Refurbishing a 1980 Yamaha SR500

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IWannaUral
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Re: Refurbishing a 1980 Yamaha SR500

Post by IWannaUral » Wed Nov 20, 2019 3:09 pm

INSUBORDINATOR wrote:
Sun Aug 04, 2019 1:39 pm
There is a lot of info on these online & an owners forum. I sold mine about 6 years ago. I ran a NEW Mikuni VM carburetor which seemed to help starting & general performance. Mine had several modifications to replace rusted out & worn parts. I sold mine to purchase a Royal Enfield with an "Electric Leg" - to help deal with my elderly legs. Both very fun Bikes to ride. The SR's handle great. Hope you enjoy it.
I like those shocks on your bike. Too bad you can't get "Street Strokers" any more. I have a mostly original 1979 Yamaha XS1100 Special that could use shocks like those.

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Claus
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Re: Refurbishing a 1980 Yamaha SR500

Post by Claus » Wed Nov 20, 2019 4:55 pm

rebelrider wrote:
Mon Nov 18, 2019 9:46 pm
Also, the flywheel came right off without any tools. And then I found this:
Image
Well, not too many good parts left in that bike, I suppose. Fingers crossed, you´ll solve that problem with a new woodruff key only...
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 » Thu Nov 21, 2019 5:20 am

I don't have quite that kind of luck, LOL.

Here's a picture of the carb in a cup setup I did before putting it back on the bike. Making sure it's not going to leak again.
Image

I changed out the old float needle and seat for the slightly different one that came in the kit I bought. Seems to be working ok.
Image

The woodruff key came in the mail, and it fits perfectly.
Image
Image

After reassembly, the bike was a little hard to start, but I managed to get it going without starter fluid. Unfortunately, it only ran for 26 seconds (I caught it on video) and then died. And wouldn't start again.

So I went to adjust the pickup coil, which has a tiny bit of movement to it until you break the screw holding it on. (Ask me how I know.)
Image

Here is a video chronicling what I like to call "delayed success".
Mike
Image2014 Ural M70 "Trogdor"
1987 Honda CMX250C "Rebel"
1979 Puch Moped "Wasp"
1971 Honda SL100

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Re: Refurbishing a 1980 Yamaha SR500

Post by Claus » Thu Nov 21, 2019 5:59 am

You get nothing for free with these bikes.
I went through that a couple of times.
What I always do once a screw won´t cooperate is to losen it with an impact driver and a copper mallet
Image
This breaks up the corrosion and releases the screw´s self-locking. 95% of all screws that would have been torn off by normal attend to losen will come out easy.
Last edited by Claus on Mon Nov 25, 2019 5:38 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 rebelrider » Mon Nov 25, 2019 4:23 am

My impact screwdriver is my least favorite tool. I must be using it wrong, as so many people love them. All I've ever gotten was rounded heads, or one time, I even twisted the bit on the driver. I've watched a lot of videos of people using them, but haven't had any insights as to what I'm doing wrong. Fortunately, I have a few alternatives that usually work.

Anyway, the screw was about halfway out before it broke. The flywheel tool won't arrive until late December, so I'll have to find something else to do in the meantime.
Mike
Image2014 Ural M70 "Trogdor"
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1979 Puch Moped "Wasp"
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Re: Refurbishing a 1980 Yamaha SR500

Post by Claus » Mon Nov 25, 2019 5:56 am

I know that some people don´t like it. I have a couple of sets from El Cheapo chinese to HAZET. What I found out is, that on ohne hand good quality drives work great but the bits are too hard and break very easy. The cheap chinese bit are more usable. Yes, they sometimes tend to twist a bit when used beyond their possibilities but still work.
Once a screw comes lose a bit and oesn´t want to move all the way ot, I turn it in and out a couple of times and stop when it´s getting hard. I spray oil or other fluids onto and turn in again, hoping the thread to be greased . If necessary (and possible) I warm up the screw or the housing with a very small blow torch jet (0,2-0.5mm) and wait, until the heat has sunk into the housing. This breaks up corrosion most of times.
(not possible in your case, where the coil had to be kept alive)

Anyway, do yourself a favour and clean the taper from rust and grease before mounting the fly wheel. The woodruff key is only for positioning, the taper is the part to hold the fly wheel on the shaft. It has to be mounted free of grease, oil and dirt.
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 » Sat Dec 28, 2019 5:24 am



I finally received the flywheel removal tool in the mail! Also got 3 o-rings. Just ordered the plastic dust cover that my wheel doesn't have. It's meant for a 78 SR500E, but I'll see if it fits when it gets here.

