Refurbishing a 1980 Yamaha SR500

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rebelrider
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Re: Refurbishing a 1980 Yamaha SR500

Post by rebelrider » Wed Oct 09, 2019 12:40 pm

Painted parts are cleaned up and repainted.
Image

I imagine the brake shoes can get pretty hot, so I put high heat paint on them.
Mike
Image2014 Ural M70 "Trogdor"
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Re: Refurbishing a 1980 Yamaha SR500

Post by rebelrider » Tue Oct 15, 2019 2:46 pm

Got it running!!!


I think I'm getting the hang of that decompressor. I'm pretty sure I had trouble starting it because of the oil I put in the cylinder when I first got it. But I wanted to make sure there wasn't any scratchy stuff in there before I started kicking it over. Now that it's run for a bit, time to finally change the oil. Also, the carburetor still needs some work. The float bowl gasket is leaking. I'll have to make a replacement. I need to make sure the float is adjusted properly. I noticed the throttle sticks, even though all the components by themselves seem fine. I'll have to look into that.

I may also need to tie it to a block or something to keep it from vibrating away, LOL. But this was the first start in 10 years! And my first time starting it. I'm pretty jazzed. This thing may actually be back on the road someday!
Mike
Image2014 Ural M70 "Trogdor"
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Re: Refurbishing a 1980 Yamaha SR500

Post by rebelrider » Thu Oct 17, 2019 12:55 am

I got my master cylinder rebuild kit today, and it has this piece I'm not familiar with. Or I wasn't until I found the old one on the floor.
Image

In the picture, I've got the parts all lined up as I think they go together. The rubber piece between the spring and plunger is the one I'm not sure of. I've seen it in blow-up diagrams and rebuild kit pictures, but not in such a way as to tell me where exactly it goes.

I started changing the oil today. Since it's been sitting so long, I decided to check the two strainers also. Everything came apart great except the tube strainer. I had to go find a 27mm socket. Best I could get was a 12 point. I hate those, but that's all anyone seems to sell locally. Anyway, I looked around and found these two forum threads:

https://www.xt500.co/oil-feed-screen-fi ... 6-s20.html
http://www.sr500forum.com/forum/viewtop ... f=9&t=6494

Most Google and You Tube searches for strainers gave me results for filters. Well, It seems that the strainer just needs a lot of leverage to get it loose.

I'm glad I decided to check the strainers though. Here is what I've found so far:
Image

I guess it would have been ok for another 5,000 miles, but may as well change it, LOL.

I also read that when you change the oil, the system needs to be bled? Or primed? I don't know how I'd go about doing that. I'd think that any air would eventually be pushed up to the reservoir, but then I'm not familiar with these dry-sump oil systems.

Here's a video of the various brake parts as they get cleaned up and made ready for reassembly:
Mike
Image2014 Ural M70 "Trogdor"
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Re: Refurbishing a 1980 Yamaha SR500

Post by rebelrider » Fri Oct 18, 2019 12:53 am

Here's the tools I ended up using to get the tube strainer loose.
Image

Before w@$#ing:
Image

And after w@$#ing:
Image

I tried to get a picture of the bottom of the engine with the sump off. After several attempts though, I only succeeded in getting oil on the lens. It's all back together now, with new oil, and I even got it to start up again for a short time. I still need to adjust the carburetor though.
Mike
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Re: Refurbishing a 1980 Yamaha SR500

Post by rebelrider » Mon Oct 21, 2019 2:32 am

Finally got the brake reservoir done.
Image
Image

Sanded off the old cracked material down to good stuff, and then built it back up with JB Weld. I cleaned up the "window" as best I could, and covered it over with clear epoxy. I had hoped it would seep into the cracks and such and make the window a little more transparent. But it didn't happen. No worse that it was though. Everything got a fresh coat of paint, and now I'm about ready to reassemble it.
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I got the muffler disassembled.
Image

Still working on getting the motor oil off my lens, LOL. The insides are in good condition. Most of it is still coated in paint. I had to clean it up a little just for my own sanity. I was getting oily soot everywhere!
Image

