Rebuilding a motor with 20K miles

[xs650newb]

Hey everyone,

I've been in France for 4 months for work, but I'm home in a little under 2 months so I've started thinking about all the fun things I want to do to my bike. It is a 1980 XS650, btw.

Anyways, I rode it around before I left and it runs great except for aluminum bits in the oil filter, which I believe is from the cam chain guide wearing out (there were also black plastic bits in the oil). I know this normally occurs around 20K miles, so it makes sense.

Anyways, I'm going to tear the engine up when I get home and while I am in there fixing replacing the cam chain guide I figured, what the hell, lets do other stuff.

So, here is my list of things to do. Please advise me if you think something is missing.

The whole point is the most HP for the buck (with the exception of the PMA).

1) I would like to put larger pistons inside. I believe 4th oversize is the largest? If so, where do you suggest I purchase them? I have been told Gary Hoos racing is top notch.

2) PMA. Hugh sells one for 319 and MikesXS for 290. Can someone chime in on the difference.

3) Possibly different CAM. I've heard of more aggressive cams that are simply drop in. Perhaps a Shell #1 (which I've heard can also be purchased from Gray Hoos).

Thanks in advance,
Adam

Also, here are some photos. http://imgur.com/a/AnuSZ

 

[ProSimex]

go with Hugh's, the difference? He cares about his customers and if there are any problems he will fix it asap. may as well get the 700cc kit from hoos if youre looking to increase displacement.

 

[5twins]

Replace the cam chain as well. At 20K, it's probably toast.

 

[xs650newb]

Thanks for the two pieces of advice.

I'll go with Hugh's and replace the cam chain as well.

Regarding the 700cc kit:
Is this the largest I can reliable go without getting the 750cc kit from Mikes?

Finally, are these three upgrades the best "bang for the buck"

Best,
Adam

 

[xjwmx]

Mine has over 39,000 and as far as I can tell the motor has never been opened. No sign of it, like scars on nuts or bolts. I can vouch personally that it hasn't been opened for the last 25,000

 

[ProSimex]

I believe hoos also has a 750 kit as well. And yes do the cam chain as well.

 

[blackbetty]

Just FYI, the Hoos 750 kit requires resleeving the stock jugs. The heiden kit from mikes utilizes completely different jugs.

 

[ProSimex]

yes, big fat ugly jugs...

 

[Punkskalar]

Bang for buck? Get a 700CC Kit from Gary Hoos, nice pistons, and high compression. Don't worry about a HP Camshaft, they are not all they are advertised for a street machine. I prefer a stock grind, and most everyone running a street machine will say as much...

As for the PMA - well I'm a bit biased