79 RM125 build - FINISHED!

Rabbit Run 41 4/19/2021 9:54am
4/19/2021 9:54am
Hammer 663s wrote:
A little more progress. Painted crank cases today too. Hope to get the crank back soon and get bottom end together and into frame. [img]https://p.vitalmx.com/photos/forums/2021/04/12/487422/s1200_512B070E_E2A3_4751_8ED5_A39CBC59ACEF.jpg[/img]
A little more progress. Painted crank cases today too. Hope to get the crank back soon and get bottom end together and into frame.

This build really tugs on the great memories on that model. That was my first “real” race bike in my youth in North Dallas as a teen. Can’t wait to see the bike together!
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PJRAUS
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PJRAUS 4/22/2021 4:48am
4/22/2021 4:48am



Been enjoying watching your progress...great work!
Soon, I'm gonna start on my own first build project.
I recently bought a 1980 yz 125 that is pretty much a spray can renovation, done as a coffee table bike.
From a distance and in photos, it looks prety good and Im sure the previous owner was happy with how it turned out.
My intention is to rebuild it from the ground up so that its better than new mechanically, with the best suspension Race Tech has to offer and lots of other good stuff you can get for these old bikes that make them better than new.
Not too concerned about keeping it totally original...the old throttle assembly with that cable that sticks straight out and routes through the front number plate for example...will just save that in a safe place and use a current straight pull design and possibly a modern flat slide carb...
Anyway, keep the updates coming!👍



3
Dick Trickle 4/25/2021 5:42am
4/25/2021 5:42am
Hammer 663s wrote:
Cases painted and bearings in. Crank will be here Saturday so I can build the bottom end. [img]https://p.vitalmx.com/photos/forums/2021/04/14/487750/s1200_IMG_0533.jpg[/img] [img]https://p.vitalmx.com/photos/forums/2021/04/14/487751/s1200_IMG_0534.jpg[/img] Hammer 663s
Cases painted and bearings in. Crank will be here Saturday so I can build the bottom end.




Hammer 663s
Love the build.

I built its little brother for my boy a few years back, the 80N

2
Dick Trickle 4/25/2021 5:54am
4/25/2021 5:54am
PJRAUS wrote:
Been enjoying watching your progress...great work! Soon, I'm gonna start on my own first build project. I recently bought a 1980 yz 125 that is pretty...



Been enjoying watching your progress...great work!
Soon, I'm gonna start on my own first build project.
I recently bought a 1980 yz 125 that is pretty much a spray can renovation, done as a coffee table bike.
From a distance and in photos, it looks prety good and Im sure the previous owner was happy with how it turned out.
My intention is to rebuild it from the ground up so that its better than new mechanically, with the best suspension Race Tech has to offer and lots of other good stuff you can get for these old bikes that make them better than new.
Not too concerned about keeping it totally original...the old throttle assembly with that cable that sticks straight out and routes through the front number plate for example...will just save that in a safe place and use a current straight pull design and possibly a modern flat slide carb...
Anyway, keep the updates coming!👍



Not to get off track from Hammers thread, but definitely cool bikes around these years.
I’ve got two G’s I’m workin on.
Lots of nice parts for it..




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The Shop

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Hammer 663s
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Hammer 663s 4/25/2021 8:57am
4/25/2021 8:57am Edited Date/Time 4/25/2021 8:58am
soggy wrote:
Saw this while browsing our local ads and thought of this build!

79 rm 125 in original condition..

https://classifieds.ksl.com/listing/63676079

That is pretty nice. Not a stock rear fender, side number plates, or I think silencer but the rest is really close. I will have more than $2600 in mine when I am done, that's for sure! Today I will install the crank and get the bottom end done and in the frame.

I'd really like to see the RD350 I see in the background. Looking for a good stock one of those too!

Hammer 663s
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Hammer 663s 4/25/2021 12:33pm
4/25/2021 12:33pm
Crank and seals all in. Clutch done. I'd forgotten how easy these old 2 strokes are to work on. It's been fun so far!

Need to replace some of the crankcase bolts so off to Ace for some stainless parts.








