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Rebuilding a 1982 Xr250r

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Hey guys, so a couple of weeks ago i picked up a 1982 XR 250 R for $350. WORD. and it started. no problem. But it smoked like tommy chong, so ya know. needs new rings. I decided that I am gonna go full retard on this old thumper and do a full frame- up rebuild.

 

1. New rings/ check timing while engine is apart/ check valves while engine is apart

2. Replace Front and rear brakes with disk brakes (shut up i can already hear you telling me its not worth it) lalalalalala

3. Repainting nearly all visible components

4. New Plastics

5. Street legal lights/ mirror and stuff

6. New gaskets everywhere.

7. Carb rebuild.

 

Plan is to motard this little guy and put a taller rear cog on it (less acceleration, higher top end speed) to make it a viable highway ride. 

 

So.... I'm gonna need ya'lls help with this!

 

So far i've stripped the bike down to the frame ( I got sooooooooo lucky with rear swingarm bolt, just took some WD40 and a breaker bar on my ratchet) and stripped most of the paint off the frame using aircraft remover and sandpaper.

 

Here's some pictures of the process of stripping it down.

 

I think that the biggest challenge at the moment is going to be converting to disk brakes.

 

From what i've read so far, a fork/ swingarm swap is going to need to happen (right?) (if i can get away with not doing that by fabbing/welding please let me know i have access to machines/welding equipment!) 
 

I'm going to look through the forum and see if i can find the proper years for the swap. BUT, the question of the day is.... If i do a fork/ swing arm swap to fit the bike with disk brakes, will i be able to mount aftermarket brakes/ masters on the forks/swingarms easily?

 

 

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I can't help with the brakes.

However, rings won't help on an 82 that is smoking badly.

Plan on an oversize bore, new piston and rings.

I would dive into the engine before you get too far. And especially before you order parts.

Check service limits on all wear items.

Most likely it is going to be more involved than you May have expected.

Do it right the first time. You will be better off.

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I can't help with the brakes.

However, rings won't help on an 82 that is smoking badly.

Plan on an oversize bore, new piston and rings.

I would dive into the engine before you get too far. And especially before you order parts.

Check service limits on all wear items.

Most likely it is going to be more involved than you May have expected.

Do it right the first time. You will be better off.

 

Really? Why will an oversize bore fix it but rings wont? 

 

I actually have an over bored cylinder that the guy i bought it from threw in. If you can explain why the overbore will help more than rings, please do!

 

I I don't want to end up rebuilding this engine twice!

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The overbore isn't the fix. A straight freshly honed bore with proper cross hatch is what will fix it.

Most likely the current bore is glazed (cross hatch worn or gone) and possibly out of spec.

If you can hone the current bore properly and remain within spec, then new rings will work.

You won't know until you take it apart. New rings in an old worn bore will not seat and you will still have blow by (smoke)

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The overbore isn't the fix. A straight freshly honed bore with proper cross hatch is what will fix it.

Most likely the current bore is glazed (cross hatch worn or gone) and possibly out of spec.

If you can hone the current bore properly and remain within spec, then new rings will work.

You won't know until you take it apart. New rings in an old worn bore will not seat and you will still have blow by (smoke)

 

Yeah I figured if I was replacing the rings i'd need to re-hone the cylinder, I haven't had time to crack the engine open yet and take a look, but I should get some decent garage time in about two weeks.

 

Hopefully a hone'll do the trick. Like I said, I have a never-been-used Overbored cylinder, but I don't really want to mess with getting a new piston for it if i can avoid it.

 

Obviously, if thats what i have to do, so be it.

 

Anyway Painting updates!

 

The frame is nearly done being painted

 

Kickstand is done and several smaller parts (brackets and suck) are also done!

 

I'll post Pictures of the paint job today or tomorrow  

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let me know if u need an engine parts , have a complete engine , it had a bad rocker arm , but was otherwise good.

was going to put it on ebay soon and part it it

 

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let me know if u need an engine parts , have a complete engine , it had a bad rocker arm , but was otherwise good.

was going to put it on ebay soon and part it it

 

 

I appreciate it! I'm going to be opening it up this coming Saturday, who knows what I'll find/ need.

 

Sorry I didn't end up posting pictures. I forgot... 

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OK! so the piston and cylinder are both out of round  :banghead:

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I looked for a big bore kit for my over bored cylinder, but apparently no one makes them anymore :banghead: .

 

So....

 

let me know if u need an engine parts , have a complete engine , it had a bad rocker arm , but was otherwise good.

was going to put it on ebay soon and part it it

 

Project89 I'm going to PM you. hopefully I can get a cylinder and piston off of you.

 

I also think the top part with the valves ( I think it's called the 'head') needs to be rebuilt. I want to get the valve seats checked and stuff. Probably going to end up taking that part to a shop to have that done. Because I've never done that before.

Unless someone can give me some pointers on that. 

 

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And here's some more pictures!

 

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Hey Everyone!

 

Updates!

 

Still haven't gotten around to pictures of painted frame and other painted components because i'm lazy.

 

But! I finally found a 1mm overbore piston kit!  :applause:  so that's cool!

 

took the cylinder to a local shop to have it overbored, picking it up tomorrow! pretty damn excited about that!

 

Also should be receiving a carburetor gasket kit in the next few days.... or whenever bike bandit decides to ship it... so the carb rebuild should go relatively smoothly.  

 

But I have made a temporary concession to my original plan.

 

1. I'm just gonna rebuild the drum brakes for the time being. I reaaaaallly want to get front and rear disk brakes on this bike, but figuring out which components i need to do that is a slow and painful process.

 

So thats it for now. 

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