My Buddy had this model back in 73. Nice bike. And it is SO Nice to see someone not choosing to Scrimp on replacement parts! I keep thinking, hey, while the Motor is apart, why not replace those Bering's and Seals etc. Cause once I tighten up all the bolts, screws and clips, I am not going to tear it all down again, 3 months later when the same Engine Blows up again. Thumbs Up!
Those soft alloy Philips-head engine bolts drove me nuts. They were on so many bikes of that era, one slip and the head is stripped. Done my share of drilling 😣.
Howdy from Texas, those cases looked primo after you put them in the ultrasonic cleaner, I’m curious how the cylinder and head would look after you hone it If you ran it through the ultrasonic cleaner. Had lots of DTs over the years so I’m really enjoying watching you rebuild these and put them back in the woods where they belong lol. I think it would be a good video if you did a comparison between the DT 175 and the Suzuki TS 185.
Hey! I’m glad you are enjoying the videos. I am going to be comparing the 72 TS185 and this bike once it’s back together and running. Looking forward to comparing them myself 😃. Thea bikes need to be ridden. I can appreciate museum quality bikes but the real fun is riding them lol
I have a cheater bar like the one used at 6:15. Mine is an old aluminum tent pole of some kind. I figure the tube will give out before I break anything. It has worked for years.
I have not. I would think two rings would be better than one for compression but from what I’ve gathered some MX models had one ring. Not sure what years.
Even on my DT125E with the airfilter door on the left side, i have to unbolt the oil tank and partially move it out the way to open the door & change the filter. If that's how Yamaha designed it I'm not too impressed.
I recall having to do that on the AT1 I just sold and the DT125B I sold last year. Poor design but Yamaha still wins in my opinion for best enduro bikes of the 70s
The vice grip holder is a Motion Pro brand tool so you can probably find that anywhere online. The puller is generic but it can be found online as well. Just search for “Yamaha flywheel puller” and I’m sure there will be a ton to choose from.
JIS or 'Japanese Industrial Standard' screw heads are NOT Philips. Totally different. If you're working on Jap bikes, a set of JIS screwdrivers is a must. There are very informative videos on TH-cam on the subject.
You can't accurately measure a bore with snap gauges and verniers.... You need a dial bore gauge. Sleeved cylinders need a rebore EVERY time they wear out a piston even if there's no apparent damage. When the visible crosshatch is gone from the cylinder around the exhaust port it's already out of spec and you will have excessive piston slap if you just hone and replace the piston. Sleeves are nothing like plated nickasil cylinders .
Thanks for the info Kyle. I haven’t dealt with any nickasill cylinders yet. I’ve done a bunch of older bikes with just hones and new pistons and rings with good luck so far. A couple of them I ride regularly. No piston slap that I can tell. None of the bikes I’ve done have been re-sleeved however.
That L shaped top piston ring is know as a Dykes ring. Saw them some back when I was into kart racing.
Thank you!
Perfect video to watch while recovering from wrist surgery yesterday.
Hope you enjoy it….Heal up quickly!
Great to have one of your videos to enjoy after a long week at work in the factory.
Thanks Peter, hope you enjoy it!
Yeah I know what you mean the factory i work at sucks
My Buddy had this model back in 73. Nice bike.
And it is SO Nice to see someone not choosing to Scrimp on replacement parts!
I keep thinking, hey, while the Motor is apart, why not replace those Bering's and Seals etc. Cause once I tighten up all the bolts, screws and clips, I am not going to tear it all down again, 3 months later when the same Engine Blows up again.
Thumbs Up!
My dad had this same bike too in ‘73. And thanks! I only use OEM stuff because I only want to do it once 😆
Great start to my weekend hope it goes as smoothly as the tear down . Cheers
Right on! 🍻
Those soft alloy Philips-head engine bolts drove me nuts. They were on so many bikes of that era, one slip and the head is stripped. Done my share of drilling 😣.
I dread those screws if it looks crusty. Usually the chisel method works and sometimes I just apply a little heat and that does it
great work
Thanks Jeff!
Good job brother.
Thanks buddy!
Howdy from Texas, those cases looked primo after you put them in the ultrasonic cleaner, I’m curious how the cylinder and head would look after you hone it If you ran it through the ultrasonic cleaner. Had lots of DTs over the years so I’m really enjoying watching you rebuild these and put them back in the woods where they belong lol. I think it would be a good video if you did a comparison between the DT 175 and the Suzuki TS 185.
Hey! I’m glad you are enjoying the videos. I am going to be comparing the 72 TS185 and this bike once it’s back together and running. Looking forward to comparing them myself 😃. Thea bikes need to be ridden. I can appreciate museum quality bikes but the real fun is riding them lol
I have a cheater bar like the one used at 6:15. Mine is an old aluminum tent pole of some kind. I figure the tube will give out before I break anything. It has worked for years.
Mine is also aluminum! Works great 👍
The top ring is referred to as a Dykes piston ring.👍🏼
Thank you Lee!
Have you seen the old Robert Redford film Little Fauss and big Halsy? Lots of cool old Yamahas similar to this in it, you might enjoy it.
I haven’t but I’ll have to check it out! Thanks for the heads up 👍
Have you rebuilt one that only had one ring? I guess less friction equals more HP?
I have not. I would think two rings would be better than one for compression but from what I’ve gathered some MX models had one ring. Not sure what years.
I’m thinking one ring ups the hp a little. Thanks. Looking forward to your next video on this project!
Even on my DT125E with the airfilter door on the left side, i have to unbolt the oil tank and partially move it out the way to open the door & change the filter. If that's how Yamaha designed it I'm not too impressed.
I recall having to do that on the AT1 I just sold and the DT125B I sold last year. Poor design but Yamaha still wins in my opinion for best enduro bikes of the 70s
Whats that tool that you removed the flywheel with. That vice grip thing
Just a flywheel puller. It threads into the flywheel via reversed threads and allow you to crank down on the bolt to separate it.
Where would you get the puller and the vice grip tool thing
The vice grip holder is a Motion Pro brand tool so you can probably find that anywhere online. The puller is generic but it can be found online as well. Just search for “Yamaha flywheel puller” and I’m sure there will be a ton to choose from.
It’s called a clutch hub holding tool. Rocky Mountain atv/mc sells some Tusk branded ones that work well for cheap.
Its not a nikisil bore is it? If it is, l wouldnt hone it.
Nahh not nickisil thankfully
There is also a subtle difference between Japanese Philips slots and the rest of world. But try to find Japanese Philips bits!
Luckily my impact screwdriver had a couple different bits with different Phillips style heads. Usually one fits perfectly
JIS or 'Japanese Industrial Standard' screw heads are NOT Philips. Totally different. If you're working on Jap bikes, a set of JIS screwdrivers is a must. There are very informative videos on TH-cam on the subject.
You can't accurately measure a bore with snap gauges and verniers.... You need a dial bore gauge. Sleeved cylinders need a rebore EVERY time they wear out a piston even if there's no apparent damage. When the visible crosshatch is gone from the cylinder around the exhaust port it's already out of spec and you will have excessive piston slap if you just hone and replace the piston. Sleeves are nothing like plated nickasil cylinders .
Thanks for the info Kyle. I haven’t dealt with any nickasill cylinders yet. I’ve done a bunch of older bikes with just hones and new pistons and rings with good luck so far. A couple of them I ride regularly. No piston slap that I can tell. None of the bikes I’ve done have been re-sleeved however.