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Author Topic: SR250 Urban Leisure Scrambler by a noob  (Read 5357 times)

Offline sincerelyadam

  • Posts: 68
SR250 Urban Leisure Scrambler by a noob
« on: Feb 01, 2016, 14:26:46 »
Hi all
I've been lurking around these boards for months now trying to absorb knowledge. I'm about a month into my first moto project and thought it was about time to start a thread for it.

A few months ago I bought a 1980 Yamaha SR250. It ran well and I drove it for a couple months until December when the weather just got too cold. But as most folks on here can empathize, I couldn't leave well enough alone and felt the strong desire to tear the bike down for a thorough rebuild and some light modifications.

Now before I get bombarded with accusations of going in over my head, I will be the first to say that I most certainly did just that. I learn by doing. And working through puzzles and problem solving is how I do my best learning.

I come from the bicycle industry, having worked as a mechanic in two shops for about 7 years. I currently work at a metal fabrication shop, so I have the skills and resources to pull off the vision.

As you know, the SR250 isn't a big bike and I don't expect to do the ton. I want this bike to be a comfortable city rider with thoughtful utilitarian mods. 

Here she is the day I brought her home.



I removed the sissy bar, engine guard, and swapped handlebars and this is the way I rode it until bringing it in for the winter.



I am finding it difficult to find a lot of information on this bike, and the service manual is incomplete and sometimes even misguiding. So one of my goals for this thread is to provide useful information to other noobs as I go along.

I hope you enjoy.


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Offline sincerelyadam

  • Posts: 68
Re: SR250 Urban Leisure Scrambler by a noob
« Reply #1 on: Feb 01, 2016, 14:31:33 »
I'm renting a corner of my friend's shop for the winter. I put together a bench and have set up a little workstation. It's a humble space but it's serving me well so far.

 

Some photos of the initial tear down.












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Offline sincerelyadam

  • Posts: 68
Re: SR250 Urban Leisure Scrambler by a noob
« Reply #2 on: Feb 01, 2016, 14:41:00 »
The first thing I did was peep around at the engine.





For the most part things look pretty good to me. Cam chain and valves seem clean. Although I guess I ought to measure the cam chain. No sediment in the right side. The left side at the drive sprocket was of course all gunked up so I gave that a thorough cleaning.



As I mentioned before the bike ran well so I don't have any major plans for the engine at this point. I would like to find a spare motor to mess around with and sort of pimp out. That way I can get the bike up and running with this engine and then just do a swap when the time comes.



I would really like to add a kickstarter which will require around $250 in new parts or a donor motor from an XT250. Preferably the latter.


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Offline sincerelyadam

  • Posts: 68
Re: SR250 Urban Leisure Scrambler by a noob
« Reply #3 on: Feb 01, 2016, 14:43:27 »
Oh yea I got some nice split wire loom wrap for those wires. The old heat shrink was brittle and cracked right off.




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Offline sincerelyadam

  • Posts: 68
Re: SR250 Urban Leisure Scrambler by a noob
« Reply #4 on: Feb 01, 2016, 14:47:23 »
My current task at hand is cleaning and painting everything. I blasted the rear sprocket in a media blaster we have at work. I've since blasted a bunch of other small parts and they're coming out great.






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Offline sincerelyadam

  • Posts: 68
Re: SR250 Urban Leisure Scrambler by a noob
« Reply #5 on: Feb 01, 2016, 15:04:10 »
My first bit of learning that could benefit a noob like me. Disassembling the forks. This is an area where the service manual failed me. Before removing the spring caps, loosen the 8mm bolt at the bottom of the fork legs! This bolt threads into the bottom of the damper, and removing it is what allows the tubes to separate. The damper has a 12 point 14mm female socket in the top of it. This is what you need to hold in place to remove the 8mm bolt. However it is about 18 inches inside the fork legs, and who has a 14mm Allen key that long? By loosening the bottom bolts before removing the spring caps, the springs create enough tension on the damper to allow you to get that first *crack*. In my case I had removed the springs first and the bottom bolts just spun along with the damper inside. So my solution was to make a tool with threaded rod and nuts. The damper is a 14mm, but if you've shopped one of the big American hardware stores you know metric is hard to find. So I got 4 3/8" nuts and a two foot threaded rod. Put two nuts (hehe) at one end of the rod and firmly tighten them against each other. Slide the rod into a fork leg and put the other two nuts just above the tube. Tighten them against each other. Now you need to grind the bottom nut because 3/8" is slightly larger than 14mm. I ground mine carefully on a bench grinder. Now you have a tool to hold the damper on place so you can loosen the bottom bolt.




PS - Removing the spring caps on these forks is a real PITA too. I didn't get any pictures of that but I will try to remember to do that on reassembly.


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Offline sincerelyadam

  • Posts: 68
Re: SR250 Urban Leisure Scrambler by a noob
« Reply #6 on: Feb 01, 2016, 15:10:13 »
Lesson to Benefit a Noob #2 - Disassembly of rear shocks

I learned this trick a couple months ago when I replaced the rear struts on my Subaru. My mechanic quoted me $800. I found the struts for $77 a piece and DIYed the sh!t out of it.

I used a ratchet strap to compress the spring just enough to get the retaining ring out.



Some people will probably tell you this is a stupid idea because you'll hurt yourself. But you're a grownup. Use your sense, be careful, and keep your finger clears when you release the tension on the strap. Worked great for me.




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Offline sincerelyadam

  • Posts: 68
Re: SR250 Urban Leisure Scrambler by a noob
« Reply #7 on: Feb 01, 2016, 15:15:51 »
More cleaning and paint prep. This time the swing arm.



My buddy was talking about this steam cleaner he saw a guy using to clean antique cars. It blasts the gunk with just steam. No chemicals, so it doesn't cause any damage. So I thought I'd give it a shot. I found this little unit on Amazon for $29.



Steam a small area for 10-15 seconds and the funk wipes off with a rag. Very happy with this purchase.



Sanded.




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Offline sincerelyadam

  • Posts: 68
Re: SR250 Urban Leisure Scrambler by a noob
« Reply #8 on: Feb 01, 2016, 15:17:40 »
That about brings us up to speed on the project. I will post updates as I have them. Thanks for tuning in.


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Offline Milpool

  • Posts: 21
Re: SR250 Urban Leisure Scrambler by a noob
« Reply #9 on: Feb 01, 2016, 16:06:09 »
Cool! Will be handy for when I start pulling my sr apart. What sort of end result are you after? Any particular bikes you're using for inspiration?