• There has been a recent cluster of spammers accessing BARFer accounts and posting spam. To safeguard your account, please consider changing your password. It would be even better to take the additional step of enabling 2 Factor Authentication (2FA) on your BARF account. Read more here.

Julian's 2022 Dirtbag Challeneg build!

bikewanker said:
No mention of a new storage shed! CR 250 deserves dirtbag glory.
Click to expand...

Nope, no new shed. But I did some cleaning and have a bunch of stuff for free or very cheap listed in the BARF Parts For Sale. The CR250 is now comfortably parked inside the current shed :thumbup
 
Now with all of these bikes and parts that have been showing up I have a few options for Dirtbag. One starting point that I keep thinking about is this old RZ350 frame... or at least what used to be an RZ350 frame...

20220506_125944 by andbike, on Flickr

The back story began probably 12 or more years ago when I met one of my best friends through a Craigslist add. He was selling a bunch of RZ350 parts, so being an RZ fanatic I jumped at the opportunity. This was back before the prices for these bike started going crazy, so maybe more than 12 years ago.

Anyway, this frame along with an engine and a box of parts got horse traded back and forth between us several times. When the frame came into my possession the first time I took care of DMV stuff and got the title into my name and registration placed on non-op (because that's how I am).

Well, the last time we traded parts back and forth the RZ frame came back to me in four pieces! (yes, because my friend does shit like that!). The title is still in my name (my friend also doesn't pay attention to DMV stuff apparently) and still on non-op. Except for being in four pieces, this would be a great starting point for a Dirtbag project. Title is taken care off. No back fees. The frame has already been cut and modified (in addition to being in four pieces) so it has no restoration value.

Today being a holiday, I decided to take a break from the big customer project I've been working on for the past few weekends and work on a personal project. Well, guess what I decided to work on? Yep, the RZ350 frame!:party

Splicing it back together starts by filing the areas to be joined so that they are free on internal burrs. Then drilling holes that will later be filled with weld. And followed by grind the paint away to expose clean metal ready for welding.

20220530_153512 by andbike, on Flickr

Next up is to select metal tubing that is a tight fit inside of the existing frame tubes. The sections of extra tubing with add strength and keep the tubes in alignment during the process of grafting the frame back together.

20220530_155502 by andbike, on Flickr

Many of the spliced pieces need to be hammered into place due to intentional tight fits. All except the last two pieces which need to be a loose fit. The last two pieces need to slide completely up into the existing frame tubes while being fit back into place, then carefully manipulated back to where they overlap both sections of frame tube being grafted back together.

Because of where some of the tubes have been cut there is very little space for overlap with the internal sleeves. But some overlap is better than none.

20220530_161042 by andbike, on Flickr

With the sleeves ready and welded to one side, I can start reconstruction of the frame.

20220530_170137 by andbike, on Flickr

I leave a little more sticking out where the main cradle will be grafted back.
20220530_170417 by andbike, on Flickr

Now a bunch of rosebud welds to fill the hole and lock the sleeves in place.

20220530_183437 by andbike, on Flickr

20220530_183529 by andbike, on Flickr

20220530_183545 by andbike, on Flickr

And back to looking more or less like a usable frame again.

20220530_191848 by andbike, on Flickr

I still have a few more hours to complete the welding. Then I'll get out a sander and files and make the joint disappear. Buts that effort is for anther day:thumbup
 
augustiron said:
I'm surprised to see you zero gapped the sleeved butts and no bevel.
Click to expand...

To the contrary... I would have preferred to have no gaps at all of the joints. Gaped weld joints are a recipe for distortion. When the weld cools it pulls the metal together. So a good tight butt join is preferred. In this case I left gaps to approximate the material that was removed when the frame was cut, otherwise I would have made all of the joints tight. However, because of the sleeves I'm not worries about getting too much distortion. The sleeves should hold everything straight and prevent the gaps from closing. The two joints that are tight were because of stress in the frame pulling it closed. I thought about fighting it to open a small gap, but in the larger scope of the project it would have been a lot of extra effort that would not really be noticed.

As for bevels, also not needed. The frame material is only 0.065" wall so no issues getting good penetration. :thumbup

I will mention that a beveled weldment is often used on heavy plates and pipes. Just not needed on thin material. And sometimes weldment gaps are used with aluminum to prevent stress cracking at the joint.
 
Last edited:
So, I have a question.
Why would your friend cut the frame up like that? Did I understand he's done this to others?
 
gixxerjeff said:
So, I have a question.
Why would your friend cut the frame up like that? Did I understand he's done this to others?
Click to expand...

