To Rebuild or Not To Rebuild

Hello fellow Thumpers, I have an 86 XR 600 that I found out has a 40% leak down (worn motor). I know it needs a top end, my question is: should I spend and how much would a top end run ($), or should I just scrap the bike? I love this bike and I'm mechanical enough to remove and replace the motor but I don't think I'm good enough to do a top end. Thanks guys

If you have the tools anyone can pull a 600 motor down to the Piston..Machine shops do the real work like rebores and maybe valve jobs,,valve seat repairs..The cost is hard to say,,I say no change from $500 if you did it semi properly..Rebore..piston/rings..Camchain,,spring,,Gaskets,Valves checked/new seals...valve seats checked..

 

Timeline::

Motor out of frame..1.5hrs

Motor stripped to Piston..1hr

Machine guys,,who knows??

Reassembly and reinstall to frame..4hrs..

Edited by Horri

Nice winter project...Good time as any to learn...If you get stuck don't  hesitate to ask any questions ;)

REBUILD!!! Buy the service and repair manuals, take lots of pictures and take your time. With a new top end it will be good for another 28 years. :ride:

REBUILD!!! You rebuild it it will give you many many more enjoyable years on the trail! Any pictures?

 Thanks guys and yes I will rebuild. I'm a bodyman/painter by trade and have restored many many cars, trucks,  airplanes and helicopters over the years (40+) witch involved a lot of mechanical so I think I can do this. I love this bike and it has served me well, wish it was electric start. I'll be hounding you guys for advice. Thanks again

 OK I need some help with this rebuild now. I have my shop manual but it's nice to have some live visual help to. I like to use Youtube for this and I found a channel, "XRland" that has a complete rebuild video on this very subject but it has no audio sound. Does anybody know of where I can find videos on this rebuild?

Rebuild for sure. What would you do otherwise, get one of these new POS water pumpers that would cost big bucks for a rebuild every couple years?? Keep that old air cooled gal running.

 Think I found some help on my top end rebuild!

Rebuild for sure. What would you do otherwise, get one of these new POS water pumpers that would cost big bucks for a rebuild every couple years?? Keep that old air cooled gal running.

Amen brother.  The sport is already expensive enough and sometimes simple still fits the bill and give us plenty of good times.

My machine shop did a 1mm over on my bore and a valve job for $270.00. I dropped a stage one hot cam, new cam chain, new tensioner, new valve springs and seals in mine. It runs like a monster. If you have the tools you can do the valves yourself but for the cash I didn't want to mess with the hassle.

 

Only thing is I took mine down to the frame and did it right, however when I redid the motor and only took it down to the bottom end. Make sure you check the trans. I just pulled my motor back out after about 2 years of good riding because my bike stuck in 3rd. And now I can't figure out how to split the case. Do yourself a favor and either have a machine shop check all your dogs and gears or do it yourself. 600's are notorious for losing 3rd I guess. Good luck to ya!

We'll finally got the old dog rebuilt and running strong. Changed my gearing and put new Kendas and have 5 hours on it now, rides like s#~t! Front wheel is so out of round it's no fun to ride. I checked the air pressure and both tires were filled to 40lbs PSI. I trusted the shop that mounted the tires before the ride, I think they wanted make sure I had plenty of nitrogen in the tires. On the shake down ride I noticed the headlight drains the battery on the Baja Designs kit so I'll have to figure that problem out but other then that I'm very happy with it for being 28 years old. Still wish it had an electric starter!

Awesome! :ride:

 

I keep my tires at 20 PSI

You did exactly what I did. 1mm over and a hot cam with valve work. Over time your kick wont be as bad but....its a 600. Suggestion on the wheels... get a spoke nipple wrench. You might be able to get the rim back pretty close...If it's a 20 year old wheel buy a new one. It's a piece of cake to true your wheel up if you were able to rebuild your motor yourself. And another funny thing I thought, my machine shop charge me 270 for the exact same stuff. Not bad eh? You can always buy new spoked if the old ones are already rusty but might as well spend the extra 50 bucks and get a nice new shiny rim.

 Think I found some help on my top end rebuild

On Youtube or where?

Honda still offers oem pistons that are one size up instead of going the 1mm jump and taking up three bores in 1mm jump

On Youtube or where?

This is a video I've gone back to time and time again. The first time I rebuild a 600 a literally watched this video as I was rebuilding. No audio but this guy does every single part. http://www.youtube.com/watch?v=HKuUSR0jUBA

This is a video I've gone back to time and time again. The first time I rebuild a 600 a literally watched this video as I was rebuilding. No audio but this guy does every single part. http://www.youtube.com/watch?v=HKuUSR0jUBA

Ok this doesn't work. Just type in "xr 600 rebuild" on google and this video will pop up at youtube.com. there are 11 videos for the total rebuild.

Cool, thank you sir! 

Old Dog Update!

Finally got my XR out in the dirt for the weekend since I had it rebuilt. I changed the gearing to 15/42 for the street and put some Kendas on it. That bike is awesome! I just loved to power from a fresh 600cc motor. I kept up with a KTM 525 and a Yamaha 250. I never ran out of power but I'll change it back to the 52 sprocket and knobbies before I ride it in the dirt again as I rarely got out of 1st and 2nd gear.

When we loaded back in my truck, the KTM owner said it felt light for a 600cc bike!

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