Most of the rust is gone now. I have a gray scotch-bright wheel on my bench grinder that made quick work of all the surface rust and loose chrome that it could reach. I still need to get to the underside of the mounting bracket with some other tools. My intention is not to make it look fantastic. I just want to protect it from future rust.
Mike
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Re: Refurbishing a 1980 Yamaha SR500

Post by rebelrider » Wed Oct 23, 2019 2:15 am

I've been thinking about tires, chain, and sprockets. Those are all going to have to be replaced. I sent out some queries and did some searching around the internet. Looks like I have a set of Kenda Challenger tires from 1995. 100/90-19 on the front, and 120/90-18 on the back.
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Not sure what I'll replace them with yet, but I'm pretty sure I don't want to ride around on 24 year old tires.

As for the chain and sprockets, I went back and forth as to whether to change the front sprocket. The chain is toast, and the rear sprocket has significant wear. I think it's best to change both sprockets though. I have what I think is the stock ratio of 16/44.
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Image

I was looking at JT sprockets, and they don't make 44 tooth rear sprockets, so I'd have to get 42. If I understand ratios right, that means I'd go down to 15 on the front. So 15/42. That's 2.75:1 vs. 2.8:1. Or I could look to see what other brands have. No decisions yet. Just researching.
Mike
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Re: Refurbishing a 1980 Yamaha SR500

Post by Claus » Wed Oct 23, 2019 6:37 am

rebelrider wrote:
Thu Oct 17, 2019 12:55 am
I also read that when you change the oil, the system needs to be bled? Or primed? I don't know how I'd go about doing that. I'd think that any air would eventually be pushed up to the reservoir, but then I'm not familiar with these dry-sump oil systems.
The oil system needs to be bled. Fill oil tank in frame to max on the dip stick.Turn bleeder screw out two or three turns( the small screw with copper washer on top of oil filter cover).Start engine and wait until oil comes out of bleeder screw. Then turn bleeder screw in. That´s how it should work.

If you want to do it perfect, bleed feeder hose from oil tank to oil pump first. Open the two screws of oil line fitting located under the cover of front secondary chain sprocket Imageand wait until oil leaks out. close screws,fill oil filter through bleeding hole with a syringe, turn bleeder screw in and again out two turns, start engine, wait for oil on bleeder screw, close bleeder screw. Look into oil tank in frame, the scavenger pump should now work and transport oil back to tank. The correct filling level should be seen after a couple of kilometers test ride (and immediately after riding, before the oil disappears through the defective ball valve into the crank case)
The difference between min and max on dip stick is 500 ml


Attention! The lower oil filter cover bolt is special.It closes a drain boring. See the link attached (sorry only German and mixed with austrian slang words, so might not be translatable so easy but you´ll see what I mean)
https://www.motorang.com/bucheli-projek ... m#schraube
Last edited by Claus on Wed Oct 23, 2019 11:34 am, edited 1 time in total.
owned bikes: 93 Ural rig domestic model, 95 Suzuki DR 650 RSE, BMW R100GS, Suzuki GSX1100G rig, BMW R100R rig with Ural sidecar, Ural rig with BMW drivetrain under construction,

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Re: Refurbishing a 1980 Yamaha SR500

Post by Claus » Wed Oct 23, 2019 10:31 am

rebelrider wrote:
Wed Oct 23, 2019 2:15 am
Looks like I have a set of Kenda Challenger tires from 1995.
Not sure what I'll replace them with yet, but I'm pretty sure I don't want to ride around on 24 year old tires.
Most of the guys here ride those types of bikes with Bridgestone BT45 Battlax. As I do on most of my solo bikes. I have no clue about the price for those tyres in your country. Here in Germany they are about in the upper middle range (like € 85 front and € 105 rear) but they are worth it in my opinion. Quite good mileage (appr 8 k miles rear and the double as front tyre on my R100 GS). They have a harder middle part and softer edge to improve going round turns safely. And still rideable when wet. ( not like a iron ring forged onto a wooden wheel)
owned bikes: 93 Ural rig domestic model, 95 Suzuki DR 650 RSE, BMW R100GS, Suzuki GSX1100G rig, BMW R100R rig with Ural sidecar, Ural rig with BMW drivetrain under construction,

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Re: Refurbishing a 1980 Yamaha SR500

Post by rebelrider » Wed Oct 23, 2019 11:46 pm

Thanks! I've read through the webpage you linked, and it is interesting. I went out and checked the oil, now that the bike has been sitting for several days. The dipstick still reads full, so I guess that check ball is still working ok.

