CB200 '73 tracker project - DONE :D

Re: CB200 '73 tracker project

I dig the tubular rear frame mod. I'm doing something similar to the "Dad and Daughter" Honda 175 twin I've been working on for ages. In my case, it started as repairs to broken lower frame tubes (where the swingarm plate bolted to my frame) but I ended up tossing the whole rear frame, too.
I'm using one of our Viper Dirt track seats, which is very narrow at the front, so my top frame rails fit inside the existing frame at the front and are a bit wider than yours at the back. I was able to find a prebent rear frame loop that fit almost perfectly. Have to get busy, finish up my alignment jig and tack and weld everything together. In my case, I did the tubing repairs following standard aircraft repair manual specs we use here in Canada, but I gather you made internal tubes or plugs so the new tubes all fit together and gave extra strength at the welds?
What seat are you using?
KEEP UP THE GREAT WORK!!!
Regards,
Pat Cowan,
Vintage Motorcycle Fiberglass

Re: CB200 '73 tracker project

thanks pat,

yes, we indeed used internal tubing. Bert made plugs on the lathe, both ends have a different diameter caused by difference in internal diameter sizes. (the new tubes have a thicker wall) On the second pic you can see it, the difference between the end going into the frame and the bushing is very small. After that, it is welded at both sides.




For the seat, I found a leather jacket in the thrift store. I like the very dark brown colour so decided to cut the jacket into pieces to use for the seat.
Seat will be DIY as well. The seatpan will be made out of metal, with some foam on top. I bought some closed-cell foam for that, looking i bit like this: http://www.austinkayak.com/products/1135/Closed-Cell-Foam-12in-x-24in-x-2in.html
Hopefully it will turn out nicely

Having a seat that fits right into the existing frame-tubes is very convenient indeed, but for my bike i like the seat straight instead of 'tail-like'. So we had to come up with a way to make it fit.

Looking forward to finish the project, all the welding- and technical stuff is more Berts thingy, but now it's time to see the results and put everything together . Just like you, i've been working on this project for ages now

Re: CB200 '73 tracker project

Frame slugs work well, just a bit heavy. I've seen them bored out before welding to lighten them up and make it easier to weld if you're using oxy-acetylene like I most likely will. I found tubing whose outside diameter was a light driving fit into the existing Honda tubing (drove them about 2" in) and left stubs sticking out about the same amount. The repair / replacement tubing I used had the same ID but a bit thicker wall and larger outside diameter for more strength (the original Honda tubing is mighty thin) and it was pushed onto the stubs - the repair is down low on my frame and isn't really noticeable.
Didn't mean to rob your great thread, should get up off my duff and take some photos and post them on my own thread LOL.
Once again, you're doing a great job! Keep it up!
Pat.

Re: CB200 '73 tracker project

I've heard mixed reviews on these. A lot of people say NOT to make them solid, as your joints WILL crack over time because the original tubes flex slightly, and the slug being solid makes it impossible to flex, thus cracking that spot. Either way, I dig your build!

Re: CB200 '73 tracker project

The heart shaped brackets are kick ass!

Re: CB200 '73 tracker project

MotorbikeBruno said:

I've heard mixed reviews on these. A lot of people say NOT to make them solid, as your joints WILL crack over time because the original tubes flex slightly, and the slug being solid makes it impossible to flex, thus cracking that spot. Either way, I dig your build!

Click to expand...

If anybody can chime in on this, please. I don't really understand how it could crack easily, just by riding it.
But if so, it's back to the drawing board. Bruno, could you explain why the welds on a normal frame don't crack? As there is the same amount of stress on them? I understand there has to be some flexibility in material but would a little tube inside the maintube really make it crack because of heavy pressure?
Our workshop-teacher didn't mention this possibility though he knows a lot about motorcycles.
And will it make any difference that there will be only a small girl driving the bike?

yawlright: thanks, i really wanted those girly details to make it really my bike. Something like a goodluck-charm or something =)

Re: CB200 '73 tracker project

Bons,
Don't get discouraged and try to drown your sorrows with a couple of litres of Navigator beer or something because you think you've done something terrible 'cause you haven't.
I asked my initial question as I had to toss a swingarm one time that had been extended by somebody who just welded in a piece of tubing - no sleeve, no slug, no nothing - and the guy was riding the thing all the time...scary.
I think what all of us "sages" were commenting on is maybe its something to think about for your next build - and I hope to see many, many builds from you.
As for myself, I guess I've been around stuff like this in aerospace for so long -you'd be amazed how much repaired tubing is out there, LOL, I don't give it a thought anymore.
I doubt whether you weigh 50 kg, and if your welder knows his stuff, you'll never have an issue. Your motor probably puts out 14 or 15 "real" horsepower too, so it's not like you're not overstressing anything, either.
Have fun with your build and don't listen to us grumpy old men too much.
Regards,
Pat

Re: CB200 '73 tracker project

This is awesome!
Keep it up.