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PJRAUS
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PJRAUS 4/25/2021 3:11pm
4/25/2021 3:11pm
PJRAUS wrote:
Been enjoying watching your progress...great work! Soon, I'm gonna start on my own first build project. I recently bought a 1980 yz 125 that is pretty...



Been enjoying watching your progress...great work!
Soon, I'm gonna start on my own first build project.
I recently bought a 1980 yz 125 that is pretty much a spray can renovation, done as a coffee table bike.
From a distance and in photos, it looks prety good and Im sure the previous owner was happy with how it turned out.
My intention is to rebuild it from the ground up so that its better than new mechanically, with the best suspension Race Tech has to offer and lots of other good stuff you can get for these old bikes that make them better than new.
Not too concerned about keeping it totally original...the old throttle assembly with that cable that sticks straight out and routes through the front number plate for example...will just save that in a safe place and use a current straight pull design and possibly a modern flat slide carb...
Anyway, keep the updates coming!👍



Dick Trickle wrote:
Not to get off track from Hammers thread, but definitely cool bikes around these years. I’ve got two G’s I’m workin on. Lots of nice parts...
Not to get off track from Hammers thread, but definitely cool bikes around these years.
I’ve got two G’s I’m workin on.
Lots of nice parts for it..




😛😛😛😛😛 Im drooling!
Hammer 663s
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Hammer 663s 4/26/2021 6:15pm
4/26/2021 6:15pm
Fitting up a few items. I think that’s the original seat cover. Pan is original and staples seem untouched.


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DaveB771
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DaveB771 4/28/2021 1:49pm
4/28/2021 1:49pm
Your build is bringing back a lot of good memories (and a few painful ones). In 1982 when my RM250 conked, I stuffed an old 36mm carb from a 1977 RM250 on my 79 RM125 and raced it at Plainview MN against all the Full Floaters. Turned out the jetting was good enough and I more than held my own against the newer bikes. Good times.
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Hammer 663s
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Hammer 663s 4/28/2021 2:12pm
4/28/2021 2:12pm
DaveB771 wrote:
Your build is bringing back a lot of good memories (and a few painful ones). In 1982 when my RM250 conked, I stuffed an old 36mm...
Your build is bringing back a lot of good memories (and a few painful ones). In 1982 when my RM250 conked, I stuffed an old 36mm carb from a 1977 RM250 on my 79 RM125 and raced it at Plainview MN against all the Full Floaters. Turned out the jetting was good enough and I more than held my own against the newer bikes. Good times.
I'm looking at a Jemco cone pipe and a 34mm carb through Boyesen reeds. I'm doing a nikasil liner on the jug and a PVL ignition to modernize it a bit. Head is getting a .5mm mill and I'll stack 2 base gaskets. I don't plan on porting it at all. A mix of 92 pump and T2 at 30:1. It should run pretty good if I can get the jetting right.

Mike
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DB505
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DB505 4/28/2021 4:05pm
4/28/2021 4:05pm
Hammer 663s wrote:
Round 2 of photos. The big question is powder coat the frame black or Suzuki blue to match the stock graphics I will put on? [img]https://p.vitalmx.com/photos/forums/2021/02/15/478852/s1200_IMG_0320.jpg[/img]...
Round 2 of photos.

The big question is powder coat the frame black or Suzuki blue to match the stock graphics I will put on?






Hammer 663s
Blue
DaveB771
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DaveB771 4/28/2021 4:23pm
4/28/2021 4:23pm
soggy wrote:
Saw this while browsing our local ads and thought of this build!

79 rm 125 in original condition..

https://classifieds.ksl.com/listing/63676079

DaveB771 wrote:
That's a 78 RM125.
DB505 wrote:
79
79 has a full-width front hub, FIM-style number plates and a different tank.RM125 script on the seat cover changed between 78 and 79. Swingarm also greatly changed from 78 to 79.

Some people were convinced the 78 was faster than a 79, but I always dropped them on the rubber band starts.
Hammer 663s
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Hammer 663s 4/28/2021 9:20pm
4/28/2021 9:20pm
soggy wrote:
Saw this while browsing our local ads and thought of this build!

