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Topics - alexbrown64

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Honda / Honda QA50 Beast
« on: July 22, 2018, 05:33:02 PM »
The K0 Honda QA50 came out about circa 1970.  Two speed fun bike that was bullet proof.
Nearly 50 years on and they are quite rare and expensive.

This one popped up on Gumtree and was screaming for me to take it home.  Its hammered, but runs OK, and its for the daughter to put around on, while the boy zooms around on his bikes..

I do already have a nice restored sprout green QA in the mancave, but its too good and rare to ride.  This one is going to be perfect for a bush basher.

A lot of guys on here would of cut their teeth on one of these back in the day.  Me and my brother did.  Dad got two for $400 and we spent all summer bashing around on these.  We even raced them at the local club against a couple of other bad dudes on QA's...

Those were the days.... I had ski goggles, and my brother had to wear a beanie under his helmet because it was too big.  But we were kings of the bush....

I remember dad taking this pic of me when i was 12....

Eventually both QA's died and wouldnt run.  Dad took them to the shop to get fixed.  When we picked them up, the service guy said "do you guys know about cleaning air filters??"  We all nodded no..... Bikes ran great again once they could breath..

Now, years later, this one is for the daughter to enjoy.  She used to ride the other one a few years back and really enjoyed it.. this is her enjoying a ride on the bike before i did the rebuild and changed the colour from gypsy yellow to sprout green...

A recond one looks great and make a great pit type bike.
The one below is in Sprout Green and has been lovingly restored...

I hope we can have a few fun years out of this old girl..


Tech Talk / Coil Ohms Readings
« on: July 19, 2018, 06:31:28 PM »
Well, i have absolutely no spark whatsoever on my little YZ80E.
It has the outer rotor style magneto assembly.
The Yamaha book i have for the year says the  Primary coil should be 1.0 Ohms
The secondary coil should be 5.9K Ohms.  And it doesnt mention a value for the tiny pulser coil.

I have uploaded a pic (below).

The exploded view diagrams online refer to both the larger coils as source coils.
I am getting about 359 Ohms through the brown wire which leads to the biggest coil.
I am getting nothing through the smaller coil which has a red lead. No Ohms and it seems to test as an open circuit.
I am getting about 9.9 Ohms through the pulser coil which is a white lead with an orange stripe.
I have tested the smaller coil lead right back from the plug to the coil, and i get a reading that the cable is OK.

So, my questions to all you guru's is... Which coil is primary and which is secondary?
I could replace the smaller coil with the red wire, but do the other values sound correct?



Yamaha / 1978 YZ80E Rebuild
« on: May 30, 2018, 12:54:47 AM »
Well, as usual i have bitten off more than i can chew.
My first real MX bike was the YZ80E.  My eyes nearly bugged out the sockets in 1978 when they arrived in the showroom. Euro white, Monoshock.. what a weapon.  Dad got me one for Christmas and i set about racing it on the sand tracks of WA.  Unfortunately, the E had a great 5 speed engine, but the frame was plagued with problems.  In fact, i broke my knee on it and 40 years later i am still feeling it.
Great looking bike and went like a rocket and lots of memories.  I have a 79 YZ80 coming so i was looking for parts.  An E pops up on Ebay with a bunch of original parts and NOS stuff.  I grab it, and now i have an E and an F coming on the truck to WA.

As this is a VMX forum, i doubt there was a kid around 78 that didnt admire the E.  The 79 F was a far superior bike, but thats another thread.

This is the old girl i have coming over...

And she also comes with these parts and more..

The guy i bought it off is a bike nut too, so we had a good chat. He has 4 YZ125K's!! That beats my two!!

Anyway, i have started to prepare for the arrival and build.  Searching for parts, the E came standard with Takasago rims.  I have found two NOS rims.  Also, i have located a NOS frame gusset kit complete with instructions.  This kit will be tig welded into the frame before blasting, zinc coating and powder coating.

Almost all the plastics are original, but i will have to use a DC front mini bike plate.  The E used the special Yamaha mounting hooks and rubber band. 
Lot of work here, but it will be a labour of love. 
Still got to get cracking on my YZ125G and all my other projects, but this is going to be fun!!


Yamaha / 1979 YZ80F
« on: May 18, 2018, 10:23:24 PM »
Hi gang,

I have added a new bike to the stable.  A 1979 YZ80F.  Had one new back in the day. Had a good season on it, as it was a rock solid mini racer.
Anyway, i have started collecting parts and am stuck for a filter cage. I believe the filter cage is the same for the E, F and G. Part number 2J5-14458.  I have searched all my regular hunting grounds and i have hit a dead end.
Anybody have a spare tucked away? Pic below of the cages was grabbed from Facebook...

The idea is to get her ready for the boy to ride (with the XR75) in some VMX meetings just for a bit of fun... then do a full rebuild later on.

Will add progress reports..

If anyone has any other nos parts they want to sell, i would be very interested. Especially plastics..


