FJ1346 from ashes to... Well, we'll see...

[skymasteres]

Now here is where things get interesting. I started with the engine. I all of my car builds I have always started from the ground up. Work on making the thing handle, then when you have reached the limit of what you can achieve with the stock horsepower level.... roll on the steam.

Why I broke with this mantra, I couldn't tell you, but the result is I started looking under every rock for better bits to go inside the case.   I basically started looking for parts to get the head back in working order. In my wondering around I stumbled upon many wonderful things. Such as a head that had already been ported and had oversized valves installed. +1mm on intake and exhaust.

[skymasteres]

Of course it's also been line honed and decked.

Then there was the issue of increasing the displacement. I ended up following the guidance on the board here and going with a set of 82mm weisco pistons from Hank Scott Racing.



The piston on the right is the stock piston after I cleaned up the crown in the sandblaster.

And of course since I was looking for more power I decided that a set of XJR rods was in order. Really I was looking to save on reciprocating weight.



Here is a comparison shot of the old and new rods.

[fj11.5]

I have a nice pic of just two of the eight burnt out exhaust valves, from my original 84 head that no po had laid a spanner on

[Pat Conlon]

Those pistons along with the added displacement, will up your compression ratio to over 13-1, you planning on a shave?

[skymasteres]

Here is the original head and the burned exhaust valve.

[skymasteres]

Those pistons along with the added displacement, will up your compression ratio to over 13-1, you planning on a shave?

Not so much a shave, but I did have Hank Scott open up the combustion chambers to accommodate the larger pistons.  This should get me back to the 11.5:1 range.

[fj11.5]

shit mate, that's just a little worse than mine, but not by much , would explain your low readings

[skymasteres]

You know it's funny how insidious the notion "Oh, well I've come this far I might as well...." becomes.  I mean, I started out saying I'll just put this new head on, do some rings, and put her back together. Then it was, nope the cylinder bores are out of max oval tolerance, time to bore the sucker out. Of course that meant new pistons. Then it was "Okay, a big bore kit isn't much more than a set of one oversize stock pistons."  After that it was, "Do I want to reuse the old cylinder block and get it re-sleeved, or go with a set of 1250 jugs"  And on and on and on....

I actually lucked out on the 1250 block. I got a used one on eBay and was wrestling with the notion of leaving it at a 1250 displacement because I liked the idea of the nikasil on the bores and was kinda looking to save some money on not putting a set of sleeves in it at $100 a pop installed and bored.  The part where I lucked out was the block had already had the largest sleeves installed and all it needed was to be bored to 82mm.

Here's a picture of the combustion chambers on the new head.

[Flying Scotsman]

Its beautiful.

[Mark Olson]

that is one sweet engine you are putting together,  I would be interested in how much it all cost?

[skymasteres]

I got to thinking about the new pistons and how there are bigger but no heavier than the stock slugs. Then I was looking at corrilo rods to save more weight. That and I knew that I definitely wanted to get the engine balance. (I couldn't believe the difference that made of the 302 I had balanced internally when I was doing cars)  Well, to be honest I was looking at getting the crank offset ground, getting some Kawasaki rods "adjusted" and adding a few millimeters to the stroke. That idea hung around for a while because I was looking at the cost of balancing and is was "only" a few hundred more to get the crank stroked. In the end it boiled down to the longevity of the crankshaft. Turns out that these things have a "missing" bearing and when you stroke them and run them hard you end up with a cracked crankshaft. I wasn't digging the idea of spending the better part of a grand on a part that was going to self-destruct if I ran it too hard.

As fate would have it, I found out that APE racing is just down the road from me. Turns out that they would do a crankshaft lightening and balance job for $220. So off the APE the crank went. They got the sucker balanced to within 0.3 grams and removed quite a bit of material from the crankshaft. Although here is an IMPORTANT note, make sure that you record the numbers on your crankshaft before sending it out for any machine work. I wasn't aware that there were numbers on the end of the crankshaft that allowed for properly sizing your bearings. I found out about this when I was shopping around for bearings and when I called APE I found that they had already machined them off. And neglected to write them down anywhere.  But long story short the crank looked beautiful and was ready for the next step.

[skymasteres]

that is one sweet engine you are putting together,  I would be interested in how much it all cost?

Well, that's a question I have been deliberately leaving unanswered. Even for myself. Just because I know I am going to end up with more than the total value of the bike just in the engine. At this point I've definitely crossed the Rubicon and the engine needs to be finished. If I stop now I'm really loosing on a big investment of time. Besides, right now all of the really time consuming stuff is getting the cases prepped from coating.
Long story short I think I'm somewhere in the range of $4000 so far.

Here a gratuitous picture of the engine split open letting parts that haven't seen daylight since they were assembled.

[JMR]

Some of the time APE records journal codes....some of the time they don't. It would have been nice if Yamaha had included journal/bearing saddle measurements with the factory manual bearing charts (like all the other bike makers). The FJ service manual is vague at best in many sections.

[Mark Olson]

don't worry about the money invested , a lot of us on this site are way over the cost we could ever hope to get out of it. you are gonna keep it forever anyway so spend away and get what you want.

[skymasteres]

don't worry about the money invested , a lot of us on this site are way over the cost we could ever hope to get out of it. you are gonna keep it forever anyway so spend away and get what you want.

Well, that's pretty much the way I was looking at it. Besides, I look at it as quite the bargain. With all that I'm saving by doing it myself that is. (I did a quick sanity check to see what it would cost to do everyting I'm doing to this motor and the price tag was coming in at over $15k. This way I get the engine that I know every nut and bolt on. Plus it has some treatments that know no one else has because it would be cost prohibitive to pay someone to do it... (More to follow on that one)

So, switching gears without a clutch. (Easier on a motorcycle than a car by the way)  My garage is full of parts from this thing and I'm just itchig to get them back together. I have so much that I want to share and I am having some difficulty trying to present this in a linear and undertsandable fasion.



Here is the fram all stripped down and ready to go out for powder coating. (It's the one thing that I send out for coating. Just because I looked into what it would cost to build a coder coating oven and decided I was better off sending this one out)