OzVMX Forum
Clubroom => Tech Talk => Topic started by: RW490 on May 07, 2014, 10:57:36 pm
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Hey guys I have pulled the old chassis out of the shed and need some help from forum members. I am in the process of doing up my Bultaco Astro 250 1976-1977 model number 163.
As this bike originally has no front brake as std and most have never had a brake fitted to the front begs the question. Can this bike be raced in the pre 1980 class Australian flat track championships with no front brake. The rear brake std is a hydraulic disc and if I want to fit new wheels and hubs, where do I stand under the current rules. I would hate to change the original design.
Also it will be fitted with a Pursang 360 motor as this is all I could find.
Can anyone help me as I am out of touch with the rules.
Regards Rick.
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Current rules say brakes front and rear. It was made pre 78 so should be eligible for pre78?
Cheers,
Steve
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yes even hagons need 2 working brakes as well
jim
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Yes, as above. There is no Pre80 class in the MoMs so you fit nicely into Pre78. Congratulations, they are an iconic model
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Rick,
When it's time to sell, let me know!!!
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Hey Rick,
I put a conical Yamaha front hub in my Astro. Very easy to find, cheap and they work well.
(http://i1258.photobucket.com/albums/ii534/yamaico/SD530085a_zpsb659adfb.jpg) (http://s1258.photobucket.com/user/yamaico/media/SD530085a_zpsb659adfb.jpg.html)
Used the same hub in my RD:
(http://i1258.photobucket.com/albums/ii534/yamaico/DSC01529a_zpsbc96ce67.jpg) (http://s1258.photobucket.com/user/yamaico/media/DSC01529a_zpsbc96ce67.jpg.html)
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Does an Astro jug fit on a pursang?
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How early did the twin pull yammy hubs come out?
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Does an Astro jug fit on a pursang?
Sure does - good thing about Bullys, heaps of mix and match.
How early did the twin pull yammy hubs come out?
YZ465G I believe. Too new for pre '78.
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I use the same hub in my 360 Yamaha short tracker too.
(http://i1112.photobucket.com/albums/k495/firko2/flattracker007_zpsf888bc9b.jpg) (http://s1112.photobucket.com/user/firko2/media/flattracker007_zpsf888bc9b.jpg.html)
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Thanks for the info guys, it's much appreciated. I read the full rebuild story on the RD last night and was amazed at your attention to detail. It's a credit to you.
I am also interested in what size 19" rims are on the Astro, ie 1.65 / 1.85 ???
I am going to fit new wheels so I want to get it right.
Feel free to put any or all pictures of your bikes up as I am toying with having my frame jigged and then selling unpainted Astro copy chassis without engine mounts so that you can fit any motor from scratch and the geometry will be spot on.
Hope to get some feedback, thanks again guys.
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over the years i have been looking at usa flattrackers i have seen all sorts of motors in astro frames even xt500 yamahas
most of the guys over there think i am mad taking out a fast cr250 1973 motor to slot in a astro motor in my champion.an astro new frame would go perfect with my new astro motor.now how do i get the rest nos
jim
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I have 2.15 rims on mine Rick but it's more about what I can find than the actual size, although they look good and the tyres fit up well. You could most probably get away with 1.85's but I wouldn't go any smaller than that.
I think you would be on a winner making frames, as the Astro works regardless of the motor.
Let me know if you need any dimension checks or any other information,
Pete.
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G'day Rick,
I know somebody that would be very interested in one or two frames if you went ahead with your
plans. Keep us posted. The Astro is a great looking bike. Do you have the fibreglass? If so,... that same person would be keen to do some moulds/forms. Hmmmm,,.....
regards Mark
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why dont you just get the finished product from forum member matcho mick(moto tumbi fiberglass)he has molds for most things
jim
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I'm rebuilding my #106 to run 19 x 2.15 front and back and run a front tyre on the back. The newer swing arm might be wider than mine so you probably could run a 2.5 and a rear. The pre 78 clamps would also be wider. If you can get 2.5's and they fit go for it.
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(http://i1061.photobucket.com/albums/t465/rw490/imagejpg1_zpsba92a9d8.jpg) (http://s1061.photobucket.com/user/rw490/media/imagejpg1_zpsba92a9d8.jpg.html)
As you can see my rebuild is just starting. I am borrowing a mates Astro so that we are comparing two frames and then getting the cost for jigging and manufacture. The guy that will be doing it for me is an aeronautical engineer and currently makes featherbed norton chassis.
I will work out pricing one I have spoken to him and presented him with the two examples.
What I would like to know is the type of steel required as I think the originals were like a Reynolds seamless tubing but some of the last ones were chrome moly ?? He can do it either way. If someone has some more info on the materials used it would be very helpful.
This guy can also CNC triple clamps to suit, so I am very interested in the dimensions for the wide front end.
