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Topics - alexbrown64

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1
Tech Talk / Coil Ohms Readings
« on: Yesterday at 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?



Cheers,

Alex


2
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!!

Cheers,


3
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..

Cheers,


4
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.

https://www.gumtree.com.au/s-ad/kelmscott/motorcycle-scooter-parts/yamaha-yz80-1974/1162582799

Cheers,


5
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...










6
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...



Cheers

7
Hi,

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.

Cheers,

8
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.

Cheers,

9
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.
Cheers,
Alex

10
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?
Cheers,
Alex

11
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?

Cheers,
Alex

12
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.

https://www.wizme.com.au/quote-flat-rate-shipping/

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.
 
https://www.wizme.com.au/shop/25kg-flat-rate-boxes-samples-a-x4-sizes-4-boxes/

Cheers,
Alex

13
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....



Cheers,
Alex

14
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.

Cheers,
Alex

15
Tech Talk / Yamaha powervalve adjustment
« on: September 30, 2015, 12:38:00 PM »
OK, just a question on the Yamaha power valve.  This one is on an 83 YZ125.  In the first pic, i can align the groove in the linkage with the hole in the case but i cannot put the second linkage plate on if i do this as it there is not enough adjustment in the plates so that it will stay in that position. The Yamaha manual shows a pic of the groove/hole aligned without a pin in.  The pin is only used to undo/tighten the nuts.  Alignment of the groove/hole should happen with the linkage relaxed and no pin necessary.  I dont have the adjustment in the plates for that to happen unless i do not fit the large linkage plate.



If i lift the large plate onto the powervalve, it throws out the groove/hole.  There is no adjustment left to align the groove/hole properly.  If i do align them, i have to lift the linkage rod up and tighten the nuts.  When i let the linkage relax again, it goes back down and turns the powervalve clockwise and misaligns the groove/slot.



This the the postition it ends up in with maximum adjustment of the plates and the linkage relaxed.



My questions are: Can you run the large linkage plate out of the powervalve boss as this is the perfect alignment but does not look right. (See pic 1)

I compared my linkage to a new one i have and it looks and measures exactly the same.  I rebuilt the governor to exact spec and photos of original, so where is the misalignment coming from.
What is the fix for this?  I could adjust the groove in the governor so the linkage sits relaxed in another position, i could put the new linkage on etc.. but does anyone have the correct way to fit adjust these valve.

Cheers,
Alex

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