Hello Dale, Did you have to have a special tool to pull the armature off the crank shaft? It seems like I've got a bad crank seal behind it as I've found some oil in the bottom of the cover and I've got to get it off to see. I've got a flywheel puller I've used on my other bike flywheels, but this seems different. Any help would be greatly appreciated. Steve
Hey Steven, yes there is a special puller bolt with a long snout that goes in the hole of the crankshaft on the AT1. They are available at times on Ebay. Just put in armature puller for AT1 Yamaha. Some folks just use a bolt the proper size and pitch (10mm 1.25) that will thread into the armature and push against the end of the crankshaft. With the bolt you just screw in till its tight and give the top of the bolt a little sharp tap on top with a brass hammer and it will usually pop off. Hope this helps.
I'm looking into getting one of these bikes, basically totally stripped. I may have to go in and do some work. I've basically got zero experience with engines. How hard would it be for me to take it apart, replace worn bearings and suck, and what I'm most worried about, putting it together. This thing looks like an absolute nightmare to put back together. What are the odds I'm never able to get it back together?
Hey Dylan, these bikes are very simple, just take lots of pictures as you do the teardown and that will help in the reassembly. Or better yet do videos and share them with us, I like to watch what others put together when I'm not doing mine. Oh, pick yourself up a manual also.
@@montana2strokeracer it's tempting for a summer project, and for $200 for an engine and frame it's a steal. You just gave me a lot of confidence to start this. Thanks so much!
Picked up two matching AT1c bikes that are complete but seized - removed screws from magneto side, tapped -nothing. I do not want to break this cover but are these always so tight? I have done some light prying with no results -what am I missing? All screws removed -thanks Dale!
Hi there and congrats on finding a couple of vintage enduros, man they are hard to come by these days. Yes, sir those can be difficult to remove at times. The thing that is your hang up are the dowel pins. There are two dowel pins (they are about a half inch long) that help locate the side cover. These tend to corrode and that makes it hard to remove. If you will look at the serial number on the case, then see the bump just behind it. That is where one is, the other one is at the bottom centered between the lower screw hole and the shift shaft. Try tapping (gently) in the vicinity of those areas with a plastic hammer while pulling and pushing back and forth with your hand were the chain goes into the case. If you get a slight separation, try to get some penetrating oil in there. just keep tapping and pulling, if you get enough separation to get a screwdriver in there, be gentle and pry out and tap back in and keep doing that till it comes loose. It will come loose; you just have to take your time and keep at it. Good luck with your project, and thanks for spending time with me in the shop!
@@montana2strokeracer Thanks Dale, I noticed those in a video and thought they have to be the culprit and no doubt corroded! Always appreciate your help and great videos! Corrosion never sleeps - especially on two badly corroded bikes!
@@montana2strokeracer thanks! I finally have some separation - does the little lock nut for clutch adjustment need to be removed as well along with it's assembly?
Good morning Dale, been doing some research on this old bike that my boys and I are working on. It indicates it was manufactured by Yamaha in 1/72, however it is saying it is an AT1 according to the SN # on the neck of the frame and engine. In my research it says they (AT1's) were only made 1969-1971. Is this some odd ball that was made in 1972, it has the '72 Mandarin Orange tank colors like the AT2's. Reason I ask, Partzilla doesn't have any AT1 models for 1972, should I just reference the 1972 AT2 model 125? Thanks in advance... Taylor
Hey Taylor, yes the CT-2 was the model for 1972 but the frame and engine VIN's still carry the CT-1 prefix. I have a 72 CT-2 it is a reed valve engine and doesnt have the badges on the tank, but it still carries the CT-1 prefix. Not sure how many years they kept that going. Your correct about the parts sites too, you just have to know or you could get the wrong parts. All this is true of the AT-2 also, and more than likely the DT and RT 2's, I believe I saw something on the yamaha facebook forum that the 73 models still carried the same prefix of the 69-71 models. Japanese wisdom...???
Appreciate the video, using it to help rebuild my grandfathers old AT-1.
Hi that's great. So glad folks are getting some good out of these videos.
Spent a lot of time riding… and working on the ct-1 ‘s.
Wish I had that engine stand back in the day.
Hey Tim, still love the CT's, and yes that engine stand comes in handy.
You are right the motors are all different. Thanks for sharing brother.