Lots of cleaning. Lots and lots and lots of sanding and polishing the brake drum. I looked around for motorcycle drum turning services, but haven't found any. The drum is clean enough, but I'm hoping I haven't put it out of round from all the sanding I did. Man, is that black oxide under the red stuff stubborn! No wonder we use it as a protective coating.

I've also ordered the rear drive sprocket. Hopefully, I'll be able to reassemble the whole thing pretty soon. Here's a picture of the "tool" I made to hold the front drive sprocket still while I took the nut off:
Image
Mike
Image2014 Ural M70 "Trogdor"
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Re: Refurbishing a 1980 Yamaha SR500

Post by rebelrider » Thu Mar 26, 2020 6:19 am

It's been a while, but I haven't been feeling well. I did manage to get some video edited cleaning up the rear wheel from back in December. Hopefully, I'll be picking this project back up soon.
Mike
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Re: Refurbishing a 1980 Yamaha SR500

Post by rebelrider » Sat May 09, 2020 2:36 am

Getting back to the Yamaha. Today I got the stator and back plate off of the engine, and got that broken bolt drilled out. Re-tapped the hole, got everything back together, and now I'm back to where I was in December. Trying to figure out why the engine won't run right.



It seems to either go full boar, or not at all. As I try to get it to idle, it seems to backfire a lot through the carburetor, and a bit through the exhaust. I can't seem to get the RPMs to settle down without stalling the engine. I'm kind of at a loss as to what to do next.

If y'all would be so kind, take a look at the video, and let me know what you think.
Mike
Image2014 Ural M70 "Trogdor"
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Re: Refurbishing a 1980 Yamaha SR500

Post by Claus » Sat May 09, 2020 6:47 am

We,, mate, it´s all aview through the glass ball.
1st, if you run it w/o air filter it will run lean. And those bikes don´t like to run without the calm down of the air stream the air filter box would provide.
Now running lean causes backfiring through the carb. Running rich would cause backfiring through the exhaust (only generally speaking, all depends on varying circumstances).
I had a Harley on the table recently that behaved the same after I had the top end down to give it new gaskets.Event with new manifold o-rings it was like that. In the end the manifold clamps were bent and after replacing them alll was good. To make long things short: I reckon, you´ve got a leak air problem between manifold and carb and a air stream problem without air filter box. and maybe a problem with a clogged or too small pilot jet and/or a clogged pilot air jet.
I would work on each problem but one after the other. It´s difficoult do hit 5 flies with one stroke...
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 » Sun May 10, 2020 2:53 am

Thanks! I will put the filter on and check for air leaks. Since the rubber manifold and gasket are cheap, I've gone ahead and ordered new ones.
Mike
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Re: Refurbishing a 1980 Yamaha SR500

Post by rebelrider » Sun May 10, 2020 10:24 pm

I went out and did a little tinkering this afternoon, and was able to get the air leak taken care of. At least I'm pretty sure it was an air leak. All the backfiring is gone!

I'm not sure exactly where it was, but I fiddled with all the hose clamps, and put the air cleaner back on. I had some stuff to spray on the carb to check for leaks, but I ended up getting it to idle at around 1,000 rpm for a few minutes. I was even able to turn the choke/enricher all the way off. The idle mixture screw responded a little, but about then the engine died and I wasn't able to start it again.

I noticed fuel leaking out the float bowl vent. I think I may have flooded the engine. That's got to be either the float or the float needle and seat, right? So it looks like the carburetor will be coming off again. But the engine sure sounded nice while it was working. :)

I appreciate you keeping me focused on the carburetor. All that backfiring was making me think it might be something else.
Mike
Image2014 Ural M70 "Trogdor"
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Re: Refurbishing a 1980 Yamaha SR500

Post by rebelrider » Fri May 29, 2020 9:41 pm

Finally got the carburetor sorted out.


I can finally move on to something else. :)
Mike
Image2014 Ural M70 "Trogdor"
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Re: Refurbishing a 1980 Yamaha SR500

Post by lendrinkard » Sat May 30, 2020 10:57 am

Good for you. You are one determined rascal. :)
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Re: Refurbishing a 1980 Yamaha SR500

Post by rebelrider » Thu Jun 04, 2020 7:03 pm

Thanks!

I worked on some miscellaneous things yesterday.
Mike
Image2014 Ural M70 "Trogdor"
1987 Honda CMX250C "Rebel"
1979 Puch Moped "Wasp"
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