Author Topic: 1979 YZ80F  (Read 1444 times)

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Offline alexbrown64

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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,


Offline skypig

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Re: 1979 YZ80F
« Reply #1 on: May 18, 2018, 11:30:38 PM »
Can’t help you with parts.

I also has one new in 1979. Won the A grade club championship on it.
(Got beat by the fast guys on their YZ80E’s the year before, when I was YZ80D mounted. Big advancements each year in those days.)

Offline Slakewell

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Re: 1979 YZ80F
« Reply #2 on: May 19, 2018, 08:32:14 AM »
The F was a big step back in the day for 80's was it the first 6 speed?
You could get a metal fab guy to make one from 5mm 316 stainless bar?
Current bikes. KTM MC 250 77 Husky CR 360 77, Husky 82 420 Auto Bitsa XR 200 project. Dont need a pickle just need to ride my motorcickle

Offline skypig

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Re: 1979 YZ80F
« Reply #3 on: May 19, 2018, 08:48:26 AM »
Can’t remember if it was the first 6 speed, but it was the first with an internal rotor ignition. The far less “flywheel” made for a free/faster reving, more “modern” engine. They put a brace on each side of the swingarm as well. The single brace on the E was far less strong.

Offline Iain Cameron

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Re: 1979 YZ80F
« Reply #4 on: May 20, 2018, 10:25:34 AM »
I might just have one , well I know I had one at this years BBB . get back to you once ive checked the shed . Iain
Yamaha tragic ; dt1, rt1, dt2, rt2, dt2mx , rt2mx , mx250, mx360,sc500, 74dt125, yzx125, yzc250, yzc400, yzd250, yzd400, yzh250, yzh80 , dt100 , xr75 ko xr80 03 , it175 82 . Not a member of any club

Offline alexbrown64

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Re: 1979 YZ80F
« Reply #5 on: May 20, 2018, 06:33:58 PM »
Thanks for all the input guys..
If you don't have one Iain, then i will have to make a temporary one out of SS tig wire and tig it together.  Will be strong and lightweight.  But i do want an original for the future restore.

Pic below of me on the F at the first round of the WA state titles.. I had an aftermarket 17" front wheel..



More stuff to come..

Cheers,

Offline alexbrown64

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Re: 1979 YZ80F
« Reply #6 on: June 14, 2018, 11:03:46 PM »
Bikes arrived...



I had already ordered a shit load of nos parts and various other items to compliment the bikes.. but when i looked closely.... im going to need a shit load more parts....

The F is OK.  Its nearly 40 years old, and its showing every year of its age.  Its flogged!!
The airbox is completely missing.  The oem plastics are beyond tired..Tyres are flogged, spokes,exhaust,  everything.
The good news is the chrome on the forks is good.  The rims are OK, Tank only has a small ding, bars only bent, etc..

I have a new front plate, new exhaust coming, new decals, new left number plate, all new hardware, new grips, levers, throttle, cables, etc..

Bad news is i have to find a 2X6 airbox, some plastics and hope the motor, tranny and clutch is OK.

Here is the pipe and some other goodies that are here, or on the way..



Muffler has been tacked to pipe because they lost the clamp. But the pipe is a 2X6 (1979) pipe and muffler, and its all in really good nick..

I was hoping to get the bike ready for my boy to ride, but she is in really poor condition.  Perhaps in the next 6 months i will get her into a ride ready bike for some vmx fun days.. then down the track she will get her 40th birthday..

As part of her birthday,.. i mangaged to find a NOS seat cover for only 45 Euros. She also has new seat foam coming, a nos side cover, new Takasago nos rim, and a host of other goodies..




Offline alexbrown64

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Re: 1979 YZ80F
« Reply #7 on: June 16, 2018, 12:30:56 PM »
The parts list is growing...

Luckily, the fork tubes are clean on the F, so i dont have to rechrome them. The tank is going to need some dents pulled, and then panel and paint.

New old stock left side number plate panel from the U.S



New old stock right side panel from Australia..



New intermediate left engine case cover from France..



New engine kill switch, throttle housing.. slightly different to the E style..



I got a new muffler and exhaust from America.  Unfortunately, the muffler is tacked to the pipe.  But its all in great condition and with some careful grinding, i can make it all like new.



There were a few other parts missing like the airbox, airbox boot, filter cage and filter.. but i have found replacements.
Looking forward to stripping it all down and getting it cleaned up.


Offline Iain Cameron

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Re: 1979 YZ80F
« Reply #8 on: June 17, 2018, 12:39:22 AM »
Sorry Alex Its not there anymore I must have sold it at Broadford .
Yamaha tragic ; dt1, rt1, dt2, rt2, dt2mx , rt2mx , mx250, mx360,sc500, 74dt125, yzx125, yzc250, yzc400, yzd250, yzd400, yzh250, yzh80 , dt100 , xr75 ko xr80 03 , it175 82 . Not a member of any club

Offline alexbrown64

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Re: 1979 YZ80F
« Reply #9 on: June 17, 2018, 08:18:57 AM »
Thats OK Iain,  i was browsing around the net and found another a few days ago.
I saw a pic of something i needed.. and then the guy said he had a uni filter he would chuck in for free.  I asked him if he had a cage, and low and behold, it was in the filter!!  So he chucked in both for free with another order.