Yes they are
Hello Dale,
Did you have to have a special tool to pull the armature off the crank shaft? It seems like I've got a bad crank seal behind it as I've found some oil in the bottom of the cover and I've got to get it off to see. I've got a flywheel puller I've used on my other bike flywheels, but this seems different. Any help would be greatly appreciated. Steve
Hey Steven, yes there is a special puller bolt with a long snout that goes in the hole of the crankshaft on the AT1. They are available at times on Ebay. Just put in armature puller for AT1 Yamaha. Some folks just use a bolt the proper size and pitch (10mm 1.25) that will thread into the armature and push against the end of the crankshaft. With the bolt you just screw in till its tight and give the top of the bolt a little sharp tap on top with a brass hammer and it will usually pop off. Hope this helps.
Thanks Dale, I did find one of those pullers online earlier and ordered it. Thanks for all the great videos and the help. @@montana2strokeracer
I'm looking into getting one of these bikes, basically totally stripped. I may have to go in and do some work. I've basically got zero experience with engines. How hard would it be for me to take it apart, replace worn bearings and suck, and what I'm most worried about, putting it together. This thing looks like an absolute nightmare to put back together. What are the odds I'm never able to get it back together?
Hey Dylan, these bikes are very simple, just take lots of pictures as you do the teardown and that will help in the reassembly. Or better yet do videos and share them with us, I like to watch what others put together when I'm not doing mine. Oh, pick yourself up a manual also.
@@montana2strokeracer it's tempting for a summer project, and for $200 for an engine and frame it's a steal. You just gave me a lot of confidence to start this. Thanks so much!
Picked up two matching AT1c bikes that are complete but seized - removed screws from magneto side, tapped -nothing. I do not want to break this cover but are these always so tight? I have done some light prying with no results -what am I missing? All screws removed -thanks Dale!
Hi there and congrats on finding a couple of vintage enduros, man they are hard to come by these days. Yes, sir those can be difficult to remove at times. The thing that is your hang up are the dowel pins. There are two dowel pins (they are about a half inch long) that help locate the side cover. These tend to corrode and that makes it hard to remove. If you will look at the serial number on the case, then see the bump just behind it. That is where one is, the other one is at the bottom centered between the lower screw hole and the shift shaft. Try tapping (gently) in the vicinity of those areas with a plastic hammer while pulling and pushing back and forth with your hand were the chain goes into the case. If you get a slight separation, try to get some penetrating oil in there. just keep tapping and pulling, if you get enough separation to get a screwdriver in there, be gentle and pry out and tap back in and keep doing that till it comes loose. It will come loose; you just have to take your time and keep at it. Good luck with your project, and thanks for spending time with me in the shop!
@@montana2strokeracer Thanks Dale, I noticed those in a video and thought they have to be the culprit and no doubt corroded! Always appreciate your help and great videos! Corrosion never sleeps - especially on two badly corroded bikes!
@@montana2strokeracer thanks! I finally have some separation - does the little lock nut for clutch adjustment need to be removed as well along with it's assembly?
@@warmblood58 No that has nothing to do with. that is the clutch adjustment
@@montana2strokeracer thanks Dale, yep discovered that- cover is off but took some coaxing!
Good morning Dale, been doing some research on this old bike that my boys and I are working on. It indicates it was manufactured by Yamaha in 1/72, however it is saying it is an AT1 according to the SN # on the neck of the frame and engine. In my research it says they (AT1's) were only made 1969-1971. Is this some odd ball that was made in 1972, it has the '72 Mandarin Orange tank colors like the AT2's. Reason I ask, Partzilla doesn't have any AT1 models for 1972, should I just reference the 1972 AT2 model 125? Thanks in advance... Taylor
Hey Taylor, yes the CT-2 was the model for 1972 but the frame and engine VIN's still carry the CT-1 prefix. I have a 72 CT-2 it is a reed valve engine and doesnt have the badges on the tank, but it still carries the CT-1 prefix. Not sure how many years they kept that going. Your correct about the parts sites too, you just have to know or you could get the wrong parts. All this is true of the AT-2 also, and more than likely the DT and RT 2's, I believe I saw something on the yamaha facebook forum that the 73 models still carried the same prefix of the 69-71 models. Japanese wisdom...???
Do you have a link to the video where you repair those 2 screw bosses?
Hi Steve, no didnt repair them yet, got another set of cases. Will do a repair on them sometime in the future. Thanks for commenting, and for watchin.