1982 Honda XL500R "$100 Find"

[MghtyQuinn]

On good Friday I started tearing the bike down in the shop ,picked the bike up 2 weeks ago with seized motor & now rear axle is seized to .Here's a pic after tearing the engine out.?

[MghtyQuinn]

Heres a pic of engine after pressure washing.

[zrxer]

Cool! So, is this gonna be a build thread? ?

[pwrpapa]

Great find, doesn't look like it's in that bad of condition either.

[MghtyQuinn]

Well thanks, & I guess umm not sure if this is going to be a build thread:excuseme: you could call it that though.

The milage that's on the bike is just over 19,000km (approx.14,000 miles) http://s757.photobucket.com/albums/xx216/MightyQuinn1/?action=view&current=IMG_0114.jpg

Heres a pic with valve cover off .I don't think it's that bad?

[MghtyQuinn]

Well after looking at the top I was very curiuos at what it was going to look like when I took off the clutch cover. When I took off the gutted muffler there was about 2 to 3 cups of water trapped in the pipe .I thought this bottom end would have a rust line where the water could have been sitting ,but all was surprisingly looking OK. ?

So after all the WD-40 that I sprayed into the cylinder ,I loosend off the timing tentioner & top cam gear I took off the head mmm yummi!

[MghtyQuinn]

Before I took off the head though I had to see if I could unsieze this motor so buy taking a socket & rachet I put it on the nut on the end of the crank shaft.Going clockwise then counterclockwise back & forth ,back& forth for a couple of minites. Then I saw it ,a frction of play in between the timing gear & the clutch gear.More back&forth for a little while longer it started to brake loose & all of a sudden she was turning:banana:? Dance to the music!

[MghtyQuinn]

With all of that done so far I had to clean the goop off the piston & there it was to little dents form the intake valves:banghead:

If you now look at the head you can see that the valves are not completly closed ,so the valves are bent also, DAM!

This tells me that the motor went out of time some how ? To much slack in the chain maybe & the tentioner not ever being tightened & probably starting it there was the nasty kickback ,jumping a tooth on the gears & bang you have bent valves & one damaged piston!

[Nutgunaspu]

Are you sure those are dents in the top of the piston? Looks like recesses machined into the piston to me.

[MghtyQuinn]

Well ... The other factory pistons that i've seen so far do not have these indents & they have sharp edging as if it were gouged in from the valves.

[DuffyDidIt]

No those valves are out and they dont make pistons with cuts in them unless they are dished.

[MghtyQuinn]

In my adventure I had to dig deeper & take the cylinder off ,piston & pin.

[MghtyQuinn]

I really don't know what to think at this point ,so if you guys have any ideas let me know,this is my first tear down of a thumper. Thanks from all you guys !

This is the greatest for me doing a rebuild , but my wife thinks it's like another girlfriend.What the funk ?Like really ! Oh...I forgot it has two tires:lol:

Thanks a lot.......?

Edited April 30, 2011 by MghtyQuinn

[341]

Ebay, craigslist, etc. There is lots of parts out there for these bikes. The '79-82 500 engines are all basically the same, only detail changes. I had to combine 3 motors to get one that is good. Make sure you have the book. They are pretty simple. Good luck. Troy341

[MghtyQuinn]

Thanks ,they don't look that terriorably bad to work on so far .Kind of cuirius on the timing chain & guides though? heres some pics of the ones I pulled out ,there dosn't seam to be anything wore ,wierd?

[341]

On all 3 motors I had the timing chain was stretched, but the guides all looked o.k. Obviously some looked better. I bought a new chain when I rebuilt mine. Troy341

[MghtyQuinn]

I really hope that the head can get new valves , seats & guides? A new piston ,rings & pin? Oh ...& the cylinder bored out to the next size over? What do you guy's think??

[MghtyQuinn]

How do you know if the timing chain is streched?

[341]

Because 2 of the three motors ran and the adjuster wouldn't take up all the slack. The chain would slap and grind on the cases. I didn't even bother to worry about whether the 3d one was stretched, I just assumed from the condition of the other 2 that it was. A new chain was cheap enough to make it a no brainer. Two motors had oversize wiseco pistons, but only one was serviceable so that is what I have. I do have to run good high octane gas since it does ping a bit when it is hot, but it does run good so I think that a bore and piston is a good idea. Troy341

[MghtyQuinn]

Because 2 of the three motors ran and the adjuster wouldn't take up all the slack. The chain would slap and grind on the cases. I didn't even bother to worry about whether the 3d one was stretched, I just assumed from the condition of the other 2 that it was. A new chain was cheap enough to make it a no brainer. Two motors had oversize wiseco pistons, but only one was serviceable so that is what I have. I do have to run good high octane gas since it does ping a bit when it is hot, but it does run good so I think that a bore and piston is a good idea. Troy341

So (Troy341) A Wiseco piston first over size would be OK ,& on 91 Octane or what do you think?