1982 xj650 complete engine rebuild and bobber conversion

Looks great! Are you putting a dust cap over the upper bearing?

 

all 650cc:

Standard bore: 63.00mm
Limit before boring required: 63.10mm
Taper limit: 0.05mm
Out-of-round limit: 0.01mm
Oversizes: plus .25mm, .50mm, .75mm, 1.00mm

Piston-to-wall clearance: 0.03 - 0.05mm
Max. clearance: 0.10mm

 

I'm just gonna use the stock cap as it fits perfectly, I'll need to get another one for the bottom though!

 

Damnit, I just measured one of the Pistons and I'm getting like 62.75....so what's a .25 oversize piston kit gonna cost me?

 

Hey fellas, I was thinking of doing a totally different intake set up than what you're used to seeing. I know there's probably a lot of math involved in terms of air flow, but I was wondering what you guys think.

Since we all know the stock air box is huge, bulky, and doesn't look good. As well, the pod filters can give you a flat spot in your power curve. I was thinking of fabing up an air intake manifold made out of aluminum. Kind of like an exhaust manifold I guess you could say, and then install one large air filter on the right side of the bike. Maybe in the same spot where Harley's have them?

I guess the purpose of this would be to allow a better amount of vacuum going into the engine, but with a cool look to it cause let's face it, the stock box is ugly and the pods can be a pain the ass to tune your engine from what I've read.

The only thing I can't really decide on is the size of piping. I was thinking maybe 2 inches max, but what kind of constrictions would I be running up against? Is 2 inches enough? Too much? I was kind of hoping one of our members is an engineer and can give me some pointers lol.

 

Do a search. There are several people who have made custom intake manifolds for the XJ series.

 

You think I could make this work?

http://m.ebay.com/itm/1982-82-Yamah...Manifold-S003475-40C-/272199908442?nav=SEARCH

 

Sure, but it doesn't meet all of your criteria. The turbo intake is uglier than the aitbox you have. It's also more restrictive without having the turbo to pressurize it under load.

 

Hmm it was just an idea

 

Not a bad one. The airbox is cheap enough that you could give it a try (without modifying it) and if it dosen't work sell it and get your money back.

 

Nah I think I'm just gonna fab up a two inch aluminum pipe, tig weld it, throw on a big Harley style air filter and let her buck.

 

'ckin loads of money - if you can even source them. Better off looking at some better jugs/pistons off ebay and maybe spring for some new rings, they'll be about 200 USD though I would think, rings that is..

 

Yeah, I'm looking at $1400 CND just for Pistons and rings, that's absolutely insane. But people are claiming that the parts are unavailable, and that's why there's such a high cost. I call bs, cause obviously people can still get them, and so can I, but like $300 a piston? Really? I'd expect that for a car, not a bike

 

They really and truly are no longer available from Yamaha. The factory supply for oversize pistons and rings dried up years ago, so everything you are finding is from someone's NOS stash, or from a manufacturer like Weisco. It doesn't matter what the piston is for, production costs are nearly the same, and short runs have to recoup setup and tooling costs faster than long runs do. Lack of demand really does drive up the price.
You can try http://japan.webike.net. They tend to carry more parts for older japanese bikes, but you'll have a big shipping cost. You could also try a Japanese or German auction site. The XJ series still has a large following in both countries.

 

Gave that site a try, and no dice

 

Well I haven't had much time lately to play around, but I found some cool stuff that I think I'm gonna install on the bike.

First, this neat little gadget.
http://motogadget.com/en/electrics/rfid-ignition-lock-m-lock/m-lock-rfid-zundschloss.html

And I'm contemplating doing up this little unit as well.
http://motogadget.com/en/electrics/...m-unit-digit-tastersteuerung-u-sicherung.html

I also thought these turn signals were pretty cool. Might as well go all motogadget for electrical lol.

 

Yay my goodies finally showed up! Here they are!