou bigger than the 41 mm

Here is a pic, but I am keeping it for now..