Re: CB200 '73 tracker project

I'll see if I can dig up the threads, but seeing as a smaller person will be on there, and it's not being ridden like a dirtbike (off-road) or racing etc. You should be just fine. Maybe I was thinking of the swingarms when people lengthen those...Keep going on this build it is AWESOME.

Re: CB200 '73 tracker project

I have a question about the intake manifolds. If anybody with a cb200 could check, it would be awesome and greatly appreciated.

We've found cb350 (well, that's what the seller said...) carbs on a oldtimer-venue last week.
Guy wanted 10 bucks for them. To me, that's a 'can't go wrong' price
Bought them and working on them right now. I already found out the holes (yes, all of them!) are alligned so i only have to mill the tubular pieces that would go into the rubber intake manifolds on the 350 to make them fit. Gotta love Honda!

But, i ran into a problem wich i can't find the answer for. The intake manifolds of the 200 are crooked. Atleast, one is. Since i tore them off a gazillion times i don't know if it's supposed to, and if so, wich one is crooked. In the first picture you can clearly see the right carb is straight with the cilinder, but the left one bends inwards. Normally, that won't be a problem as the cb200 carbs are not on one rail or something. The 350's are however and i need to know if one of the manifolds on the 200 is crooked. Could be, for clearance issues or something..

The m6 blue rod is in there for measuring, i'm gonna make a new throttle axle from stainless and ditch the mounting plate. Cablestopper and such is going on a little mounting plate i still have to make.

On the second picture i'm holding the crooked carb straight but you can see on picture 3 it creates a gap between cilinder and intake. Do not want

Question once again: Is it original that one intake is crooked, and if so, is it the left or the right one? They're interchangeble so i'm gonna order another straight one. Just need to know if it's the lefty or righty.

Before you go and start a conversation about why i want it:

1. the ori's are 18mm and these are 20mm
2. they look a LOT better
3. easier to get needles and such for them
4. keeps me of the street

For some reason my phone goes crazy with the angle so it all looks crooked








Cheers!

Re: CB200 '73 tracker project

Definitely looks like someone dropped the bike and bent the intake. To my knowledge they are supposed to be straight.

Re: CB200 '73 tracker project

Hmm that's a bummer if it's bent. But to be honest, i don't think it's possible to bent it by the amount it is in right now and not break it. It's a fairly decent thickness.. Gonna go ebayin' for an intake anyway.
Thanks!

Re: CB200 '73 tracker project

Mine are straight as well. The intake is not solid metal all the way through, so is it possible it got stretched while leaning on something over time?

Re: CB200 '73 tracker project

Most def possible. Bike sat in a shed for couple years without jiffy or centerstand. Figured it out btw. i had a scrap piece of aluminium square tubing lying around and i drilled holes in them, as if it were the carburators. Wrenched it all down and the manifold was forced straight again. I left it that way overnight and it's all good now. Thanks!

Re: CB200 '73 tracker project

Hi Bons, I' m building a cb200 tracker too. I love your work!!!!
You can see my cb here:
http://www.caferacer351.com/forum/index.php?topic=1396.0

It's in Portuguese, so any doubt just ask!!!

In the beginning I thought to turn it into a cafe but...no! tracker

Re: CB200 '73 tracker project

Question - Started on the wheels, prepping them for powdercoating. Retainers and bearings came out like they were put in last week so that's goooood

The only thing i can't figure out how to take the rubber bushings out. If anybody can shine some light on that, it would be awesome:


And for all of you asking about the front brake, here's a preview
The cardboard will be aluminium or steel, not sure of that right now.

Re: CB200 '73 tracker project

I suspect that you have those on the wrong sides, but they are different for sure. I didn't believe it, so I had a look at a 200 head in the shop and for sure, they are not parallel. On this one, the right side is angled out slightly and teh left is almost straight.

Fortunately you need new manifolds anyway, so you can make them to fit the new carbs.

Re: CB200 '73 tracker project

Very interesting set up on the brake. Do you think the hole at the bottom of the fork will hold up? I mean the last thing that was mounted in that was the front fender not a really load bearing piece. But otherwise great idea!

Re: CB200 '73 tracker project

caveman592 said:

Very interesting set up on the brake. Do you think the hole at the bottom of the fork will hold up? I mean the last thing that was mounted in that was the front fender not a really load bearing piece. But otherwise great idea!

Click to expand...

For sure. Had a similar setup on my cb550f with a brembo 4 caliper claw and 320mm disc. okidoki

(middle of the first page)
http://www.dotheton.com/forum/index.php?topic=26406.0


Besides, the caliper wants to travel the route the disc pushes it. That's away from the lower bolt, but against the m8 bolt at the top. The claw will be just fine, it can't go anywhere and i've never seen a brake caliper mount snapped off. That's because they don't need to hold any power, they're just transferring it straight into the fork leg.
As the bike including the girlfriend will be weighing 200kg max@120km's i dont think we'll have a problem

Re: CB200 '73 tracker project

I see.