I knew the lower bolt on the filter cover was a drain, but I didn't know there was more to it than that. Also knew that the little screw on top of the filter cover was a pressure relieve screw, but didn't know it was also used to bleed the oil system. I'll do that next time I get the engine started.

The folks at the SR400/500 forum also seem to like the Bridgestone tires. I'll look into those.

I've been working on the carburetor again. The old float bowl was leaking, so I made a new one. Unfortunately, I couldn't find one already made that fits my carburetor. One little spot is different than all the others it seems. While it was open, I also adjusted the float height. It was already pretty close to where it should have been, so it didn't need much adjusting.

It only recently occurred to me, that the vacuum port that goes up to the gas tank valve is open. I bet that's why it's running so weird! I'll get that blocked off and see if the engine runs any better.

I finally got the last of the rust off the muffler today. Now it has some spots of chrome, and some areas of bare steel. Interesting how different it is. Sandpaper and wire wheels skate right across the chrome, but bite into the steel. I suppose I should get all the chrome off before I paint it.
Mike
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Re: Refurbishing a 1980 Yamaha SR500

Post by rebelrider » Fri Nov 08, 2019 6:34 am

New Video.
I misplaced a clip, so you all get to fast-forward to seeing the brake fluid reservoir done, and how the oil change went. Also, the last bit is just me making my own float bowl gasket. It's time compressed, but I won't be offended if you skip it, LOL.

It turns out I have built up enough footage for three videos. I was hoping to do the muffler in a single one, but I ended up doing other things at the same time. Anyway, here it is:

Mike
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Re: Refurbishing a 1980 Yamaha SR500

Post by rebelrider » Tue Nov 12, 2019 2:34 am

Here is the next video:

Starts with some misplaced footage from changing the oil, and ends with me being confused as to exactly how to best apply the paint to the muffler. It's done now, so we'll see how it holds up. Here is the muffler and baffle primed:
Image

Also, I finally got new oil on the K&N air filter.
Image
Mike
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Re: Refurbishing a 1980 Yamaha SR500

Post by rebelrider » Wed Nov 13, 2019 11:20 pm

Got the muffler assembled.
Mike
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Re: Refurbishing a 1980 Yamaha SR500

Post by rebelrider » Thu Nov 14, 2019 3:43 pm

I forgot I had taken this picture. Baking the paint. With the vent on high! LOL.
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Muffler temporarily back on the bike. You can see from the rust on the tailpipe that it was originally shoved way further on there than it needed to be.
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The front brake has finally been reassembled. I decided to leave in a lot of footage, as maybe it will help someone someday to put theirs back together. But it meant I had to cut it into 2 parts.



Here it is back on the bike. So far, I've managed not to melt the paint off with brake fluid. But then, I've not filled it up yet.
Image
Image
Mike
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Re: Refurbishing a 1980 Yamaha SR500

Post by Peter Pan » Fri Nov 15, 2019 3:22 pm

the front sprocket seems to have been turned already once by the former owner, better get a new one too.
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Re: Refurbishing a 1980 Yamaha SR500

Post by rebelrider » Mon Nov 18, 2019 9:46 pm

I got the muffler, front brake, and carburetor back on the bike, and I wanted to see how it behaves with the vacuum port plugged. And how it sounds with the muffler. It started up and ran great for a couple minutes. Then it died and wouldn't star again. You can see it in the latest video:


I spent quite a while trying to diagnose the carburetor and electrical system. I finally started to suspect the timing, which isn't supposed to be a thing. When I took the cover off, I noticed that the bolt holding the flywheel on was only finger tight. Also, the flywheel came right off without any tools. And then I found this:
Image

How about that woodruff key? A little short? I've got a new one ordered.
Mike
Image2014 Ural M70 "Trogdor"
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