Yamaha / YZ80A $1500
« on: October 15, 2017, 12:08:47 AM »
YZ80A on gumtree for $1500.  Dont know much about them but this one looks like it could be a great bike.


Tech Talk / White Smoke
« on: August 26, 2017, 01:16:12 AM »
Had a great day out at Ducks Nuts Ride Park 2 hours out of Perth. Went with a mate who has a CR500.  I took both my YZ125K's.  Run the yellow one in with its new ProX piston.  However, after about 30-40 minutes on each bike, they both blew white smoke and died. Still kicking over but no life.  I pulled the plugs and both had antifreeze on the plugs.
A couple of things... i used a torque wrench to torque up the yellow bikes head (18ft/pounds 25nm).. but it never felt very tight. The white bike had a lot tighter head nuts using a 12mm spanner "hand tight".. both done in a crisscross pattern.
The white bike had the rad cap swapped out for a 1.6 bar one, as i was loosing fluid through the overflow. 
Both bikes use after market Mitaka head gaskets.

Just wondering if you guys have any idea's on what can cause the problem with both bikes. Does anyone use yamabond either side of the head gasket.. could the head studs be stretching, cap holding too much pressure, bad quality head gaskets, head not tight enough, any other things??

Will order a few OEM head gaskets anyway, but i also have a few more new Mitaka head gaskets.
I haven't pulled the heads off yet, as we only went riding today.. is there anything i should look for?
Did some research tonight and Wiseco do produce a 58mm head gasket.  Have put 3 hours on this top end without a problem, but perhaps with the higher pressure cap, something has let go. Will also order the W4053 gasket kit.

One other thing... the white bike has a 2mm oversize piston. Have been using a stock size head gasket. 

Cheers guys...

Honda / New XR75 K1 1974 Project
« on: August 19, 2017, 08:30:26 PM »
Well, my sister sends me a pic of this bike today and says her partner picked it up for me..
Checked serial numbers and starts with 11..... she's a 74 K1.

Luckily i have just purchased a full Jane zinc kit and heaps of other goodies to rebuild VMX bikes. She seems to be mostly all original, but the side number plates seem to be painted like a 75.
Lots of time to be spent on this old girl...



I want to get the swingarm powdercoated on the YZ125G.  I had my XR500 swingarm powdercoated silver once, and it looked grey. 
Has anyone had any luck powder coating a swing arm silver/aluminium and looks like the original e/f/g painted swingarms.

Also, has anyone had their fork legs clear powder coated.


Yamaha / YZ125G Build
« on: July 07, 2017, 04:19:47 PM »
Well, i am just about to test out my OneDrive Microsoft account.  Had it for years and never really used its features.  Its part of my HotMail account. My Photobucket account has gone mad and is asking for big bucks.. wont be using that again..
So here goes.
I raced the YZ125G back in 1980 as a 16 year old.
Here is a Pic of me on the new old girl...

OK, that works good.. free, reliable and easy.  I just uploaded my pics to my OneDrive account, select the pic, click the embed tag.. it generates the code which you copy.  I then put the code between the tags and bobs your uncle.


Wanted / Bridgestone M22
« on: July 07, 2017, 03:50:34 PM »
Hi, chasing a Bridgestone M22 for my YZ125.  It came with a M20 rear, but that was discontinued about 30 years ago.. noticed the M22 was almost identical and was only discontinued a few years back.  After 100/100/18.  Anyone know of any lurking about.

Bike Transport / Mount Barker, SA
« on: June 29, 2017, 11:38:23 PM »
Anybody around mount barker, SA area that could help me get a bike, and help get it to Wa?

Wanted / 1980 YZ125G
« on: June 29, 2017, 12:38:41 PM »
Wanted is a YZ125G. Can be in bits, partly restored, restored..old project you can't finish etc.. Will need help getting it to Perth.
Anything out there?


Bike Transport / WizMe
« on: October 29, 2015, 01:43:24 PM »
Anybody used WizMe to send bike parts? 

Seems almost to good to be true..I just had a quick search online for courier company's. This one may be quite cool for anyone wanting to send bike parts.

You buy some boxes from them delivered for about $30.  You pack your stuff in their boxes and they pick up and deliver aus wide.  I got a quote from Ipswich to Rockingham using a 25kg box for just $16 door to door.  You get 4 x 25kg boxes for $30 delivered to your house (The boxes come in various sizes, see website), and then pack everything in and send.  I reckon i could get most of a bike in parts door to door for under a $100.  Here are the 4 boxes sizes.


Yamaha / YZ80F
« on: October 21, 2015, 10:12:30 AM »
Missed out on this YZ80F for $400 in Adelaide.
Looks in good overall condition but check out the front forks.... some people....


For Sale / 1984 YZ125L Parts
« on: October 02, 2015, 11:48:51 AM »
I have a few L parts for sale for an 84 125L

Exhaust- You would think it was practically new... $75
Cases- Great condition - Matching set for $75

Can post at ur expense.  Can use PayPal or direct debit. Can send Pics.


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