I figured someone would ask... What my friend told me was that he wanted to graft in a big single cylinder 4-stroke engine, but then moved on to other projects.

He builds not only custom motos (mostly from older gen Ducati Monsters), but he also makes beautiful furniture from old cut up motorcycle and bicycle parts. So I wasn't too surprised when I got the RZ frame back like this.
 
I've started reading Stephen Hawking's A Brief History of Time where he states that time is finite. Yes, time will eventually end! ...and then I read on the General sub-forum that BARF is dying! Well, FUCK, I better get going on these projects before time ends and BARF is dead!

Well, Dirtbag has not announced the magic word yet. Never the less, I'm still getting boxes in the mail from eBay. One box in particular came from China. It contains a relatively fragile part, so not only did they put it in a very flimsy box, they also threw some "gift tools" inside... WTF!!! I don't mind a free gift, except when the free gift could have easily destroyed the original package content during "shake n bake" shipping transit. Luckily, the content is still in good condition.

20220712_190550 by andbike, on Flickr

A few days earlier a large domestic box arrived. Kinda heavy. I wonder whats inside this one?

20220712_191005 by andbike, on Flickr

Okay, this last one is really weird... somehow this fatty expansion chamber shows up in my driveway. Some poser out in Oakdale somehow figured out how to make a pipe that would fit only God knows what kind of bike that hasn't been built yet. Really got my head scratching on this one. Anyway, got a cool pipe, just gotta figure out what it goes on:dunno

20220716_130349 by andbike, on Flickr

Anyway, hoping they'll say the magic word soon and we can find out what's in all of these boxes and what in Hell this expansion chamber is supposed to go on!:teeth
 
That pipe is a thing of beauty.
 
bikewanker said:
Tease!!
Click to expand...

Ha ha... I'm just giving you an idea of what its like for us Dirtbags who sit around for the first half (or more) of the year with no idea when the build-off is going to start. Check Facebook. Nope, not today. Check Facebook again. Nope, not today. And again. Nope, not today.

In the past I have done lots of sketches and even prepared elaborate CAD models leading up to the official build kick-off. This year because of some other very consuming projects I don't have a bunch of sketches or CAD models to share. My concept this year is to simply take a bunch of random parts and smash them together with minimal "new build".

Yesterday I did however sit down and sketched out a few ideas for the sub-frame which will be scratch built. So here are a few of those sketches. I've used a lot of tubing on past builds, with exception of the Ducati Monster I built in 2014 which used a lot of sheet metal combined with tubing. So I'm playing with ideas of integrating a bit of sheet metal into the sub-frame. Or maybe not:dunno

20220718_211954 by andbike, on Flickr

20220718_212049 by andbike, on Flickr

20220718_130943 by andbike, on Flickr

Anyway, I'm hoping this will get started for real very soon. Till then keep on enjoying these "tease" moments:twofinger
 
And so it begins. This year is extra special in that this is both the 20th anniversary and final edition of the DBC. That's correct. No more after this year:(

295338886_10158305908261330_5212871336523685165_n.jpg
 
Before I post my Day#1 activities, I feel that a little rewind is in order...

Going back to my plan #A. Because I've been buried in other projects this year I didn't have time to do an elaborate design with the usual sketches and CAD models. So my plan was to do a basic Frankenstein build where I'd just collect a bunch of parts and glue them together into something interesting.

On one of the FaceBook groups I came across this RD350 which I thought looks really nice with the CBR250 wheels and suspension. I don't care too much for the bodywork, but I like the upgrades done to the chassis. So with this as inspiration I found an RD400 frame in my shed that is titled and non-op'd. With the frame ready, it was just a matter of finding CBR250 wheels, forks, and brakes. The swingarm is 250 Ninja, so I found one of those. Then I even found a great deal on a Ninja 250 Penske Shock on CL. The plan was to use the RD400 engine out of my 2012 Dirtbag bike which also happened to be an RD400.

272885352_10158043582297587_7465620106219297378_n.jpg


Here's the RD frame and all of the pieces (sorry, not going to unpack everything just for a photo:x)...

20220221_164952 by andbike, on Flickr

Well, plan #A went to shit when all of these free motorcycles started showing up. Especially when several of them were given to my by Mr. Dirtbag himself. How could I not use at least some of the free stuff for my build.

So, plan #B is to use as much of the free stuff as possible. Here's the list of ingredients:

- Frame - RZ350, this was traded back and forth several times with a good friend of mine only for me to receive it back in four pieces after our final transaction. I consider the frame value to be free since its useless to anyone else.

- Engine - CR250, this is out of one of the free motos.

