Planet Minis

alpinaclone

I put up a thread a couple days ago about a 79 Z I just bought. The reason I picked it up was for parts for my son's (right) QA50 project.

I almost said forget the QA and just get the Z up to snuff, but I like the lighter weight that the simplicity of the hard tail frame brings, especially for a kids 1st bike.

I will be using the engine, wheels, and now the forks of the Z on the QA frame. I had some almost new CRF50 forks I was going to use, but as you guys probably know, they are too narrow to work with the Z wheel. Fortunately the crf guts go right into the Z forks, along with thier stiffer springs, handily replacing the bent and booger welded originals. The Z rear wheel also directly slots into the QA frame and lines up perfectly with no mods. The headstock and steering stem interface are another matter entirely, I havn't quite worked out how I'm gonna tackle that yet.

Here are a couple mock up pics;
One wth the Z tank:


QA tank:


Which does everyone prefer?

I also can't decide if the rear end looks funny or not. I know an exhaust and fender will take up some space but If I can't get it to look right I'll probably go back to the Z frame.

Matt

mexicanyella

Now see, I LIKE the look of hardtails when they're stripped at the back.

Looks like a fun project. I love the QA tank; I'd go with that but then again if it's for your kid and the tank's in nice shape, you might cry a little whenever he leans it against a fence or tree or whatever. Or wipes out.

Where'd the QA's original motor go? Did it crap out due to 2nd gear trouble?

alpinaclone

The QA tank is not nice, it has some pinholes and a tiny dent, but I will make it presentable.

I bought "the QA" as a frame and a tank on a whim. I had one when I was younger, so I thought it would be neat if my boys had one too.

alpinaclone

More mock up pics. I have decided that I like the QA frame and that is the direction I am going to go.



That is an '06 CRF50 exhaust, I think it is almost perfect the way it sits. It will of course need some tweaking to clear everything, but I like the ridiculous length.

The engine will move back a bit and I need to shorten the forks about an inch, but I like the way this is heading.

mexicanyella

The fact that QAs and hardtail Zs existed around the same time makes me wonder if they share steering stem and head tube dimensions. I know my hardtail has a different arrangement than a softtail Z50A or Z50R; the head tube on the frame is a constant diameter its whole length and the ball bearing outer races are machined things that you tap into each end of the tube. The stem then has the usual cone inner races.

As I see it one thing you could do would be to find a set of Z50A hardtail fork uppers/triples/stem to work with rather than altering your frame or later-type stem. But from the photo it looks to me like you could trim a lot off the top of the QA head tube, surely enough to get it to work with the stem length you have. Don't know if the inner conical races are the same between a QA, A and R but I know the stem diameter and thread's the same, because I just test-fitted a Z50R top clamp on my hardtail forks yesterday and the top nuts are the same. Seems like cutting the head tube's top edge squarely after careful measuring might be the biggest issue there.

You may already know this but on the few hardtail forks, A forks and R forks I've seen apart, there are a few other differences besides steering stems: The A bikes hold the fork legs in the uppers with an aluminum collar with extremely fine threads inside it, which screw onto the lower end of the fork uppers. R bikes use a big circlip in there to do the same thing. And the roll pins that hold the lower leg to the spring, etc. are oriented differently between one and the other. I have one set of legs here that's drilled both ways so it can be used in either style.

That exhaust looks like it belongs there more than I'd have pictured.

alpinaclone

I really like the exhaust. And it was free, so the inevitable carnage that will be dished upon it by a 4 year old won't upset me too much.

As far as the front end is concerned, I am committed to these forks, the guts are all new and I already own them. The frame will be modified to suit. I will get them on there one way or the other.

Motor mounts are the first thing that needs doing. A lot hinges on where that 49cc beast ends up.

alpinaclone

I've been busy with other things, but have made a bit of progress. The frame is almost ready for paint. The engine mounts are done and it now has a Z neck to accept my shortened by 1.5 inch Z/crf50 forks.

Pics;

mexicanyella

Does it also have the first couple inches of Z frame spine? Looks like a weld took place there on the spine. If I'm seeing that right, how'd you do the joint? Does the Z tube slip over the QA tube, or is there an internal sleeve you rigged up or what?

alpinaclone

Yup, with a little massaging, the z tube fits over the qa tube, so it is plenty strong. A little weld and Robert is your father's brother.

I have made a bit more progress. I now have spark and I threw a bit of color on the tank. I may change it up, but it is growing on me. Not much left to do now.



I painted the engine quicky quick but it will be redone. I have a feeling that the old girl is a little sick, so I did not want to spend too much time prettying it up if I am just going to tear it down again.

alpinaclone

Also, I need some cheap metal fenders. I don't care how beat they are, I just need something to work with. If anyone has a twisted up set of hardtail Z fenders hit me up so I can add to the clutter in my garage.

mexicanyella

Hey, I'm digging the green QA tank. That's going to look cool.

I might have a slightly wrinkly and somewhat shortened hardtail fender...all the mounts are intact but the rear lip might need a little trimming/contouring/smoothing. It will end up slightly shorter than a '69-'70 hardtail fender, which is way shorter than a '71 hardtail fender.

You might be envisioning something a little nicer than that to start with, but if it sounds interesting to you I'll send you a pic and you can decide.

alpinaclone

Yeah, I may be interested. I am pretty good at making metal do what I want. PM me a pic and what you would be looking to get out of it.

mexicanyella

PM sent.