My first restoration: ST/300/D

[Duck89]

Okay, here it goes:

I am going to be starting the restoration on my ST/300/D that has been in may family since the early '70's. I think it should be a pretty straight forward restoration, with only a few problem areas that I know of right off the bat. I have an idea of how I am going to do this, but figured I would ask the experts since this is my first build! I am going to start with removing the engine/transmisison and keep on working my way down until its just a grimey yellow tub so I can clean it and put 'er back together.

Here are my question/problems:

1. The engine cover hinge is junk, along with the area where the hinge meets the engine cover. What methods have you found that work well to replace this hinge while having a bad edge along the engine cover?

2. The only crack on the tub is in the right front corner under the axle, and it is a pretty significant one. Tips for fixing this?

3. There is a lot of fresh looking residue on the head of the engine- Possible blown head gasket or something? I don't know a lot about these 2 strokes so im just guessing

Anytips you guys could give me would be greatly appreciated!


here's some pics:

[hydromike]

Cool project. It doesn't look like you have all that much work to do.

1. I've not seen replacement hinges before, but it would be relatively easy to find a hinge that would work just fine. I had a machine years-back that only had a fabric "hinge", and other machines I've seen have a rigid metal "piano hinge". I can't tell which you have. Regardless of hinge style, is the metal brace that the hinge mounts to deteriorated? If it's just steel, you can replace it. The down side, is that it may require splitting the body to do a real good job of getting a new one in there. With some creativity, you can get it fixed up.

2. Have you researched the "ABS goo" method for fixing cracks? You have a pretty good crack there, but it's nowhere near the worst we've seen. Mixing up some spare ABS in some acetone and applying it to the crack will fix it up pretty well. Just do a search for "ABS goo" and dozens of results come up.

3. You may have a leaky head gasket, but the oil you see isn't that uncommon for a 40 year old machine that may have never been apart. If you get the motiviation, take the head off and bring it over with you on Saturday and I'll see if I have a spare head gasket for you. Chances are pretty good I do. Just take the tins off the top and bump off the five (13mm?) bolts that hold the head on. I remember my ST/295 had 175psi of compression with a similar little leak. It ran fine, but if you want to go the extra step, I'll throw you the head gasket....

Solid looking 300, and a cool winter project.

[LarryW]

Cool! I love first generation builds! Good luck with it!

[Duck89]

Well guys, I know you all love seeing build pics as much as I do, so here are a few current ones below. I have been working on this project, slowly but surely! This is my first build so I am taking my time, asking a lot of questions and making sure I do it right the first time!

I have almost everything out of it, except for the frame, control levers and the 5 of the axles. After I get those out I can begin to remove the 40 years of grime, dirt, pine needles and a lot of other good stuff I have scraped a few places with my fingernails, which allowed me to discover that there is bright yellow plastic underneath that grime! After I get it cleaned with a little bit of acetone and light sanding, the outside and inside of the body should be gleaming good as new!

I have a couple of questions at this stage:

-How do I remove the axle from the outer bearing housing as shown below?

-Is there a removable bearing inside that external housing or is it all one unit? When turing the axle with this housing around it, there is nothing smooth about it and I am thinking that a bearing needs replacing in there?

DSCN0858.jpgDSCN0862.jpgDSCN0853.jpgDSCN0860.jpgDSCN0865.jpg

[LarryW]

Sweet!!! Pictures!!!!! lol

For the bearing, they are pressed fit. You can press the bearings off the axles before or after taking the housing off. But it is easier on the internal snap rings and the groove to press the bearings off the axle last. So I recommend taking the bearing out of the housing with the axle still in. So with the axle/bearing assembly off the machine, you will see a internal snap ring inside the bore of the housing. It is on the back side. Take that out with internal snap ring pliers and then the bearing OD is a slightly tight fit. But the housing will slid off the bearing. Then once the bearing is out of the housing, press it off the axle. Make sure your pressing the bearing off on the wheel side of the axle(outer), not the sprocket side(Inner). The wheel side is the 25mm end and the inner side is 25.4mm. So the axle has a step in it.

[jpswift1]

Larry certainly is the man when it comes to first generation Attex questions. I know he helped me out a lot too. It looks like you're doing a great job, Martin. You're really lucky that you got 5 of the 6 axles out without resorting to a torch or cutting the axles. Soak that last one with penetrating oil for a little while and you might be able to work it loose. Also, while you're doing a frame out restoration, replace every chain and bearing......you'll be so glad you spent the time and money on it down the road when you don't have to do it again because something might have went bad. Keep up the great work!

[Duck89]

Thanks for the info guys! I haven't been able to work on it the last couple of nights, but I am hoping to start back up again soon. I will definitely be replacing all the chains and bearings for sure! As far as the inner bearings on the frame are concerned, does anybody know of a replacement BCA or Timken number for them? I believe they are originally an SKF Nice bearing #6916B? The only bearing even close to this that I was able to look up/had in stock at my parts store was a BCA #NPS-100-RRC (I think, don't quote me). This was a 1'' bearing, but the outer edge was rounded, unlike the orignial bearings. I can remeasure it with the caliper at work to get the exact measurements, but I am not thinking that this bearing will work because of the rounded edge, is this correct?

The original is on the right. The bearing on the left isn't too much bigger than the original, it just looks that way because of the plastic I put underneath it to get it to stand up.

bearing_comparison.jpg

[jpswift1]

Thanks for the info guys! I haven't been able to work on it the last couple of nights, but I am hoping to start back up again soon. I will definitely be replacing all the chains and bearings for sure! As far as the inner bearings on the frame are concerned, does anybody know of a replacement BCA or Timken number for them? I believe they are originally an SKF Nice bearing #6916B? The only bearing even close to this that I was able to look up/had in stock at my parts store was a BCA #NPS-100-RRC (I think, don't quote me). This was a 1'' bearing, but the outer edge was rounded, unlike the orignial bearings. I can remeasure it with the caliper at work to get the exact measurements, but I am not thinking that this bearing will work because of the rounded edge, is this correct?

The original is on the right. The bearing on the left isn't too much bigger than the original, it just looks that way because of the plastic I put underneath it to get it to stand up.

Attachment 7973

Martin,

The bearing on the left with the rounded outer race will not work since it is actually for a later model Attex like a Superchief or Wild Wolf that uses two bearing flnages to "sandwich" in the bearing.

[Duck89]

Jeff,

Yeah, I didn't figure it would work. Ill have to remember that the bearing will fit a later model if I ever get one of those and not another first gen! The bearing on the right, which I am trying to find a new one of, is one that you gave me from last fall when I bought those 2 tires from you. I believe those are the same bearing that are in my machine right now. Do you know if those bearings are still made and, if so, by what manufacturer/part number?

Thanks

[hydromike]

A Timken YA100RR should get you in the right direction. This is 52mm O.D. flat outer race bearing, so make sure your stamped flanges are 52mm.