- Wheels - KTM 620 Duke, also free stuff.

- Forks - Yamaha FZ8 found on CL for $100

- Gas tank - CBR400RR (NC29), this is off a rolling chassis that a friend had given to Mr. Dirtbag last year, then Mr. Dirtbag gave to me.

- Seat and cowl - Ducati 1200 Monster purchased on eBay.

- Shock - R6, currently borrowed off another bike, but will need to find one on eBay.

- Exhaust expansion chamber - Custom made by Mr. Brian Turfrey himself.

Okay, so lets see how this is going to start coming together. First a disclosure... I took some liberties with the rule which stipulate "no chopping" until given the "GO". Since the frame had been cut into four pieces I consider "un-chopping" back into one piece to NOT be a violation of the "no chopping" rule since I was technically putting back (closer) to original. If someone has a problem with this, well lets see what you build and we can discuss semantics while on the ride:twofinger

Today I removed one of the frame cross tubes (actual chopping to remove features) and built temporary shock mounts. Normally I model my suspension in CAD so I have a good idea of what will work. This was more of a back of a napkin calculation so I have a rough idea of what should work. But still wanting to make a mock up that I can push on (it does feel good so far):thumbup

Anyway, here are some photos from earlier today...

20220724_161136 by andbike, on Flickr

20220724_161143 by andbike, on Flickr

20220724_173221 by andbike, on Flickr

At this point there are no bearings installed in the swingarm or headtube, so this a is a very rough mock-up of a rolling chassis simply to get an idea of the overall deign...

20220724_180122 by andbike, on Flickr

Here's the same loosely assembled parts with the Ducati bits just to see if the overall proportions are working. Lets just say I'm liking where this is going...

20220717_160330 by andbike, on Flickr

Okay, that was day #1. Stay tuned for more!
 
That looks great Julian. Interesting mix of parts as usual.

I am curious where you end up with sprockets on that thing with the dirt bike engine. You need to set it up for a few hundred mile ride, eh? And probably don't want to scream at redline the whole time?
 
kpke said:
That looks great Julian. Interesting mix of parts as usual.

I am curious where you end up with sprockets on that thing with the dirt bike engine. You need to set it up for a few hundred mile ride, eh? And probably don't want to scream at redline the whole time?
Click to expand...

Thanks Ken!

Yes, I also am concerned with the gearing. Stock gearing on a 1997 CR250 looks to be 13:50. Looking online, I see lots of people suggesting one tooth higher (14:50) on C/S sprocket for desert racing with a suggested top speed of ~75mph. I also will have a smaller rolling diameter with the 17" sumo setup. So I'm looking at 14:45 which is significantly higher than the desert setup. I also purchased a 15 tooth C/S sprocket to go even taller if needed. I'm gonna try the 14T first as it will allow for a case saver to be used (extra security). I'm may also look at going a bit smaller on the rear sprocket so that I can use the 14T and get a little taller. Anyway, I'll probably end up with a variety of sprockets and do some experimenting when time allows.
 
In case anyone was wondering what keeps Dirtbags up late at night... we sit around making paper dolls:party A few years back I worked in an advanced concept engineering group at GoPro. We were in early development of the Hero 5 camera. I was involved in the design of the main housing. One of my sub-tasks was to validate the routing of flex circuits withing the housing. The process involved CAD design, then printing the circuits onto regular paper. I would then cut out the paper and fold it into the correct shape for the test fit. We referred to this process as making "paper dolls". So there you go, making paper dolls is a legitimate engineering process:teeth

So here I am at 2am on a school night making paper dolls to check my engine mounts and shock mounts. The chassis mock up in outside in the dark, so I'd be back an forth between kitchen table, computer, and outside in the dark with flashlights and caliper. After a few adjustments and re-fits, I'll save the flat patterns and send out for laser cutting.

20220728_003922 by andbike, on Flickr



Meanwhile, during the day its starting to feel like Christmas in July with all of the packages that continue to arrive (many more still on the way).

20220728_184422 by andbike, on Flickr


Because I'm build a motorcycle from just a few basic major components, rather than from an existing complete bike, there are many many small parts that need to be purchased. Some of those purchases don't go as planned. For example I purchased a new aftermarket CR250 radiator only to find out its too tall to fit in front of my RZ350 frame. So a few measurements of my SV650 radiator confirms it should work. So another cheap aftermarket radiator is purchased off eBay. And so is the life of a Dirtbag... at least this one:twofinger

20220728_185826 by andbike, on Flickr


Just like the packages of parts... more to come!
 
You must log in or register to reply here.
Back
Top