The motor is supposed to be on the original standard bore.. we shall see.  Looks a bit rough, but its all there... except the airbox and its accessories.  I was wondering why the side cover was cable tied.. Its because there is no airbox behind it.



Anyway, a bit of debate going on at the moment.  I have my E manual, but not my F manual yet.  CSMNL and Partzilla list the part number for the airbox differently for the E as for the F/G.  They use the same picture for the E,F, but the F part number is 2x6.  The E airbox is 2J5.  Some say they are the same..but a close look at the pics shows that they flipped the triangle airfilter upside down for some reason.  All the alignment holes and everything else fits for the side covers, airboot etc.. on all 3 models.

2J5 E airbox..



2X6 F/G airbox



Strange one.. i guess i will find out when i get my F manual, as they usually show a pic of the airfilter arrangement.

Cheers,



Cheers,

« Last Edit: June 17, 2018, 08:36:24 AM by alexbrown64 »

Offline 80-85 husky

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Re: 1979 YZ80F
« Reply #10 on: June 17, 2018, 09:54:33 AM »
with no filter, it will be interesting to see whats inside ::)

Offline OverTheHill

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Re: 1979 YZ80F
« Reply #11 on: June 17, 2018, 11:13:49 AM »
Had one new for the kids or the eldest one [now touching 49 lol] Think it was the F but maybe the G that we were sent a frame gusseting kit that we had to weld in straight out of the crate before bike left the shop. Can't quite remember where but i think part of it was where the subframe support joins down by the swing/arm pivot point. Someone will remember [if old enough lol]. Was quite a few little gussets to weld in i think. Looking at the parts drawing reminds me the reed block is the same as my RT2-360, maybe has a sharpened dividing bar inside for better gas flow out through the reeds but same unit realy. Put boyesen reeds in ours & ran it on alky but half way through the day i had to turn them over as curled their toes up due to the fuel. Might be getting my wires crossed & could all be the G in 1980 but had both. Then the H model changed everything--was an even faster rocket.

Offline alexbrown64

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Re: 1979 YZ80F
« Reply #12 on: June 17, 2018, 01:59:07 PM »
with no filter, it will be interesting to see whats inside ::)
Yes.. i am thinking the same thing.  Will have to take a peek inside soon.  I think it has only been run up the street in the last few years i think, so hopefully all OK.  Bike needs A LOT of work. 

Offline alexbrown64

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Re: 1979 YZ80F
« Reply #13 on: June 17, 2018, 02:16:20 PM »
Had one new for the kids or the eldest one [now touching 49 lol] Think it was the F but maybe the G that we were sent a frame gusseting kit that we had to weld in straight out of the crate before bike left the shop. Can't quite remember where but i think part of it was where the subframe support joins down by the swing/arm pivot point. Someone will remember [if old enough lol]. Was quite a few little gussets to weld in i think. Looking at the parts drawing reminds me the reed block is the same as my RT2-360, maybe has a sharpened dividing bar inside for better gas flow out through the reeds but same unit realy. Put boyesen reeds in ours & ran it on alky but half way through the day i had to turn them over as curled their toes up due to the fuel. Might be getting my wires crossed & could all be the G in 1980 but had both. Then the H model changed everything--was an even faster rocket.
Hey OverTheHill, it was the 78 YZ80E that had the gusset kit, as the frames were like cheese.  I have the other thread going with that bike.  I have a NOS gusset kit that i am going to tig in on that bike, as well as some frame repairs.
Here is a pic of the kit to help you jog your memory....



I also pulled the monoshock on the F this morning while the kids were asleep.  It was a fight to the death, as the bolt through the swingarm to monoshock was seized in and i dont think had been removed in 38 years.  Lots of work and it came out, but destroyed the pin.
The shock is in great condition.  Lots of damping and not much corrosion.  They were anodized in that mottle dark green that some of the Yamaha bolts and foot brake levers came in.
I took the spring off and took a picture of the KYB decal and its serial number.  I sent it to Tim Lee in Canada who is on Facebook, and he is going to reproduce it exactly with my 2X6-00 preface and my shocks serial number.



The chrome shaft on the F is good, and the fork chrome is good too... so it will just be seals in the forks and some fresh oil..

Cheers,


Offline alexbrown64

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Re: 1979 YZ80F
« Reply #14 on: June 26, 2018, 11:07:03 PM »
I get my YZ80F workshop manual, but its not a workshop manual. Its a guide that mostly shows the difference between the E and the F.  Its interesting because many believe that the E and F parts are the same.  Reading this book shows that almost all parts on the two bikes are different.

The airboxes are indeed different...



The cylinders and cylinder heads are also different..



Other things that are different are the exhaust pipes, tank mount, seat base, right side engine cover, ignition, bars, levers, transmission, frame pegs, brake lever, front wheel (F has larger spokes), swingarm, swingarm seal guard, front and rear suspension (forks go from 27mm to 30mm), rear mudguard, throttle.

So, as i am rebuilding both models, and they look pretty much the same, Yamaha totally revised the model and not much really is compatible between the two models.

Cheers,