Also can the front brake be a disc or is that not allowed.
Appreciate the help guys.
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G'day Rick,
I know somebody that would be very interested in one or two frames if you went ahead with your
plans. Keep us posted. The Astro is a great looking bike. Do you have the fibreglass? If so,... that same person would be keen to do some moulds/forms. Hmmmm,,.....
regards Mark
Hey Mark
Yes I have the glass as per the photo and would love to start a match and build through forum members. That is a great idea.
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why dont you just get the finished product from forum member matcho mick(moto tumbi fiberglass)he has molds for most things
jim
That's the go Jim, as I said to Mark we could have a match and build through forum members at good pricing so that someone could take their motocross motor out and slip it into an Astro copy for a flat track meeting.
Sounds like a plan to me.
Rick
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Great Idea Guys
About 10 years ago I imported a Champion Bultaco Flattrack frame and sold it to a friend
He was very into VMX / VFT at the time and lots of forum members know him
I have a few Champion single and double down tube frames
As much as I love Astros and Bultacos I think a Champion is the frame to copy as a Universal
I would gladly lend them all to you if that will help
Whilst on jigging a Universal frame
I have a Brand New Trackmaster in pieces for the XS 650 and have Firkos adjustable TT frame as a template that needs to be copied as well
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Hi Rick,
This is a set of triple clamps I made for my Astro. They are 195 between centres which is the norm for USA flat trackers.
(http://i1258.photobucket.com/albums/ii534/yamaico/SD530025_zps9c0e8ab0.jpg) (http://s1258.photobucket.com/user/yamaico/media/SD530025_zps9c0e8ab0.jpg.html)
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Mark are you talking about Steve? J
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Guys I am salivating with all this talk of building frames etc! Let the short track revolution begin!
Anyway, there are plenty of guys in the state doing cnc bits & bobs, but if can do it yourself all the better (It's about time). To cut out the trial and error it might be best adopting the Chinese business model and getting some that are proven performers and replicating if you wanna do it yourself.
Clamps, quick change hubs, swing arms bla bla bla.
My favourite aftermarket frame id the knight, love those things for some reason.
Cheers,
Steve
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(http://i1061.photobucket.com/albums/t465/rw490/imagejpg1_zpsba92a9d8.jpg) (http://s1061.photobucket.com/user/rw490/media/imagejpg1_zpsba92a9d8.jpg.html)
As you can see my rebuild is just starting. I am borrowing a mates Astro so that we are comparing two frames and then getting the cost for jigging and manufacture. The guy that will be doing it for me is an aeronautical engineer and currently makes featherbed norton chassis.
I will work out pricing one I have spoken to him and presented him with the two examples.
What I would like to know is the type of steel required as I think the originals were like a Reynolds seamless tubing but some of the last ones were chrome moly ?? He can do it either way. If someone has some more info on the materials used it would be very helpful.
This guy can also CNC triple clamps to suit, so I am very interested in the dimensions for the wide front end.
Also can the front brake be a disc or is that not allowed.
Appreciate the help guys.
Reynolds is/was CrMo tubing manufacturer. Originally manufacturing tubing for bicycle frames. A would think that majority of Reynolds tubing is CrMo.
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why dont you just get the finished product from forum member matcho mick(moto tumbi fiberglass)he has molds for most things
jim
Can you supply me a phone number contact please Jim.
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Champion Astro frame on its way to my shop, I will email Jim the photos
he can post them
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Champion Astro frame on its way to my shop, I will email Jim the photos
he can post them
I haven't been able to get the other Astro frame yet. Hopefully this week coming. I will be interested to see the pictures of the Champion frame.
As my Astro originally had no brakes do I fit drum style or can I fit a disc as I want to try and ride this bike at the titles next year. If the bike must stay period is what I mean so that it is legal.
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As my Astro originally had no brakes do I fit drum style or can I fit a disc as I want to try and ride this bike at the titles next year. If the bike must stay period is what I mean so that it is legal.
The rear disc will be OK as it was standard equipment and I would think that as it had no front brake from the factory that you would be able to use a period disc brake off anything on the front. Having said that, if it was me I would still go for the conical Yamaha hub on the front.
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Thanks for the reply Pete. I will do the same as yours I think.
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No worries Rick, I reckon that's the way to go. You should be able to find any number of hubs and backing plates at your local wreckers. You could probably find a magnesium one if you look hard enough.
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(http://i1061.photobucket.com/albums/t465/rw490/imagejpg1_zps27301b4f.jpg) (http://s1061.photobucket.com/user/rw490/media/imagejpg1_zps27301b4f.jpg.html)
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Good pic of Chris Kelly leading ???? on Charlie Edwards' Yammie twin?? I 'm sure you will tell me Rick!,....
and the year.
regards Mark