79 rm 125 in original condition..

https://classifieds.ksl.com/listing/63676079

DaveB771 wrote:
That's a 78 RM125.
DB505 wrote:
79
No he’s right. 78 has the Cable rear brake too. Swing arm a dead giveaway. The 79 Swing-arm is way more robust.
Hammer 663s
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Hammer 663s 5/1/2021 11:53am
5/1/2021 11:53am
Bottom end all done and motor in the frame. Waiting on the top end and shocks, plus some minor parts, to finish it.



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Pit Row

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Spat24
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Spat24 5/19/2021 8:01pm
5/19/2021 8:01pm

This is really looking great!!
Excited to see when it gets finished.
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Hammer 663s
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Hammer 663s 5/20/2021 8:42am
5/20/2021 8:42am
Been waiting on parts - last night the jug and head came back from PowerSeal USA. I had the cylinder bored to 54.5mm and nickasil coated, plus the head milled .5mm. This weekend the jug will get painted and the top end installed. My hope is that by Saturday evening I will have the new PVL ignition timing set (12d BTDC) and I will start it for the first time.

Shocks should be here soon, and other than some rear spokes that's the last of the parts I need. I have touched literally every single nut and bolt on the bike. It's been a lot of fun!






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Hammer 663s
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Hammer 663s 5/21/2021 6:24pm
5/21/2021 6:24pm
More progress today. Top end together. Need to torque it all down tomorrow and set ignition timing. Kicks over super smooth so I guess I got it all back together correctly and it might run ok. Hope that I can actually start it tomorrow.









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Hammer 663s
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Hammer 663s 5/23/2021 2:26pm
5/23/2021 2:26pm
Well it's running!!! It tried to fire on the 4th or 5th kick. It takes a lot of throttle and choke to get it going, and it sounds fat, but considering all the changes I expect to take some time to tune it right. Carb puking out the overflow too so floats are off. Still, after all the work and so many new parts I'm just happy that it fired up without a lot of cussing.

Hammer 663s
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MaxPower
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MaxPower 5/24/2021 8:51pm
5/24/2021 8:51pm
I'm so happy that you didn't paint the frame blue. It's cool you stayed with the 79 fenders
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Hammer 663s
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Hammer 663s 6/7/2021 8:13pm
6/7/2021 8:13pm
Shocks came in today - they fit perfect and look pretty good too. All I am waiting on is 18 damn spokes for the rear wheel. The set I bought was for an asymetrical hub and the 79 hub uses the same lengths on both sides (166mm). THe vendor I bought the kit from has been less than helpful in getting me the correct spokes. Very frustrated, but that's the only issue I've run into so I'm trying to be patient. So close.......



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Hammer 663s
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Hammer 663s 6/18/2021 5:37pm
6/18/2021 5:37pm
It's done! It started quite easily, and I did some minor tuning on the 34mm carb, and it flat out rips when it comes on the pipe! We will take it with us to MountainView MX tomorrow and the boy will give it its maiden ride to gently to break it in.












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sandman768
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sandman768 6/18/2021 6:03pm
6/18/2021 6:03pm
Sounds great👍Well done
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Johnny Lock 6/18/2021 9:00pm
6/18/2021 9:00pm
DaveB771 wrote:
Your build is bringing back a lot of good memories (and a few painful ones). In 1982 when my RM250 conked, I stuffed an old 36mm...
Your build is bringing back a lot of good memories (and a few painful ones). In 1982 when my RM250 conked, I stuffed an old 36mm carb from a 1977 RM250 on my 79 RM125 and raced it at Plainview MN against all the Full Floaters. Turned out the jetting was good enough and I more than held my own against the newer bikes. Good times.
Plainview - haven’t heard that name in a long time. Last I rode there was in ‘99.
profeshenal125 6/18/2021 10:54pm
6/18/2021 10:54pm
So sharp, Great job. I remember seeing the 80,125 and 250 lined up at the dealer in 79. I was 12.5 yrs old I wanted the 80 so bad. I was a little big for it tho. I thought the rm,s looked so cool.
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PJRAUS
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PJRAUS 6/19/2021 4:19am
6/19/2021 4:19am
What an amazing achievement..brilliant work! I just love seeing people build an old bike like that..I hope yo have all the fun in the world riding it !
Look forward to following your next project!
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